diff --git a/Tethering/src/com/android/networkstack/tethering/Tethering.java b/Tethering/src/com/android/networkstack/tethering/Tethering.java
index 3277363..da3b584 100644
--- a/Tethering/src/com/android/networkstack/tethering/Tethering.java
+++ b/Tethering/src/com/android/networkstack/tethering/Tethering.java
@@ -2734,84 +2734,73 @@
         }
     }
 
-    private IpServer.Callback makeControlCallback() {
-        return new IpServer.Callback() {
-            @Override
-            public void updateInterfaceState(IpServer who, int state, int lastError) {
-                notifyInterfaceStateChange(who, state, lastError);
+    private class ControlCallback extends IpServer.Callback {
+        @Override
+        public void updateInterfaceState(IpServer who, int state, int lastError) {
+            final String iface = who.interfaceName();
+            final TetherState tetherState = mTetherStates.get(iface);
+            if (tetherState != null && tetherState.ipServer.equals(who)) {
+                tetherState.lastState = state;
+                tetherState.lastError = lastError;
+            } else {
+                if (DBG) Log.d(TAG, "got notification from stale iface " + iface);
             }
 
-            @Override
-            public void updateLinkProperties(IpServer who, LinkProperties newLp) {
-                notifyLinkPropertiesChanged(who, newLp);
-            }
+            mLog.log(String.format("OBSERVED iface=%s state=%s error=%s", iface, state, lastError));
 
-            @Override
-            public void dhcpLeasesChanged() {
-                maybeDhcpLeasesChanged();
+            // If TetherMainSM is in ErrorState, TetherMainSM stays there.
+            // Thus we give a chance for TetherMainSM to recover to InitialState
+            // by sending CMD_CLEAR_ERROR
+            if (lastError == TETHER_ERROR_INTERNAL_ERROR) {
+                mTetherMainSM.sendMessage(TetherMainSM.CMD_CLEAR_ERROR, who);
             }
-
-            @Override
-            public void requestEnableTethering(int tetheringType, boolean enabled) {
-                mTetherMainSM.sendMessage(TetherMainSM.EVENT_REQUEST_CHANGE_DOWNSTREAM,
-                        tetheringType, 0, enabled ? Boolean.TRUE : Boolean.FALSE);
+            int which;
+            switch (state) {
+                case IpServer.STATE_UNAVAILABLE:
+                case IpServer.STATE_AVAILABLE:
+                    which = TetherMainSM.EVENT_IFACE_SERVING_STATE_INACTIVE;
+                    break;
+                case IpServer.STATE_TETHERED:
+                case IpServer.STATE_LOCAL_ONLY:
+                    which = TetherMainSM.EVENT_IFACE_SERVING_STATE_ACTIVE;
+                    break;
+                default:
+                    Log.wtf(TAG, "Unknown interface state: " + state);
+                    return;
             }
-        };
-    }
-
-    // TODO: Move into TetherMainSM.
-    private void notifyInterfaceStateChange(IpServer who, int state, int error) {
-        final String iface = who.interfaceName();
-        final TetherState tetherState = mTetherStates.get(iface);
-        if (tetherState != null && tetherState.ipServer.equals(who)) {
-            tetherState.lastState = state;
-            tetherState.lastError = error;
-        } else {
-            if (DBG) Log.d(TAG, "got notification from stale iface " + iface);
+            mTetherMainSM.sendMessage(which, state, 0, who);
+            sendTetherStateChangedBroadcast();
         }
 
-        mLog.log(String.format("OBSERVED iface=%s state=%s error=%s", iface, state, error));
-
-        // If TetherMainSM is in ErrorState, TetherMainSM stays there.
-        // Thus we give a chance for TetherMainSM to recover to InitialState
-        // by sending CMD_CLEAR_ERROR
-        if (error == TETHER_ERROR_INTERNAL_ERROR) {
-            mTetherMainSM.sendMessage(TetherMainSM.CMD_CLEAR_ERROR, who);
-        }
-        int which;
-        switch (state) {
-            case IpServer.STATE_UNAVAILABLE:
-            case IpServer.STATE_AVAILABLE:
-                which = TetherMainSM.EVENT_IFACE_SERVING_STATE_INACTIVE;
-                break;
-            case IpServer.STATE_TETHERED:
-            case IpServer.STATE_LOCAL_ONLY:
-                which = TetherMainSM.EVENT_IFACE_SERVING_STATE_ACTIVE;
-                break;
-            default:
-                Log.wtf(TAG, "Unknown interface state: " + state);
+        @Override
+        public void updateLinkProperties(IpServer who, LinkProperties newLp) {
+            final String iface = who.interfaceName();
+            final int state;
+            final TetherState tetherState = mTetherStates.get(iface);
+            if (tetherState != null && tetherState.ipServer.equals(who)) {
+                state = tetherState.lastState;
+            } else {
+                mLog.log("got notification from stale iface " + iface);
                 return;
-        }
-        mTetherMainSM.sendMessage(which, state, 0, who);
-        sendTetherStateChangedBroadcast();
-    }
+            }
 
-    private void notifyLinkPropertiesChanged(IpServer who, LinkProperties newLp) {
-        final String iface = who.interfaceName();
-        final int state;
-        final TetherState tetherState = mTetherStates.get(iface);
-        if (tetherState != null && tetherState.ipServer.equals(who)) {
-            state = tetherState.lastState;
-        } else {
-            mLog.log("got notification from stale iface " + iface);
-            return;
+            mLog.log(String.format(
+                    "OBSERVED LinkProperties update iface=%s state=%s lp=%s",
+                    iface, IpServer.getStateString(state), newLp));
+            final int which = TetherMainSM.EVENT_IFACE_UPDATE_LINKPROPERTIES;
+            mTetherMainSM.sendMessage(which, state, 0, newLp);
         }
 
-        mLog.log(String.format(
-                "OBSERVED LinkProperties update iface=%s state=%s lp=%s",
-                iface, IpServer.getStateString(state), newLp));
-        final int which = TetherMainSM.EVENT_IFACE_UPDATE_LINKPROPERTIES;
-        mTetherMainSM.sendMessage(which, state, 0, newLp);
+        @Override
+        public void dhcpLeasesChanged() {
+            maybeDhcpLeasesChanged();
+        }
+
+        @Override
+        public void requestEnableTethering(int tetheringType, boolean enabled) {
+            mTetherMainSM.sendMessage(TetherMainSM.EVENT_REQUEST_CHANGE_DOWNSTREAM,
+                    tetheringType, 0, enabled ? Boolean.TRUE : Boolean.FALSE);
+        }
     }
 
     private boolean hasSystemFeature(final String feature) {
@@ -2853,7 +2842,7 @@
         mLog.i("adding IpServer for: " + iface);
         final TetherState tetherState = new TetherState(
                 new IpServer(iface, mHandler, interfaceType, mLog, mNetd, mBpfCoordinator,
-                        mRoutingCoordinator, makeControlCallback(), mConfig,
+                        mRoutingCoordinator, new ControlCallback(), mConfig,
                         mPrivateAddressCoordinator, mTetheringMetrics,
                         mDeps.getIpServerDependencies()), isNcm);
         mTetherStates.put(iface, tetherState);
diff --git a/Tethering/tests/unit/src/com/android/networkstack/tethering/BpfCoordinatorTest.java b/Tethering/tests/unit/src/com/android/networkstack/tethering/BpfCoordinatorTest.java
index 01600b8..47ecf58 100644
--- a/Tethering/tests/unit/src/com/android/networkstack/tethering/BpfCoordinatorTest.java
+++ b/Tethering/tests/unit/src/com/android/networkstack/tethering/BpfCoordinatorTest.java
@@ -1280,9 +1280,9 @@
         final Ipv6DownstreamRule rule = buildTestDownstreamRule(mobileIfIndex, NEIGH_A, MAC_A);
 
         final TetherDownstream6Key key = rule.makeTetherDownstream6Key();
-        assertEquals(key.iif, mobileIfIndex);
-        assertEquals(key.dstMac, MacAddress.ALL_ZEROS_ADDRESS);  // rawip upstream
-        assertTrue(Arrays.equals(key.neigh6, NEIGH_A.getAddress()));
+        assertEquals(mobileIfIndex, key.iif);
+        assertEquals(MacAddress.ALL_ZEROS_ADDRESS, key.dstMac);  // rawip upstream
+        assertArrayEquals(NEIGH_A.getAddress(), key.neigh6);
         // iif (4) + dstMac(6) + padding(2) + neigh6 (16) = 28.
         assertEquals(28, key.writeToBytes().length);
     }
@@ -1293,12 +1293,12 @@
         final Ipv6DownstreamRule rule = buildTestDownstreamRule(mobileIfIndex, NEIGH_A, MAC_A);
 
         final Tether6Value value = rule.makeTether6Value();
-        assertEquals(value.oif, DOWNSTREAM_IFINDEX);
-        assertEquals(value.ethDstMac, MAC_A);
-        assertEquals(value.ethSrcMac, DOWNSTREAM_MAC);
-        assertEquals(value.ethProto, ETH_P_IPV6);
-        assertEquals(value.pmtu, NetworkStackConstants.ETHER_MTU);
-        // oif (4) + ethDstMac (6) + ethSrcMac (6) + ethProto (2) + pmtu (2) = 20.
+        assertEquals(DOWNSTREAM_IFINDEX, value.oif);
+        assertEquals(MAC_A, value.ethDstMac);
+        assertEquals(DOWNSTREAM_MAC, value.ethSrcMac);
+        assertEquals(ETH_P_IPV6, value.ethProto);
+        assertEquals(NetworkStackConstants.ETHER_MTU, value.pmtu);
+        // oif (4) + ethDstMac (6) + ethSrcMac (6) + ethProto (2) + pmtu (2) = 20
         assertEquals(20, value.writeToBytes().length);
     }
 
diff --git a/framework-t/src/android/net/nsd/NsdManager.java b/framework-t/src/android/net/nsd/NsdManager.java
index ef0e34b..dae8914 100644
--- a/framework-t/src/android/net/nsd/NsdManager.java
+++ b/framework-t/src/android/net/nsd/NsdManager.java
@@ -34,10 +34,10 @@
 import android.content.Context;
 import android.net.ConnectivityManager;
 import android.net.ConnectivityManager.NetworkCallback;
+import android.net.ConnectivityThread;
 import android.net.Network;
 import android.net.NetworkRequest;
 import android.os.Handler;
-import android.os.HandlerThread;
 import android.os.Looper;
 import android.os.Message;
 import android.os.RemoteException;
@@ -632,10 +632,9 @@
      */
     public NsdManager(Context context, INsdManager service) {
         mContext = context;
-
-        HandlerThread t = new HandlerThread("NsdManager");
-        t.start();
-        mHandler = new ServiceHandler(t.getLooper());
+        // Use a common singleton thread ConnectivityThread to be shared among all nsd tasks.
+        // Instead of launching separate threads to handle tasks from the various instances.
+        mHandler = new ServiceHandler(ConnectivityThread.getInstanceLooper());
 
         try {
             mService = service.connect(new NsdCallbackImpl(mHandler), CompatChanges.isChangeEnabled(
diff --git a/tests/unit/java/android/net/nsd/NsdManagerTest.java b/tests/unit/java/android/net/nsd/NsdManagerTest.java
index 0965193..550a9ee 100644
--- a/tests/unit/java/android/net/nsd/NsdManagerTest.java
+++ b/tests/unit/java/android/net/nsd/NsdManagerTest.java
@@ -51,6 +51,7 @@
 import org.mockito.Mock;
 import org.mockito.MockitoAnnotations;
 
+@DevSdkIgnoreRunner.MonitorThreadLeak
 @RunWith(DevSdkIgnoreRunner.class)
 @SmallTest
 @DevSdkIgnoreRule.IgnoreUpTo(Build.VERSION_CODES.S_V2)
diff --git a/tests/unit/java/com/android/server/NsdServiceTest.java b/tests/unit/java/com/android/server/NsdServiceTest.java
index 771edb2..ffc8aa1 100644
--- a/tests/unit/java/com/android/server/NsdServiceTest.java
+++ b/tests/unit/java/com/android/server/NsdServiceTest.java
@@ -145,6 +145,7 @@
 // TODOs:
 //  - test client can send requests and receive replies
 //  - test NSD_ON ENABLE/DISABLED listening
+@DevSdkIgnoreRunner.MonitorThreadLeak
 @RunWith(DevSdkIgnoreRunner.class)
 @SmallTest
 @DevSdkIgnoreRule.IgnoreUpTo(Build.VERSION_CODES.S_V2)