diff --git a/apishim/29/com/android/networkstack/apishim/api29/CaptivePortalDataShimImpl.java b/apishim/29/com/android/networkstack/apishim/api29/CaptivePortalDataShimImpl.java
index 9e27666..8719e83 100644
--- a/apishim/29/com/android/networkstack/apishim/api29/CaptivePortalDataShimImpl.java
+++ b/apishim/29/com/android/networkstack/apishim/api29/CaptivePortalDataShimImpl.java
@@ -51,7 +51,7 @@
     }
 
     @Override
-    public String getVenueFriendlyName() {
+    public CharSequence getVenueFriendlyName() {
         // Not supported in API level 29
         return null;
     }
diff --git a/apishim/29/com/android/networkstack/apishim/api29/NetworkRequestShimImpl.java b/apishim/29/com/android/networkstack/apishim/api29/NetworkRequestShimImpl.java
new file mode 100644
index 0000000..0c1d837
--- /dev/null
+++ b/apishim/29/com/android/networkstack/apishim/api29/NetworkRequestShimImpl.java
@@ -0,0 +1,49 @@
+/*
+ * 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.networkstack.apishim.api29;
+
+import android.net.NetworkRequest;
+import android.util.Range;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+import com.android.networkstack.apishim.common.NetworkRequestShim;
+import com.android.networkstack.apishim.common.UnsupportedApiLevelException;
+
+import java.util.Set;
+
+/**
+ * Implementation of {@link NetworkRequestShim} for API 29.
+ */
+public class NetworkRequestShimImpl implements NetworkRequestShim {
+    protected NetworkRequestShimImpl() {}
+
+    /**
+     * Get a new instance of {@link NetworkRequestShim}.
+     */
+    public static NetworkRequestShim newInstance() {
+        return new NetworkRequestShimImpl();
+    }
+
+    @Override
+    public void setUids(@NonNull NetworkRequest.Builder builder,
+            @Nullable Set<Range<Integer>> uids) throws UnsupportedApiLevelException {
+        // Not supported before API 31.
+        throw new UnsupportedApiLevelException("Not supported before API 31.");
+    }
+}
diff --git a/apishim/30/com/android/networkstack/apishim/api30/NetworkRequestShimImpl.java b/apishim/30/com/android/networkstack/apishim/api30/NetworkRequestShimImpl.java
new file mode 100644
index 0000000..b65a556
--- /dev/null
+++ b/apishim/30/com/android/networkstack/apishim/api30/NetworkRequestShimImpl.java
@@ -0,0 +1,43 @@
+/*
+ * 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.networkstack.apishim.api30;
+
+import android.os.Build;
+
+import com.android.networkstack.apishim.common.NetworkRequestShim;
+import com.android.networkstack.apishim.common.ShimUtils;
+
+/**
+ * Implementation of {@link NetworkRequestShim} for API 30.
+ */
+public class NetworkRequestShimImpl
+        extends com.android.networkstack.apishim.api29.NetworkRequestShimImpl {
+    protected NetworkRequestShimImpl() {
+        super();
+    }
+
+    /**
+     * Get a new instance of {@link NetworkRequestShim}.
+     */
+    public static NetworkRequestShim newInstance() {
+        if (!ShimUtils.isReleaseOrDevelopmentApiAbove(Build.VERSION_CODES.Q)) {
+            return com.android.networkstack.apishim.api29.NetworkRequestShimImpl
+                    .newInstance();
+        }
+        return new NetworkRequestShimImpl();
+    }
+}
diff --git a/apishim/31/com/android/networkstack/apishim/CaptivePortalDataShimImpl.java b/apishim/31/com/android/networkstack/apishim/CaptivePortalDataShimImpl.java
index 6e3eb19..5af7412 100644
--- a/apishim/31/com/android/networkstack/apishim/CaptivePortalDataShimImpl.java
+++ b/apishim/31/com/android/networkstack/apishim/CaptivePortalDataShimImpl.java
@@ -33,7 +33,7 @@
     }
 
     @Override
-    public String getVenueFriendlyName() {
+    public CharSequence getVenueFriendlyName() {
         return mData.getVenueFriendlyName();
     }
 
diff --git a/apishim/31/com/android/networkstack/apishim/NetworkRequestShimImpl.java b/apishim/31/com/android/networkstack/apishim/NetworkRequestShimImpl.java
new file mode 100644
index 0000000..b0d5827
--- /dev/null
+++ b/apishim/31/com/android/networkstack/apishim/NetworkRequestShimImpl.java
@@ -0,0 +1,56 @@
+/*
+ * 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.networkstack.apishim;
+
+import android.net.NetworkRequest;
+import android.os.Build;
+import android.util.Range;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+import com.android.networkstack.apishim.common.NetworkRequestShim;
+import com.android.networkstack.apishim.common.ShimUtils;
+
+import java.util.Set;
+
+/**
+ * Implementation of {@link NetworkRequestShim} for API 31.
+ */
+public class NetworkRequestShimImpl
+        extends com.android.networkstack.apishim.api30.NetworkRequestShimImpl {
+    protected NetworkRequestShimImpl() {
+        super();
+    }
+
+    /**
+     * Get a new instance of {@link NetworkRequestShim}.
+     */
+    public static NetworkRequestShim newInstance() {
+        if (!ShimUtils.isReleaseOrDevelopmentApiAbove(Build.VERSION_CODES.R)) {
+            return com.android.networkstack.apishim.api30.NetworkRequestShimImpl
+                    .newInstance();
+        }
+        return new NetworkRequestShimImpl();
+    }
+
+    @Override
+    public void setUids(@NonNull NetworkRequest.Builder builder,
+            @Nullable Set<Range<Integer>> uids) {
+        builder.setUids(uids);
+    }
+}
diff --git a/apishim/common/com/android/networkstack/apishim/common/CaptivePortalDataShim.java b/apishim/common/com/android/networkstack/apishim/common/CaptivePortalDataShim.java
index 26ac9d4..13bf257 100644
--- a/apishim/common/com/android/networkstack/apishim/common/CaptivePortalDataShim.java
+++ b/apishim/common/com/android/networkstack/apishim/common/CaptivePortalDataShim.java
@@ -54,7 +54,7 @@
     /**
      * @see CaptivePortalData#getVenueFriendlyName()
      */
-    String getVenueFriendlyName();
+    CharSequence getVenueFriendlyName();
 
     /**
      * @see CaptivePortalData#getUserPortalUrlSource()
diff --git a/apishim/common/com/android/networkstack/apishim/common/NetworkRequestShim.java b/apishim/common/com/android/networkstack/apishim/common/NetworkRequestShim.java
new file mode 100644
index 0000000..7b53efa
--- /dev/null
+++ b/apishim/common/com/android/networkstack/apishim/common/NetworkRequestShim.java
@@ -0,0 +1,38 @@
+/*
+ * 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.networkstack.apishim.common;
+
+import android.net.NetworkRequest;
+import android.util.Range;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+import java.util.Set;
+
+/**
+ * Interface used to access API methods in {@link android.net.NetworkRequest}, with
+ * appropriate fallbacks if the methods are not yet part of the released API.
+ */
+public interface NetworkRequestShim {
+    /**
+     * See android.net.NetworkRequest.Builder#setUids.
+     * Set the {@code uids} into {@code builder}.
+     */
+    void setUids(@NonNull NetworkRequest.Builder builder,
+            @Nullable Set<Range<Integer>> uids) throws UnsupportedApiLevelException;
+}
diff --git a/src/android/net/ip/IpClient.java b/src/android/net/ip/IpClient.java
index a73e997..980c6d6 100644
--- a/src/android/net/ip/IpClient.java
+++ b/src/android/net/ip/IpClient.java
@@ -18,8 +18,14 @@
 
 import static android.net.RouteInfo.RTN_UNICAST;
 import static android.net.dhcp.DhcpResultsParcelableUtil.toStableParcelable;
+import static android.net.util.NetworkStackUtils.IPCLIENT_GRATUITOUS_NA_VERSION;
 import static android.provider.DeviceConfig.NAMESPACE_CONNECTIVITY;
+import static android.system.OsConstants.AF_PACKET;
+import static android.system.OsConstants.ETH_P_IPV6;
+import static android.system.OsConstants.SOCK_NONBLOCK;
+import static android.system.OsConstants.SOCK_RAW;
 
+import static com.android.net.module.util.NetworkStackConstants.IPV6_ADDR_ALL_ROUTERS_MULTICAST;
 import static com.android.net.module.util.NetworkStackConstants.VENDOR_SPECIFIC_IE_ID;
 import static com.android.server.util.PermissionUtil.enforceNetworkStackCallingPermission;
 
@@ -52,6 +58,7 @@
 import android.net.shared.ProvisioningConfiguration.ScanResultInfo;
 import android.net.shared.ProvisioningConfiguration.ScanResultInfo.InformationElement;
 import android.net.util.InterfaceParams;
+import android.net.util.NetworkStackUtils;
 import android.net.util.SharedLog;
 import android.os.Build;
 import android.os.ConditionVariable;
@@ -61,6 +68,8 @@
 import android.os.ServiceSpecificException;
 import android.os.SystemClock;
 import android.stats.connectivity.DisconnectCode;
+import android.system.ErrnoException;
+import android.system.Os;
 import android.text.TextUtils;
 import android.util.LocalLog;
 import android.util.Log;
@@ -79,16 +88,21 @@
 import com.android.internal.util.WakeupMessage;
 import com.android.net.module.util.DeviceConfigUtils;
 import com.android.networkstack.apishim.NetworkInformationShimImpl;
+import com.android.networkstack.apishim.SocketUtilsShimImpl;
 import com.android.networkstack.apishim.common.NetworkInformationShim;
 import com.android.networkstack.apishim.common.ShimUtils;
 import com.android.networkstack.metrics.IpProvisioningMetrics;
+import com.android.networkstack.packets.NeighborAdvertisement;
 import com.android.server.NetworkObserverRegistry;
 import com.android.server.NetworkStackService.NetworkStackServiceManager;
 
 import java.io.FileDescriptor;
 import java.io.PrintWriter;
+import java.net.Inet6Address;
 import java.net.InetAddress;
 import java.net.MalformedURLException;
+import java.net.SocketAddress;
+import java.net.SocketException;
 import java.net.URL;
 import java.nio.BufferUnderflowException;
 import java.nio.ByteBuffer;
@@ -479,6 +493,8 @@
     private final MessageHandlingLogger mMsgStateLogger;
     private final IpConnectivityLog mMetricsLog;
     private final InterfaceController mInterfaceCtrl;
+    // Set of IPv6 addresses for which unsolicited gratuitous NA packets have been sent.
+    private final Set<Inet6Address> mGratuitousNaTargetAddresses = new HashSet<>();
 
     // Ignore nonzero RDNSS option lifetimes below this value. 0 = disabled.
     private final int mMinRdnssLifetimeSec;
@@ -564,6 +580,16 @@
         public IpConnectivityLog getIpConnectivityLog() {
             return new IpConnectivityLog();
         }
+
+        /**
+         * Return whether a feature guarded by a feature flag is enabled.
+         * @see NetworkStackUtils#isFeatureEnabled(Context, String, String)
+         */
+        public boolean isFeatureEnabled(final Context context, final String name,
+                boolean defaultEnabled) {
+            return DeviceConfigUtils.isFeatureEnabled(context, NAMESPACE_CONNECTIVITY, name,
+                    defaultEnabled);
+        }
     }
 
     public IpClient(Context context, String ifName, IIpClientCallbacks callback,
@@ -647,6 +673,21 @@
                 logMsg(msg);
             }
 
+            @Override
+            public void onInterfaceAddressRemoved(LinkAddress address, String iface) {
+                super.onInterfaceAddressRemoved(address, iface);
+                if (!mInterfaceName.equals(iface)) return;
+                if (!address.isIpv6()) return;
+                final Inet6Address targetIp = (Inet6Address) address.getAddress();
+                if (mGratuitousNaTargetAddresses.contains(targetIp)) {
+                    mGratuitousNaTargetAddresses.remove(targetIp);
+
+                    final String msg = "Global IPv6 address: " + targetIp
+                            + " has removed from the set of gratuitous NA target address.";
+                    logMsg(msg);
+                }
+            }
+
             private void logMsg(String msg) {
                 Log.d(mTag, msg);
                 getHandler().post(() -> mLog.log("OBSERVED " + msg));
@@ -793,6 +834,11 @@
         mLinkObserver.shutdown();
     }
 
+    private boolean isGratuitousNaEnabled() {
+        return mDependencies.isFeatureEnabled(mContext, IPCLIENT_GRATUITOUS_NA_VERSION,
+                false /* defaultEnabled */);
+    }
+
     @Override
     protected void onQuitting() {
         mCallback.onQuit();
@@ -1377,6 +1423,57 @@
         }
     }
 
+    private void sendGratuitousNA(final Inet6Address srcIp, final Inet6Address target) {
+        final int flags = 0; // R=0, S=0, O=0
+        final Inet6Address dstIp = IPV6_ADDR_ALL_ROUTERS_MULTICAST;
+        // Ethernet multicast destination address: 33:33:00:00:00:02.
+        final MacAddress dstMac = NetworkStackUtils.ipv6MulticastToEthernetMulticast(dstIp);
+        final ByteBuffer packet = NeighborAdvertisement.build(mInterfaceParams.macAddr, dstMac,
+                srcIp, dstIp, flags, target);
+        FileDescriptor sock = null;
+        try {
+            sock = Os.socket(AF_PACKET, SOCK_RAW | SOCK_NONBLOCK, 0 /* protocol */);
+            final SocketAddress sockAddress =
+                    SocketUtilsShimImpl.newInstance().makePacketSocketAddress(ETH_P_IPV6,
+                            mInterfaceParams.index, dstMac.toByteArray());
+            Os.sendto(sock, packet.array(), 0 /* byteOffset */, packet.limit() /* byteCount */,
+                    0 /* flags */, sockAddress);
+        } catch (SocketException | ErrnoException e) {
+            logError("Fail to send Gratuitous Neighbor Advertisement", e);
+        } finally {
+            NetworkStackUtils.closeSocketQuietly(sock);
+        }
+    }
+
+    private Inet6Address getIpv6LinkLocalAddress(final LinkProperties newLp) {
+        Inet6Address src = null;
+        for (LinkAddress la : newLp.getLinkAddresses()) {
+            if (!la.isIpv6()) continue;
+            final Inet6Address ip = (Inet6Address) la.getAddress();
+            if (ip.isLinkLocalAddress()) return ip;
+        }
+        return null;
+    }
+
+    private void maybeSendGratuitousNAs(final LinkProperties newLp) {
+        if (!newLp.hasGlobalIpv6Address() || !isGratuitousNaEnabled()) return;
+
+        final Inet6Address src = getIpv6LinkLocalAddress(newLp);
+        if (src == null) return;
+        for (LinkAddress la : newLp.getLinkAddresses()) {
+            if (!la.isIpv6() || !la.isGlobalPreferred()) continue;
+            final Inet6Address targetIp = (Inet6Address) la.getAddress();
+            // Already sent gratuitous NA with this target global IPv6 address.
+            if (mGratuitousNaTargetAddresses.contains(targetIp)) continue;
+            if (DBG) {
+                Log.d(mTag, "send Gratuitous NA from " + src + ", target Address is "
+                            + targetIp);
+            }
+            sendGratuitousNA(src, targetIp);
+            mGratuitousNaTargetAddresses.add(targetIp);
+        }
+    }
+
     // Returns false if we have lost provisioning, true otherwise.
     private boolean handleLinkPropertiesUpdate(boolean sendCallbacks) {
         final LinkProperties newLp = assembleLinkProperties();
@@ -1384,6 +1481,11 @@
             return true;
         }
 
+        // Check if new assigned IPv6 GUA is available in the LinkProperties now. If so, initiate
+        // gratuitous multicast unsolicited Neighbor Advertisements as soon as possible to inform
+        // first-hop routers that the new GUA host is goning to use.
+        maybeSendGratuitousNAs(newLp);
+
         // Either success IPv4 or IPv6 provisioning triggers new LinkProperties update,
         // wait for the provisioning completion and record the latency.
         mIpProvisioningMetrics.setIPv4ProvisionedLatencyOnFirstTime(newLp.isIpv4Provisioned());
@@ -1662,6 +1764,7 @@
         public void enter() {
             stopAllIP();
             mHasDisabledIPv6OnProvLoss = false;
+            mGratuitousNaTargetAddresses.clear();
 
             mLinkObserver.clearInterfaceParams();
             resetLinkProperties();
diff --git a/src/android/net/util/NetworkStackUtils.java b/src/android/net/util/NetworkStackUtils.java
index 5c11733..6e32833 100755
--- a/src/android/net/util/NetworkStackUtils.java
+++ b/src/android/net/util/NetworkStackUtils.java
@@ -17,12 +17,16 @@
 package android.net.util;
 
 import android.content.Context;
+import android.net.MacAddress;
+
+import androidx.annotation.NonNull;
 
 import com.android.net.module.util.DeviceConfigUtils;
 
 import java.io.FileDescriptor;
 import java.io.IOException;
 import java.net.Inet4Address;
+import java.net.Inet6Address;
 import java.net.SocketException;
 
 /**
@@ -232,6 +236,12 @@
      */
     public static final String VALIDATION_METRICS_VERSION = "validation_metrics_version";
 
+    /**
+     * Experiment flag to enable sending gratuitous multicast unsolicited Neighbor Advertisements
+     * to propagate new assigned IPv6 GUA as quickly as possible.
+     */
+    public static final String IPCLIENT_GRATUITOUS_NA_VERSION = "ipclient_gratuitous_na_version";
+
     static {
         System.loadLibrary("networkstackutilsjni");
     }
@@ -247,6 +257,21 @@
     }
 
     /**
+     * Convert IPv6 multicast address to ethernet multicast address in network order.
+     */
+    public static MacAddress ipv6MulticastToEthernetMulticast(@NonNull final Inet6Address addr) {
+        final byte[] etherMulticast = new byte[6];
+        final byte[] ipv6Multicast = addr.getAddress();
+        etherMulticast[0] = (byte) 0x33;
+        etherMulticast[1] = (byte) 0x33;
+        etherMulticast[2] = ipv6Multicast[12];
+        etherMulticast[3] = ipv6Multicast[13];
+        etherMulticast[4] = ipv6Multicast[14];
+        etherMulticast[5] = ipv6Multicast[15];
+        return MacAddress.fromBytes(etherMulticast);
+    }
+
+    /**
      * Attaches a socket filter that accepts DHCP packets to the given socket.
      */
     public static native void attachDhcpFilter(FileDescriptor fd) throws SocketException;
diff --git a/src/com/android/networkstack/NetworkStackNotifier.java b/src/com/android/networkstack/NetworkStackNotifier.java
index 0558d3a..acf3c95 100644
--- a/src/com/android/networkstack/NetworkStackNotifier.java
+++ b/src/com/android/networkstack/NetworkStackNotifier.java
@@ -237,8 +237,8 @@
 
             // If the venue friendly name is available (in Passpoint use-case), display it.
             // Otherwise, display the SSID.
-            final String friendlyName = capportData.getVenueFriendlyName();
-            final String venueDisplayName = TextUtils.isEmpty(friendlyName)
+            final CharSequence friendlyName = capportData.getVenueFriendlyName();
+            final CharSequence venueDisplayName = TextUtils.isEmpty(friendlyName)
                     ? getSsid(networkStatus) : friendlyName;
 
             builder = getNotificationBuilder(channel, networkStatus, res, venueDisplayName)
@@ -284,9 +284,9 @@
 
     private Notification.Builder getNotificationBuilder(@NonNull String channelId,
             @NonNull TrackedNetworkStatus networkStatus, @NonNull Resources res,
-            @NonNull String ssid) {
+            @NonNull CharSequence networkIdentifier) {
         return new Notification.Builder(mContext, channelId)
-                .setContentTitle(ssid)
+                .setContentTitle(networkIdentifier)
                 .setSmallIcon(R.drawable.icon_wifi);
     }
 
diff --git a/tests/integration/src/android/net/ip/IpClientIntegrationTest.kt b/tests/integration/src/android/net/ip/IpClientIntegrationTest.kt
index 9f29a2e..eb0a799 100644
--- a/tests/integration/src/android/net/ip/IpClientIntegrationTest.kt
+++ b/tests/integration/src/android/net/ip/IpClientIntegrationTest.kt
@@ -17,6 +17,7 @@
 package android.net.ip
 
 import android.net.ipmemorystore.NetworkAttributes
+import android.util.ArrayMap
 import org.mockito.Mockito.any
 import org.mockito.ArgumentCaptor
 import org.mockito.Mockito.eq
@@ -28,22 +29,20 @@
  * Tests for IpClient, run with signature permissions.
  */
 class IpClientIntegrationTest : IpClientIntegrationTestCommon() {
+    private val mEnabledFeatures = ArrayMap<String, Boolean>()
+
     override fun makeIIpClient(ifaceName: String, cb: IIpClientCallbacks): IIpClient {
         return mIpc.makeConnector()
     }
 
     override fun useNetworkStackSignature() = true
 
-    override fun setDhcpFeatures(
-        isDhcpLeaseCacheEnabled: Boolean,
-        isRapidCommitEnabled: Boolean,
-        isDhcpIpConflictDetectEnabled: Boolean,
-        isIPv6OnlyPreferredEnabled: Boolean
-    ) {
-        mDependencies.setDhcpLeaseCacheEnabled(isDhcpLeaseCacheEnabled)
-        mDependencies.setDhcpRapidCommitEnabled(isRapidCommitEnabled)
-        mDependencies.setDhcpIpConflictDetectEnabled(isDhcpIpConflictDetectEnabled)
-        mDependencies.setIPv6OnlyPreferredEnabled(isIPv6OnlyPreferredEnabled)
+    override fun isFeatureEnabled(name: String, defaultEnabled: Boolean): Boolean {
+        return mEnabledFeatures.get(name) ?: defaultEnabled
+    }
+
+    override fun setFeatureEnabled(name: String, enabled: Boolean) {
+        mEnabledFeatures.put(name, enabled)
     }
 
     override fun getStoredNetworkAttributes(l2Key: String, timeout: Long): NetworkAttributes {
diff --git a/tests/integration/src/android/net/ip/IpClientIntegrationTestCommon.java b/tests/integration/src/android/net/ip/IpClientIntegrationTestCommon.java
index 451437e..ae68362 100644
--- a/tests/integration/src/android/net/ip/IpClientIntegrationTestCommon.java
+++ b/tests/integration/src/android/net/ip/IpClientIntegrationTestCommon.java
@@ -39,11 +39,15 @@
 import static com.android.net.module.util.NetworkStackConstants.ETHER_ADDR_LEN;
 import static com.android.net.module.util.NetworkStackConstants.ETHER_HEADER_LEN;
 import static com.android.net.module.util.NetworkStackConstants.ETHER_TYPE_OFFSET;
+import static com.android.net.module.util.NetworkStackConstants.ICMPV6_NEIGHBOR_ADVERTISEMENT;
 import static com.android.net.module.util.NetworkStackConstants.ICMPV6_ROUTER_SOLICITATION;
 import static com.android.net.module.util.NetworkStackConstants.IPV4_ADDR_ANY;
 import static com.android.net.module.util.NetworkStackConstants.IPV6_ADDR_ALL_NODES_MULTICAST;
+import static com.android.net.module.util.NetworkStackConstants.IPV6_ADDR_ALL_ROUTERS_MULTICAST;
 import static com.android.net.module.util.NetworkStackConstants.IPV6_HEADER_LEN;
 import static com.android.net.module.util.NetworkStackConstants.IPV6_PROTOCOL_OFFSET;
+import static com.android.net.module.util.NetworkStackConstants.PIO_FLAG_AUTONOMOUS;
+import static com.android.net.module.util.NetworkStackConstants.PIO_FLAG_ON_LINK;
 
 import static junit.framework.Assert.fail;
 
@@ -141,6 +145,7 @@
 import com.android.networkstack.apishim.common.ShimUtils;
 import com.android.networkstack.arp.ArpPacket;
 import com.android.networkstack.metrics.IpProvisioningMetrics;
+import com.android.networkstack.packets.NeighborAdvertisement;
 import com.android.server.NetworkObserver;
 import com.android.server.NetworkObserverRegistry;
 import com.android.server.NetworkStackService.NetworkStackServiceManager;
@@ -343,32 +348,12 @@
     };
 
     protected class Dependencies extends IpClient.Dependencies {
-        private boolean mIsDhcpLeaseCacheEnabled;
-        private boolean mIsDhcpRapidCommitEnabled;
-        private boolean mIsDhcpIpConflictDetectEnabled;
         // Can't use SparseIntArray, it doesn't have an easy way to know if a key is not present.
         private HashMap<String, Integer> mIntConfigProperties = new HashMap<>();
         private DhcpClient mDhcpClient;
         private boolean mIsHostnameConfigurationEnabled;
         private String mHostname;
         private boolean mIsInterfaceRecovered;
-        private boolean mIsIPv6OnlyPreferredEnabled;
-
-        public void setDhcpLeaseCacheEnabled(final boolean enable) {
-            mIsDhcpLeaseCacheEnabled = enable;
-        }
-
-        public void setDhcpRapidCommitEnabled(final boolean enable) {
-            mIsDhcpRapidCommitEnabled = enable;
-        }
-
-        public void setDhcpIpConflictDetectEnabled(final boolean enable) {
-            mIsDhcpIpConflictDetectEnabled = enable;
-        }
-
-        public void setIPv6OnlyPreferredEnabled(final boolean enable) {
-            mIsIPv6OnlyPreferredEnabled = enable;
-        }
 
         public void setHostnameConfiguration(final boolean enable, final String hostname) {
             mIsHostnameConfigurationEnabled = enable;
@@ -411,25 +396,19 @@
         }
 
         @Override
+        public boolean isFeatureEnabled(final Context context, final String name,
+                final boolean defaultEnabled) {
+            return IpClientIntegrationTestCommon.this.isFeatureEnabled(name, defaultEnabled);
+        }
+
+        @Override
         public DhcpClient.Dependencies getDhcpClientDependencies(
                 NetworkStackIpMemoryStore ipMemoryStore, IpProvisioningMetrics metrics) {
             return new DhcpClient.Dependencies(ipMemoryStore, metrics) {
                 @Override
                 public boolean isFeatureEnabled(final Context context, final String name,
                         final boolean defaultEnabled) {
-                    switch (name) {
-                        case NetworkStackUtils.DHCP_RAPID_COMMIT_VERSION:
-                            return mIsDhcpRapidCommitEnabled;
-                        case NetworkStackUtils.DHCP_INIT_REBOOT_VERSION:
-                            return mIsDhcpLeaseCacheEnabled;
-                        case NetworkStackUtils.DHCP_IP_CONFLICT_DETECT_VERSION:
-                            return mIsDhcpIpConflictDetectEnabled;
-                        case NetworkStackUtils.DHCP_IPV6_ONLY_PREFERRED_VERSION:
-                            return mIsIPv6OnlyPreferredEnabled;
-                        default:
-                            fail("Invalid experiment flag: " + name);
-                            return false;
-                    }
+                    return Dependencies.this.isFeatureEnabled(context, name, defaultEnabled);
                 }
 
                 @Override
@@ -473,9 +452,9 @@
     protected abstract IIpClient makeIIpClient(
             @NonNull String ifaceName, @NonNull IIpClientCallbacks cb);
 
-    protected abstract void setDhcpFeatures(boolean isDhcpLeaseCacheEnabled,
-            boolean isRapidCommitEnabled, boolean isDhcpIpConflictDetectEnabled,
-            boolean isIPv6OnlyPreferredEnabled);
+    protected abstract void setFeatureEnabled(String name, boolean enabled);
+
+    protected abstract boolean isFeatureEnabled(String name, boolean defaultEnabled);
 
     protected abstract boolean useNetworkStackSignature();
 
@@ -490,6 +469,17 @@
                 && (mIsSignatureRequiredTest || !TestNetworkStackServiceClient.isSupported());
     }
 
+    protected void setDhcpFeatures(final boolean isDhcpLeaseCacheEnabled,
+            final boolean isRapidCommitEnabled, final boolean isDhcpIpConflictDetectEnabled,
+            final boolean isIPv6OnlyPreferredEnabled) {
+        setFeatureEnabled(NetworkStackUtils.DHCP_INIT_REBOOT_VERSION, isDhcpLeaseCacheEnabled);
+        setFeatureEnabled(NetworkStackUtils.DHCP_RAPID_COMMIT_VERSION, isRapidCommitEnabled);
+        setFeatureEnabled(NetworkStackUtils.DHCP_IP_CONFLICT_DETECT_VERSION,
+                isDhcpIpConflictDetectEnabled);
+        setFeatureEnabled(NetworkStackUtils.DHCP_IPV6_ONLY_PREFERRED_VERSION,
+                isIPv6OnlyPreferredEnabled);
+    }
+
     @Before
     public void setUp() throws Exception {
         final Method testMethod = IpClientIntegrationTestCommon.class.getMethod(
@@ -704,6 +694,14 @@
         }
     }
 
+    private NeighborAdvertisement parseNeighborAdvertisementOrNull(final byte[] packet) {
+        try {
+            return NeighborAdvertisement.parse(packet, packet.length);
+        } catch (NeighborAdvertisement.ParseException e) {
+            return null;
+        }
+    }
+
     private static ByteBuffer buildDhcpOfferPacket(final DhcpPacket packet,
             final Inet4Address clientAddress, final Integer leaseTimeSec, final short mtu,
             final String captivePortalUrl, final Integer ipv6OnlyWaitTime) {
@@ -1434,6 +1432,24 @@
                         == (byte) ICMPV6_ROUTER_SOLICITATION;
     }
 
+    private boolean isNeighborAdvertisement(final byte[] packetBytes) {
+        ByteBuffer packet = ByteBuffer.wrap(packetBytes);
+        return packet.getShort(ETHER_TYPE_OFFSET) == (short) ETH_P_IPV6
+                && packet.get(ETHER_HEADER_LEN + IPV6_PROTOCOL_OFFSET) == (byte) IPPROTO_ICMPV6
+                && packet.get(ETHER_HEADER_LEN + IPV6_HEADER_LEN)
+                        == (byte) ICMPV6_NEIGHBOR_ADVERTISEMENT;
+    }
+
+    private NeighborAdvertisement getNextNeighborAdvertisement() throws ParseException {
+        final byte[] packet = mPacketReader.popPacket(PACKET_TIMEOUT_MS,
+                this::isNeighborAdvertisement);
+        if (packet == null) return null;
+
+        final NeighborAdvertisement na = parseNeighborAdvertisementOrNull(packet);
+        assertNotNull("Invalid neighbour advertisement received", na);
+        return na;
+    }
+
     private void waitForRouterSolicitation() throws ParseException {
         assertNotNull("No router solicitation received on interface within timeout",
                 mPacketReader.popPacket(PACKET_TIMEOUT_MS, this::isRouterSolicitation));
@@ -1464,7 +1480,7 @@
     private static ByteBuffer buildPioOption(int valid, int preferred, String prefixString)
             throws Exception {
         return PrefixInformationOption.build(new IpPrefix(prefixString),
-                (byte) 0b11000000 /* L = 1, A = 1 */, valid, preferred);
+                (byte) (PIO_FLAG_ON_LINK | PIO_FLAG_AUTONOMOUS), valid, preferred);
     }
 
     private static ByteBuffer buildRdnssOption(int lifetime, String... servers) throws Exception {
@@ -2760,4 +2776,50 @@
         assertArrayEquals(packet.mUserClass, TEST_OEM_USER_CLASS_INFO);
         assertFalse(packet.hasRequestedParam((byte) 42 /* NTP_SERVER */));
     }
+
+    private void assertGratuitousNa(final NeighborAdvertisement na) throws Exception {
+        final MacAddress etherMulticast =
+                NetworkStackUtils.ipv6MulticastToEthernetMulticast(IPV6_ADDR_ALL_ROUTERS_MULTICAST);
+        final LinkAddress target = new LinkAddress(na.naHdr.target, 64);
+
+        assertEquals(etherMulticast, na.ethHdr.dstMac);
+        assertEquals(ETH_P_IPV6, na.ethHdr.etherType);
+        assertEquals(IPPROTO_ICMPV6, na.ipv6Hdr.nextHeader);
+        assertEquals(0xff, na.ipv6Hdr.hopLimit);
+        assertTrue(na.ipv6Hdr.srcIp.isLinkLocalAddress());
+        assertEquals(IPV6_ADDR_ALL_ROUTERS_MULTICAST, na.ipv6Hdr.dstIp);
+        assertEquals(ICMPV6_NEIGHBOR_ADVERTISEMENT, na.icmpv6Hdr.type);
+        assertEquals(0, na.icmpv6Hdr.code);
+        assertEquals(0, na.naHdr.flags);
+        assertTrue(target.isGlobalPreferred());
+    }
+
+    @Test
+    public void testGratuitousNa() throws Exception {
+        final ProvisioningConfiguration config = new ProvisioningConfiguration.Builder()
+                .withoutIpReachabilityMonitor()
+                .withoutIPv4()
+                .build();
+
+        setFeatureEnabled(NetworkStackUtils.IPCLIENT_GRATUITOUS_NA_VERSION,
+                true /* isGratuitousNaEnabled */);
+        assertTrue(isFeatureEnabled(NetworkStackUtils.IPCLIENT_GRATUITOUS_NA_VERSION, false));
+        startIpClientProvisioning(config);
+
+        final InOrder inOrder = inOrder(mCb);
+        final String dnsServer = "2001:4860:4860::64";
+        final ByteBuffer pio = buildPioOption(3600, 1800, "2001:db8:1::/64");
+        final ByteBuffer rdnss = buildRdnssOption(3600, dnsServer);
+        final ByteBuffer ra = buildRaPacket(pio, rdnss);
+
+        doIpv6OnlyProvisioning(inOrder, ra);
+
+        final List<NeighborAdvertisement> naList = new ArrayList<>();
+        NeighborAdvertisement packet;
+        while ((packet = getNextNeighborAdvertisement()) != null) {
+            assertGratuitousNa(packet);
+            naList.add(packet);
+        }
+        assertEquals(2, naList.size()); // privacy address and stable privacy address
+    }
 }
diff --git a/tests/integration/src/android/net/ip/IpClientRootTest.kt b/tests/integration/src/android/net/ip/IpClientRootTest.kt
index ea2ec11..68d8aab 100644
--- a/tests/integration/src/android/net/ip/IpClientRootTest.kt
+++ b/tests/integration/src/android/net/ip/IpClientRootTest.kt
@@ -26,12 +26,12 @@
 import android.net.ipmemorystore.NetworkAttributes
 import android.net.ipmemorystore.Status
 import android.net.networkstack.TestNetworkStackServiceClient
-import android.net.util.NetworkStackUtils
 import android.os.Process
 import android.provider.DeviceConfig
 import android.util.ArrayMap
 import android.util.Log
 import androidx.test.platform.app.InstrumentationRegistry
+import com.android.net.module.util.DeviceConfigUtils
 import java.lang.System.currentTimeMillis
 import java.util.concurrent.CompletableFuture
 import java.util.concurrent.CountDownLatch
@@ -194,37 +194,33 @@
         return ipClientCaptor.value
     }
 
-    override fun setDhcpFeatures(
-        isDhcpLeaseCacheEnabled: Boolean,
-        isRapidCommitEnabled: Boolean,
-        isDhcpIpConflictDetectEnabled: Boolean,
-        isIPv6OnlyPreferredEnabled: Boolean
-    ) {
+    override fun setFeatureEnabled(feature: String, enabled: Boolean) {
         automation.adoptShellPermissionIdentity(READ_DEVICE_CONFIG, WRITE_DEVICE_CONFIG)
         try {
-            setFeatureEnabled(NetworkStackUtils.DHCP_INIT_REBOOT_VERSION, isDhcpLeaseCacheEnabled)
-            setFeatureEnabled(NetworkStackUtils.DHCP_RAPID_COMMIT_VERSION, isRapidCommitEnabled)
-            setFeatureEnabled(NetworkStackUtils.DHCP_IP_CONFLICT_DETECT_VERSION,
-                    isDhcpIpConflictDetectEnabled)
-            setFeatureEnabled(NetworkStackUtils.DHCP_IPV6_ONLY_PREFERRED_VERSION,
-                    isIPv6OnlyPreferredEnabled)
+            // Do not use computeIfAbsent as it would overwrite null values (flag originally unset)
+            if (!originalFlagValues.containsKey(feature)) {
+                originalFlagValues[feature] =
+                        DeviceConfig.getProperty(DeviceConfig.NAMESPACE_CONNECTIVITY, feature)
+            }
+            // The feature is enabled if the flag is lower than the package version.
+            // Package versions follow a standard format with 9 digits.
+            // TODO: consider resetting flag values on reboot when set to special values like "1" or
+            // "999999999"
+            DeviceConfig.setProperty(DeviceConfig.NAMESPACE_CONNECTIVITY, feature,
+                    if (enabled) "1" else "999999999", false)
         } finally {
             automation.dropShellPermissionIdentity()
         }
     }
 
-    private fun setFeatureEnabled(feature: String, enabled: Boolean) {
-        // Do not use computeIfAbsent as it would overwrite null values (flag originally unset)
-        if (!originalFlagValues.containsKey(feature)) {
-            originalFlagValues[feature] =
-                    DeviceConfig.getProperty(DeviceConfig.NAMESPACE_CONNECTIVITY, feature)
+    override fun isFeatureEnabled(name: String, defaultEnabled: Boolean): Boolean {
+        automation.adoptShellPermissionIdentity(READ_DEVICE_CONFIG, WRITE_DEVICE_CONFIG)
+        try {
+            return DeviceConfigUtils.isFeatureEnabled(mContext, DeviceConfig.NAMESPACE_CONNECTIVITY,
+                    name, defaultEnabled)
+        } finally {
+            automation.dropShellPermissionIdentity()
         }
-        // The feature is enabled if the flag is lower than the package version.
-        // Package versions follow a standard format with 9 digits.
-        // TODO: consider resetting flag values on reboot when set to special values like "1" or
-        // "999999999"
-        DeviceConfig.setProperty(DeviceConfig.NAMESPACE_CONNECTIVITY, feature,
-                if (enabled) "1" else "999999999", false)
     }
 
     private class TestAttributesRetrievedListener : OnNetworkAttributesRetrievedListener {