diff --git a/Tethering/src/com/android/networkstack/tethering/TetheringConfiguration.java b/Tethering/src/com/android/networkstack/tethering/TetheringConfiguration.java
index b6240c4..dd0d567 100644
--- a/Tethering/src/com/android/networkstack/tethering/TetheringConfiguration.java
+++ b/Tethering/src/com/android/networkstack/tethering/TetheringConfiguration.java
@@ -23,6 +23,8 @@
 import static android.net.ConnectivityManager.TYPE_MOBILE_HIPRI;
 import static android.provider.DeviceConfig.NAMESPACE_CONNECTIVITY;
 
+import static com.android.net.module.util.DeviceConfigUtils.TETHERING_MODULE_NAME;
+
 import android.content.ContentResolver;
 import android.content.Context;
 import android.content.res.Resources;
@@ -60,8 +62,6 @@
 
     private static final String[] EMPTY_STRING_ARRAY = new String[0];
 
-    private static final String TETHERING_MODULE_NAME = "com.android.tethering";
-
     // Default ranges used for the legacy DHCP server.
     // USB is  192.168.42.1 and 255.255.255.0
     // Wifi is 192.168.43.1 and 255.255.255.0
diff --git a/service/src/com/android/server/ConnectivityService.java b/service/src/com/android/server/ConnectivityService.java
index 9e88890..222f5c8 100644
--- a/service/src/com/android/server/ConnectivityService.java
+++ b/service/src/com/android/server/ConnectivityService.java
@@ -87,9 +87,12 @@
 import static android.net.shared.NetworkMonitorUtils.isPrivateDnsValidationRequired;
 import static android.os.Process.INVALID_UID;
 import static android.os.Process.VPN_UID;
+import static android.provider.DeviceConfig.NAMESPACE_CONNECTIVITY;
 import static android.system.OsConstants.IPPROTO_TCP;
 import static android.system.OsConstants.IPPROTO_UDP;
 
+import static com.android.net.module.util.DeviceConfigUtils.TETHERING_MODULE_NAME;
+
 import static java.util.Map.Entry;
 
 import android.Manifest;
@@ -232,6 +235,7 @@
 import com.android.modules.utils.build.SdkLevel;
 import com.android.net.module.util.BaseNetdUnsolicitedEventListener;
 import com.android.net.module.util.CollectionUtils;
+import com.android.net.module.util.DeviceConfigUtils;
 import com.android.net.module.util.LinkPropertiesUtils.CompareOrUpdateResult;
 import com.android.net.module.util.LinkPropertiesUtils.CompareResult;
 import com.android.net.module.util.LocationPermissionChecker;
@@ -239,6 +243,7 @@
 import com.android.net.module.util.PermissionUtils;
 import com.android.net.module.util.netlink.InetDiagMessage;
 import com.android.server.connectivity.AutodestructReference;
+import com.android.server.connectivity.ConnectivityFlags;
 import com.android.server.connectivity.DnsManager;
 import com.android.server.connectivity.DnsManager.PrivateDnsValidationUpdate;
 import com.android.server.connectivity.FullScore;
@@ -371,6 +376,7 @@
     // The Context is created for UserHandle.ALL.
     private final Context mUserAllContext;
     private final Dependencies mDeps;
+    private final ConnectivityFlags mFlags;
     // 0 is full bad, 100 is full good
     private int mDefaultInetConditionPublished = 0;
 
@@ -1309,6 +1315,14 @@
         public LocationPermissionChecker makeLocationPermissionChecker(Context context) {
             return new LocationPermissionChecker(context);
         }
+
+        /**
+         * @see DeviceConfigUtils#isFeatureEnabled
+         */
+        public boolean isFeatureEnabled(Context context, String name, boolean defaultEnabled) {
+            return DeviceConfigUtils.isFeatureEnabled(context, NAMESPACE_CONNECTIVITY, name,
+                    TETHERING_MODULE_NAME, defaultEnabled);
+        }
     }
 
     public ConnectivityService(Context context) {
@@ -1323,6 +1337,7 @@
         if (DBG) log("ConnectivityService starting up");
 
         mDeps = Objects.requireNonNull(deps, "missing Dependencies");
+        mFlags = new ConnectivityFlags();
         mSystemProperties = mDeps.getSystemProperties();
         mNetIdManager = mDeps.makeNetIdManager();
         mContext = Objects.requireNonNull(context, "missing Context");
@@ -2790,6 +2805,9 @@
      */
     @VisibleForTesting
     public void systemReadyInternal() {
+        // Load flags after PackageManager is ready to query module version
+        mFlags.loadFlags(mDeps, mContext);
+
         // Since mApps in PermissionMonitor needs to be populated first to ensure that
         // listening network request which is sent by MultipathPolicyTracker won't be added
         // NET_CAPABILITY_FOREGROUND capability. Thus, MultipathPolicyTracker.start() must
@@ -4101,7 +4119,11 @@
             }
         }
 
-        rematchAllNetworksAndRequests();
+        if (mFlags.noRematchAllRequestsOnRegister()) {
+            rematchNetworksAndRequests(nris);
+        } else {
+            rematchAllNetworksAndRequests();
+        }
 
         // Requests that have not been matched to a network will not have been sent to the
         // providers, because the old satisfier and the new satisfier are the same (null in this
diff --git a/service/src/com/android/server/connectivity/ConnectivityFlags.java b/service/src/com/android/server/connectivity/ConnectivityFlags.java
new file mode 100644
index 0000000..122ea1c
--- /dev/null
+++ b/service/src/com/android/server/connectivity/ConnectivityFlags.java
@@ -0,0 +1,66 @@
+/*
+ * Copyright (C) 2021 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.connectivity;
+
+import android.content.Context;
+
+import com.android.internal.annotations.VisibleForTesting;
+import com.android.server.ConnectivityService;
+
+/**
+ * Collection of constants for the connectivity module.
+ */
+public final class ConnectivityFlags {
+    /**
+     * Minimum module version at which to avoid rematching all requests when a network request is
+     * registered, and rematch only the registered requests instead.
+     */
+    @VisibleForTesting
+    public static final String NO_REMATCH_ALL_REQUESTS_ON_REGISTER =
+            "no_rematch_all_requests_on_register";
+
+    private boolean mNoRematchAllRequestsOnRegister;
+
+    /**
+     * Whether ConnectivityService should avoid avoid rematching all requests when a network
+     * request is registered, and rematch only the registered requests instead.
+     *
+     * This flag is disabled by default.
+     *
+     * IMPORTANT NOTE: This flag is false by default and will only be loaded in ConnectivityService
+     * systemReady. It is also not volatile for performance reasons, so for most threads it may
+     * only change to true after some time. This is fine for this particular flag because it only
+     * controls whether all requests or a subset of requests should be rematched, which is only
+     * a performance optimization, so its value does not need to be consistent over time; but most
+     * flags will not have these properties and should not use the same model.
+     *
+     * TODO: when adding other flags, consider the appropriate timing to load them, and necessary
+     * threading guarantees according to the semantics of the flags.
+     */
+    public boolean noRematchAllRequestsOnRegister() {
+        return mNoRematchAllRequestsOnRegister;
+    }
+
+    /**
+     * Load flag values. Should only be called once, and can only be called once PackageManager is
+     * ready.
+     */
+    public void loadFlags(ConnectivityService.Dependencies deps, Context ctx) {
+        mNoRematchAllRequestsOnRegister = deps.isFeatureEnabled(
+                ctx, NO_REMATCH_ALL_REQUESTS_ON_REGISTER, false /* defaultEnabled */);
+    }
+}
diff --git a/tests/common/java/android/net/NetworkCapabilitiesTest.java b/tests/common/java/android/net/NetworkCapabilitiesTest.java
index a619d6b..27a3cc2 100644
--- a/tests/common/java/android/net/NetworkCapabilitiesTest.java
+++ b/tests/common/java/android/net/NetworkCapabilitiesTest.java
@@ -92,6 +92,7 @@
 
 @RunWith(AndroidJUnit4.class)
 @SmallTest
+@ConnectivityModuleTest
 public class NetworkCapabilitiesTest {
     private static final String TEST_SSID = "TEST_SSID";
     private static final String DIFFERENT_TEST_SSID = "DIFFERENT_TEST_SSID";
@@ -345,10 +346,16 @@
     }
 
     private void testParcelSane(NetworkCapabilities cap) {
-        if (isAtLeastT()) {
+        // This test can be run as unit test against the latest system image, as CTS to verify
+        // an Android release that is as recent as the test, or as MTS to verify the
+        // Connectivity module. In the first two cases NetworkCapabilities will be as recent
+        // as the test. In the last case, starting from S NetworkCapabilities is updated as part
+        // of Connectivity, so it is also as recent as the test. For MTS on Q and R,
+        // NetworkCapabilities is not updatable, so it may have a different number of fields.
+        if (isAtLeastS()) {
+            // When this test is run on S+, NetworkCapabilities is as recent as the test,
+            // so this should be the most recent known number of fields.
             assertParcelSane(cap, 17);
-        } else if (isAtLeastS()) {
-            assertParcelSane(cap, 16);
         } else if (isAtLeastR()) {
             assertParcelSane(cap, 15);
         } else {
@@ -1226,12 +1233,12 @@
         assertEquals(0, nc.getCapabilities().length);
     }
 
-    @Test @IgnoreUpTo(Build.VERSION_CODES.R) @ConnectivityModuleTest
+    @Test @IgnoreUpTo(Build.VERSION_CODES.R)
     public void testRestrictCapabilitiesForTestNetworkByNotOwnerWithNonRestrictedNc() {
         testRestrictCapabilitiesForTestNetworkWithNonRestrictedNc(false /* isOwner */);
     }
 
-    @Test @IgnoreUpTo(Build.VERSION_CODES.R) @ConnectivityModuleTest
+    @Test @IgnoreUpTo(Build.VERSION_CODES.R)
     public void testRestrictCapabilitiesForTestNetworkByOwnerWithNonRestrictedNc() {
         testRestrictCapabilitiesForTestNetworkWithNonRestrictedNc(true /* isOwner */);
     }
@@ -1276,12 +1283,12 @@
         assertEquals(expectedNcBuilder.build(), nonRestrictedNc);
     }
 
-    @Test @IgnoreUpTo(Build.VERSION_CODES.R) @ConnectivityModuleTest
+    @Test @IgnoreUpTo(Build.VERSION_CODES.R)
     public void testRestrictCapabilitiesForTestNetworkByNotOwnerWithRestrictedNc() {
         testRestrictCapabilitiesForTestNetworkWithRestrictedNc(false /* isOwner */);
     }
 
-    @Test @IgnoreUpTo(Build.VERSION_CODES.R) @ConnectivityModuleTest
+    @Test @IgnoreUpTo(Build.VERSION_CODES.R)
     public void testRestrictCapabilitiesForTestNetworkByOwnerWithRestrictedNc() {
         testRestrictCapabilitiesForTestNetworkWithRestrictedNc(true /* isOwner */);
     }
diff --git a/tests/cts/net/src/android/net/cts/IpSecManagerTest.java b/tests/cts/net/src/android/net/cts/IpSecManagerTest.java
index 7323c59..7bce3d2 100644
--- a/tests/cts/net/src/android/net/cts/IpSecManagerTest.java
+++ b/tests/cts/net/src/android/net/cts/IpSecManagerTest.java
@@ -723,11 +723,10 @@
         algoToRequiredMinSdk.put(AUTH_HMAC_SHA512, Build.VERSION_CODES.P);
         algoToRequiredMinSdk.put(AUTH_CRYPT_AES_GCM, Build.VERSION_CODES.P);
 
-        // TODO: b/170424293 Use Build.VERSION_CODES.S when is finalized
-        algoToRequiredMinSdk.put(CRYPT_AES_CTR, Build.VERSION_CODES.R + 1);
-        algoToRequiredMinSdk.put(AUTH_AES_CMAC, Build.VERSION_CODES.R + 1);
-        algoToRequiredMinSdk.put(AUTH_AES_XCBC, Build.VERSION_CODES.R + 1);
-        algoToRequiredMinSdk.put(AUTH_CRYPT_CHACHA20_POLY1305, Build.VERSION_CODES.R + 1);
+        algoToRequiredMinSdk.put(CRYPT_AES_CTR, Build.VERSION_CODES.S);
+        algoToRequiredMinSdk.put(AUTH_AES_CMAC, Build.VERSION_CODES.S);
+        algoToRequiredMinSdk.put(AUTH_AES_XCBC, Build.VERSION_CODES.S);
+        algoToRequiredMinSdk.put(AUTH_CRYPT_CHACHA20_POLY1305, Build.VERSION_CODES.S);
 
         final Set<String> supportedAlgos = IpSecAlgorithm.getSupportedAlgorithms();
 
diff --git a/tests/unit/java/com/android/server/ConnectivityServiceTest.java b/tests/unit/java/com/android/server/ConnectivityServiceTest.java
index bc50d0d..e0dd886 100644
--- a/tests/unit/java/com/android/server/ConnectivityServiceTest.java
+++ b/tests/unit/java/com/android/server/ConnectivityServiceTest.java
@@ -327,6 +327,7 @@
 import com.android.server.ConnectivityService.ConnectivityDiagnosticsCallbackInfo;
 import com.android.server.ConnectivityService.NetworkRequestInfo;
 import com.android.server.ConnectivityServiceTest.ConnectivityServiceDependencies.ReportedInterfaces;
+import com.android.server.connectivity.ConnectivityFlags;
 import com.android.server.connectivity.MockableSystemProperties;
 import com.android.server.connectivity.Nat464Xlat;
 import com.android.server.connectivity.NetworkAgentInfo;
@@ -1916,6 +1917,16 @@
             mReportedInterfaceHistory.add(new ReportedInterfaces(context, iface, transportTypes));
             super.reportNetworkInterfaceForTransports(context, iface, transportTypes);
         }
+
+        @Override
+        public boolean isFeatureEnabled(Context context, String name, boolean defaultEnabled) {
+            switch (name) {
+                case ConnectivityFlags.NO_REMATCH_ALL_REQUESTS_ON_REGISTER:
+                    return true;
+                default:
+                    return super.isFeatureEnabled(context, name, defaultEnabled);
+            }
+        }
     }
 
     private static void initAlarmManager(final AlarmManager am, final Handler alarmHandler) {