diff --git a/Tethering/tests/integration/base/android/net/TetheringTester.java b/Tethering/tests/integration/base/android/net/TetheringTester.java
index ae39b24..1c0803e 100644
--- a/Tethering/tests/integration/base/android/net/TetheringTester.java
+++ b/Tethering/tests/integration/base/android/net/TetheringTester.java
@@ -628,7 +628,7 @@
         return false;
     }
 
-    private void sendUploadPacket(ByteBuffer packet) throws Exception {
+    public void sendUploadPacket(ByteBuffer packet) throws Exception {
         mDownstreamReader.sendResponse(packet);
     }
 
@@ -680,4 +680,12 @@
 
         return verifyPacketNotNull("Download fail", getDownloadPacket(filter));
     }
+
+    // Send DHCPDISCOVER to DHCP server to see if DHCP server is still alive to handle
+    // the upcoming DHCP packets. This method should be only used when we know the DHCP
+    // server has been created successfully before.
+    public boolean testDhcpServerAlive(final MacAddress mac) throws Exception {
+        sendDhcpDiscover(mac.toByteArray());
+        return getNextDhcpPacket() != null;
+    }
 }
diff --git a/Tethering/tests/integration/src/android/net/EthernetTetheringTest.java b/Tethering/tests/integration/src/android/net/EthernetTetheringTest.java
index 55854e2..21927df 100644
--- a/Tethering/tests/integration/src/android/net/EthernetTetheringTest.java
+++ b/Tethering/tests/integration/src/android/net/EthernetTetheringTest.java
@@ -39,6 +39,7 @@
 import static com.android.net.module.util.NetworkStackConstants.IPV4_LENGTH_OFFSET;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
@@ -839,4 +840,41 @@
                 REMOTE_NAT64_ADDR /* downloadSrcIp */, clatIp6 /* downloadDstIp */,
                 tester, true /* isClat */);
     }
+
+    private static final byte[] ZeroLengthDhcpPacket = new byte[] {
+            // scapy.Ether(
+            //   dst="ff:ff:ff:ff:ff:ff")
+            // scapy.IP(
+            //   dst="255.255.255.255")
+            // scapy.UDP(sport=68, dport=67)
+            /* Ethernet Header */
+            (byte) 0xff, (byte) 0xff, (byte) 0xff, (byte) 0xff, (byte) 0xff, (byte) 0xff,
+            (byte) 0xe0, (byte) 0x4f, (byte) 0x43, (byte) 0xe6, (byte) 0xfb, (byte) 0xd2,
+            (byte) 0x08, (byte) 0x00,
+            /* Ip header */
+            (byte) 0x45, (byte) 0x00, (byte) 0x00, (byte) 0x1c, (byte) 0x00, (byte) 0x01,
+            (byte) 0x00, (byte) 0x00, (byte) 0x40, (byte) 0x11, (byte) 0xb6, (byte) 0x58,
+            (byte) 0x64, (byte) 0x4f, (byte) 0x60, (byte) 0x29, (byte) 0xff, (byte) 0xff,
+            (byte) 0xff, (byte) 0xff,
+            /* UDP header */
+            (byte) 0x00, (byte) 0x44, (byte) 0x00, (byte) 0x43,
+            (byte) 0x00, (byte) 0x08, (byte) 0x3a, (byte) 0xdf
+    };
+
+    @Test
+    public void testTetherZeroLengthDhcpPacket() throws Exception {
+        final TetheringTester tester = initTetheringTester(toList(TEST_IP4_ADDR),
+                toList(TEST_IP4_DNS));
+        tester.createTetheredDevice(TEST_MAC, false /* hasIpv6 */);
+
+        // Send a zero-length DHCP packet to upstream DHCP server.
+        final ByteBuffer packet = ByteBuffer.wrap(ZeroLengthDhcpPacket);
+        tester.sendUploadPacket(packet);
+
+        // Send DHCPDISCOVER packet from another downstream tethered device to verify that upstream
+        // DHCP server has closed the listening socket and stopped reading, then we will not receive
+        // any DHCPOFFER in this case.
+        final MacAddress macAddress = MacAddress.fromString("11:22:33:44:55:66");
+        assertFalse(tester.testDhcpServerAlive(macAddress));
+    }
 }
diff --git a/nearby/service/java/com/android/server/nearby/NearbyConfiguration.java b/nearby/service/java/com/android/server/nearby/NearbyConfiguration.java
index 07e6f0c..0c10af2 100644
--- a/nearby/service/java/com/android/server/nearby/NearbyConfiguration.java
+++ b/nearby/service/java/com/android/server/nearby/NearbyConfiguration.java
@@ -22,6 +22,7 @@
 import androidx.annotation.NonNull;
 
 import com.android.internal.annotations.GuardedBy;
+import com.android.server.nearby.managers.DiscoveryProviderManager;
 
 import java.util.concurrent.Executors;
 
@@ -46,6 +47,12 @@
      */
     public static final String NEARBY_SUPPORT_TEST_APP = "nearby_support_test_app";
 
+    /**
+     * Flag to control which version of DiscoveryProviderManager should be used.
+     */
+    public static final String NEARBY_REFACTOR_DISCOVERY_MANAGER =
+            "nearby_refactor_discovery_manager";
+
     private static final boolean IS_USER_BUILD = "user".equals(Build.TYPE);
 
     private final DeviceConfigListener mDeviceConfigListener = new DeviceConfigListener();
@@ -57,11 +64,27 @@
     private int mNanoAppMinVersion;
     @GuardedBy("mDeviceConfigLock")
     private boolean mSupportTestApp;
+    @GuardedBy("mDeviceConfigLock")
+    private boolean mRefactorDiscoveryManager;
 
     public NearbyConfiguration() {
         mDeviceConfigListener.start();
     }
 
+    private static boolean getDeviceConfigBoolean(final String name, final boolean defaultValue) {
+        final String value = getDeviceConfigProperty(name);
+        return value != null ? Boolean.parseBoolean(value) : defaultValue;
+    }
+
+    private static int getDeviceConfigInt(final String name, final int defaultValue) {
+        final String value = getDeviceConfigProperty(name);
+        return value != null ? Integer.parseInt(value) : defaultValue;
+    }
+
+    private static String getDeviceConfigProperty(String name) {
+        return DeviceConfig.getProperty(DeviceConfig.NAMESPACE_NEARBY, name);
+    }
+
     /**
      * Returns whether broadcasting legacy presence spec is enabled.
      */
@@ -86,6 +109,16 @@
         }
     }
 
+    /**
+     * @return {@code true} if use {@link DiscoveryProviderManager} or use
+     * DiscoveryProviderManagerLegacy if {@code false}.
+     */
+    public boolean refactorDiscoveryManager() {
+        synchronized (mDeviceConfigLock) {
+            return mRefactorDiscoveryManager;
+        }
+    }
+
     private class DeviceConfigListener implements DeviceConfig.OnPropertiesChangedListener {
         public void start() {
             DeviceConfig.addOnPropertiesChangedListener(DeviceConfig.NAMESPACE_NEARBY,
@@ -102,21 +135,9 @@
                         NEARBY_MAINLINE_NANO_APP_MIN_VERSION, 0 /* defaultValue */);
                 mSupportTestApp = !IS_USER_BUILD && getDeviceConfigBoolean(
                         NEARBY_SUPPORT_TEST_APP, false /* defaultValue */);
+                mRefactorDiscoveryManager = getDeviceConfigBoolean(
+                        NEARBY_REFACTOR_DISCOVERY_MANAGER, false /* defaultValue */);
             }
         }
     }
-
-    private static boolean getDeviceConfigBoolean(final String name, final boolean defaultValue) {
-        final String value = getDeviceConfigProperty(name);
-        return value != null ? Boolean.parseBoolean(value) : defaultValue;
-    }
-
-    private static int getDeviceConfigInt(final String name, final int defaultValue) {
-        final String value = getDeviceConfigProperty(name);
-        return value != null ? Integer.parseInt(value) : defaultValue;
-    }
-
-    private static String getDeviceConfigProperty(String name) {
-        return DeviceConfig.getProperty(DeviceConfig.NAMESPACE_NEARBY, name);
-    }
 }
diff --git a/nearby/service/java/com/android/server/nearby/NearbyService.java b/nearby/service/java/com/android/server/nearby/NearbyService.java
index 8d35e08..2ac2b00 100644
--- a/nearby/service/java/com/android/server/nearby/NearbyService.java
+++ b/nearby/service/java/com/android/server/nearby/NearbyService.java
@@ -45,7 +45,9 @@
 import com.android.server.nearby.fastpair.FastPairManager;
 import com.android.server.nearby.injector.Injector;
 import com.android.server.nearby.managers.BroadcastProviderManager;
+import com.android.server.nearby.managers.DiscoveryManager;
 import com.android.server.nearby.managers.DiscoveryProviderManager;
+import com.android.server.nearby.managers.DiscoveryProviderManagerLegacy;
 import com.android.server.nearby.presence.PresenceManager;
 import com.android.server.nearby.provider.FastPairDataProvider;
 import com.android.server.nearby.util.identity.CallerIdentity;
@@ -80,18 +82,21 @@
                     }
                 }
             };
-    private final DiscoveryProviderManager mProviderManager;
+    private final DiscoveryManager mDiscoveryProviderManager;
     private final BroadcastProviderManager mBroadcastProviderManager;
 
     public NearbyService(Context context) {
         mContext = context;
         mInjector = new SystemInjector(context);
-        mProviderManager = new DiscoveryProviderManager(context, mInjector);
         mBroadcastProviderManager = new BroadcastProviderManager(context, mInjector);
         final LocatorContextWrapper lcw = new LocatorContextWrapper(context, null);
         mFastPairManager = new FastPairManager(lcw);
         mPresenceManager = new PresenceManager(lcw);
         mNearbyConfiguration = new NearbyConfiguration();
+        mDiscoveryProviderManager =
+                mNearbyConfiguration.refactorDiscoveryManager()
+                        ? new DiscoveryProviderManager(context, mInjector)
+                        : new DiscoveryProviderManagerLegacy(context, mInjector);
     }
 
     @VisibleForTesting
@@ -108,7 +113,7 @@
         CallerIdentity identity = CallerIdentity.fromBinder(mContext, packageName, attributionTag);
         DiscoveryPermissions.enforceDiscoveryPermission(mContext, identity);
 
-        return mProviderManager.registerScanListener(scanRequest, listener, identity);
+        return mDiscoveryProviderManager.registerScanListener(scanRequest, listener, identity);
     }
 
     @Override
@@ -119,7 +124,7 @@
         CallerIdentity identity = CallerIdentity.fromBinder(mContext, packageName, attributionTag);
         DiscoveryPermissions.enforceDiscoveryPermission(mContext, identity);
 
-        mProviderManager.unregisterScanListener(listener);
+        mDiscoveryProviderManager.unregisterScanListener(listener);
     }
 
     @Override
@@ -147,7 +152,7 @@
 
     @Override
     public void queryOffloadCapability(IOffloadCallback callback) {
-        mProviderManager.queryOffloadCapability(callback);
+        mDiscoveryProviderManager.queryOffloadCapability(callback);
     }
 
     /**
@@ -174,7 +179,7 @@
                     // Initialize ContextManager for CHRE scan.
                     ((SystemInjector) mInjector).initializeContextHubManager();
                 }
-                mProviderManager.init();
+                mDiscoveryProviderManager.init();
                 mContext.registerReceiver(
                         mBluetoothReceiver,
                         new IntentFilter(BluetoothAdapter.ACTION_STATE_CHANGED));
diff --git a/nearby/service/java/com/android/server/nearby/managers/DiscoveryManager.java b/nearby/service/java/com/android/server/nearby/managers/DiscoveryManager.java
new file mode 100644
index 0000000..c9b9a43
--- /dev/null
+++ b/nearby/service/java/com/android/server/nearby/managers/DiscoveryManager.java
@@ -0,0 +1,49 @@
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.server.nearby.managers;
+
+import android.nearby.IScanListener;
+import android.nearby.NearbyManager;
+import android.nearby.ScanRequest;
+import android.nearby.aidl.IOffloadCallback;
+
+import com.android.server.nearby.util.identity.CallerIdentity;
+
+/**
+ * Interface added for flagging DiscoveryProviderManager refactor. After the
+ * nearby_refactor_discovery_manager flag is fully rolled out, this can be deleted.
+ */
+public interface DiscoveryManager {
+
+    /**
+     * Registers the listener in the manager and starts scan according to the requested scan mode.
+     */
+    @NearbyManager.ScanStatus
+    int registerScanListener(ScanRequest scanRequest, IScanListener listener,
+            CallerIdentity callerIdentity);
+
+    /**
+     * Unregisters the listener in the manager and adjusts the scan mode if necessary afterwards.
+     */
+    void unregisterScanListener(IScanListener listener);
+
+    /** Query offload capability in a device. */
+    void queryOffloadCapability(IOffloadCallback callback);
+
+    /** Called after boot completed. */
+    void init();
+}
diff --git a/nearby/service/java/com/android/server/nearby/managers/DiscoveryProviderManager.java b/nearby/service/java/com/android/server/nearby/managers/DiscoveryProviderManager.java
index 29b18f3..4cda93a 100644
--- a/nearby/service/java/com/android/server/nearby/managers/DiscoveryProviderManager.java
+++ b/nearby/service/java/com/android/server/nearby/managers/DiscoveryProviderManager.java
@@ -21,320 +21,74 @@
 import static com.android.server.nearby.NearbyService.TAG;
 
 import android.annotation.Nullable;
-import android.app.AppOpsManager;
 import android.content.Context;
 import android.nearby.DataElement;
 import android.nearby.IScanListener;
 import android.nearby.NearbyDeviceParcelable;
 import android.nearby.NearbyManager;
 import android.nearby.PresenceScanFilter;
-import android.nearby.ScanCallback;
 import android.nearby.ScanFilter;
 import android.nearby.ScanRequest;
 import android.nearby.aidl.IOffloadCallback;
-import android.os.IBinder;
-import android.os.RemoteException;
 import android.util.Log;
 
-import com.android.internal.annotations.GuardedBy;
+import androidx.annotation.NonNull;
+
 import com.android.internal.annotations.VisibleForTesting;
 import com.android.server.nearby.injector.Injector;
-import com.android.server.nearby.metrics.NearbyMetrics;
-import com.android.server.nearby.presence.PresenceDiscoveryResult;
+import com.android.server.nearby.managers.registration.DiscoveryRegistration;
 import com.android.server.nearby.provider.AbstractDiscoveryProvider;
 import com.android.server.nearby.provider.BleDiscoveryProvider;
 import com.android.server.nearby.provider.ChreCommunication;
 import com.android.server.nearby.provider.ChreDiscoveryProvider;
-import com.android.server.nearby.provider.PrivacyFilter;
 import com.android.server.nearby.util.identity.CallerIdentity;
-import com.android.server.nearby.util.permissions.DiscoveryPermissions;
 
 import java.util.ArrayList;
-import java.util.HashMap;
+import java.util.Collection;
 import java.util.List;
-import java.util.Map;
-import java.util.Objects;
+import java.util.Set;
 import java.util.concurrent.Executor;
 import java.util.concurrent.Executors;
-import java.util.stream.Collectors;
+
+import javax.annotation.concurrent.GuardedBy;
 
 /** Manages all aspects of discovery providers. */
-public class DiscoveryProviderManager implements AbstractDiscoveryProvider.Listener {
+public class DiscoveryProviderManager extends
+        ListenerMultiplexer<IScanListener, DiscoveryRegistration, MergedDiscoveryRequest> implements
+        AbstractDiscoveryProvider.Listener,
+        DiscoveryManager {
 
     protected final Object mLock = new Object();
-    private final Context mContext;
-    private final BleDiscoveryProvider mBleDiscoveryProvider;
     @VisibleForTesting
     @Nullable
     final ChreDiscoveryProvider mChreDiscoveryProvider;
-    private @ScanRequest.ScanMode int mScanMode;
+    private final Context mContext;
+    private final BleDiscoveryProvider mBleDiscoveryProvider;
     private final Injector mInjector;
-
-    @GuardedBy("mLock")
-    private Map<IBinder, ScanListenerRecord> mScanTypeScanListenerRecordMap;
-
-    @Override
-    public void onNearbyDeviceDiscovered(NearbyDeviceParcelable nearbyDevice) {
-        synchronized (mLock) {
-            AppOpsManager appOpsManager = Objects.requireNonNull(mInjector.getAppOpsManager());
-            for (IBinder listenerBinder : mScanTypeScanListenerRecordMap.keySet()) {
-                ScanListenerRecord record = mScanTypeScanListenerRecordMap.get(listenerBinder);
-                if (record == null) {
-                    Log.w(TAG, "DiscoveryProviderManager cannot find the scan record.");
-                    continue;
-                }
-                CallerIdentity callerIdentity = record.getCallerIdentity();
-                if (!DiscoveryPermissions.noteDiscoveryResultDelivery(
-                        appOpsManager, callerIdentity)) {
-                    Log.w(TAG, "[DiscoveryProviderManager] scan permission revoked "
-                            + "- not forwarding results");
-                    try {
-                        record.getScanListener().onError(ScanCallback.ERROR_PERMISSION_DENIED);
-                    } catch (RemoteException e) {
-                        Log.w(TAG, "DiscoveryProviderManager failed to report error.", e);
-                    }
-                    return;
-                }
-
-                if (nearbyDevice.getScanType() == SCAN_TYPE_NEARBY_PRESENCE) {
-                    List<ScanFilter> presenceFilters =
-                            record.getScanRequest().getScanFilters().stream()
-                                    .filter(
-                                            scanFilter ->
-                                                    scanFilter.getType()
-                                                            == SCAN_TYPE_NEARBY_PRESENCE)
-                                    .collect(Collectors.toList());
-                    if (!presenceFilterMatches(nearbyDevice, presenceFilters)) {
-                        Log.d(TAG, "presence filter does not match for "
-                                + "the scanned Presence Device");
-                        continue;
-                    }
-                }
-                try {
-                    record.getScanListener()
-                            .onDiscovered(
-                                    PrivacyFilter.filter(
-                                            record.getScanRequest().getScanType(), nearbyDevice));
-                    NearbyMetrics.logScanDeviceDiscovered(
-                            record.hashCode(), record.getScanRequest(), nearbyDevice);
-                } catch (RemoteException e) {
-                    Log.w(TAG, "DiscoveryProviderManager failed to report onDiscovered.", e);
-                }
-            }
-        }
-    }
-
-    @Override
-    public void onError(int errorCode) {
-        synchronized (mLock) {
-            AppOpsManager appOpsManager = Objects.requireNonNull(mInjector.getAppOpsManager());
-            for (IBinder listenerBinder : mScanTypeScanListenerRecordMap.keySet()) {
-                ScanListenerRecord record = mScanTypeScanListenerRecordMap.get(listenerBinder);
-                if (record == null) {
-                    Log.w(TAG, "DiscoveryProviderManager cannot find the scan record.");
-                    continue;
-                }
-                CallerIdentity callerIdentity = record.getCallerIdentity();
-                if (!DiscoveryPermissions.noteDiscoveryResultDelivery(
-                        appOpsManager, callerIdentity)) {
-                    Log.w(TAG, "[DiscoveryProviderManager] scan permission revoked "
-                            + "- not forwarding results");
-                    try {
-                        record.getScanListener().onError(ScanCallback.ERROR_PERMISSION_DENIED);
-                    } catch (RemoteException e) {
-                        Log.w(TAG, "DiscoveryProviderManager failed to report error.", e);
-                    }
-                    return;
-                }
-
-                try {
-                    record.getScanListener().onError(errorCode);
-                } catch (RemoteException e) {
-                    Log.w(TAG, "DiscoveryProviderManager failed to report onError.", e);
-                }
-            }
-        }
-    }
+    private final Executor mExecutor;
 
     public DiscoveryProviderManager(Context context, Injector injector) {
+        Log.v(TAG, "DiscoveryProviderManager: ");
         mContext = context;
         mBleDiscoveryProvider = new BleDiscoveryProvider(mContext, injector);
-        Executor executor = Executors.newSingleThreadExecutor();
-        mChreDiscoveryProvider =
-                new ChreDiscoveryProvider(
-                        mContext, new ChreCommunication(injector, mContext, executor), executor);
-        mScanTypeScanListenerRecordMap = new HashMap<>();
+        mExecutor = Executors.newSingleThreadExecutor();
+        mChreDiscoveryProvider = new ChreDiscoveryProvider(mContext,
+                new ChreCommunication(injector, mContext, mExecutor), mExecutor);
         mInjector = injector;
     }
 
     @VisibleForTesting
-    DiscoveryProviderManager(Context context, Injector injector,
+    DiscoveryProviderManager(Context context, Executor executor, Injector injector,
             BleDiscoveryProvider bleDiscoveryProvider,
-            ChreDiscoveryProvider chreDiscoveryProvider,
-            Map<IBinder, ScanListenerRecord> scanTypeScanListenerRecordMap) {
+            ChreDiscoveryProvider chreDiscoveryProvider) {
         mContext = context;
+        mExecutor = executor;
         mInjector = injector;
         mBleDiscoveryProvider = bleDiscoveryProvider;
         mChreDiscoveryProvider = chreDiscoveryProvider;
-        mScanTypeScanListenerRecordMap = scanTypeScanListenerRecordMap;
     }
 
-    /** Called after boot completed. */
-    public void init() {
-        if (mInjector.getContextHubManager() != null) {
-            mChreDiscoveryProvider.init();
-        }
-        mChreDiscoveryProvider.getController().setListener(this);
-    }
-
-    /**
-     * Registers the listener in the manager and starts scan according to the requested scan mode.
-     */
-    @NearbyManager.ScanStatus
-    public int registerScanListener(ScanRequest scanRequest, IScanListener listener,
-            CallerIdentity callerIdentity) {
-        synchronized (mLock) {
-            ScanListenerDeathRecipient deathRecipient = (listener != null)
-                    ? new ScanListenerDeathRecipient(listener) : null;
-            IBinder listenerBinder = listener.asBinder();
-            if (listenerBinder != null && deathRecipient != null) {
-                try {
-                    listenerBinder.linkToDeath(deathRecipient, 0);
-                } catch (RemoteException e) {
-                    throw new IllegalArgumentException("Can't link to scan listener's death");
-                }
-            }
-            if (mScanTypeScanListenerRecordMap.containsKey(listener.asBinder())) {
-                ScanRequest savedScanRequest =
-                        mScanTypeScanListenerRecordMap.get(listenerBinder).getScanRequest();
-                if (scanRequest.equals(savedScanRequest)) {
-                    Log.d(TAG, "Already registered the scanRequest: " + scanRequest);
-                    return NearbyManager.ScanStatus.SUCCESS;
-                }
-            }
-            ScanListenerRecord scanListenerRecord =
-                    new ScanListenerRecord(scanRequest, listener, callerIdentity, deathRecipient);
-
-            Boolean started = startProviders(scanRequest);
-            if (started == null) {
-                return NearbyManager.ScanStatus.UNKNOWN;
-            }
-            if (!started) {
-                return NearbyManager.ScanStatus.ERROR;
-            }
-            mScanTypeScanListenerRecordMap.put(listenerBinder, scanListenerRecord);
-            NearbyMetrics.logScanStarted(scanListenerRecord.hashCode(), scanRequest);
-            if (mScanMode < scanRequest.getScanMode()) {
-                mScanMode = scanRequest.getScanMode();
-                invalidateProviderScanMode();
-            }
-            return NearbyManager.ScanStatus.SUCCESS;
-        }
-    }
-
-    /**
-     * Unregisters the listener in the manager and adjusts the scan mode if necessary afterwards.
-     */
-    public void unregisterScanListener(IScanListener listener) {
-        IBinder listenerBinder = listener.asBinder();
-        synchronized (mLock) {
-            if (!mScanTypeScanListenerRecordMap.containsKey(listenerBinder)) {
-                Log.w(
-                        TAG,
-                        "Cannot unregister the scanRequest because the request is never "
-                                + "registered.");
-                return;
-            }
-
-            ScanListenerRecord removedRecord =
-                    mScanTypeScanListenerRecordMap.remove(listenerBinder);
-            ScanListenerDeathRecipient deathRecipient = removedRecord.getDeathRecipient();
-            if (listenerBinder != null && deathRecipient != null) {
-                listenerBinder.unlinkToDeath(removedRecord.getDeathRecipient(), 0);
-            }
-            Log.v(TAG, "DiscoveryProviderManager unregistered scan listener.");
-            NearbyMetrics.logScanStopped(removedRecord.hashCode(), removedRecord.getScanRequest());
-            if (mScanTypeScanListenerRecordMap.isEmpty()) {
-                Log.v(TAG, "DiscoveryProviderManager stops provider because there is no "
-                        + "scan listener registered.");
-                stopProviders();
-                return;
-            }
-
-            // TODO(b/221082271): updates the scan with reduced filters.
-
-            // Removes current highest scan mode requested and sets the next highest scan mode.
-            if (removedRecord.getScanRequest().getScanMode() == mScanMode) {
-                Log.v(TAG, "DiscoveryProviderManager starts to find the new highest scan mode "
-                        + "because the highest scan mode listener was unregistered.");
-                @ScanRequest.ScanMode int highestScanModeRequested = ScanRequest.SCAN_MODE_NO_POWER;
-                // find the next highest scan mode;
-                for (ScanListenerRecord record : mScanTypeScanListenerRecordMap.values()) {
-                    @ScanRequest.ScanMode int scanMode = record.getScanRequest().getScanMode();
-                    if (scanMode > highestScanModeRequested) {
-                        highestScanModeRequested = scanMode;
-                    }
-                }
-                if (mScanMode != highestScanModeRequested) {
-                    mScanMode = highestScanModeRequested;
-                    invalidateProviderScanMode();
-                }
-            }
-        }
-    }
-
-    /**
-     * Query offload capability in a device.
-     */
-    public void queryOffloadCapability(IOffloadCallback callback) {
-        mChreDiscoveryProvider.queryOffloadCapability(callback);
-    }
-
-    /**
-     * @return {@code null} when all providers are initializing
-     * {@code false} when fail to start all the providers
-     * {@code true} when any one of the provider starts successfully
-     */
-    @VisibleForTesting
-    @Nullable
-    Boolean startProviders(ScanRequest scanRequest) {
-        if (!scanRequest.isBleEnabled()) {
-            Log.w(TAG, "failed to start any provider because client disabled BLE");
-            return false;
-        }
-        List<ScanFilter> scanFilters = getPresenceScanFilters();
-        boolean chreOnly = isChreOnly(scanFilters);
-        Boolean chreAvailable = mChreDiscoveryProvider.available();
-        if (chreAvailable == null) {
-            if (chreOnly) {
-                Log.w(TAG, "client wants CHRE only and Nearby service is still querying CHRE"
-                        + " status");
-                return null;
-            }
-            startBleProvider(scanFilters);
-            return true;
-        }
-
-        if (!chreAvailable) {
-            if (chreOnly) {
-                Log.w(TAG, "failed to start any provider because client wants CHRE only and CHRE"
-                        + " is not available");
-                return false;
-            }
-            startBleProvider(scanFilters);
-            return true;
-        }
-
-        if (scanRequest.getScanType() == SCAN_TYPE_NEARBY_PRESENCE) {
-            startChreProvider(scanFilters);
-            return true;
-        }
-
-        startBleProvider(scanFilters);
-        return true;
-    }
-
-    private static boolean isChreOnly(List<ScanFilter> scanFilters) {
+    private static boolean isChreOnly(Set<ScanFilter> scanFilters) {
         for (ScanFilter scanFilter : scanFilters) {
             List<DataElement> dataElements =
                     ((PresenceScanFilter) scanFilter).getExtendedProperties();
@@ -355,41 +109,160 @@
         return false;
     }
 
-    private void startBleProvider(List<ScanFilter> scanFilters) {
+    @Override
+    public void onNearbyDeviceDiscovered(NearbyDeviceParcelable nearbyDevice) {
+        synchronized (mMultiplexerLock) {
+            Log.d(TAG, "Found device" + nearbyDevice);
+            deliverToListeners(registration -> {
+                try {
+                    return registration.onNearbyDeviceDiscovered(nearbyDevice);
+                } catch (Exception e) {
+                    Log.w(TAG, "DiscoveryProviderManager failed to report callback.", e);
+                    return null;
+                }
+            });
+        }
+    }
+
+    @Override
+    public void onError(int errorCode) {
+        synchronized (mMultiplexerLock) {
+            Log.e(TAG, "Error found during scanning.");
+            deliverToListeners(registration -> {
+                try {
+                    return registration.reportError(errorCode);
+                } catch (Exception e) {
+                    Log.w(TAG, "DiscoveryProviderManager failed to report error.", e);
+                    return null;
+                }
+            });
+        }
+    }
+
+    /** Called after boot completed. */
+    public void init() {
+        if (mInjector.getContextHubManager() != null) {
+            mChreDiscoveryProvider.init();
+        }
+        mChreDiscoveryProvider.getController().setListener(this);
+    }
+
+    /**
+     * Registers the listener in the manager and starts scan according to the requested scan mode.
+     */
+    @NearbyManager.ScanStatus
+    public int registerScanListener(ScanRequest scanRequest, IScanListener listener,
+            CallerIdentity callerIdentity) {
+        DiscoveryRegistration registration = new DiscoveryRegistration(this, scanRequest, listener,
+                mExecutor, callerIdentity, mMultiplexerLock, mInjector.getAppOpsManager());
+        synchronized (mMultiplexerLock) {
+            putRegistration(listener.asBinder(), registration);
+            return NearbyManager.ScanStatus.SUCCESS;
+        }
+    }
+
+    @Override
+    public void onRegister() {
+        Log.v(TAG, "Registering the DiscoveryProviderManager.");
+        startProviders();
+    }
+
+    @Override
+    public void onUnregister() {
+        Log.v(TAG, "Unregistering the DiscoveryProviderManager.");
+        stopProviders();
+    }
+
+    /**
+     * Unregisters the listener in the manager and adjusts the scan mode if necessary afterwards.
+     */
+    public void unregisterScanListener(IScanListener listener) {
+        Log.v(TAG, "Unregister scan listener");
+        synchronized (mMultiplexerLock) {
+            removeRegistration(listener.asBinder());
+        }
+        // TODO(b/221082271): updates the scan with reduced filters.
+    }
+
+    /**
+     * Query offload capability in a device.
+     */
+    public void queryOffloadCapability(IOffloadCallback callback) {
+        mChreDiscoveryProvider.queryOffloadCapability(callback);
+    }
+
+    /**
+     * @return {@code null} when all providers are initializing
+     * {@code false} when fail to start all the providers
+     * {@code true} when any one of the provider starts successfully
+     */
+    @VisibleForTesting
+    @Nullable
+    Boolean startProviders() {
+        synchronized (mMultiplexerLock) {
+            if (!mMerged.getMediums().contains(MergedDiscoveryRequest.Medium.BLE)) {
+                Log.w(TAG, "failed to start any provider because client disabled BLE");
+                return false;
+            }
+            Set<ScanFilter> scanFilters = mMerged.getScanFilters();
+            boolean chreOnly = isChreOnly(scanFilters);
+            Boolean chreAvailable = mChreDiscoveryProvider.available();
+            Log.v(TAG, "startProviders: chreOnly " + chreOnly + " chreAvailable " + chreAvailable);
+            if (chreAvailable == null) {
+                if (chreOnly) {
+                    Log.w(TAG, "client wants CHRE only and Nearby service is still querying CHRE"
+                            + " status");
+                    return null;
+                }
+                startBleProvider(scanFilters);
+                return true;
+            }
+
+            if (!chreAvailable) {
+                if (chreOnly) {
+                    Log.w(TAG,
+                            "failed to start any provider because client wants CHRE only and CHRE"
+                                    + " is not available");
+                    return false;
+                }
+                startBleProvider(scanFilters);
+                return true;
+            }
+
+            if (mMerged.getScanTypes().contains(SCAN_TYPE_NEARBY_PRESENCE)) {
+                startChreProvider(scanFilters);
+                Log.d(TAG, "startProviders: heeey");
+                return true;
+            }
+
+            Log.d(TAG, "startProviders: geagewage");
+
+            startBleProvider(scanFilters);
+            return true;
+        }
+    }
+
+    @GuardedBy("mMultiplexerLock")
+    private void startBleProvider(Set<ScanFilter> scanFilters) {
         if (!mBleDiscoveryProvider.getController().isStarted()) {
             Log.d(TAG, "DiscoveryProviderManager starts Ble scanning.");
             mBleDiscoveryProvider.getController().setListener(this);
-            mBleDiscoveryProvider.getController().setProviderScanMode(mScanMode);
-            mBleDiscoveryProvider.getController().setProviderScanFilters(scanFilters);
+            mBleDiscoveryProvider.getController().setProviderScanMode(mMerged.getScanMode());
+            mBleDiscoveryProvider.getController().setProviderScanFilters(
+                    new ArrayList<>(scanFilters));
             mBleDiscoveryProvider.getController().start();
         }
     }
 
     @VisibleForTesting
-    void startChreProvider(List<ScanFilter> scanFilters) {
-        Log.d(TAG, "DiscoveryProviderManager starts CHRE scanning.");
-        mChreDiscoveryProvider.getController().setProviderScanFilters(scanFilters);
-        mChreDiscoveryProvider.getController().setProviderScanMode(mScanMode);
+    @GuardedBy("mMultiplexerLock")
+    void startChreProvider(Collection<ScanFilter> scanFilters) {
+        Log.d(TAG, "DiscoveryProviderManager starts CHRE scanning. " + mMerged);
+        mChreDiscoveryProvider.getController().setProviderScanFilters(new ArrayList<>(scanFilters));
+        mChreDiscoveryProvider.getController().setProviderScanMode(mMerged.getScanMode());
         mChreDiscoveryProvider.getController().start();
     }
 
-    private List<ScanFilter> getPresenceScanFilters() {
-        synchronized (mLock) {
-            List<ScanFilter> scanFilters = new ArrayList();
-            for (IBinder listenerBinder : mScanTypeScanListenerRecordMap.keySet()) {
-                ScanListenerRecord record = mScanTypeScanListenerRecordMap.get(listenerBinder);
-                List<ScanFilter> presenceFilters =
-                        record.getScanRequest().getScanFilters().stream()
-                                .filter(
-                                        scanFilter ->
-                                                scanFilter.getType() == SCAN_TYPE_NEARBY_PRESENCE)
-                                .collect(Collectors.toList());
-                scanFilters.addAll(presenceFilters);
-            }
-            return scanFilters;
-        }
-    }
-
     private void stopProviders() {
         stopBleProvider();
         stopChreProvider();
@@ -407,96 +280,40 @@
     @VisibleForTesting
     void invalidateProviderScanMode() {
         if (mBleDiscoveryProvider.getController().isStarted()) {
-            mBleDiscoveryProvider.getController().setProviderScanMode(mScanMode);
+            synchronized (mMultiplexerLock) {
+                mBleDiscoveryProvider.getController().setProviderScanMode(mMerged.getScanMode());
+            }
         } else {
-            Log.d(
-                    TAG,
-                    "Skip invalidating BleDiscoveryProvider scan mode because the provider not "
-                            + "started.");
+            Log.d(TAG, "Skip invalidating BleDiscoveryProvider scan mode because the provider not "
+                    + "started.");
         }
     }
 
-    @VisibleForTesting
-    static boolean presenceFilterMatches(
-            NearbyDeviceParcelable device, List<ScanFilter> scanFilters) {
-        if (scanFilters.isEmpty()) {
-            return true;
-        }
-        PresenceDiscoveryResult discoveryResult = PresenceDiscoveryResult.fromDevice(device);
-        for (ScanFilter scanFilter : scanFilters) {
-            PresenceScanFilter presenceScanFilter = (PresenceScanFilter) scanFilter;
-            if (discoveryResult.matches(presenceScanFilter)) {
-                return true;
+    @Override
+    public MergedDiscoveryRequest mergeRegistrations(
+            @NonNull Collection<DiscoveryRegistration> registrations) {
+        MergedDiscoveryRequest.Builder builder = new MergedDiscoveryRequest.Builder();
+        int scanMode = ScanRequest.SCAN_MODE_NO_POWER;
+        for (DiscoveryRegistration registration : registrations) {
+            builder.addActions(registration.getActions());
+            builder.addScanFilters(registration.getPresenceScanFilters());
+            Log.d(TAG,
+                    "mergeRegistrations: type is " + registration.getScanRequest().getScanType());
+            builder.addScanType(registration.getScanRequest().getScanType());
+            if (registration.getScanRequest().isBleEnabled()) {
+                builder.addMedium(MergedDiscoveryRequest.Medium.BLE);
+            }
+            int requestScanMode = registration.getScanRequest().getScanMode();
+            if (scanMode < requestScanMode) {
+                scanMode = requestScanMode;
             }
         }
-        return false;
+        builder.setScanMode(scanMode);
+        return builder.build();
     }
 
-    /**
-     * Class to make listener unregister after the binder is dead.
-     */
-    public class ScanListenerDeathRecipient implements IBinder.DeathRecipient {
-        public IScanListener listener;
-
-        ScanListenerDeathRecipient(IScanListener listener) {
-            this.listener = listener;
-        }
-
-        @Override
-        public void binderDied() {
-            Log.d(TAG, "Binder is dead - unregistering scan listener");
-            unregisterScanListener(listener);
-        }
-    }
-
-    @VisibleForTesting
-    static class ScanListenerRecord {
-
-        private final ScanRequest mScanRequest;
-
-        private final IScanListener mScanListener;
-
-        private final CallerIdentity mCallerIdentity;
-
-        private final ScanListenerDeathRecipient mDeathRecipient;
-
-        ScanListenerRecord(ScanRequest scanRequest, IScanListener iScanListener,
-                CallerIdentity callerIdentity, ScanListenerDeathRecipient deathRecipient) {
-            mScanListener = iScanListener;
-            mScanRequest = scanRequest;
-            mCallerIdentity = callerIdentity;
-            mDeathRecipient = deathRecipient;
-        }
-
-        IScanListener getScanListener() {
-            return mScanListener;
-        }
-
-        ScanRequest getScanRequest() {
-            return mScanRequest;
-        }
-
-        CallerIdentity getCallerIdentity() {
-            return mCallerIdentity;
-        }
-
-        ScanListenerDeathRecipient getDeathRecipient()  {
-            return mDeathRecipient;
-        }
-
-        @Override
-        public boolean equals(Object other) {
-            if (other instanceof ScanListenerRecord) {
-                ScanListenerRecord otherScanListenerRecord = (ScanListenerRecord) other;
-                return Objects.equals(mScanRequest, otherScanListenerRecord.mScanRequest)
-                        && Objects.equals(mScanListener, otherScanListenerRecord.mScanListener);
-            }
-            return false;
-        }
-
-        @Override
-        public int hashCode() {
-            return Objects.hash(mScanListener, mScanRequest);
-        }
+    @Override
+    public void onMergedRegistrationsUpdated() {
+        invalidateProviderScanMode();
     }
 }
diff --git a/nearby/service/java/com/android/server/nearby/managers/DiscoveryProviderManagerLegacy.java b/nearby/service/java/com/android/server/nearby/managers/DiscoveryProviderManagerLegacy.java
new file mode 100644
index 0000000..e68d22a
--- /dev/null
+++ b/nearby/service/java/com/android/server/nearby/managers/DiscoveryProviderManagerLegacy.java
@@ -0,0 +1,504 @@
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.server.nearby.managers;
+
+import static android.nearby.ScanRequest.SCAN_TYPE_NEARBY_PRESENCE;
+
+import static com.android.server.nearby.NearbyService.TAG;
+
+import android.annotation.Nullable;
+import android.app.AppOpsManager;
+import android.content.Context;
+import android.nearby.DataElement;
+import android.nearby.IScanListener;
+import android.nearby.NearbyDeviceParcelable;
+import android.nearby.NearbyManager;
+import android.nearby.PresenceScanFilter;
+import android.nearby.ScanCallback;
+import android.nearby.ScanFilter;
+import android.nearby.ScanRequest;
+import android.nearby.aidl.IOffloadCallback;
+import android.os.IBinder;
+import android.os.RemoteException;
+import android.util.Log;
+
+import com.android.internal.annotations.GuardedBy;
+import com.android.internal.annotations.VisibleForTesting;
+import com.android.server.nearby.injector.Injector;
+import com.android.server.nearby.metrics.NearbyMetrics;
+import com.android.server.nearby.presence.PresenceDiscoveryResult;
+import com.android.server.nearby.provider.AbstractDiscoveryProvider;
+import com.android.server.nearby.provider.BleDiscoveryProvider;
+import com.android.server.nearby.provider.ChreCommunication;
+import com.android.server.nearby.provider.ChreDiscoveryProvider;
+import com.android.server.nearby.provider.PrivacyFilter;
+import com.android.server.nearby.util.identity.CallerIdentity;
+import com.android.server.nearby.util.permissions.DiscoveryPermissions;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+import java.util.concurrent.Executor;
+import java.util.concurrent.Executors;
+import java.util.stream.Collectors;
+
+/** Manages all aspects of discovery providers. */
+public class DiscoveryProviderManagerLegacy implements AbstractDiscoveryProvider.Listener,
+        DiscoveryManager {
+
+    protected final Object mLock = new Object();
+    @VisibleForTesting
+    @Nullable
+    final ChreDiscoveryProvider mChreDiscoveryProvider;
+    private final Context mContext;
+    private final BleDiscoveryProvider mBleDiscoveryProvider;
+    private final Injector mInjector;
+    @ScanRequest.ScanMode
+    private int mScanMode;
+    @GuardedBy("mLock")
+    private final Map<IBinder, ScanListenerRecord> mScanTypeScanListenerRecordMap;
+
+    public DiscoveryProviderManagerLegacy(Context context, Injector injector) {
+        mContext = context;
+        mBleDiscoveryProvider = new BleDiscoveryProvider(mContext, injector);
+        Executor executor = Executors.newSingleThreadExecutor();
+        mChreDiscoveryProvider =
+                new ChreDiscoveryProvider(
+                        mContext, new ChreCommunication(injector, mContext, executor), executor);
+        mScanTypeScanListenerRecordMap = new HashMap<>();
+        mInjector = injector;
+        Log.v(TAG, "DiscoveryProviderManagerLegacy: ");
+    }
+
+    @VisibleForTesting
+    DiscoveryProviderManagerLegacy(Context context, Injector injector,
+            BleDiscoveryProvider bleDiscoveryProvider,
+            ChreDiscoveryProvider chreDiscoveryProvider,
+            Map<IBinder, ScanListenerRecord> scanTypeScanListenerRecordMap) {
+        mContext = context;
+        mInjector = injector;
+        mBleDiscoveryProvider = bleDiscoveryProvider;
+        mChreDiscoveryProvider = chreDiscoveryProvider;
+        mScanTypeScanListenerRecordMap = scanTypeScanListenerRecordMap;
+    }
+
+    private static boolean isChreOnly(List<ScanFilter> scanFilters) {
+        for (ScanFilter scanFilter : scanFilters) {
+            List<DataElement> dataElements =
+                    ((PresenceScanFilter) scanFilter).getExtendedProperties();
+            for (DataElement dataElement : dataElements) {
+                if (dataElement.getKey() != DataElement.DataType.SCAN_MODE) {
+                    continue;
+                }
+                byte[] scanModeValue = dataElement.getValue();
+                if (scanModeValue == null || scanModeValue.length == 0) {
+                    break;
+                }
+                if (Byte.toUnsignedInt(scanModeValue[0]) == ScanRequest.SCAN_MODE_CHRE_ONLY) {
+                    return true;
+                }
+            }
+
+        }
+        return false;
+    }
+
+    @VisibleForTesting
+    static boolean presenceFilterMatches(
+            NearbyDeviceParcelable device, List<ScanFilter> scanFilters) {
+        if (scanFilters.isEmpty()) {
+            return true;
+        }
+        PresenceDiscoveryResult discoveryResult = PresenceDiscoveryResult.fromDevice(device);
+        for (ScanFilter scanFilter : scanFilters) {
+            PresenceScanFilter presenceScanFilter = (PresenceScanFilter) scanFilter;
+            if (discoveryResult.matches(presenceScanFilter)) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    @Override
+    public void onNearbyDeviceDiscovered(NearbyDeviceParcelable nearbyDevice) {
+        synchronized (mLock) {
+            AppOpsManager appOpsManager = Objects.requireNonNull(mInjector.getAppOpsManager());
+            for (IBinder listenerBinder : mScanTypeScanListenerRecordMap.keySet()) {
+                ScanListenerRecord record = mScanTypeScanListenerRecordMap.get(listenerBinder);
+                if (record == null) {
+                    Log.w(TAG, "DiscoveryProviderManager cannot find the scan record.");
+                    continue;
+                }
+                CallerIdentity callerIdentity = record.getCallerIdentity();
+                if (!DiscoveryPermissions.noteDiscoveryResultDelivery(
+                        appOpsManager, callerIdentity)) {
+                    Log.w(TAG, "[DiscoveryProviderManager] scan permission revoked "
+                            + "- not forwarding results");
+                    try {
+                        record.getScanListener().onError(ScanCallback.ERROR_PERMISSION_DENIED);
+                    } catch (RemoteException e) {
+                        Log.w(TAG, "DiscoveryProviderManager failed to report error.", e);
+                    }
+                    return;
+                }
+
+                if (nearbyDevice.getScanType() == SCAN_TYPE_NEARBY_PRESENCE) {
+                    List<ScanFilter> presenceFilters =
+                            record.getScanRequest().getScanFilters().stream()
+                                    .filter(
+                                            scanFilter ->
+                                                    scanFilter.getType()
+                                                            == SCAN_TYPE_NEARBY_PRESENCE)
+                                    .collect(Collectors.toList());
+                    if (!presenceFilterMatches(nearbyDevice, presenceFilters)) {
+                        Log.d(TAG, "presence filter does not match for "
+                                + "the scanned Presence Device");
+                        continue;
+                    }
+                }
+                try {
+                    record.getScanListener()
+                            .onDiscovered(
+                                    PrivacyFilter.filter(
+                                            record.getScanRequest().getScanType(), nearbyDevice));
+                    NearbyMetrics.logScanDeviceDiscovered(
+                            record.hashCode(), record.getScanRequest(), nearbyDevice);
+                } catch (RemoteException e) {
+                    Log.w(TAG, "DiscoveryProviderManager failed to report onDiscovered.", e);
+                }
+            }
+        }
+    }
+
+    @Override
+    public void onError(int errorCode) {
+        synchronized (mLock) {
+            AppOpsManager appOpsManager = Objects.requireNonNull(mInjector.getAppOpsManager());
+            for (IBinder listenerBinder : mScanTypeScanListenerRecordMap.keySet()) {
+                ScanListenerRecord record = mScanTypeScanListenerRecordMap.get(listenerBinder);
+                if (record == null) {
+                    Log.w(TAG, "DiscoveryProviderManager cannot find the scan record.");
+                    continue;
+                }
+                CallerIdentity callerIdentity = record.getCallerIdentity();
+                if (!DiscoveryPermissions.noteDiscoveryResultDelivery(
+                        appOpsManager, callerIdentity)) {
+                    Log.w(TAG, "[DiscoveryProviderManager] scan permission revoked "
+                            + "- not forwarding results");
+                    try {
+                        record.getScanListener().onError(ScanCallback.ERROR_PERMISSION_DENIED);
+                    } catch (RemoteException e) {
+                        Log.w(TAG, "DiscoveryProviderManager failed to report error.", e);
+                    }
+                    return;
+                }
+
+                try {
+                    record.getScanListener().onError(errorCode);
+                } catch (RemoteException e) {
+                    Log.w(TAG, "DiscoveryProviderManager failed to report onError.", e);
+                }
+            }
+        }
+    }
+
+    /** Called after boot completed. */
+    public void init() {
+        if (mInjector.getContextHubManager() != null) {
+            mChreDiscoveryProvider.init();
+        }
+        mChreDiscoveryProvider.getController().setListener(this);
+    }
+
+    /**
+     * Registers the listener in the manager and starts scan according to the requested scan mode.
+     */
+    @NearbyManager.ScanStatus
+    public int registerScanListener(ScanRequest scanRequest, IScanListener listener,
+            CallerIdentity callerIdentity) {
+        synchronized (mLock) {
+            ScanListenerDeathRecipient deathRecipient = (listener != null)
+                    ? new ScanListenerDeathRecipient(listener) : null;
+            IBinder listenerBinder = listener.asBinder();
+            if (listenerBinder != null && deathRecipient != null) {
+                try {
+                    listenerBinder.linkToDeath(deathRecipient, 0);
+                } catch (RemoteException e) {
+                    throw new IllegalArgumentException("Can't link to scan listener's death");
+                }
+            }
+            if (mScanTypeScanListenerRecordMap.containsKey(listener.asBinder())) {
+                ScanRequest savedScanRequest =
+                        mScanTypeScanListenerRecordMap.get(listenerBinder).getScanRequest();
+                if (scanRequest.equals(savedScanRequest)) {
+                    Log.d(TAG, "Already registered the scanRequest: " + scanRequest);
+                    return NearbyManager.ScanStatus.SUCCESS;
+                }
+            }
+            ScanListenerRecord scanListenerRecord =
+                    new ScanListenerRecord(scanRequest, listener, callerIdentity, deathRecipient);
+
+            Boolean started = startProviders(scanRequest);
+            if (started == null) {
+                return NearbyManager.ScanStatus.UNKNOWN;
+            }
+            if (!started) {
+                return NearbyManager.ScanStatus.ERROR;
+            }
+            mScanTypeScanListenerRecordMap.put(listenerBinder, scanListenerRecord);
+            NearbyMetrics.logScanStarted(scanListenerRecord.hashCode(), scanRequest);
+            if (mScanMode < scanRequest.getScanMode()) {
+                mScanMode = scanRequest.getScanMode();
+                invalidateProviderScanMode();
+            }
+            return NearbyManager.ScanStatus.SUCCESS;
+        }
+    }
+
+    /**
+     * Unregisters the listener in the manager and adjusts the scan mode if necessary afterwards.
+     */
+    public void unregisterScanListener(IScanListener listener) {
+        IBinder listenerBinder = listener.asBinder();
+        synchronized (mLock) {
+            if (!mScanTypeScanListenerRecordMap.containsKey(listenerBinder)) {
+                Log.w(
+                        TAG,
+                        "Cannot unregister the scanRequest because the request is never "
+                                + "registered.");
+                return;
+            }
+
+            ScanListenerRecord removedRecord =
+                    mScanTypeScanListenerRecordMap.remove(listenerBinder);
+            ScanListenerDeathRecipient deathRecipient = removedRecord.getDeathRecipient();
+            if (listenerBinder != null && deathRecipient != null) {
+                listenerBinder.unlinkToDeath(removedRecord.getDeathRecipient(), 0);
+            }
+            Log.v(TAG, "DiscoveryProviderManager unregistered scan listener.");
+            NearbyMetrics.logScanStopped(removedRecord.hashCode(), removedRecord.getScanRequest());
+            if (mScanTypeScanListenerRecordMap.isEmpty()) {
+                Log.v(TAG, "DiscoveryProviderManager stops provider because there is no "
+                        + "scan listener registered.");
+                stopProviders();
+                return;
+            }
+
+            // TODO(b/221082271): updates the scan with reduced filters.
+
+            // Removes current highest scan mode requested and sets the next highest scan mode.
+            if (removedRecord.getScanRequest().getScanMode() == mScanMode) {
+                Log.v(TAG, "DiscoveryProviderManager starts to find the new highest scan mode "
+                        + "because the highest scan mode listener was unregistered.");
+                @ScanRequest.ScanMode int highestScanModeRequested = ScanRequest.SCAN_MODE_NO_POWER;
+                // find the next highest scan mode;
+                for (ScanListenerRecord record : mScanTypeScanListenerRecordMap.values()) {
+                    @ScanRequest.ScanMode int scanMode = record.getScanRequest().getScanMode();
+                    if (scanMode > highestScanModeRequested) {
+                        highestScanModeRequested = scanMode;
+                    }
+                }
+                if (mScanMode != highestScanModeRequested) {
+                    mScanMode = highestScanModeRequested;
+                    invalidateProviderScanMode();
+                }
+            }
+        }
+    }
+
+    /**
+     * Query offload capability in a device.
+     */
+    public void queryOffloadCapability(IOffloadCallback callback) {
+        mChreDiscoveryProvider.queryOffloadCapability(callback);
+    }
+
+    /**
+     * @return {@code null} when all providers are initializing
+     * {@code false} when fail to start all the providers
+     * {@code true} when any one of the provider starts successfully
+     */
+    @VisibleForTesting
+    @Nullable
+    Boolean startProviders(ScanRequest scanRequest) {
+        if (!scanRequest.isBleEnabled()) {
+            Log.w(TAG, "failed to start any provider because client disabled BLE");
+            return false;
+        }
+        List<ScanFilter> scanFilters = getPresenceScanFilters();
+        boolean chreOnly = isChreOnly(scanFilters);
+        Boolean chreAvailable = mChreDiscoveryProvider.available();
+        if (chreAvailable == null) {
+            if (chreOnly) {
+                Log.w(TAG, "client wants CHRE only and Nearby service is still querying CHRE"
+                        + " status");
+                return null;
+            }
+            startBleProvider(scanFilters);
+            return true;
+        }
+
+        if (!chreAvailable) {
+            if (chreOnly) {
+                Log.w(TAG, "failed to start any provider because client wants CHRE only and CHRE"
+                        + " is not available");
+                return false;
+            }
+            startBleProvider(scanFilters);
+            return true;
+        }
+
+        if (scanRequest.getScanType() == SCAN_TYPE_NEARBY_PRESENCE) {
+            startChreProvider(scanFilters);
+            return true;
+        }
+
+        startBleProvider(scanFilters);
+        return true;
+    }
+
+    private void startBleProvider(List<ScanFilter> scanFilters) {
+        if (!mBleDiscoveryProvider.getController().isStarted()) {
+            Log.d(TAG, "DiscoveryProviderManager starts Ble scanning.");
+            mBleDiscoveryProvider.getController().setListener(this);
+            mBleDiscoveryProvider.getController().setProviderScanMode(mScanMode);
+            mBleDiscoveryProvider.getController().setProviderScanFilters(scanFilters);
+            mBleDiscoveryProvider.getController().start();
+        }
+    }
+
+    @VisibleForTesting
+    void startChreProvider(List<ScanFilter> scanFilters) {
+        Log.d(TAG, "DiscoveryProviderManager starts CHRE scanning.");
+        mChreDiscoveryProvider.getController().setProviderScanFilters(scanFilters);
+        mChreDiscoveryProvider.getController().setProviderScanMode(mScanMode);
+        mChreDiscoveryProvider.getController().start();
+    }
+
+    private List<ScanFilter> getPresenceScanFilters() {
+        synchronized (mLock) {
+            List<ScanFilter> scanFilters = new ArrayList();
+            for (IBinder listenerBinder : mScanTypeScanListenerRecordMap.keySet()) {
+                ScanListenerRecord record = mScanTypeScanListenerRecordMap.get(listenerBinder);
+                List<ScanFilter> presenceFilters =
+                        record.getScanRequest().getScanFilters().stream()
+                                .filter(
+                                        scanFilter ->
+                                                scanFilter.getType() == SCAN_TYPE_NEARBY_PRESENCE)
+                                .collect(Collectors.toList());
+                scanFilters.addAll(presenceFilters);
+            }
+            return scanFilters;
+        }
+    }
+
+    private void stopProviders() {
+        stopBleProvider();
+        stopChreProvider();
+    }
+
+    private void stopBleProvider() {
+        mBleDiscoveryProvider.getController().stop();
+    }
+
+    @VisibleForTesting
+    protected void stopChreProvider() {
+        mChreDiscoveryProvider.getController().stop();
+    }
+
+    @VisibleForTesting
+    void invalidateProviderScanMode() {
+        if (mBleDiscoveryProvider.getController().isStarted()) {
+            mBleDiscoveryProvider.getController().setProviderScanMode(mScanMode);
+        } else {
+            Log.d(
+                    TAG,
+                    "Skip invalidating BleDiscoveryProvider scan mode because the provider not "
+                            + "started.");
+        }
+    }
+
+    @VisibleForTesting
+    static class ScanListenerRecord {
+
+        private final ScanRequest mScanRequest;
+
+        private final IScanListener mScanListener;
+
+        private final CallerIdentity mCallerIdentity;
+
+        private final ScanListenerDeathRecipient mDeathRecipient;
+
+        ScanListenerRecord(ScanRequest scanRequest, IScanListener iScanListener,
+                CallerIdentity callerIdentity, ScanListenerDeathRecipient deathRecipient) {
+            mScanListener = iScanListener;
+            mScanRequest = scanRequest;
+            mCallerIdentity = callerIdentity;
+            mDeathRecipient = deathRecipient;
+        }
+
+        IScanListener getScanListener() {
+            return mScanListener;
+        }
+
+        ScanRequest getScanRequest() {
+            return mScanRequest;
+        }
+
+        CallerIdentity getCallerIdentity() {
+            return mCallerIdentity;
+        }
+
+        ScanListenerDeathRecipient getDeathRecipient() {
+            return mDeathRecipient;
+        }
+
+        @Override
+        public boolean equals(Object other) {
+            if (other instanceof ScanListenerRecord) {
+                ScanListenerRecord otherScanListenerRecord = (ScanListenerRecord) other;
+                return Objects.equals(mScanRequest, otherScanListenerRecord.mScanRequest)
+                        && Objects.equals(mScanListener, otherScanListenerRecord.mScanListener);
+            }
+            return false;
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(mScanListener, mScanRequest);
+        }
+    }
+
+    /**
+     * Class to make listener unregister after the binder is dead.
+     */
+    public class ScanListenerDeathRecipient implements IBinder.DeathRecipient {
+        public IScanListener listener;
+
+        ScanListenerDeathRecipient(IScanListener listener) {
+            this.listener = listener;
+        }
+
+        @Override
+        public void binderDied() {
+            Log.d(TAG, "Binder is dead - unregistering scan listener");
+            unregisterScanListener(listener);
+        }
+    }
+}
diff --git a/nearby/service/java/com/android/server/nearby/managers/ListenerMultiplexer.java b/nearby/service/java/com/android/server/nearby/managers/ListenerMultiplexer.java
new file mode 100644
index 0000000..a6a9388
--- /dev/null
+++ b/nearby/service/java/com/android/server/nearby/managers/ListenerMultiplexer.java
@@ -0,0 +1,189 @@
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.server.nearby.managers;
+
+import static com.android.server.nearby.NearbyService.TAG;
+
+import android.annotation.NonNull;
+import android.os.IBinder;
+import android.util.ArrayMap;
+import android.util.Log;
+
+import com.android.internal.annotations.GuardedBy;
+import com.android.server.nearby.managers.registration.BinderListenerRegistration;
+import com.android.server.nearby.managers.registration.BinderListenerRegistration.ListenerOperation;
+
+import java.util.Collection;
+import java.util.Objects;
+import java.util.function.Function;
+
+/**
+ * A simplified class based on {@link com.android.server.location.listeners.ListenerMultiplexer}.
+ * It is a base class to multiplex broadcast and discovery events to multiple listener
+ * registrations. Every listener is represented by a registration object which stores all required
+ * state for a listener.
+ * Registrations will be merged to one request for the service to operate.
+ *
+ * @param <TListener>           callback type for clients
+ * @param <TRegistration>       child of {@link BinderListenerRegistration}
+ * @param <TMergedRegistration> merged registration type
+ */
+public abstract class ListenerMultiplexer<TListener,
+        TRegistration extends BinderListenerRegistration<TListener>, TMergedRegistration> {
+
+    /**
+     * The lock object used by the multiplexer. Acquiring this lock allows for multiple operations
+     * on the multiplexer to be completed atomically. Otherwise, it is not required to hold this
+     * lock. This lock is held while invoking all lifecycle callbacks on both the multiplexer and
+     * any registrations.
+     */
+    public final Object mMultiplexerLock = new Object();
+
+    @GuardedBy("mMultiplexerLock")
+    final ArrayMap<IBinder, TRegistration> mRegistrations = new ArrayMap<>();
+
+    // this is really @NonNull in many ways, but we explicitly null this out to allow for GC when
+    // not
+    // in use, so we can't annotate with @NonNull
+    @GuardedBy("mMultiplexerLock")
+    public TMergedRegistration mMerged;
+
+    /**
+     * Invoked when the multiplexer goes from having no registrations to having some registrations.
+     * This is a convenient entry point for registering listeners, etc, which only need to be
+     * present
+     * while there are any registrations. Invoked while holding the multiplexer's internal lock.
+     */
+    @GuardedBy("mMultiplexerLock")
+    public void onRegister() {
+        Log.v(TAG, "ListenerMultiplexer registered.");
+    }
+
+    /**
+     * Invoked when the multiplexer goes from having some registrations to having no registrations.
+     * This is a convenient entry point for unregistering listeners, etc, which only need to be
+     * present while there are any registrations. Invoked while holding the multiplexer's internal
+     * lock.
+     */
+    @GuardedBy("mMultiplexerLock")
+    public void onUnregister() {
+        Log.v(TAG, "ListenerMultiplexer unregistered.");
+    }
+
+    /**
+     * Puts a new registration with the given key, replacing any previous registration under the
+     * same key. This method cannot be called to put a registration re-entrantly.
+     */
+    public final void putRegistration(@NonNull IBinder key, @NonNull TRegistration registration) {
+        Objects.requireNonNull(key);
+        Objects.requireNonNull(registration);
+        synchronized (mMultiplexerLock) {
+            boolean wasEmpty = mRegistrations.isEmpty();
+
+            int index = mRegistrations.indexOfKey(key);
+            if (index > 0) {
+                BinderListenerRegistration<TListener> oldRegistration = mRegistrations.valueAt(
+                        index);
+                oldRegistration.onUnregister();
+                mRegistrations.setValueAt(index, registration);
+            } else {
+                mRegistrations.put(key, registration);
+            }
+
+            registration.onRegister();
+            onRegistrationsUpdated();
+            if (wasEmpty) {
+                onRegister();
+            }
+        }
+    }
+
+    /**
+     * Removes the registration with the given key.
+     */
+    public final void removeRegistration(IBinder key) {
+        synchronized (mMultiplexerLock) {
+            int index = mRegistrations.indexOfKey(key);
+            if (index < 0) {
+                return;
+            }
+
+            removeRegistration(index);
+        }
+    }
+
+    @GuardedBy("mMultiplexerLock")
+    private void removeRegistration(int index) {
+        TRegistration registration = mRegistrations.valueAt(index);
+
+        registration.onUnregister();
+        mRegistrations.removeAt(index);
+
+        onRegistrationsUpdated();
+
+        if (mRegistrations.isEmpty()) {
+            onUnregister();
+        }
+    }
+
+    /**
+     * Invoked when a registration is added, removed, or replaced. Invoked while holding the
+     * multiplexer's internal lock.
+     */
+    @GuardedBy("mMultiplexerLock")
+    public final void onRegistrationsUpdated() {
+        TMergedRegistration newMerged = mergeRegistrations(mRegistrations.values());
+        if (newMerged.equals(mMerged)) {
+            return;
+        }
+        mMerged = newMerged;
+        onMergedRegistrationsUpdated();
+    }
+
+    /**
+     * Called in order to generate a merged registration from the given set of active registrations.
+     * The list of registrations will never be empty. If the resulting merged registration is equal
+     * to the currently registered merged registration, nothing further will happen. If the merged
+     * registration differs,{@link #onMergedRegistrationsUpdated()} will be invoked with the new
+     * merged registration so that the backing service can be updated.
+     */
+    @GuardedBy("mMultiplexerLock")
+    public abstract TMergedRegistration mergeRegistrations(
+            @NonNull Collection<TRegistration> registrations);
+
+    /**
+     * The operation that the manager wants to handle when there is an update for the merged
+     * registration.
+     */
+    @GuardedBy("mMultiplexerLock")
+    public abstract void onMergedRegistrationsUpdated();
+
+    protected final void deliverToListeners(
+            Function<TRegistration, ListenerOperation<TListener>> function) {
+        synchronized (mMultiplexerLock) {
+            final int size = mRegistrations.size();
+            for (int i = 0; i < size; i++) {
+                TRegistration registration = mRegistrations.valueAt(i);
+                BinderListenerRegistration.ListenerOperation<TListener> operation = function.apply(
+                        registration);
+                if (operation != null) {
+                    registration.executeOperation(operation);
+                }
+            }
+        }
+    }
+}
diff --git a/nearby/service/java/com/android/server/nearby/managers/MergedDiscoveryRequest.java b/nearby/service/java/com/android/server/nearby/managers/MergedDiscoveryRequest.java
new file mode 100644
index 0000000..dcfb602
--- /dev/null
+++ b/nearby/service/java/com/android/server/nearby/managers/MergedDiscoveryRequest.java
@@ -0,0 +1,162 @@
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.server.nearby.managers;
+
+import android.annotation.IntDef;
+import android.nearby.ScanFilter;
+import android.nearby.ScanRequest;
+import android.util.ArraySet;
+
+import com.google.common.collect.ImmutableSet;
+
+import java.util.Collection;
+import java.util.Set;
+
+/** Internal discovery request to {@link DiscoveryProviderManager} and providers */
+public class MergedDiscoveryRequest {
+
+    private static final MergedDiscoveryRequest EMPTY_REQUEST = new MergedDiscoveryRequest(
+            /* scanMode= */ ScanRequest.SCAN_MODE_NO_POWER,
+            /* scanTypes= */ ImmutableSet.of(),
+            /* actions= */ ImmutableSet.of(),
+            /* scanFilters= */ ImmutableSet.of(),
+            /* mediums= */ ImmutableSet.of());
+    @ScanRequest.ScanMode
+    private final int mScanMode;
+    private final Set<Integer> mScanTypes;
+    private final Set<Integer> mActions;
+    private final Set<ScanFilter> mScanFilters;
+    private final Set<Integer> mMediums;
+
+    private MergedDiscoveryRequest(@ScanRequest.ScanMode int scanMode, Set<Integer> scanTypes,
+            Set<Integer> actions, Set<ScanFilter> scanFilters, Set<Integer> mediums) {
+        mScanMode = scanMode;
+        mScanTypes = scanTypes;
+        mActions = actions;
+        mScanFilters = scanFilters;
+        mMediums = mediums;
+    }
+
+    /**
+     * Returns an empty discovery request.
+     *
+     * <p>The empty request is used as the default request when the discovery engine is enabled,
+     * but
+     * there is no request yet. It's also used to notify the discovery engine all clients have
+     * removed
+     * their requests.
+     */
+    public static MergedDiscoveryRequest empty() {
+        return EMPTY_REQUEST;
+    }
+
+    /** Returns the priority of the request */
+    @ScanRequest.ScanMode
+    public final int getScanMode() {
+        return mScanMode;
+    }
+
+    /** Returns all requested scan types. */
+    public ImmutableSet<Integer> getScanTypes() {
+        return ImmutableSet.copyOf(mScanTypes);
+    }
+
+    /** Returns the actions of the request */
+    public ImmutableSet<Integer> getActions() {
+        return ImmutableSet.copyOf(mActions);
+    }
+
+    /** Returns the scan filters of the request */
+    public ImmutableSet<ScanFilter> getScanFilters() {
+        return ImmutableSet.copyOf(mScanFilters);
+    }
+
+    /** Returns the enabled scan mediums */
+    public ImmutableSet<Integer> getMediums() {
+        return ImmutableSet.copyOf(mMediums);
+    }
+
+    /**
+     * The medium where the broadcast request should be sent.
+     *
+     * @hide
+     */
+    @IntDef({Medium.BLE})
+    public @interface Medium {
+        int BLE = 1;
+    }
+
+    /** Builder for {@link MergedDiscoveryRequest}. */
+    public static class Builder {
+        private final Set<Integer> mScanTypes;
+        private final Set<Integer> mActions;
+        private final Set<ScanFilter> mScanFilters;
+        private final Set<Integer> mMediums;
+        @ScanRequest.ScanMode
+        private int mScanMode;
+
+        public Builder() {
+            mScanMode = ScanRequest.SCAN_MODE_NO_POWER;
+            mScanTypes = new ArraySet<>();
+            mActions = new ArraySet<>();
+            mScanFilters = new ArraySet<>();
+            mMediums = new ArraySet<>();
+        }
+
+        /**
+         * Sets the priority for the engine request.
+         */
+        public Builder setScanMode(@ScanRequest.ScanMode int scanMode) {
+            mScanMode = scanMode;
+            return this;
+        }
+
+        /**
+         * Adds scan type to the request.
+         */
+        public Builder addScanType(@ScanRequest.ScanType int type) {
+            mScanTypes.add(type);
+            return this;
+        }
+
+        /** Add actions to the request. */
+        public Builder addActions(Collection<Integer> actions) {
+            mActions.addAll(actions);
+            return this;
+        }
+
+        /** Add actions to the request. */
+        public Builder addScanFilters(Collection<ScanFilter> scanFilters) {
+            mScanFilters.addAll(scanFilters);
+            return this;
+        }
+
+        /**
+         * Add mediums to the request.
+         */
+        public Builder addMedium(@Medium int medium) {
+            mMediums.add(medium);
+            return this;
+        }
+
+        /** Builds an instance of {@link MergedDiscoveryRequest}. */
+        public MergedDiscoveryRequest build() {
+            return new MergedDiscoveryRequest(mScanMode, mScanTypes, mActions, mScanFilters,
+                    mMediums);
+        }
+    }
+}
diff --git a/nearby/service/java/com/android/server/nearby/managers/registration/BinderListenerRegistration.java b/nearby/service/java/com/android/server/nearby/managers/registration/BinderListenerRegistration.java
new file mode 100644
index 0000000..4aaa08f
--- /dev/null
+++ b/nearby/service/java/com/android/server/nearby/managers/registration/BinderListenerRegistration.java
@@ -0,0 +1,208 @@
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.server.nearby.managers.registration;
+
+import static com.android.server.nearby.NearbyService.TAG;
+
+import android.annotation.Nullable;
+import android.os.IBinder;
+import android.os.RemoteException;
+import android.util.Log;
+
+import com.android.server.nearby.managers.ListenerMultiplexer;
+
+import java.util.NoSuchElementException;
+import java.util.concurrent.Executor;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+/**
+ * A listener registration object which holds data associated with the listener, such as an optional
+ * request, and an executor responsible for listener invocations. Key is the IBinder.
+ *
+ * @param <TListener> listener for the callback
+ */
+public abstract class BinderListenerRegistration<TListener> implements IBinder.DeathRecipient {
+
+    private final AtomicBoolean mRemoved = new AtomicBoolean(false);
+    private final Executor mExecutor;
+    private final Object mListenerLock = new Object();
+    @Nullable
+    TListener mListener;
+    @Nullable
+    private final IBinder mKey;
+
+    public BinderListenerRegistration(IBinder key, Executor executor, TListener listener) {
+        this.mKey = key;
+        this.mExecutor = executor;
+        this.mListener = listener;
+    }
+
+    /**
+     * Must be implemented to return the
+     * {@link com.android.server.nearby.managers.ListenerMultiplexer} this registration is
+     * registered
+     * with. Often this is easiest to accomplish by defining registration subclasses as non-static
+     * inner classes of the multiplexer they are to be used with.
+     */
+    public abstract ListenerMultiplexer<TListener, ?
+            extends BinderListenerRegistration<TListener>, ?> getOwner();
+
+    public final IBinder getBinder() {
+        return mKey;
+    }
+
+    public final Executor getExecutor() {
+        return mExecutor;
+    }
+
+    /**
+     * Called when the registration is put in the Multiplexer.
+     */
+    public void onRegister() {
+        try {
+            getBinder().linkToDeath(this, 0);
+        } catch (RemoteException e) {
+            remove();
+        }
+    }
+
+    /**
+     * Called when the registration is removed in the Multiplexer.
+     */
+    public void onUnregister() {
+        this.mListener = null;
+        try {
+            getBinder().unlinkToDeath(this, 0);
+        } catch (NoSuchElementException e) {
+            Log.w(TAG, "failed to unregister binder death listener", e);
+        }
+    }
+
+    /**
+     * Removes this registration. All pending listener invocations will fail.
+     *
+     * <p>Does nothing if invoked before {@link #onRegister()} or after {@link #onUnregister()}.
+     */
+    public final void remove() {
+        IBinder key = mKey;
+        if (key != null && !mRemoved.getAndSet(true)) {
+            getOwner().removeRegistration(key);
+        }
+    }
+
+    @Override
+    public void binderDied() {
+        remove();
+    }
+
+    /**
+     * May be overridden by subclasses to handle listener operation failures. The default behavior
+     * is
+     * to further propagate any exceptions. Will always be invoked on the executor thread.
+     */
+    protected void onOperationFailure(Exception exception) {
+        throw new AssertionError(exception);
+    }
+
+    /**
+     * Executes the given listener operation on the registration executor, invoking {@link
+     * #onOperationFailure(Exception)} in case the listener operation fails. If the registration is
+     * removed prior to the operation running, the operation is considered canceled. If a null
+     * operation is supplied, nothing happens.
+     */
+    public final void executeOperation(@Nullable ListenerOperation<TListener> operation) {
+        if (operation == null) {
+            return;
+        }
+
+        synchronized (mListenerLock) {
+            if (mListener == null) {
+                return;
+            }
+
+            AtomicBoolean complete = new AtomicBoolean(false);
+            mExecutor.execute(() -> {
+                TListener listener;
+                synchronized (mListenerLock) {
+                    listener = mListener;
+                }
+
+                Exception failure = null;
+                if (listener != null) {
+                    try {
+                        operation.operate(listener);
+                    } catch (Exception e) {
+                        if (e instanceof RuntimeException) {
+                            throw (RuntimeException) e;
+                        } else {
+                            failure = e;
+                        }
+                    }
+                }
+
+                operation.onComplete(failure == null);
+                complete.set(true);
+
+                if (failure != null) {
+                    onOperationFailure(failure);
+                }
+            });
+            operation.onScheduled(complete.get());
+        }
+    }
+
+    /**
+     * An listener operation to perform.
+     *
+     * @param <ListenerT> listener type
+     */
+    public interface ListenerOperation<ListenerT> {
+
+        /**
+         * Invoked after the operation has been scheduled for execution. The {@code complete}
+         * argument
+         * will be true if {@link #onComplete(boolean)} was invoked prior to this callback (such as
+         * if
+         * using a direct executor), or false if {@link #onComplete(boolean)} will be invoked after
+         * this
+         * callback. This method is always invoked on the calling thread.
+         */
+        default void onScheduled(boolean complete) {
+        }
+
+        /**
+         * Invoked to perform an operation on the given listener. This method is always invoked on
+         * the
+         * executor thread. If this method throws a checked exception, the operation will fail and
+         * result in {@link #onOperationFailure(Exception)} being invoked. If this method throws an
+         * unchecked exception, this propagates normally and should result in a crash.
+         */
+        void operate(ListenerT listener) throws Exception;
+
+        /**
+         * Invoked after the operation is complete. The {@code success} argument will be true if
+         * the
+         * operation completed without throwing any exceptions, and false otherwise (such as if the
+         * operation was canceled prior to executing, or if it threw an exception). This invocation
+         * may
+         * happen either before or after (but never during) the invocation of {@link
+         * #onScheduled(boolean)}. This method is always invoked on the executor thread.
+         */
+        default void onComplete(boolean success) {
+        }
+    }
+}
diff --git a/nearby/service/java/com/android/server/nearby/managers/registration/DiscoveryRegistration.java b/nearby/service/java/com/android/server/nearby/managers/registration/DiscoveryRegistration.java
new file mode 100644
index 0000000..bef319ec
--- /dev/null
+++ b/nearby/service/java/com/android/server/nearby/managers/registration/DiscoveryRegistration.java
@@ -0,0 +1,363 @@
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.server.nearby.managers.registration;
+
+import static android.nearby.ScanRequest.SCAN_TYPE_NEARBY_PRESENCE;
+
+import static com.android.server.nearby.NearbyService.TAG;
+
+import android.annotation.IntDef;
+import android.annotation.Nullable;
+import android.app.AppOpsManager;
+import android.nearby.IScanListener;
+import android.nearby.NearbyDeviceParcelable;
+import android.nearby.PresenceScanFilter;
+import android.nearby.ScanCallback;
+import android.nearby.ScanFilter;
+import android.nearby.ScanRequest;
+import android.util.ArrayMap;
+import android.util.ArraySet;
+import android.util.Log;
+
+import com.android.internal.annotations.GuardedBy;
+import com.android.internal.annotations.VisibleForTesting;
+import com.android.server.nearby.common.CancelableAlarm;
+import com.android.server.nearby.managers.ListenerMultiplexer;
+import com.android.server.nearby.managers.MergedDiscoveryRequest;
+import com.android.server.nearby.presence.PresenceDiscoveryResult;
+import com.android.server.nearby.util.identity.CallerIdentity;
+import com.android.server.nearby.util.permissions.DiscoveryPermissions;
+
+import com.google.common.collect.ImmutableSet;
+
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Set;
+import java.util.concurrent.Executor;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.stream.Collectors;
+
+/**
+ * Class responsible for all client based operations. Each {@link DiscoveryRegistration} is for one
+ * valid unique {@link android.nearby.NearbyManager#startScan(ScanRequest, Executor, ScanCallback)}
+ */
+public class DiscoveryRegistration extends BinderListenerRegistration<IScanListener> {
+
+    /**
+     * Timeout before a previous discovered device is reported as lost.
+     */
+    @VisibleForTesting
+    static final int ON_LOST_TIME_OUT_MS = 10000;
+    /** Lock for registration operations. */
+    final Object mMultiplexerLock;
+    private final ListenerMultiplexer<IScanListener, DiscoveryRegistration, MergedDiscoveryRequest>
+            mOwner;
+    private final AppOpsManager mAppOpsManager;
+    /** Presence devices that are currently discovered, and not lost yet. */
+    @GuardedBy("mMultiplexerLock")
+    private final Map<Long, NearbyDeviceParcelable> mDiscoveredDevices;
+    /** A map of deviceId and alarms for reporting device lost. */
+    @GuardedBy("mMultiplexerLock")
+    private final Map<Long, DeviceOnLostAlarm> mDiscoveryOnLostAlarmPerDevice = new ArrayMap<>();
+    /**
+     * The single thread executor to run {@link CancelableAlarm} to report
+     * {@link NearbyDeviceParcelable} on lost after timeout.
+     */
+    private final ScheduledExecutorService mAlarmExecutor =
+            Executors.newSingleThreadScheduledExecutor();
+    private final ScanRequest mScanRequest;
+    private final CallerIdentity mCallerIdentity;
+
+    public DiscoveryRegistration(
+            ListenerMultiplexer<IScanListener, DiscoveryRegistration, MergedDiscoveryRequest> owner,
+            ScanRequest scanRequest, IScanListener scanListener, Executor executor,
+            CallerIdentity callerIdentity, Object multiplexerLock, AppOpsManager appOpsManager) {
+        super(scanListener.asBinder(), executor, scanListener);
+        mOwner = owner;
+        mListener = scanListener;
+        mScanRequest = scanRequest;
+        mCallerIdentity = callerIdentity;
+        mMultiplexerLock = multiplexerLock;
+        mDiscoveredDevices = new ArrayMap<>();
+        mAppOpsManager = appOpsManager;
+    }
+
+    /**
+     * Gets the scan request.
+     */
+    public ScanRequest getScanRequest() {
+        return mScanRequest;
+    }
+
+    /**
+     * Gets the actions from the scan filter(s).
+     */
+    public Set<Integer> getActions() {
+        Set<Integer> result = new ArraySet<>();
+        List<ScanFilter> filters = mScanRequest.getScanFilters();
+        for (ScanFilter filter : filters) {
+            if (filter instanceof PresenceScanFilter) {
+                result.addAll(((PresenceScanFilter) filter).getPresenceActions());
+            }
+        }
+        return ImmutableSet.copyOf(result);
+    }
+
+    /**
+     * Gets all the filters that are for Nearby Presence.
+     */
+    public Set<ScanFilter> getPresenceScanFilters() {
+        Set<ScanFilter> result = new ArraySet<>();
+        List<ScanFilter> filters = mScanRequest.getScanFilters();
+        for (ScanFilter filter : filters) {
+            if (filter.getType() == SCAN_TYPE_NEARBY_PRESENCE) {
+                result.add(filter);
+            }
+        }
+        return ImmutableSet.copyOf(result);
+    }
+
+    @VisibleForTesting
+    Map<Long, DeviceOnLostAlarm> getDiscoveryOnLostAlarms() {
+        synchronized (mMultiplexerLock) {
+            return mDiscoveryOnLostAlarmPerDevice;
+        }
+    }
+
+    @Override
+    public boolean equals(Object other) {
+        if (other instanceof DiscoveryRegistration) {
+            DiscoveryRegistration otherRegistration = (DiscoveryRegistration) other;
+            return Objects.equals(mScanRequest, otherRegistration.mScanRequest) && Objects.equals(
+                    mListener, otherRegistration.mListener);
+        }
+        return false;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(mListener, mScanRequest);
+    }
+
+    @Override
+    public ListenerMultiplexer<
+            IScanListener, DiscoveryRegistration, MergedDiscoveryRequest> getOwner() {
+        return mOwner;
+    }
+
+    @VisibleForTesting
+    ListenerOperation<IScanListener> reportDeviceLost(NearbyDeviceParcelable device) {
+        long deviceId = device.getDeviceId();
+        return reportResult(DiscoveryResult.DEVICE_LOST, device, () -> {
+            synchronized (mMultiplexerLock) {
+                // Remove the device from reporting devices after reporting lost.
+                mDiscoveredDevices.remove(deviceId);
+                DeviceOnLostAlarm alarm = mDiscoveryOnLostAlarmPerDevice.remove(deviceId);
+                if (alarm != null) {
+                    alarm.cancel();
+                }
+            }
+        });
+    }
+
+    /**
+     * Called when there is device discovered from the server.
+     */
+    public ListenerOperation<IScanListener> onNearbyDeviceDiscovered(
+            NearbyDeviceParcelable device) {
+        if (!filterCheck(device)) {
+            Log.d(TAG, "presence filter does not match for the scanned Presence Device");
+            return null;
+        }
+        synchronized (mMultiplexerLock) {
+            long deviceId = device.getDeviceId();
+            boolean deviceReported = mDiscoveredDevices.containsKey(deviceId);
+            scheduleOnLostAlarm(device);
+            if (deviceReported) {
+                NearbyDeviceParcelable oldDevice = mDiscoveredDevices.get(deviceId);
+                if (device.equals(oldDevice)) {
+                    return null;
+                }
+                return reportUpdated(device);
+            }
+            return reportDiscovered(device);
+        }
+    }
+
+    @VisibleForTesting
+    static boolean presenceFilterMatches(NearbyDeviceParcelable device,
+            List<ScanFilter> scanFilters) {
+        if (scanFilters.isEmpty()) {
+            return true;
+        }
+        PresenceDiscoveryResult discoveryResult = PresenceDiscoveryResult.fromDevice(device);
+        for (ScanFilter scanFilter : scanFilters) {
+            PresenceScanFilter presenceScanFilter = (PresenceScanFilter) scanFilter;
+            if (discoveryResult.matches(presenceScanFilter)) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    @Nullable
+    ListenerOperation<IScanListener> reportDiscovered(NearbyDeviceParcelable device) {
+        long deviceId = device.getDeviceId();
+        return reportResult(DiscoveryResult.DEVICE_DISCOVERED, device, () -> {
+            synchronized (mMultiplexerLock) {
+                // Add the device to discovered devices after reporting device is
+                // discovered.
+                mDiscoveredDevices.put(deviceId, device);
+                scheduleOnLostAlarm(device);
+            }
+        });
+    }
+
+    @Nullable
+    ListenerOperation<IScanListener> reportUpdated(NearbyDeviceParcelable device) {
+        long deviceId = device.getDeviceId();
+        return reportResult(DiscoveryResult.DEVICE_UPDATED, device, () -> {
+            synchronized (mMultiplexerLock) {
+                // Update the new device to discovered devices after reporting device is
+                // discovered.
+                mDiscoveredDevices.put(deviceId, device);
+                scheduleOnLostAlarm(device);
+            }
+        });
+
+    }
+
+    /** Reports an error to the client. */
+    public ListenerOperation<IScanListener> reportError(@ScanCallback.ErrorCode int errorCode) {
+        return listener -> listener.onError(errorCode);
+    }
+
+    @Nullable
+    ListenerOperation<IScanListener> reportResult(@DiscoveryResult int result,
+            NearbyDeviceParcelable device, @Nullable Runnable successReportCallback) {
+        // Report the operation to AppOps.
+        // NOTE: AppOps report has to be the last operation before delivering the result. Otherwise
+        // we may over-report when the discovery result doesn't end up being delivered.
+        if (!checkIdentity()) {
+            return reportError(ScanCallback.ERROR_PERMISSION_DENIED);
+        }
+
+        return new ListenerOperation<>() {
+
+            @Override
+            public void operate(IScanListener listener) throws Exception {
+                switch (result) {
+                    case DiscoveryResult.DEVICE_DISCOVERED:
+                        listener.onDiscovered(device);
+                        break;
+                    case DiscoveryResult.DEVICE_UPDATED:
+                        listener.onUpdated(device);
+                        break;
+                    case DiscoveryResult.DEVICE_LOST:
+                        listener.onLost(device);
+                        break;
+                }
+            }
+
+            @Override
+            public void onComplete(boolean success) {
+                if (success) {
+                    if (successReportCallback != null) {
+                        successReportCallback.run();
+                        Log.d(TAG, "Successfully delivered result to caller.");
+                    }
+                }
+            }
+        };
+    }
+
+    private boolean filterCheck(NearbyDeviceParcelable device) {
+        if (device.getScanType() != SCAN_TYPE_NEARBY_PRESENCE) {
+            return true;
+        }
+        List<ScanFilter> presenceFilters = mScanRequest.getScanFilters().stream().filter(
+                scanFilter -> scanFilter.getType() == SCAN_TYPE_NEARBY_PRESENCE).collect(
+                Collectors.toList());
+        return presenceFilterMatches(device, presenceFilters);
+    }
+
+    private boolean checkIdentity() {
+        boolean result = DiscoveryPermissions.noteDiscoveryResultDelivery(mAppOpsManager,
+                mCallerIdentity);
+        Log.v(TAG, "checkIdentity: result is " + result + " mAppOpsManager " + mAppOpsManager);
+        if (!result) {
+            Log.w(TAG, "[DiscoveryProviderManager] scan permission revoked "
+                    + "- not forwarding results for the registration.");
+        }
+        return result;
+    }
+
+    @GuardedBy("mMultiplexerLock")
+    private void scheduleOnLostAlarm(NearbyDeviceParcelable device) {
+        long deviceId = device.getDeviceId();
+        DeviceOnLostAlarm alarm = mDiscoveryOnLostAlarmPerDevice.get(deviceId);
+        if (alarm == null) {
+            alarm = new DeviceOnLostAlarm(device, mAlarmExecutor);
+            mDiscoveryOnLostAlarmPerDevice.put(deviceId, alarm);
+        }
+        alarm.start();
+        Log.d(TAG, "DiscoveryProviderManager updated state for " + device.getDeviceId());
+    }
+
+    /** Status of the discovery result. */
+    @IntDef({DiscoveryResult.DEVICE_DISCOVERED, DiscoveryResult.DEVICE_UPDATED,
+            DiscoveryResult.DEVICE_LOST})
+    public @interface DiscoveryResult {
+        int DEVICE_DISCOVERED = 0;
+        int DEVICE_UPDATED = 1;
+        int DEVICE_LOST = 2;
+    }
+
+    private class DeviceOnLostAlarm {
+
+        private static final String NAME = "DeviceOnLostAlarm";
+        private final NearbyDeviceParcelable mDevice;
+        private final ScheduledExecutorService mAlarmExecutor;
+        @Nullable
+        private CancelableAlarm mTimeoutAlarm;
+
+        DeviceOnLostAlarm(NearbyDeviceParcelable device, ScheduledExecutorService alarmExecutor) {
+            mDevice = device;
+            mAlarmExecutor = alarmExecutor;
+        }
+
+        synchronized void start() {
+            cancel();
+            this.mTimeoutAlarm = CancelableAlarm.createSingleAlarm(NAME, () -> {
+                Log.d(TAG, String.format("%s timed out after %d ms. Reporting %s on lost.", NAME,
+                        ON_LOST_TIME_OUT_MS, mDevice.getName()));
+                synchronized (mMultiplexerLock) {
+                    executeOperation(reportDeviceLost(mDevice));
+                }
+            }, ON_LOST_TIME_OUT_MS, mAlarmExecutor);
+        }
+
+        synchronized void cancel() {
+            if (mTimeoutAlarm != null) {
+                mTimeoutAlarm.cancel();
+                mTimeoutAlarm = null;
+            }
+        }
+    }
+}
diff --git a/nearby/service/java/com/android/server/nearby/provider/BleDiscoveryProvider.java b/nearby/service/java/com/android/server/nearby/provider/BleDiscoveryProvider.java
index 2cb9d38..c9098a6 100644
--- a/nearby/service/java/com/android/server/nearby/provider/BleDiscoveryProvider.java
+++ b/nearby/service/java/com/android/server/nearby/provider/BleDiscoveryProvider.java
@@ -44,12 +44,14 @@
 import com.android.server.nearby.injector.Injector;
 import com.android.server.nearby.presence.ExtendedAdvertisement;
 import com.android.server.nearby.presence.PresenceConstants;
+import com.android.server.nearby.util.ArrayUtils;
 import com.android.server.nearby.util.ForegroundThread;
 import com.android.server.nearby.util.encryption.CryptorImpIdentityV1;
 
 import com.google.common.annotations.VisibleForTesting;
 
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.List;
 import java.util.Map;
 import java.util.concurrent.Executor;
@@ -86,10 +88,12 @@
                 @Override
                 public void onScanResult(int callbackType, ScanResult scanResult) {
                     NearbyDeviceParcelable.Builder builder = new NearbyDeviceParcelable.Builder();
-                    builder.setMedium(NearbyDevice.Medium.BLE)
+                    String bleAddress = scanResult.getDevice().getAddress();
+                    builder.setDeviceId(bleAddress.hashCode())
+                            .setMedium(NearbyDevice.Medium.BLE)
                             .setRssi(scanResult.getRssi())
                             .setTxPower(scanResult.getTxPower())
-                            .setBluetoothAddress(scanResult.getDevice().getAddress());
+                            .setBluetoothAddress(bleAddress);
 
                     ScanRecord record = scanResult.getScanRecord();
                     if (record != null) {
@@ -300,6 +304,9 @@
                             builder.setPresenceDevice(getPresenceDevice(advertisement, deviceName,
                                     rssi));
                             builder.setEncryptionKeyTag(credential.getEncryptedMetadataKeyTag());
+                            if (!ArrayUtils.isEmpty(credential.getSecretId())) {
+                                builder.setDeviceId(Arrays.hashCode(credential.getSecretId()));
+                            }
                             return;
                         }
                     }
diff --git a/nearby/service/java/com/android/server/nearby/provider/ChreDiscoveryProvider.java b/nearby/service/java/com/android/server/nearby/provider/ChreDiscoveryProvider.java
index aa18517..7ab0523 100644
--- a/nearby/service/java/com/android/server/nearby/provider/ChreDiscoveryProvider.java
+++ b/nearby/service/java/com/android/server/nearby/provider/ChreDiscoveryProvider.java
@@ -44,6 +44,7 @@
 
 import com.google.protobuf.ByteString;
 
+import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
 import java.util.concurrent.Executor;
@@ -362,6 +363,7 @@
 
                         NearbyDeviceParcelable device =
                                 new NearbyDeviceParcelable.Builder()
+                                        .setDeviceId(Arrays.hashCode(secretId))
                                         .setScanType(SCAN_TYPE_NEARBY_PRESENCE)
                                         .setMedium(NearbyDevice.Medium.BLE)
                                         .setTxPower(filterResult.getTxPower())
diff --git a/nearby/tests/unit/src/com/android/server/nearby/NearbyServiceTest.java b/nearby/tests/unit/src/com/android/server/nearby/NearbyServiceTest.java
index 0d46d3e..90c85ab 100644
--- a/nearby/tests/unit/src/com/android/server/nearby/NearbyServiceTest.java
+++ b/nearby/tests/unit/src/com/android/server/nearby/NearbyServiceTest.java
@@ -36,6 +36,7 @@
 import android.content.Context;
 import android.nearby.IScanListener;
 import android.nearby.ScanRequest;
+import android.os.IBinder;
 import android.provider.DeviceConfig;
 
 import androidx.test.platform.app.InstrumentationRegistry;
@@ -61,10 +62,14 @@
     private IScanListener mScanListener;
     @Mock
     private AppOpsManager mMockAppOpsManager;
+    @Mock
+    private IBinder mIBinder;
 
     @Before
     public void setUp()  {
         initMocks(this);
+        when(mScanListener.asBinder()).thenReturn(mIBinder);
+
         mUiAutomation.adoptShellPermissionIdentity(
                 READ_DEVICE_CONFIG, WRITE_DEVICE_CONFIG, BLUETOOTH_PRIVILEGED);
         mContext = InstrumentationRegistry.getInstrumentation().getContext();
diff --git a/nearby/tests/unit/src/com/android/server/nearby/common/CancelableAlarmTest.java b/nearby/tests/unit/src/com/android/server/nearby/common/CancelableAlarmTest.java
index c7d3e25..719e816 100644
--- a/nearby/tests/unit/src/com/android/server/nearby/common/CancelableAlarmTest.java
+++ b/nearby/tests/unit/src/com/android/server/nearby/common/CancelableAlarmTest.java
@@ -80,14 +80,14 @@
     @Test
     public void cancelOfRunAlarmReturnsFalse() throws InterruptedException {
         TestCountDownLatch latch = new TestCountDownLatch(1);
-        long delayMillis = 1000;
+        long delayMillis = 500;
         CancelableAlarm alarm =
                 CancelableAlarm.createSingleAlarm(
                         "cancelOfRunAlarmReturnsFalse",
                         new CountDownRunnable(latch),
                         delayMillis,
                         mExecutor);
-        latch.awaitAndExpectDelay(delayMillis);
+        latch.awaitAndExpectDelay(delayMillis - 1);
 
         assertThat(alarm.cancel()).isFalse();
     }
diff --git a/nearby/tests/unit/src/com/android/server/nearby/managers/DiscoveryProviderManagerLegacyTest.java b/nearby/tests/unit/src/com/android/server/nearby/managers/DiscoveryProviderManagerLegacyTest.java
new file mode 100644
index 0000000..aa0dad3
--- /dev/null
+++ b/nearby/tests/unit/src/com/android/server/nearby/managers/DiscoveryProviderManagerLegacyTest.java
@@ -0,0 +1,378 @@
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.server.nearby.managers;
+
+import static android.nearby.PresenceCredential.IDENTITY_TYPE_PRIVATE;
+import static android.nearby.ScanRequest.SCAN_TYPE_NEARBY_PRESENCE;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import static org.mockito.Mockito.atLeastOnce;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import android.app.AppOpsManager;
+import android.content.Context;
+import android.nearby.DataElement;
+import android.nearby.IScanListener;
+import android.nearby.NearbyDeviceParcelable;
+import android.nearby.PresenceScanFilter;
+import android.nearby.PublicCredential;
+import android.nearby.ScanRequest;
+import android.os.IBinder;
+
+import com.android.server.nearby.injector.Injector;
+import com.android.server.nearby.provider.BleDiscoveryProvider;
+import com.android.server.nearby.provider.ChreCommunication;
+import com.android.server.nearby.provider.ChreDiscoveryProvider;
+import com.android.server.nearby.provider.DiscoveryProviderController;
+import com.android.server.nearby.util.identity.CallerIdentity;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+
+/**
+ * Unit test for {@link DiscoveryProviderManagerLegacy} class.
+ */
+public class DiscoveryProviderManagerLegacyTest {
+    private static final int SCAN_MODE_CHRE_ONLY = 3;
+    private static final int DATA_TYPE_SCAN_MODE = 102;
+    private static final int UID = 1234;
+    private static final int PID = 5678;
+    private static final String PACKAGE_NAME = "android.nearby.test";
+    private static final int RSSI = -60;
+    @Mock
+    Injector mInjector;
+    @Mock
+    Context mContext;
+    @Mock
+    AppOpsManager mAppOpsManager;
+    @Mock
+    BleDiscoveryProvider mBleDiscoveryProvider;
+    @Mock
+    ChreDiscoveryProvider mChreDiscoveryProvider;
+    @Mock
+    DiscoveryProviderController mBluetoothController;
+    @Mock
+    DiscoveryProviderController mChreController;
+    @Mock
+    IScanListener mScanListener;
+    @Mock
+    CallerIdentity mCallerIdentity;
+    @Mock
+    DiscoveryProviderManagerLegacy.ScanListenerDeathRecipient mScanListenerDeathRecipient;
+    @Mock
+    IBinder mIBinder;
+    private DiscoveryProviderManagerLegacy mDiscoveryProviderManager;
+    private Map<IBinder, DiscoveryProviderManagerLegacy.ScanListenerRecord>
+            mScanTypeScanListenerRecordMap;
+
+    private static PresenceScanFilter getPresenceScanFilter() {
+        final byte[] secretId = new byte[]{1, 2, 3, 4};
+        final byte[] authenticityKey = new byte[]{0, 1, 1, 1};
+        final byte[] publicKey = new byte[]{1, 1, 2, 2};
+        final byte[] encryptedMetadata = new byte[]{1, 2, 3, 4, 5};
+        final byte[] metadataEncryptionKeyTag = new byte[]{1, 1, 3, 4, 5};
+
+        PublicCredential credential = new PublicCredential.Builder(
+                secretId, authenticityKey, publicKey, encryptedMetadata, metadataEncryptionKeyTag)
+                .setIdentityType(IDENTITY_TYPE_PRIVATE)
+                .build();
+
+        final int action = 123;
+        return new PresenceScanFilter.Builder()
+                .addCredential(credential)
+                .setMaxPathLoss(RSSI)
+                .addPresenceAction(action)
+                .build();
+    }
+
+    private static PresenceScanFilter getChreOnlyPresenceScanFilter() {
+        final byte[] secretId = new byte[]{1, 2, 3, 4};
+        final byte[] authenticityKey = new byte[]{0, 1, 1, 1};
+        final byte[] publicKey = new byte[]{1, 1, 2, 2};
+        final byte[] encryptedMetadata = new byte[]{1, 2, 3, 4, 5};
+        final byte[] metadataEncryptionKeyTag = new byte[]{1, 1, 3, 4, 5};
+
+        PublicCredential credential = new PublicCredential.Builder(
+                secretId, authenticityKey, publicKey, encryptedMetadata, metadataEncryptionKeyTag)
+                .setIdentityType(IDENTITY_TYPE_PRIVATE)
+                .build();
+
+        final int action = 123;
+        DataElement scanModeElement = new DataElement(DATA_TYPE_SCAN_MODE,
+                new byte[]{SCAN_MODE_CHRE_ONLY});
+        return new PresenceScanFilter.Builder()
+                .addCredential(credential)
+                .setMaxPathLoss(RSSI)
+                .addPresenceAction(action)
+                .addExtendedProperty(scanModeElement)
+                .build();
+    }
+
+    @Before
+    public void setup() {
+        MockitoAnnotations.initMocks(this);
+        when(mInjector.getAppOpsManager()).thenReturn(mAppOpsManager);
+        when(mBleDiscoveryProvider.getController()).thenReturn(mBluetoothController);
+        when(mChreDiscoveryProvider.getController()).thenReturn(mChreController);
+
+        mScanTypeScanListenerRecordMap = new HashMap<>();
+        mDiscoveryProviderManager =
+                new DiscoveryProviderManagerLegacy(mContext, mInjector,
+                        mBleDiscoveryProvider,
+                        mChreDiscoveryProvider,
+                        mScanTypeScanListenerRecordMap);
+        mCallerIdentity = CallerIdentity
+                .forTest(UID, PID, PACKAGE_NAME, /* attributionTag= */ null);
+    }
+
+    @Test
+    public void testOnNearbyDeviceDiscovered() {
+        NearbyDeviceParcelable nearbyDeviceParcelable = new NearbyDeviceParcelable.Builder()
+                .setScanType(SCAN_TYPE_NEARBY_PRESENCE)
+                .build();
+        mDiscoveryProviderManager.onNearbyDeviceDiscovered(nearbyDeviceParcelable);
+    }
+
+    @Test
+    public void testInvalidateProviderScanMode() {
+        mDiscoveryProviderManager.invalidateProviderScanMode();
+    }
+
+    @Test
+    public void testStartProviders_chreOnlyChreAvailable_bleProviderNotStarted() {
+        when(mChreDiscoveryProvider.available()).thenReturn(true);
+
+        ScanRequest scanRequest = new ScanRequest.Builder()
+                .setScanType(SCAN_TYPE_NEARBY_PRESENCE)
+                .addScanFilter(getChreOnlyPresenceScanFilter()).build();
+        DiscoveryProviderManagerLegacy.ScanListenerRecord record =
+                new DiscoveryProviderManagerLegacy.ScanListenerRecord(
+                        scanRequest, mScanListener,
+                        mCallerIdentity, mScanListenerDeathRecipient);
+        mScanTypeScanListenerRecordMap.put(mIBinder, record);
+
+        Boolean start = mDiscoveryProviderManager.startProviders(scanRequest);
+        verify(mBluetoothController, never()).start();
+        assertThat(start).isTrue();
+    }
+
+    @Test
+    public void testStartProviders_chreOnlyChreAvailable_multipleFilters_bleProviderNotStarted() {
+        when(mChreDiscoveryProvider.available()).thenReturn(true);
+
+        ScanRequest scanRequest = new ScanRequest.Builder()
+                .setScanType(SCAN_TYPE_NEARBY_PRESENCE)
+                .addScanFilter(getChreOnlyPresenceScanFilter())
+                .addScanFilter(getPresenceScanFilter()).build();
+        DiscoveryProviderManagerLegacy.ScanListenerRecord record =
+                new DiscoveryProviderManagerLegacy.ScanListenerRecord(
+                        scanRequest, mScanListener,
+                        mCallerIdentity, mScanListenerDeathRecipient);
+        mScanTypeScanListenerRecordMap.put(mIBinder, record);
+
+        Boolean start = mDiscoveryProviderManager.startProviders(scanRequest);
+        verify(mBluetoothController, never()).start();
+        assertThat(start).isTrue();
+    }
+
+    @Test
+    public void testStartProviders_chreOnlyChreUnavailable_bleProviderNotStarted() {
+        when(mChreDiscoveryProvider.available()).thenReturn(false);
+
+        ScanRequest scanRequest = new ScanRequest.Builder()
+                .setScanType(SCAN_TYPE_NEARBY_PRESENCE)
+                .addScanFilter(getChreOnlyPresenceScanFilter()).build();
+        DiscoveryProviderManagerLegacy.ScanListenerRecord record =
+                new DiscoveryProviderManagerLegacy.ScanListenerRecord(
+                        scanRequest, mScanListener,
+                        mCallerIdentity, mScanListenerDeathRecipient);
+        mScanTypeScanListenerRecordMap.put(mIBinder, record);
+
+        Boolean start = mDiscoveryProviderManager.startProviders(scanRequest);
+        verify(mBluetoothController, never()).start();
+        assertThat(start).isFalse();
+    }
+
+    @Test
+    public void testStartProviders_notChreOnlyChreAvailable_bleProviderNotStarted() {
+        when(mChreDiscoveryProvider.available()).thenReturn(true);
+
+        ScanRequest scanRequest = new ScanRequest.Builder()
+                .setScanType(SCAN_TYPE_NEARBY_PRESENCE)
+                .addScanFilter(getPresenceScanFilter()).build();
+        DiscoveryProviderManagerLegacy.ScanListenerRecord record =
+                new DiscoveryProviderManagerLegacy.ScanListenerRecord(
+                        scanRequest, mScanListener,
+                        mCallerIdentity, mScanListenerDeathRecipient);
+        mScanTypeScanListenerRecordMap.put(mIBinder, record);
+
+        Boolean start = mDiscoveryProviderManager.startProviders(scanRequest);
+        verify(mBluetoothController, never()).start();
+        assertThat(start).isTrue();
+    }
+
+    @Test
+    public void testStartProviders_notChreOnlyChreUnavailable_bleProviderStarted() {
+        when(mChreDiscoveryProvider.available()).thenReturn(false);
+
+        ScanRequest scanRequest = new ScanRequest.Builder()
+                .setScanType(SCAN_TYPE_NEARBY_PRESENCE)
+                .addScanFilter(getPresenceScanFilter()).build();
+        DiscoveryProviderManagerLegacy.ScanListenerRecord record =
+                new DiscoveryProviderManagerLegacy.ScanListenerRecord(
+                        scanRequest, mScanListener,
+                        mCallerIdentity, mScanListenerDeathRecipient);
+        mScanTypeScanListenerRecordMap.put(mIBinder, record);
+
+        Boolean start = mDiscoveryProviderManager.startProviders(scanRequest);
+        verify(mBluetoothController, atLeastOnce()).start();
+        assertThat(start).isTrue();
+    }
+
+    @Test
+    public void testStartProviders_chreOnlyChreUndetermined_bleProviderNotStarted() {
+        when(mChreDiscoveryProvider.available()).thenReturn(null);
+
+        ScanRequest scanRequest = new ScanRequest.Builder()
+                .setScanType(SCAN_TYPE_NEARBY_PRESENCE)
+                .addScanFilter(getChreOnlyPresenceScanFilter()).build();
+        DiscoveryProviderManagerLegacy.ScanListenerRecord record =
+                new DiscoveryProviderManagerLegacy.ScanListenerRecord(
+                        scanRequest, mScanListener,
+                        mCallerIdentity, mScanListenerDeathRecipient);
+        mScanTypeScanListenerRecordMap.put(mIBinder, record);
+
+        Boolean start = mDiscoveryProviderManager.startProviders(scanRequest);
+        verify(mBluetoothController, never()).start();
+        assertThat(start).isNull();
+    }
+
+    @Test
+    public void testStartProviders_notChreOnlyChreUndetermined_bleProviderStarted() {
+        when(mChreDiscoveryProvider.available()).thenReturn(null);
+
+        ScanRequest scanRequest = new ScanRequest.Builder()
+                .setScanType(SCAN_TYPE_NEARBY_PRESENCE)
+                .addScanFilter(getPresenceScanFilter()).build();
+        DiscoveryProviderManagerLegacy.ScanListenerRecord record =
+                new DiscoveryProviderManagerLegacy.ScanListenerRecord(
+                        scanRequest, mScanListener,
+                        mCallerIdentity, mScanListenerDeathRecipient);
+        mScanTypeScanListenerRecordMap.put(mIBinder, record);
+
+        Boolean start = mDiscoveryProviderManager.startProviders(scanRequest);
+        verify(mBluetoothController, atLeastOnce()).start();
+        assertThat(start).isTrue();
+    }
+
+    @Test
+    public void test_stopChreProvider_clearFilters() throws Exception {
+        // Cannot use mocked ChreDiscoveryProvider,
+        // so we cannot use class variable mDiscoveryProviderManager
+        ExecutorService executor = Executors.newSingleThreadExecutor();
+        DiscoveryProviderManagerLegacy manager =
+                new DiscoveryProviderManagerLegacy(mContext, mInjector,
+                        mBleDiscoveryProvider,
+                        new ChreDiscoveryProvider(
+                                mContext,
+                                new ChreCommunication(mInjector, mContext, executor), executor),
+                        mScanTypeScanListenerRecordMap);
+        ScanRequest scanRequest = new ScanRequest.Builder()
+                .setScanType(SCAN_TYPE_NEARBY_PRESENCE)
+                .addScanFilter(getPresenceScanFilter()).build();
+        DiscoveryProviderManagerLegacy.ScanListenerRecord record =
+                new DiscoveryProviderManagerLegacy.ScanListenerRecord(
+                        scanRequest, mScanListener,
+                        mCallerIdentity, mScanListenerDeathRecipient);
+        mScanTypeScanListenerRecordMap.put(mIBinder, record);
+        manager.startChreProvider(List.of(getPresenceScanFilter()));
+        // This is an asynchronized process. The filters will be set in executor thread. So we need
+        // to wait for some time to get the correct result.
+        Thread.sleep(200);
+
+        assertThat(manager.mChreDiscoveryProvider.getController().isStarted())
+                .isTrue();
+        assertThat(manager.mChreDiscoveryProvider.getFiltersLocked()).isNotNull();
+
+        manager.stopChreProvider();
+        Thread.sleep(200);
+        // The filters should be cleared right after.
+        assertThat(manager.mChreDiscoveryProvider.getController().isStarted())
+                .isFalse();
+        assertThat(manager.mChreDiscoveryProvider.getFiltersLocked()).isEmpty();
+    }
+
+    @Test
+    public void test_restartChreProvider() throws Exception {
+        // Cannot use mocked ChreDiscoveryProvider,
+        // so we cannot use class variable mDiscoveryProviderManager
+        ExecutorService executor = Executors.newSingleThreadExecutor();
+        DiscoveryProviderManagerLegacy manager =
+                new DiscoveryProviderManagerLegacy(mContext, mInjector,
+                        mBleDiscoveryProvider,
+                        new ChreDiscoveryProvider(
+                                mContext,
+                                new ChreCommunication(mInjector, mContext, executor), executor),
+                        mScanTypeScanListenerRecordMap);
+        ScanRequest scanRequest = new ScanRequest.Builder()
+                .setScanType(SCAN_TYPE_NEARBY_PRESENCE)
+                .addScanFilter(getPresenceScanFilter()).build();
+        DiscoveryProviderManagerLegacy.ScanListenerRecord record =
+                new DiscoveryProviderManagerLegacy.ScanListenerRecord(scanRequest, mScanListener,
+                        mCallerIdentity, mScanListenerDeathRecipient);
+        mScanTypeScanListenerRecordMap.put(mIBinder, record);
+        manager.startChreProvider(List.of(getPresenceScanFilter()));
+        // This is an asynchronized process. The filters will be set in executor thread. So we need
+        // to wait for some time to get the correct result.
+        Thread.sleep(200);
+
+        assertThat(manager.mChreDiscoveryProvider.getController().isStarted())
+                .isTrue();
+        assertThat(manager.mChreDiscoveryProvider.getFiltersLocked()).isNotNull();
+
+        // We want to make sure quickly restart the provider the filters should
+        // be reset correctly.
+        // See b/255922206, there can be a race condition that filters get cleared because onStop()
+        // get executed after onStart() if they are called from different threads.
+        manager.stopChreProvider();
+        manager.mChreDiscoveryProvider.getController().setProviderScanFilters(
+                List.of(getPresenceScanFilter()));
+        manager.startChreProvider(List.of(getPresenceScanFilter()));
+        Thread.sleep(200);
+        assertThat(manager.mChreDiscoveryProvider.getController().isStarted())
+                .isTrue();
+        assertThat(manager.mChreDiscoveryProvider.getFiltersLocked()).isNotNull();
+
+        // Wait for enough time
+        Thread.sleep(1000);
+
+        assertThat(manager.mChreDiscoveryProvider.getController().isStarted())
+                .isTrue();
+        assertThat(manager.mChreDiscoveryProvider.getFiltersLocked()).isNotNull();
+    }
+}
diff --git a/nearby/tests/unit/src/com/android/server/nearby/managers/DiscoveryProviderManagerTest.java b/nearby/tests/unit/src/com/android/server/nearby/managers/DiscoveryProviderManagerTest.java
index 542ceed..7ecf631 100644
--- a/nearby/tests/unit/src/com/android/server/nearby/managers/DiscoveryProviderManagerTest.java
+++ b/nearby/tests/unit/src/com/android/server/nearby/managers/DiscoveryProviderManagerTest.java
@@ -23,6 +23,7 @@
 
 import static org.mockito.Mockito.atLeastOnce;
 import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.reset;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
 
@@ -48,10 +49,8 @@
 import org.mockito.Mock;
 import org.mockito.MockitoAnnotations;
 
-import java.util.HashMap;
 import java.util.List;
-import java.util.Map;
-import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executor;
 import java.util.concurrent.Executors;
 
 public class DiscoveryProviderManagerTest {
@@ -80,12 +79,9 @@
     @Mock
     CallerIdentity mCallerIdentity;
     @Mock
-    DiscoveryProviderManager.ScanListenerDeathRecipient mScanListenerDeathRecipient;
-    @Mock
     IBinder mIBinder;
+    private Executor mExecutor;
     private DiscoveryProviderManager mDiscoveryProviderManager;
-    private Map<IBinder, DiscoveryProviderManager.ScanListenerRecord>
-            mScanTypeScanListenerRecordMap;
 
     private static PresenceScanFilter getPresenceScanFilter() {
         final byte[] secretId = new byte[]{1, 2, 3, 4};
@@ -133,16 +129,16 @@
     @Before
     public void setup() {
         MockitoAnnotations.initMocks(this);
+        mExecutor = Executors.newSingleThreadExecutor();
         when(mInjector.getAppOpsManager()).thenReturn(mAppOpsManager);
         when(mBleDiscoveryProvider.getController()).thenReturn(mBluetoothController);
         when(mChreDiscoveryProvider.getController()).thenReturn(mChreController);
+        when(mScanListener.asBinder()).thenReturn(mIBinder);
 
-        mScanTypeScanListenerRecordMap = new HashMap<>();
         mDiscoveryProviderManager =
-                new DiscoveryProviderManager(mContext, mInjector,
+                new DiscoveryProviderManager(mContext, mExecutor, mInjector,
                         mBleDiscoveryProvider,
-                        mChreDiscoveryProvider,
-                        mScanTypeScanListenerRecordMap);
+                        mChreDiscoveryProvider);
         mCallerIdentity = CallerIdentity
                 .forTest(UID, PID, PACKAGE_NAME, /* attributionTag= */ null);
     }
@@ -162,55 +158,45 @@
 
     @Test
     public void testStartProviders_chreOnlyChreAvailable_bleProviderNotStarted() {
+        reset(mBluetoothController);
         when(mChreDiscoveryProvider.available()).thenReturn(true);
 
         ScanRequest scanRequest = new ScanRequest.Builder()
                 .setScanType(SCAN_TYPE_NEARBY_PRESENCE)
                 .addScanFilter(getChreOnlyPresenceScanFilter()).build();
-        DiscoveryProviderManager.ScanListenerRecord record =
-                new DiscoveryProviderManager.ScanListenerRecord(
-                        scanRequest, mScanListener,
-                        mCallerIdentity, mScanListenerDeathRecipient);
-        mScanTypeScanListenerRecordMap.put(mIBinder, record);
+        mDiscoveryProviderManager.registerScanListener(scanRequest, mScanListener, mCallerIdentity);
 
-        Boolean start = mDiscoveryProviderManager.startProviders(scanRequest);
+        Boolean start = mDiscoveryProviderManager.startProviders();
         verify(mBluetoothController, never()).start();
         assertThat(start).isTrue();
     }
 
     @Test
     public void testStartProviders_chreOnlyChreAvailable_multipleFilters_bleProviderNotStarted() {
+        reset(mBluetoothController);
         when(mChreDiscoveryProvider.available()).thenReturn(true);
 
         ScanRequest scanRequest = new ScanRequest.Builder()
                 .setScanType(SCAN_TYPE_NEARBY_PRESENCE)
-                .addScanFilter(getChreOnlyPresenceScanFilter())
-                .addScanFilter(getPresenceScanFilter()).build();
-        DiscoveryProviderManager.ScanListenerRecord record =
-                new DiscoveryProviderManager.ScanListenerRecord(
-                        scanRequest, mScanListener,
-                        mCallerIdentity, mScanListenerDeathRecipient);
-        mScanTypeScanListenerRecordMap.put(mIBinder, record);
+                .addScanFilter(getChreOnlyPresenceScanFilter()).build();
+        mDiscoveryProviderManager.registerScanListener(scanRequest, mScanListener, mCallerIdentity);
 
-        Boolean start = mDiscoveryProviderManager.startProviders(scanRequest);
+        Boolean start = mDiscoveryProviderManager.startProviders();
         verify(mBluetoothController, never()).start();
         assertThat(start).isTrue();
     }
 
     @Test
     public void testStartProviders_chreOnlyChreUnavailable_bleProviderNotStarted() {
+        reset(mBluetoothController);
         when(mChreDiscoveryProvider.available()).thenReturn(false);
 
         ScanRequest scanRequest = new ScanRequest.Builder()
                 .setScanType(SCAN_TYPE_NEARBY_PRESENCE)
                 .addScanFilter(getChreOnlyPresenceScanFilter()).build();
-        DiscoveryProviderManager.ScanListenerRecord record =
-                new DiscoveryProviderManager.ScanListenerRecord(
-                        scanRequest, mScanListener,
-                        mCallerIdentity, mScanListenerDeathRecipient);
-        mScanTypeScanListenerRecordMap.put(mIBinder, record);
+        mDiscoveryProviderManager.registerScanListener(scanRequest, mScanListener, mCallerIdentity);
 
-        Boolean start = mDiscoveryProviderManager.startProviders(scanRequest);
+        Boolean start = mDiscoveryProviderManager.startProviders();
         verify(mBluetoothController, never()).start();
         assertThat(start).isFalse();
     }
@@ -218,17 +204,14 @@
     @Test
     public void testStartProviders_notChreOnlyChreAvailable_bleProviderNotStarted() {
         when(mChreDiscoveryProvider.available()).thenReturn(true);
+        reset(mBluetoothController);
 
         ScanRequest scanRequest = new ScanRequest.Builder()
                 .setScanType(SCAN_TYPE_NEARBY_PRESENCE)
                 .addScanFilter(getPresenceScanFilter()).build();
-        DiscoveryProviderManager.ScanListenerRecord record =
-                new DiscoveryProviderManager.ScanListenerRecord(
-                        scanRequest, mScanListener,
-                        mCallerIdentity, mScanListenerDeathRecipient);
-        mScanTypeScanListenerRecordMap.put(mIBinder, record);
+        mDiscoveryProviderManager.registerScanListener(scanRequest, mScanListener, mCallerIdentity);
 
-        Boolean start = mDiscoveryProviderManager.startProviders(scanRequest);
+        Boolean start = mDiscoveryProviderManager.startProviders();
         verify(mBluetoothController, never()).start();
         assertThat(start).isTrue();
     }
@@ -236,17 +219,14 @@
     @Test
     public void testStartProviders_notChreOnlyChreUnavailable_bleProviderStarted() {
         when(mChreDiscoveryProvider.available()).thenReturn(false);
+        reset(mBluetoothController);
 
         ScanRequest scanRequest = new ScanRequest.Builder()
                 .setScanType(SCAN_TYPE_NEARBY_PRESENCE)
                 .addScanFilter(getPresenceScanFilter()).build();
-        DiscoveryProviderManager.ScanListenerRecord record =
-                new DiscoveryProviderManager.ScanListenerRecord(
-                        scanRequest, mScanListener,
-                        mCallerIdentity, mScanListenerDeathRecipient);
-        mScanTypeScanListenerRecordMap.put(mIBinder, record);
+        mDiscoveryProviderManager.registerScanListener(scanRequest, mScanListener, mCallerIdentity);
 
-        Boolean start = mDiscoveryProviderManager.startProviders(scanRequest);
+        Boolean start = mDiscoveryProviderManager.startProviders();
         verify(mBluetoothController, atLeastOnce()).start();
         assertThat(start).isTrue();
     }
@@ -254,17 +234,14 @@
     @Test
     public void testStartProviders_chreOnlyChreUndetermined_bleProviderNotStarted() {
         when(mChreDiscoveryProvider.available()).thenReturn(null);
+        reset(mBluetoothController);
 
         ScanRequest scanRequest = new ScanRequest.Builder()
                 .setScanType(SCAN_TYPE_NEARBY_PRESENCE)
                 .addScanFilter(getChreOnlyPresenceScanFilter()).build();
-        DiscoveryProviderManager.ScanListenerRecord record =
-                new DiscoveryProviderManager.ScanListenerRecord(
-                        scanRequest, mScanListener,
-                        mCallerIdentity, mScanListenerDeathRecipient);
-        mScanTypeScanListenerRecordMap.put(mIBinder, record);
+        mDiscoveryProviderManager.registerScanListener(scanRequest, mScanListener, mCallerIdentity);
 
-        Boolean start = mDiscoveryProviderManager.startProviders(scanRequest);
+        Boolean start = mDiscoveryProviderManager.startProviders();
         verify(mBluetoothController, never()).start();
         assertThat(start).isNull();
     }
@@ -272,17 +249,14 @@
     @Test
     public void testStartProviders_notChreOnlyChreUndetermined_bleProviderStarted() {
         when(mChreDiscoveryProvider.available()).thenReturn(null);
+        reset(mBluetoothController);
 
         ScanRequest scanRequest = new ScanRequest.Builder()
                 .setScanType(SCAN_TYPE_NEARBY_PRESENCE)
                 .addScanFilter(getPresenceScanFilter()).build();
-        DiscoveryProviderManager.ScanListenerRecord record =
-                new DiscoveryProviderManager.ScanListenerRecord(
-                        scanRequest, mScanListener,
-                        mCallerIdentity, mScanListenerDeathRecipient);
-        mScanTypeScanListenerRecordMap.put(mIBinder, record);
+        mDiscoveryProviderManager.registerScanListener(scanRequest, mScanListener, mCallerIdentity);
 
-        Boolean start = mDiscoveryProviderManager.startProviders(scanRequest);
+        Boolean start = mDiscoveryProviderManager.startProviders();
         verify(mBluetoothController, atLeastOnce()).start();
         assertThat(start).isTrue();
     }
@@ -291,22 +265,16 @@
     public void test_stopChreProvider_clearFilters() throws Exception {
         // Cannot use mocked ChreDiscoveryProvider,
         // so we cannot use class variable mDiscoveryProviderManager
-        ExecutorService executor = Executors.newSingleThreadExecutor();
         DiscoveryProviderManager manager =
-                new DiscoveryProviderManager(mContext, mInjector,
+                new DiscoveryProviderManager(mContext, mExecutor, mInjector,
                         mBleDiscoveryProvider,
                         new ChreDiscoveryProvider(
                                 mContext,
-                                new ChreCommunication(mInjector, mContext, executor), executor),
-                        mScanTypeScanListenerRecordMap);
+                                new ChreCommunication(mInjector, mContext, mExecutor), mExecutor));
         ScanRequest scanRequest = new ScanRequest.Builder()
                 .setScanType(SCAN_TYPE_NEARBY_PRESENCE)
                 .addScanFilter(getPresenceScanFilter()).build();
-        DiscoveryProviderManager.ScanListenerRecord record =
-                new DiscoveryProviderManager.ScanListenerRecord(
-                        scanRequest, mScanListener,
-                        mCallerIdentity, mScanListenerDeathRecipient);
-        mScanTypeScanListenerRecordMap.put(mIBinder, record);
+        manager.registerScanListener(scanRequest, mScanListener, mCallerIdentity);
         manager.startChreProvider(List.of(getPresenceScanFilter()));
         // This is an asynchronized process. The filters will be set in executor thread. So we need
         // to wait for some time to get the correct result.
@@ -328,21 +296,17 @@
     public void test_restartChreProvider() throws Exception {
         // Cannot use mocked ChreDiscoveryProvider,
         // so we cannot use class variable mDiscoveryProviderManager
-        ExecutorService executor = Executors.newSingleThreadExecutor();
         DiscoveryProviderManager manager =
-                new DiscoveryProviderManager(mContext, mInjector,
+                new DiscoveryProviderManager(mContext, mExecutor, mInjector,
                         mBleDiscoveryProvider,
                         new ChreDiscoveryProvider(
                                 mContext,
-                                new ChreCommunication(mInjector, mContext, executor), executor),
-                        mScanTypeScanListenerRecordMap);
+                                new ChreCommunication(mInjector, mContext, mExecutor), mExecutor));
         ScanRequest scanRequest = new ScanRequest.Builder()
                 .setScanType(SCAN_TYPE_NEARBY_PRESENCE)
                 .addScanFilter(getPresenceScanFilter()).build();
-        DiscoveryProviderManager.ScanListenerRecord record =
-                new DiscoveryProviderManager.ScanListenerRecord(scanRequest, mScanListener,
-                        mCallerIdentity, mScanListenerDeathRecipient);
-        mScanTypeScanListenerRecordMap.put(mIBinder, record);
+        manager.registerScanListener(scanRequest, mScanListener, mCallerIdentity);
+
         manager.startChreProvider(List.of(getPresenceScanFilter()));
         // This is an asynchronized process. The filters will be set in executor thread. So we need
         // to wait for some time to get the correct result.
diff --git a/nearby/tests/unit/src/com/android/server/nearby/managers/ListenerMultiplexerTest.java b/nearby/tests/unit/src/com/android/server/nearby/managers/ListenerMultiplexerTest.java
new file mode 100644
index 0000000..104d762
--- /dev/null
+++ b/nearby/tests/unit/src/com/android/server/nearby/managers/ListenerMultiplexerTest.java
@@ -0,0 +1,302 @@
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.server.nearby.managers;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.reset;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.MockitoAnnotations.initMocks;
+
+import android.os.IBinder;
+
+import androidx.annotation.NonNull;
+
+import com.android.server.nearby.managers.registration.BinderListenerRegistration;
+
+import com.google.common.util.concurrent.MoreExecutors;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import java.util.Collection;
+
+public class ListenerMultiplexerTest {
+
+    @Before
+    public void setUp() {
+        initMocks(this);
+    }
+
+    @Test
+    public void testAdd() {
+        TestMultiplexer multiplexer = new TestMultiplexer();
+
+        Runnable listener = mock(Runnable.class);
+        IBinder binder = mock(IBinder.class);
+        int value = 2;
+        multiplexer.addListener(binder, listener, value);
+
+        synchronized (multiplexer.mMultiplexerLock) {
+            assertThat(multiplexer.mRegistered).isTrue();
+            assertThat(multiplexer.mOnRegisterCalledCount).isEqualTo(1);
+            assertThat(multiplexer.mMergeOperationCount).isEqualTo(1);
+            assertThat(multiplexer.mMergeUpdatedCount).isEqualTo(1);
+            assertThat(multiplexer.mMerged).isEqualTo(value);
+        }
+        Runnable listener2 = mock(Runnable.class);
+        IBinder binder2 = mock(IBinder.class);
+        int value2 = 1;
+        multiplexer.addListener(binder2, listener2, value2);
+        synchronized (multiplexer.mMultiplexerLock) {
+            assertThat(multiplexer.mRegistered).isTrue();
+            assertThat(multiplexer.mOnRegisterCalledCount).isEqualTo(1);
+            assertThat(multiplexer.mMergeOperationCount).isEqualTo(2);
+            assertThat(multiplexer.mMergeUpdatedCount).isEqualTo(1);
+            assertThat(multiplexer.mMerged).isEqualTo(value);
+        }
+    }
+
+    @Test
+    public void testReplace() {
+        TestMultiplexer multiplexer = new TestMultiplexer();
+        Runnable listener = mock(Runnable.class);
+        IBinder binder = mock(IBinder.class);
+        int value = 2;
+        multiplexer.addListener(binder, listener, value);
+        synchronized (multiplexer.mMultiplexerLock) {
+            assertThat(multiplexer.mRegistered).isTrue();
+            assertThat(multiplexer.mOnRegisterCalledCount).isEqualTo(1);
+            assertThat(multiplexer.mMerged).isEqualTo(value);
+        }
+        multiplexer.notifyListeners();
+        verify(listener, times(1)).run();
+        reset(listener);
+
+        // Same key, different value
+        Runnable listener2 = mock(Runnable.class);
+        int value2 = 1;
+        multiplexer.addListener(binder, listener2, value2);
+        synchronized (multiplexer.mMultiplexerLock) {
+            assertThat(multiplexer.mRegistered).isTrue();
+            // Should not be called again
+            assertThat(multiplexer.mOnRegisterCalledCount).isEqualTo(1);
+            assertThat(multiplexer.mOnUnregisterCalledCount).isEqualTo(0);
+            assertThat(multiplexer.mMerged).isEqualTo(value2);
+        }
+        // Run on the new listener
+        multiplexer.notifyListeners();
+        verify(listener, never()).run();
+        verify(listener2, times(1)).run();
+
+        multiplexer.removeRegistration(binder);
+
+        synchronized (multiplexer.mMultiplexerLock) {
+            assertThat(multiplexer.mRegistered).isFalse();
+            assertThat(multiplexer.mOnRegisterCalledCount).isEqualTo(1);
+            assertThat(multiplexer.mOnUnregisterCalledCount).isEqualTo(1);
+            assertThat(multiplexer.mMerged).isEqualTo(Integer.MIN_VALUE);
+        }
+    }
+
+    @Test
+    public void testRemove() {
+        TestMultiplexer multiplexer = new TestMultiplexer();
+        Runnable listener = mock(Runnable.class);
+        IBinder binder = mock(IBinder.class);
+        int value = 2;
+        multiplexer.addListener(binder, listener, value);
+        synchronized (multiplexer.mMultiplexerLock) {
+            assertThat(multiplexer.mRegistered).isTrue();
+            assertThat(multiplexer.mMerged).isEqualTo(value);
+        }
+        multiplexer.notifyListeners();
+        verify(listener, times(1)).run();
+        reset(listener);
+
+        multiplexer.removeRegistration(binder);
+        synchronized (multiplexer.mMultiplexerLock) {
+            assertThat(multiplexer.mRegistered).isFalse();
+            assertThat(multiplexer.mMerged).isEqualTo(Integer.MIN_VALUE);
+        }
+        multiplexer.notifyListeners();
+        verify(listener, never()).run();
+    }
+
+    @Test
+    public void testMergeMultiple() {
+        TestMultiplexer multiplexer = new TestMultiplexer();
+
+        Runnable listener = mock(Runnable.class);
+        IBinder binder = mock(IBinder.class);
+        int value = 2;
+
+        Runnable listener2 = mock(Runnable.class);
+        IBinder binder2 = mock(IBinder.class);
+        int value2 = 1;
+
+        Runnable listener3 = mock(Runnable.class);
+        IBinder binder3 = mock(IBinder.class);
+        int value3 = 5;
+
+        multiplexer.addListener(binder, listener, value);
+        synchronized (multiplexer.mMultiplexerLock) {
+            assertThat(multiplexer.mRegistered).isTrue();
+            assertThat(multiplexer.mOnRegisterCalledCount).isEqualTo(1);
+            assertThat(multiplexer.mMergeOperationCount).isEqualTo(1);
+            assertThat(multiplexer.mMergeUpdatedCount).isEqualTo(1);
+            assertThat(multiplexer.mMerged).isEqualTo(value);
+        }
+        multiplexer.notifyListeners();
+        verify(listener, times(1)).run();
+        verify(listener2, never()).run();
+        verify(listener3, never()).run();
+
+        multiplexer.addListener(binder2, listener2, value2);
+        synchronized (multiplexer.mMultiplexerLock) {
+            assertThat(multiplexer.mRegistered).isTrue();
+            assertThat(multiplexer.mOnRegisterCalledCount).isEqualTo(1);
+            assertThat(multiplexer.mMergeOperationCount).isEqualTo(2);
+            assertThat(multiplexer.mMergeUpdatedCount).isEqualTo(1);
+            assertThat(multiplexer.mMerged).isEqualTo(value);
+        }
+        multiplexer.notifyListeners();
+        verify(listener, times(2)).run();
+        verify(listener2, times(1)).run();
+        verify(listener3, never()).run();
+
+        multiplexer.addListener(binder3, listener3, value3);
+        synchronized (multiplexer.mMultiplexerLock) {
+            assertThat(multiplexer.mRegistered).isTrue();
+            assertThat(multiplexer.mOnRegisterCalledCount).isEqualTo(1);
+            assertThat(multiplexer.mMergeOperationCount).isEqualTo(3);
+            assertThat(multiplexer.mMergeUpdatedCount).isEqualTo(2);
+            assertThat(multiplexer.mMerged).isEqualTo(value3);
+        }
+        multiplexer.notifyListeners();
+        verify(listener, times(3)).run();
+        verify(listener2, times(2)).run();
+        verify(listener3, times(1)).run();
+
+        multiplexer.removeRegistration(binder);
+        synchronized (multiplexer.mMultiplexerLock) {
+            assertThat(multiplexer.mRegistered).isTrue();
+            assertThat(multiplexer.mOnRegisterCalledCount).isEqualTo(1);
+            assertThat(multiplexer.mMergeOperationCount).isEqualTo(4);
+            assertThat(multiplexer.mMergeUpdatedCount).isEqualTo(2);
+            assertThat(multiplexer.mMerged).isEqualTo(value3);
+        }
+        multiplexer.notifyListeners();
+        verify(listener, times(3)).run();
+        verify(listener2, times(3)).run();
+        verify(listener3, times(2)).run();
+
+        multiplexer.removeRegistration(binder3);
+        synchronized (multiplexer.mMultiplexerLock) {
+            assertThat(multiplexer.mRegistered).isTrue();
+            assertThat(multiplexer.mOnRegisterCalledCount).isEqualTo(1);
+            assertThat(multiplexer.mMergeOperationCount).isEqualTo(5);
+            assertThat(multiplexer.mMergeUpdatedCount).isEqualTo(3);
+            assertThat(multiplexer.mMerged).isEqualTo(value2);
+        }
+        multiplexer.notifyListeners();
+        verify(listener, times(3)).run();
+        verify(listener2, times(4)).run();
+        verify(listener3, times(2)).run();
+
+        multiplexer.removeRegistration(binder2);
+        synchronized (multiplexer.mMultiplexerLock) {
+            assertThat(multiplexer.mRegistered).isFalse();
+            assertThat(multiplexer.mOnRegisterCalledCount).isEqualTo(1);
+            assertThat(multiplexer.mMergeOperationCount).isEqualTo(6);
+            assertThat(multiplexer.mMergeUpdatedCount).isEqualTo(4);
+            assertThat(multiplexer.mMerged).isEqualTo(Integer.MIN_VALUE);
+        }
+        multiplexer.notifyListeners();
+        verify(listener, times(3)).run();
+        verify(listener2, times(4)).run();
+        verify(listener3, times(2)).run();
+    }
+
+    private class TestMultiplexer extends
+            ListenerMultiplexer<Runnable, TestMultiplexer.TestListenerRegistration, Integer> {
+        int mOnRegisterCalledCount;
+        int mOnUnregisterCalledCount;
+        boolean mRegistered;
+        private int mMergeOperationCount;
+        private int mMergeUpdatedCount;
+
+        @Override
+        public void onRegister() {
+            mOnRegisterCalledCount++;
+            mRegistered = true;
+        }
+
+        @Override
+        public void onUnregister() {
+            mOnUnregisterCalledCount++;
+            mRegistered = false;
+        }
+
+        @Override
+        public Integer mergeRegistrations(
+                @NonNull Collection<TestListenerRegistration> testListenerRegistrations) {
+            mMergeOperationCount++;
+            int max = Integer.MIN_VALUE;
+            for (TestListenerRegistration registration : testListenerRegistrations) {
+                max = Math.max(max, registration.getValue());
+            }
+            return max;
+        }
+
+        @Override
+        public void onMergedRegistrationsUpdated() {
+            mMergeUpdatedCount++;
+        }
+
+        public void addListener(IBinder binder, Runnable runnable, int value) {
+            TestListenerRegistration registration = new TestListenerRegistration(binder, runnable,
+                    value);
+            putRegistration(binder, registration);
+        }
+
+        public void notifyListeners() {
+            deliverToListeners(registration -> Runnable::run);
+        }
+
+        private class TestListenerRegistration extends BinderListenerRegistration<Runnable> {
+            private final int mValue;
+
+            protected TestListenerRegistration(IBinder binder, Runnable runnable, int value) {
+                super(binder, MoreExecutors.directExecutor(), runnable);
+                mValue = value;
+            }
+
+            @Override
+            public TestMultiplexer getOwner() {
+                return TestMultiplexer.this;
+            }
+
+            public int getValue() {
+                return mValue;
+            }
+        }
+    }
+}
diff --git a/nearby/tests/unit/src/com/android/server/nearby/managers/MergedDiscoveryRequestTest.java b/nearby/tests/unit/src/com/android/server/nearby/managers/MergedDiscoveryRequestTest.java
new file mode 100644
index 0000000..9281e42
--- /dev/null
+++ b/nearby/tests/unit/src/com/android/server/nearby/managers/MergedDiscoveryRequestTest.java
@@ -0,0 +1,104 @@
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.server.nearby.managers;
+
+import static android.nearby.PresenceCredential.IDENTITY_TYPE_PRIVATE;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import android.nearby.DataElement;
+import android.nearby.PresenceScanFilter;
+import android.nearby.PublicCredential;
+import android.nearby.ScanFilter;
+import android.nearby.ScanRequest;
+import android.util.ArraySet;
+
+import org.junit.Test;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.Set;
+
+/**
+ * Unit test for {@link MergedDiscoveryRequest} class.
+ */
+public class MergedDiscoveryRequestTest {
+
+    @Test
+    public void test_addScanType() {
+        MergedDiscoveryRequest.Builder builder = new MergedDiscoveryRequest.Builder();
+        builder.addScanType(ScanRequest.SCAN_TYPE_FAST_PAIR);
+        builder.addScanType(ScanRequest.SCAN_TYPE_NEARBY_PRESENCE);
+        MergedDiscoveryRequest request = builder.build();
+
+        assertThat(request.getScanTypes()).isEqualTo(new ArraySet<>(
+                Arrays.asList(ScanRequest.SCAN_TYPE_FAST_PAIR,
+                        ScanRequest.SCAN_TYPE_NEARBY_PRESENCE)));
+    }
+
+    @Test
+    public void test_addActions() {
+        MergedDiscoveryRequest.Builder builder = new MergedDiscoveryRequest.Builder();
+        builder.addActions(new ArrayList<>(Arrays.asList(1, 2, 3)));
+        builder.addActions(new ArraySet<>(Arrays.asList(2, 3, 4)));
+        builder.addActions(new ArraySet<>(Collections.singletonList(5)));
+
+        MergedDiscoveryRequest request = builder.build();
+        assertThat(request.getActions()).isEqualTo(new ArraySet<>(new Integer[]{1, 2, 3, 4, 5}));
+    }
+
+    @Test
+    public void test_addFilters() {
+        final int rssi = -40;
+        final int action = 123;
+        final byte[] secreteId = new byte[]{1, 2, 3, 4};
+        final byte[] authenticityKey = new byte[]{0, 1, 1, 1};
+        final byte[] publicKey = new byte[]{1, 1, 2, 2};
+        final byte[] encryptedMetadata = new byte[]{1, 2, 3, 4, 5};
+        final byte[] metadataEncryptionKeyTag = new byte[]{1, 1, 3, 4, 5};
+        final int key = 3;
+        final byte[] value = new byte[]{1, 1, 1, 1};
+
+        PublicCredential mPublicCredential = new PublicCredential.Builder(secreteId,
+                authenticityKey, publicKey, encryptedMetadata,
+                metadataEncryptionKeyTag).setIdentityType(IDENTITY_TYPE_PRIVATE).build();
+        PresenceScanFilter scanFilterBuilder = new PresenceScanFilter.Builder().setMaxPathLoss(
+                rssi).addCredential(mPublicCredential).addPresenceAction(
+                action).addExtendedProperty(new DataElement(key, value)).build();
+
+        MergedDiscoveryRequest.Builder builder = new MergedDiscoveryRequest.Builder();
+        builder.addScanFilters(Collections.singleton(scanFilterBuilder));
+        MergedDiscoveryRequest request = builder.build();
+
+        Set<ScanFilter> expectedResult = new ArraySet<>();
+        expectedResult.add(scanFilterBuilder);
+        assertThat(request.getScanFilters()).isEqualTo(expectedResult);
+    }
+
+    @Test
+    public void test_addMedium() {
+        MergedDiscoveryRequest.Builder builder = new MergedDiscoveryRequest.Builder();
+        builder.addMedium(MergedDiscoveryRequest.Medium.BLE);
+        builder.addMedium(MergedDiscoveryRequest.Medium.BLE);
+        MergedDiscoveryRequest request = builder.build();
+
+        Set<Integer> expectedResult = new ArraySet<>();
+        expectedResult.add(MergedDiscoveryRequest.Medium.BLE);
+        assertThat(request.getMediums()).isEqualTo(expectedResult);
+    }
+}
diff --git a/nearby/tests/unit/src/com/android/server/nearby/managers/registration/BinderListenerRegistrationTest.java b/nearby/tests/unit/src/com/android/server/nearby/managers/registration/BinderListenerRegistrationTest.java
new file mode 100644
index 0000000..8814190
--- /dev/null
+++ b/nearby/tests/unit/src/com/android/server/nearby/managers/registration/BinderListenerRegistrationTest.java
@@ -0,0 +1,163 @@
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.server.nearby.managers.registration;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyInt;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.reset;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+
+import android.os.IBinder;
+import android.os.RemoteException;
+
+import androidx.annotation.NonNull;
+
+import com.android.server.nearby.managers.ListenerMultiplexer;
+
+import com.google.common.util.concurrent.MoreExecutors;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import java.util.Collection;
+
+/**
+ * Unit test for {@link BinderListenerRegistration} class.
+ */
+public class BinderListenerRegistrationTest {
+    private TestMultiplexer mMultiplexer;
+    private boolean mOnRegisterCalled;
+    private boolean mOnUnRegisterCalled;
+
+    @Before
+    public void setUp() {
+        mMultiplexer = new TestMultiplexer();
+    }
+
+    @Test
+    public void test_addAndRemove() throws RemoteException {
+        Runnable listener = mock(Runnable.class);
+        IBinder binder = mock(IBinder.class);
+        int value = 2;
+        BinderListenerRegistration<Runnable> registration = mMultiplexer.addListener(binder,
+                listener, value);
+        // First element, onRegister should be called
+        assertThat(mOnRegisterCalled).isTrue();
+        verify(binder, times(1)).linkToDeath(any(), anyInt());
+        mMultiplexer.notifyListeners();
+        verify(listener, times(1)).run();
+        synchronized (mMultiplexer.mMultiplexerLock) {
+            assertThat(mMultiplexer.mMerged).isEqualTo(value);
+        }
+        reset(listener);
+
+        Runnable listener2 = mock(Runnable.class);
+        IBinder binder2 = mock(IBinder.class);
+        int value2 = 1;
+        BinderListenerRegistration<Runnable> registration2 = mMultiplexer.addListener(binder2,
+                listener2, value2);
+        verify(binder2, times(1)).linkToDeath(any(), anyInt());
+        mMultiplexer.notifyListeners();
+        verify(listener2, times(1)).run();
+        synchronized (mMultiplexer.mMultiplexerLock) {
+            assertThat(mMultiplexer.mMerged).isEqualTo(value);
+        }
+        reset(listener);
+        reset(listener2);
+
+        registration2.remove();
+        verify(binder2, times(1)).unlinkToDeath(any(), anyInt());
+        // Remove one element, onUnregister should NOT be called
+        assertThat(mOnUnRegisterCalled).isFalse();
+        mMultiplexer.notifyListeners();
+        verify(listener, times(1)).run();
+        synchronized (mMultiplexer.mMultiplexerLock) {
+            assertThat(mMultiplexer.mMerged).isEqualTo(value);
+        }
+        reset(listener);
+        reset(listener2);
+
+        registration.remove();
+        verify(binder, times(1)).unlinkToDeath(any(), anyInt());
+        // Remove all elements, onUnregister should NOT be called
+        assertThat(mOnUnRegisterCalled).isTrue();
+        synchronized (mMultiplexer.mMultiplexerLock) {
+            assertThat(mMultiplexer.mMerged).isEqualTo(Integer.MIN_VALUE);
+        }
+    }
+
+    private class TestMultiplexer extends
+            ListenerMultiplexer<Runnable, TestMultiplexer.TestListenerRegistration, Integer> {
+        @Override
+        public void onRegister() {
+            mOnRegisterCalled = true;
+        }
+
+        @Override
+        public void onUnregister() {
+            mOnUnRegisterCalled = true;
+        }
+
+        @Override
+        public Integer mergeRegistrations(
+                @NonNull Collection<TestListenerRegistration> testListenerRegistrations) {
+            int max = Integer.MIN_VALUE;
+            for (TestListenerRegistration registration : testListenerRegistrations) {
+                max = Math.max(max, registration.getValue());
+            }
+            return max;
+        }
+
+        @Override
+        public void onMergedRegistrationsUpdated() {
+        }
+
+        public BinderListenerRegistration<Runnable> addListener(IBinder binder, Runnable runnable,
+                int value) {
+            TestListenerRegistration registration = new TestListenerRegistration(binder, runnable,
+                    value);
+            putRegistration(binder, registration);
+            return registration;
+        }
+
+        public void notifyListeners() {
+            deliverToListeners(registration -> Runnable::run);
+        }
+
+        private class TestListenerRegistration extends BinderListenerRegistration<Runnable> {
+            private final int mValue;
+
+            protected TestListenerRegistration(IBinder binder, Runnable runnable, int value) {
+                super(binder, MoreExecutors.directExecutor(), runnable);
+                mValue = value;
+            }
+
+            @Override
+            public TestMultiplexer getOwner() {
+                return TestMultiplexer.this;
+            }
+
+            public int getValue() {
+                return mValue;
+            }
+        }
+    }
+}
diff --git a/nearby/tests/unit/src/com/android/server/nearby/managers/registration/DiscoveryRegistrationTest.java b/nearby/tests/unit/src/com/android/server/nearby/managers/registration/DiscoveryRegistrationTest.java
new file mode 100644
index 0000000..03c4f75
--- /dev/null
+++ b/nearby/tests/unit/src/com/android/server/nearby/managers/registration/DiscoveryRegistrationTest.java
@@ -0,0 +1,252 @@
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.server.nearby.managers.registration;
+
+import static android.nearby.PresenceCredential.IDENTITY_TYPE_PRIVATE;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyInt;
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.reset;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+import static org.mockito.MockitoAnnotations.initMocks;
+
+import android.app.AppOpsManager;
+import android.nearby.DataElement;
+import android.nearby.IScanListener;
+import android.nearby.NearbyDeviceParcelable;
+import android.nearby.PresenceScanFilter;
+import android.nearby.PublicCredential;
+import android.nearby.ScanCallback;
+import android.nearby.ScanFilter;
+import android.nearby.ScanRequest;
+import android.os.IBinder;
+import android.util.ArraySet;
+
+import androidx.annotation.NonNull;
+
+import com.android.server.nearby.managers.ListenerMultiplexer;
+import com.android.server.nearby.managers.MergedDiscoveryRequest;
+import com.android.server.nearby.util.identity.CallerIdentity;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.Mock;
+
+import java.util.Collection;
+import java.util.List;
+import java.util.Set;
+import java.util.concurrent.Executors;
+
+/**
+ * Unit test for {@link DiscoveryRegistration} class.
+ */
+public class DiscoveryRegistrationTest {
+    private static final int RSSI = -40;
+    private static final int ACTION = 123;
+    private static final byte[] SECRETE_ID = new byte[]{1, 2, 3, 4};
+    private static final byte[] AUTHENTICITY_KEY = new byte[]{0, 1, 1, 1};
+    private static final byte[] PUBLIC_KEY = new byte[]{1, 1, 2, 2};
+    private static final byte[] ENCRYPTED_METADATA = new byte[]{1, 2, 3, 4, 5};
+    private static final byte[] METADATA_ENCRYPTION_KEY_TAG = new byte[]{1, 1, 3, 4, 5};
+    private static final int KEY = 3;
+    private static final byte[] VALUE = new byte[]{1, 1, 1, 1};
+    private final PublicCredential mPublicCredential = new PublicCredential.Builder(SECRETE_ID,
+            AUTHENTICITY_KEY, PUBLIC_KEY, ENCRYPTED_METADATA,
+            METADATA_ENCRYPTION_KEY_TAG).setIdentityType(IDENTITY_TYPE_PRIVATE).build();
+    private final PresenceScanFilter mFilter = new PresenceScanFilter.Builder().setMaxPathLoss(
+            50).addCredential(mPublicCredential).addPresenceAction(ACTION).addExtendedProperty(
+            new DataElement(KEY, VALUE)).build();
+    private DiscoveryRegistration mDiscoveryRegistration;
+    private ScanRequest mScanRequest;
+    private TestDiscoveryManager mOwner;
+    private Object mMultiplexLock;
+    @Mock
+    private IScanListener mCallback;
+    @Mock
+    private CallerIdentity mIdentity;
+    @Mock
+    private AppOpsManager mAppOpsManager;
+    @Mock
+    private IBinder mBinder;
+
+    @Before
+    public void setUp() {
+        initMocks(this);
+        when(mCallback.asBinder()).thenReturn(mBinder);
+        when(mAppOpsManager.noteOp(eq("android:bluetooth_scan"), eq(0), eq(null), eq(null),
+                eq(null))).thenReturn(AppOpsManager.MODE_ALLOWED);
+
+        mOwner = new TestDiscoveryManager();
+        mMultiplexLock = new Object();
+        mScanRequest = new ScanRequest.Builder().setScanType(
+                ScanRequest.SCAN_TYPE_NEARBY_PRESENCE).addScanFilter(mFilter).build();
+        mDiscoveryRegistration = new DiscoveryRegistration(mOwner, mScanRequest, mCallback,
+                Executors.newSingleThreadExecutor(), mIdentity, mMultiplexLock, mAppOpsManager);
+    }
+
+    @Test
+    public void test_getScanRequest() {
+        assertThat(mDiscoveryRegistration.getScanRequest()).isEqualTo(mScanRequest);
+    }
+
+    @Test
+    public void test_getActions() {
+        Set<Integer> result = new ArraySet<>();
+        result.add(ACTION);
+        assertThat(mDiscoveryRegistration.getActions()).isEqualTo(result);
+    }
+
+    @Test
+    public void test_getOwner() {
+        assertThat(mDiscoveryRegistration.getOwner()).isEqualTo(mOwner);
+    }
+
+    @Test
+    public void test_getPresenceScanFilters() {
+        Set<ScanFilter> result = new ArraySet<>();
+        result.add(mFilter);
+        assertThat(mDiscoveryRegistration.getPresenceScanFilters()).isEqualTo(result);
+    }
+
+    @Test
+    public void test_presenceFilterMatches_match() {
+        NearbyDeviceParcelable device = new NearbyDeviceParcelable.Builder().setDeviceId(
+                123).setName("test").setTxPower(RSSI + 1).setRssi(RSSI).setScanType(
+                ScanRequest.SCAN_TYPE_NEARBY_PRESENCE).setAction(ACTION).setEncryptionKeyTag(
+                METADATA_ENCRYPTION_KEY_TAG).build();
+        assertThat(DiscoveryRegistration.presenceFilterMatches(device, List.of(mFilter))).isTrue();
+    }
+
+    @Test
+    public void test_presenceFilterMatches_emptyFilter() {
+        NearbyDeviceParcelable device = new NearbyDeviceParcelable.Builder().setDeviceId(
+                123).setName("test").setScanType(ScanRequest.SCAN_TYPE_NEARBY_PRESENCE).build();
+        assertThat(DiscoveryRegistration.presenceFilterMatches(device, List.of())).isTrue();
+    }
+
+    @Test
+    public void test_presenceFilterMatches_actionNotMatch() {
+        NearbyDeviceParcelable device = new NearbyDeviceParcelable.Builder().setDeviceId(
+                12).setName("test").setRssi(RSSI).setScanType(
+                ScanRequest.SCAN_TYPE_NEARBY_PRESENCE).setAction(5).setEncryptionKeyTag(
+                METADATA_ENCRYPTION_KEY_TAG).build();
+        assertThat(DiscoveryRegistration.presenceFilterMatches(device, List.of(mFilter))).isFalse();
+    }
+
+    @Test
+    public void test_onDiscoveredOnUpdatedCalled() throws Exception {
+        final long deviceId = 122;
+        NearbyDeviceParcelable.Builder builder = new NearbyDeviceParcelable.Builder().setDeviceId(
+                deviceId).setName("test").setTxPower(RSSI + 1).setRssi(RSSI).setScanType(
+                ScanRequest.SCAN_TYPE_NEARBY_PRESENCE).setAction(ACTION).setEncryptionKeyTag(
+                METADATA_ENCRYPTION_KEY_TAG);
+        runOperation(mDiscoveryRegistration.onNearbyDeviceDiscovered(builder.build()));
+
+        verify(mCallback, times(1)).onDiscovered(eq(builder.build()));
+        verify(mCallback, never()).onUpdated(any());
+        verify(mCallback, never()).onLost(any());
+        verify(mCallback, never()).onError(anyInt());
+        assertThat(mDiscoveryRegistration.getDiscoveryOnLostAlarms().get(deviceId)).isNotNull();
+        reset(mCallback);
+
+        // Update RSSI
+        runOperation(
+                mDiscoveryRegistration.onNearbyDeviceDiscovered(builder.setRssi(RSSI - 1).build()));
+        verify(mCallback, never()).onDiscovered(any());
+        verify(mCallback, times(1)).onUpdated(eq(builder.build()));
+        verify(mCallback, never()).onLost(any());
+        verify(mCallback, never()).onError(anyInt());
+        assertThat(mDiscoveryRegistration.getDiscoveryOnLostAlarms().get(deviceId)).isNotNull();
+    }
+
+    @Test
+    public void test_onLost() throws Exception {
+        final long deviceId = 123;
+        NearbyDeviceParcelable device = new NearbyDeviceParcelable.Builder().setDeviceId(
+                deviceId).setName("test").setTxPower(RSSI + 1).setRssi(RSSI).setScanType(
+                ScanRequest.SCAN_TYPE_NEARBY_PRESENCE).setAction(ACTION).setEncryptionKeyTag(
+                METADATA_ENCRYPTION_KEY_TAG).build();
+        runOperation(mDiscoveryRegistration.onNearbyDeviceDiscovered(device));
+        assertThat(mDiscoveryRegistration.getDiscoveryOnLostAlarms().get(deviceId)).isNotNull();
+        verify(mCallback, times(1)).onDiscovered(eq(device));
+        verify(mCallback, never()).onUpdated(any());
+        verify(mCallback, never()).onError(anyInt());
+        verify(mCallback, never()).onLost(any());
+        reset(mCallback);
+
+        runOperation(mDiscoveryRegistration.reportDeviceLost(device));
+
+        assertThat(mDiscoveryRegistration.getDiscoveryOnLostAlarms().get(deviceId)).isNull();
+        verify(mCallback, never()).onDiscovered(eq(device));
+        verify(mCallback, never()).onUpdated(any());
+        verify(mCallback, never()).onError(anyInt());
+        verify(mCallback, times(1)).onLost(eq(device));
+    }
+
+    @Test
+    public void test_onError() throws Exception {
+        AppOpsManager manager = mock(AppOpsManager.class);
+        when(manager.noteOp(eq("android:bluetooth_scan"), eq(0), eq(null), eq(null),
+                eq(null))).thenReturn(AppOpsManager.MODE_IGNORED);
+
+        DiscoveryRegistration r = new DiscoveryRegistration(mOwner, mScanRequest, mCallback,
+                Executors.newSingleThreadExecutor(), mIdentity, mMultiplexLock, manager);
+
+        NearbyDeviceParcelable device = new NearbyDeviceParcelable.Builder().setDeviceId(
+                123).setName("test").setTxPower(RSSI + 1).setRssi(RSSI).setScanType(
+                ScanRequest.SCAN_TYPE_NEARBY_PRESENCE).setAction(ACTION).setEncryptionKeyTag(
+                METADATA_ENCRYPTION_KEY_TAG).build();
+        runOperation(r.onNearbyDeviceDiscovered(device));
+
+        verify(mCallback, never()).onDiscovered(any());
+        verify(mCallback, never()).onUpdated(any());
+        verify(mCallback, never()).onLost(any());
+        verify(mCallback, times(1)).onError(eq(ScanCallback.ERROR_PERMISSION_DENIED));
+    }
+
+    private void runOperation(BinderListenerRegistration.ListenerOperation<IScanListener> operation)
+            throws Exception {
+        if (operation == null) {
+            return;
+        }
+        operation.onScheduled(false);
+        operation.operate(mCallback);
+        operation.onComplete(/* success= */ true);
+    }
+
+    private static class TestDiscoveryManager extends
+            ListenerMultiplexer<IScanListener, DiscoveryRegistration, MergedDiscoveryRequest> {
+
+        @Override
+        public MergedDiscoveryRequest mergeRegistrations(
+                @NonNull Collection<DiscoveryRegistration> discoveryRegistrations) {
+            return null;
+        }
+
+        @Override
+        public void onMergedRegistrationsUpdated() {
+
+        }
+    }
+}
diff --git a/service-t/src/com/android/server/NsdService.java b/service-t/src/com/android/server/NsdService.java
index a62ee7f..1d99190 100644
--- a/service-t/src/com/android/server/NsdService.java
+++ b/service-t/src/com/android/server/NsdService.java
@@ -23,6 +23,7 @@
 import static android.provider.DeviceConfig.NAMESPACE_TETHERING;
 
 import static com.android.modules.utils.build.SdkLevel.isAtLeastU;
+import static com.android.server.connectivity.mdns.MdnsRecord.MAX_LABEL_LENGTH;
 
 import android.annotation.NonNull;
 import android.annotation.Nullable;
@@ -73,6 +74,7 @@
 import com.android.server.connectivity.mdns.MdnsServiceInfo;
 import com.android.server.connectivity.mdns.MdnsSocketClientBase;
 import com.android.server.connectivity.mdns.MdnsSocketProvider;
+import com.android.server.connectivity.mdns.util.MdnsUtils;
 
 import java.io.FileDescriptor;
 import java.io.PrintWriter;
@@ -81,11 +83,6 @@
 import java.net.NetworkInterface;
 import java.net.SocketException;
 import java.net.UnknownHostException;
-import java.nio.ByteBuffer;
-import java.nio.CharBuffer;
-import java.nio.charset.Charset;
-import java.nio.charset.CharsetEncoder;
-import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
@@ -108,8 +105,6 @@
      */
     private static final String MDNS_DISCOVERY_MANAGER_VERSION = "mdns_discovery_manager_version";
     private static final String LOCAL_DOMAIN_NAME = "local";
-    // Max label length as per RFC 1034/1035
-    private static final int MAX_LABEL_LENGTH = 63;
 
     /**
      * Enable advertising using the Java MdnsAdvertiser, instead of the legacy mdnsresponder
@@ -570,18 +565,7 @@
              */
             @NonNull
             private String truncateServiceName(@NonNull String originalName) {
-                // UTF-8 is at most 4 bytes per character; return early in the common case where
-                // the name can't possibly be over the limit given its string length.
-                if (originalName.length() <= MAX_LABEL_LENGTH / 4) return originalName;
-
-                final Charset utf8 = StandardCharsets.UTF_8;
-                final CharsetEncoder encoder = utf8.newEncoder();
-                final ByteBuffer out = ByteBuffer.allocate(MAX_LABEL_LENGTH);
-                // encode will write as many characters as possible to the out buffer, and just
-                // return an overflow code if there were too many characters (no need to check the
-                // return code here, this method truncates the name on purpose).
-                encoder.encode(CharBuffer.wrap(originalName), out, true /* endOfInput */);
-                return new String(out.array(), 0, out.position(), utf8);
+                return MdnsUtils.truncateServiceName(originalName, MAX_LABEL_LENGTH);
             }
 
             private void stopDiscoveryManagerRequest(ClientRequest request, int clientId, int id,
diff --git a/service-t/src/com/android/server/connectivity/mdns/MdnsAdvertiser.java b/service-t/src/com/android/server/connectivity/mdns/MdnsAdvertiser.java
index 33fef9d..a332da7 100644
--- a/service-t/src/com/android/server/connectivity/mdns/MdnsAdvertiser.java
+++ b/service-t/src/com/android/server/connectivity/mdns/MdnsAdvertiser.java
@@ -16,6 +16,8 @@
 
 package com.android.server.connectivity.mdns;
 
+import static com.android.server.connectivity.mdns.MdnsRecord.MAX_LABEL_LENGTH;
+
 import android.annotation.NonNull;
 import android.annotation.Nullable;
 import android.net.LinkAddress;
@@ -29,6 +31,7 @@
 
 import com.android.internal.annotations.VisibleForTesting;
 import com.android.net.module.util.SharedLog;
+import com.android.server.connectivity.mdns.util.MdnsUtils;
 
 import java.io.PrintWriter;
 import java.util.List;
@@ -359,7 +362,7 @@
             // "Name (2)", then "Name (3)" etc.
             // TODO: use a hidden method in NsdServiceInfo once MdnsAdvertiser is moved to service-t
             final NsdServiceInfo newInfo = new NsdServiceInfo();
-            newInfo.setServiceName(mOriginalName + " (" + (mConflictCount + renameCount + 1) + ")");
+            newInfo.setServiceName(getUpdatedServiceName(renameCount));
             newInfo.setServiceType(mServiceInfo.getServiceType());
             for (Map.Entry<String, byte[]> attr : mServiceInfo.getAttributes().entrySet()) {
                 newInfo.setAttribute(attr.getKey(),
@@ -372,6 +375,13 @@
             return newInfo;
         }
 
+        private String getUpdatedServiceName(int renameCount) {
+            final String suffix = " (" + (mConflictCount + renameCount + 1) + ")";
+            final String truncatedServiceName = MdnsUtils.truncateServiceName(mOriginalName,
+                    MAX_LABEL_LENGTH - suffix.length());
+            return truncatedServiceName + suffix;
+        }
+
         @NonNull
         public NsdServiceInfo getServiceInfo() {
             return mServiceInfo;
diff --git a/service-t/src/com/android/server/connectivity/mdns/MdnsRecord.java b/service-t/src/com/android/server/connectivity/mdns/MdnsRecord.java
index bcee9d1..19630e3 100644
--- a/service-t/src/com/android/server/connectivity/mdns/MdnsRecord.java
+++ b/service-t/src/com/android/server/connectivity/mdns/MdnsRecord.java
@@ -46,6 +46,8 @@
 
     public static final long RECEIPT_TIME_NOT_SENT = 0L;
     public static final int CLASS_ANY = 0x00ff;
+    /** Max label length as per RFC 1034/1035 */
+    public static final int MAX_LABEL_LENGTH = 63;
 
     /** Status indicating that the record is current. */
     public static final int STATUS_OK = 0;
diff --git a/service-t/src/com/android/server/connectivity/mdns/util/MdnsUtils.java b/service-t/src/com/android/server/connectivity/mdns/util/MdnsUtils.java
index 4b9759d..5cc789f 100644
--- a/service-t/src/com/android/server/connectivity/mdns/util/MdnsUtils.java
+++ b/service-t/src/com/android/server/connectivity/mdns/util/MdnsUtils.java
@@ -21,6 +21,12 @@
 import android.net.Network;
 import android.os.Handler;
 
+import java.nio.ByteBuffer;
+import java.nio.CharBuffer;
+import java.nio.charset.Charset;
+import java.nio.charset.CharsetEncoder;
+import java.nio.charset.StandardCharsets;
+
 /**
  * Mdns utility functions.
  */
@@ -73,4 +79,22 @@
             @Nullable Network currentNetwork) {
         return targetNetwork == null || targetNetwork.equals(currentNetwork);
     }
-}
+
+    /**
+     * Truncate a service name to up to maxLength UTF-8 bytes.
+     */
+    public static String truncateServiceName(@NonNull String originalName, int maxLength) {
+        // UTF-8 is at most 4 bytes per character; return early in the common case where
+        // the name can't possibly be over the limit given its string length.
+        if (originalName.length() <= maxLength / 4) return originalName;
+
+        final Charset utf8 = StandardCharsets.UTF_8;
+        final CharsetEncoder encoder = utf8.newEncoder();
+        final ByteBuffer out = ByteBuffer.allocate(maxLength);
+        // encode will write as many characters as possible to the out buffer, and just
+        // return an overflow code if there were too many characters (no need to check the
+        // return code here, this method truncates the name on purpose).
+        encoder.encode(CharBuffer.wrap(originalName), out, true /* endOfInput */);
+        return new String(out.array(), 0, out.position(), utf8);
+    }
+}
\ No newline at end of file
diff --git a/service/jni/com_android_server_connectivity_ClatCoordinator.cpp b/service/jni/com_android_server_connectivity_ClatCoordinator.cpp
index 8d909ed..d966070 100644
--- a/service/jni/com_android_server_connectivity_ClatCoordinator.cpp
+++ b/service/jni/com_android_server_connectivity_ClatCoordinator.cpp
@@ -90,11 +90,6 @@
 
 #undef ALOGF
 
-bool isGsiImage() {
-    // this implementation matches 2 other places in the codebase (same function name too)
-    return !access("/system/system_ext/etc/init/init.gsi.rc", F_OK);
-}
-
 static const char* kClatdDir = "/apex/com.android.tethering/bin/for-system";
 static const char* kClatdBin = "/apex/com.android.tethering/bin/for-system/clatd";
 
@@ -135,14 +130,6 @@
 
 #undef V2
 
-    // HACK: Some old vendor kernels lack ~5.10 backport of 'bpffs selinux genfscon' support.
-    // This is *NOT* supported, but let's allow, at least for now, U+ GSI to boot on them.
-    // (without this hack pixel5 R vendor + U gsi breaks)
-    if (isGsiImage() && !bpf::isAtLeastKernelVersion(5, 10, 0)) {
-        ALOGE("GSI with *BAD* pre-5.10 kernel lacking bpffs selinux genfscon support.");
-        return;
-    }
-
     if (fatal) abort();
 }
 
diff --git a/tests/cts/hostside/app/src/com/android/cts/net/hostside/AbstractRestrictBackgroundNetworkTestCase.java b/tests/cts/hostside/app/src/com/android/cts/net/hostside/AbstractRestrictBackgroundNetworkTestCase.java
index cdfa0d0..106a49c 100644
--- a/tests/cts/hostside/app/src/com/android/cts/net/hostside/AbstractRestrictBackgroundNetworkTestCase.java
+++ b/tests/cts/hostside/app/src/com/android/cts/net/hostside/AbstractRestrictBackgroundNetworkTestCase.java
@@ -719,12 +719,13 @@
         Log.i(TAG, "Setting Battery Saver Mode to " + enabled);
         if (enabled) {
             turnBatteryOn();
+            AmUtils.waitForBroadcastBarrier();
             executeSilentShellCommand("cmd power set-mode 1");
         } else {
             executeSilentShellCommand("cmd power set-mode 0");
             turnBatteryOff();
+            AmUtils.waitForBroadcastBarrier();
         }
-        AmUtils.waitForBroadcastBarrier();
     }
 
     protected void setDozeMode(boolean enabled) throws Exception {
diff --git a/tests/unit/java/com/android/server/connectivity/mdns/MdnsAdvertiserTest.kt b/tests/unit/java/com/android/server/connectivity/mdns/MdnsAdvertiserTest.kt
index a917361..4b495cd 100644
--- a/tests/unit/java/com/android/server/connectivity/mdns/MdnsAdvertiserTest.kt
+++ b/tests/unit/java/com/android/server/connectivity/mdns/MdnsAdvertiserTest.kt
@@ -47,6 +47,8 @@
 
 private const val SERVICE_ID_1 = 1
 private const val SERVICE_ID_2 = 2
+private const val LONG_SERVICE_ID_1 = 3
+private const val LONG_SERVICE_ID_2 = 4
 private const val TIMEOUT_MS = 10_000L
 private val TEST_ADDR = parseNumericAddress("2001:db8::123")
 private val TEST_LINKADDR = LinkAddress(TEST_ADDR, 64 /* prefixLength */)
@@ -56,16 +58,30 @@
 
 private val SERVICE_1 = NsdServiceInfo("TestServiceName", "_advertisertest._tcp").apply {
     port = 12345
-    host = TEST_ADDR
+    hostAddresses = listOf(TEST_ADDR)
     network = TEST_NETWORK_1
 }
 
+private val LONG_SERVICE_1 =
+    NsdServiceInfo("a".repeat(48) + "TestServiceName", "_longadvertisertest._tcp").apply {
+    port = 12345
+    hostAddresses = listOf(TEST_ADDR)
+    network = TEST_NETWORK_1
+    }
+
 private val ALL_NETWORKS_SERVICE = NsdServiceInfo("TestServiceName", "_advertisertest._tcp").apply {
     port = 12345
-    host = TEST_ADDR
+    hostAddresses = listOf(TEST_ADDR)
     network = null
 }
 
+private val LONG_ALL_NETWORKS_SERVICE =
+    NsdServiceInfo("a".repeat(48) + "TestServiceName", "_longadvertisertest._tcp").apply {
+        port = 12345
+        hostAddresses = listOf(TEST_ADDR)
+        network = null
+    }
+
 @RunWith(DevSdkIgnoreRunner::class)
 @IgnoreUpTo(Build.VERSION_CODES.S_V2)
 class MdnsAdvertiserTest {
@@ -191,6 +207,9 @@
         verify(socketProvider).requestSocket(eq(null), allNetSocketCbCaptor.capture())
         val allNetSocketCb = allNetSocketCbCaptor.value
 
+        postSync { advertiser.addService(LONG_SERVICE_ID_1, LONG_SERVICE_1) }
+        postSync { advertiser.addService(LONG_SERVICE_ID_2, LONG_ALL_NETWORKS_SERVICE) }
+
         // Callbacks for matching network and all networks both get the socket
         postSync {
             oneNetSocketCb.onSocketCreated(TEST_NETWORK_1, mockSocket1, listOf(TEST_LINKADDR))
@@ -200,10 +219,18 @@
         val expectedRenamed = NsdServiceInfo(
                 "${ALL_NETWORKS_SERVICE.serviceName} (2)", ALL_NETWORKS_SERVICE.serviceType).apply {
             port = ALL_NETWORKS_SERVICE.port
-            host = ALL_NETWORKS_SERVICE.host
+            hostAddresses = ALL_NETWORKS_SERVICE.hostAddresses
             network = ALL_NETWORKS_SERVICE.network
         }
 
+        val expectedLongRenamed = NsdServiceInfo(
+            "${LONG_ALL_NETWORKS_SERVICE.serviceName.dropLast(4)} (2)",
+            LONG_ALL_NETWORKS_SERVICE.serviceType).apply {
+            port = LONG_ALL_NETWORKS_SERVICE.port
+            hostAddresses = LONG_ALL_NETWORKS_SERVICE.hostAddresses
+            network = LONG_ALL_NETWORKS_SERVICE.network
+        }
+
         val intAdvCbCaptor = ArgumentCaptor.forClass(MdnsInterfaceAdvertiser.Callback::class.java)
         verify(mockDeps).makeAdvertiser(eq(mockSocket1), eq(listOf(TEST_LINKADDR)),
                 eq(thread.looper), any(), intAdvCbCaptor.capture(), eq(TEST_HOSTNAME)
@@ -212,6 +239,10 @@
                 argThat { it.matches(SERVICE_1) })
         verify(mockInterfaceAdvertiser1).addService(eq(SERVICE_ID_2),
                 argThat { it.matches(expectedRenamed) })
+        verify(mockInterfaceAdvertiser1).addService(eq(LONG_SERVICE_ID_1),
+                argThat { it.matches(LONG_SERVICE_1) })
+        verify(mockInterfaceAdvertiser1).addService(eq(LONG_SERVICE_ID_2),
+            argThat { it.matches(expectedLongRenamed) })
 
         doReturn(false).`when`(mockInterfaceAdvertiser1).isProbing(SERVICE_ID_1)
         postSync { intAdvCbCaptor.value.onRegisterServiceSucceeded(
@@ -251,7 +282,7 @@
     return Objects.equals(serviceName, other.serviceName) &&
             Objects.equals(serviceType, other.serviceType) &&
             Objects.equals(attributes, other.attributes) &&
-            Objects.equals(host, other.host) &&
+            Objects.equals(hostAddresses, other.hostAddresses) &&
             port == other.port &&
             Objects.equals(network, other.network)
 }
diff --git a/tests/unit/java/com/android/server/connectivity/mdns/util/MdnsUtilsTest.kt b/tests/unit/java/com/android/server/connectivity/mdns/util/MdnsUtilsTest.kt
index f584ed5..61c3a70 100644
--- a/tests/unit/java/com/android/server/connectivity/mdns/util/MdnsUtilsTest.kt
+++ b/tests/unit/java/com/android/server/connectivity/mdns/util/MdnsUtilsTest.kt
@@ -19,6 +19,7 @@
 import android.os.Build
 import com.android.server.connectivity.mdns.util.MdnsUtils.equalsIgnoreDnsCase
 import com.android.server.connectivity.mdns.util.MdnsUtils.toDnsLowerCase
+import com.android.server.connectivity.mdns.util.MdnsUtils.truncateServiceName
 import com.android.testutils.DevSdkIgnoreRule
 import com.android.testutils.DevSdkIgnoreRunner
 import org.junit.Assert.assertEquals
@@ -65,4 +66,10 @@
                 "Test: >\ud83c\udff4\udb40\udc67\udb40\udc62\udb40" +
                         "\udc77\udb40\udc6c\udb40\udc73\udb40\udc7f<"))
     }
+
+    @Test
+    fun testTruncateServiceName() {
+        assertEquals(truncateServiceName("测试abcde", 7), "测试a")
+        assertEquals(truncateServiceName("测试abcde", 100), "测试abcde")
+    }
 }