diff --git a/Tethering/src/android/net/ip/IpServer.java b/Tethering/src/android/net/ip/IpServer.java
index ebc9e4e..d6f4572 100644
--- a/Tethering/src/android/net/ip/IpServer.java
+++ b/Tethering/src/android/net/ip/IpServer.java
@@ -19,6 +19,12 @@
 import static android.net.RouteInfo.RTN_UNICAST;
 import static android.net.TetheringManager.CONNECTIVITY_SCOPE_GLOBAL;
 import static android.net.TetheringManager.CONNECTIVITY_SCOPE_LOCAL;
+import static android.net.TetheringManager.TETHERING_BLUETOOTH;
+import static android.net.TetheringManager.TETHERING_ETHERNET;
+import static android.net.TetheringManager.TETHERING_NCM;
+import static android.net.TetheringManager.TETHERING_WIFI;
+import static android.net.TetheringManager.TETHERING_WIFI_P2P;
+import static android.net.TetheringManager.TETHERING_WIGIG;
 import static android.net.TetheringManager.TETHER_ERROR_DHCPSERVER_ERROR;
 import static android.net.TetheringManager.TETHER_ERROR_ENABLE_FORWARDING_ERROR;
 import static android.net.TetheringManager.TETHER_ERROR_IFACE_CFG_ERROR;
@@ -45,7 +51,6 @@
 import android.net.MacAddress;
 import android.net.RouteInfo;
 import android.net.TetheredClient;
-import android.net.TetheringManager;
 import android.net.TetheringManager.TetheringRequest;
 import android.net.dhcp.DhcpLeaseParcelable;
 import android.net.dhcp.DhcpServerCallbacks;
@@ -589,8 +594,8 @@
             @NonNull final Inet4Address dnsServer, @NonNull LinkAddress serverAddr,
             @Nullable Inet4Address clientAddr) {
         final boolean changePrefixOnDecline =
-                (mInterfaceType == TetheringManager.TETHERING_NCM && clientAddr == null);
-        final int subnetPrefixLength = mInterfaceType == TetheringManager.TETHERING_WIFI_P2P
+                (mInterfaceType == TETHERING_NCM && clientAddr == null);
+        final int subnetPrefixLength = mInterfaceType == TETHERING_WIFI_P2P
                 ? mP2pLeasesSubnetPrefixLength : 0 /* default value */;
 
         return new DhcpServingParamsParcelExt()
@@ -690,10 +695,10 @@
         final IpPrefix ipv4Prefix = asIpPrefix(mIpv4Address);
 
         final Boolean setIfaceUp;
-        if (mInterfaceType == TetheringManager.TETHERING_WIFI
-                || mInterfaceType == TetheringManager.TETHERING_WIFI_P2P
-                || mInterfaceType == TetheringManager.TETHERING_ETHERNET
-                || mInterfaceType == TetheringManager.TETHERING_WIGIG) {
+        if (mInterfaceType == TETHERING_WIFI
+                || mInterfaceType == TETHERING_WIFI_P2P
+                || mInterfaceType == TETHERING_ETHERNET
+                || mInterfaceType == TETHERING_WIGIG) {
             // The WiFi and Ethernet stack has ownership of the interface up/down state.
             // It is unclear whether the Bluetooth or USB stacks will manage their own
             // state.
@@ -719,12 +724,12 @@
 
     private boolean shouldNotConfigureBluetoothInterface() {
         // Before T, bluetooth tethering configures the interface elsewhere.
-        return (mInterfaceType == TetheringManager.TETHERING_BLUETOOTH) && !SdkLevel.isAtLeastT();
+        return (mInterfaceType == TETHERING_BLUETOOTH) && !SdkLevel.isAtLeastT();
     }
 
     private boolean shouldUseWifiP2pDedicatedIp() {
         return mIsWifiP2pDedicatedIpEnabled
-                && mInterfaceType == TetheringManager.TETHERING_WIFI_P2P;
+                && mInterfaceType == TETHERING_WIFI_P2P;
     }
 
     private LinkAddress requestIpv4Address(final int scope, final boolean useLastAddress) {
@@ -844,12 +849,13 @@
         }
     }
 
-    private void removeRoutesFromLocalNetwork(@NonNull final List<RouteInfo> toBeRemoved) {
-        final int removalFailures = NetdUtils.removeRoutesFromLocalNetwork(
-                mNetd, toBeRemoved);
+    private void removeRoutesFromNetworkAndLinkProperties(int netId,
+            @NonNull final List<RouteInfo> toBeRemoved) {
+        final int removalFailures = NetdUtils.removeRoutesFromNetwork(
+                mNetd, netId, toBeRemoved);
         if (removalFailures > 0) {
-            mLog.e(String.format("Failed to remove %d IPv6 routes from local table.",
-                    removalFailures));
+            mLog.e("Failed to remove " + removalFailures
+                    + " IPv6 routes from network " + netId + ".");
         }
 
         for (RouteInfo route : toBeRemoved) mLinkProperties.removeRoute(route);
@@ -879,14 +885,15 @@
         }
     }
 
-    private void addRoutesToLocalNetwork(@NonNull final List<RouteInfo> toBeAdded) {
+    private void addRoutesToNetworkAndLinkProperties(int netId,
+            @NonNull final List<RouteInfo> toBeAdded) {
         // It's safe to call addInterfaceToNetwork() even if
-        // the interface is already in the local_network.
-        addInterfaceToNetwork(INetd.LOCAL_NET_ID, mIfaceName);
+        // the interface is already in the network.
+        addInterfaceToNetwork(netId, mIfaceName);
         try {
             // Add routes from local network. Note that adding routes that
             // already exist does not cause an error (EEXIST is silently ignored).
-            NetdUtils.addRoutesToLocalNetwork(mNetd, mIfaceName, toBeAdded);
+            NetdUtils.addRoutesToNetwork(mNetd, netId, mIfaceName, toBeAdded);
         } catch (IllegalStateException e) {
             mLog.e("Failed to add IPv4/v6 routes to local table: " + e);
             return;
@@ -899,7 +906,8 @@
             ArraySet<IpPrefix> deprecatedPrefixes, ArraySet<IpPrefix> newPrefixes) {
         // [1] Remove the routes that are deprecated.
         if (!deprecatedPrefixes.isEmpty()) {
-            removeRoutesFromLocalNetwork(getLocalRoutesFor(mIfaceName, deprecatedPrefixes));
+            removeRoutesFromNetworkAndLinkProperties(INetd.LOCAL_NET_ID,
+                    getLocalRoutesFor(mIfaceName, deprecatedPrefixes));
         }
 
         // [2] Add only the routes that have not previously been added.
@@ -910,7 +918,8 @@
             }
 
             if (!addedPrefixes.isEmpty()) {
-                addRoutesToLocalNetwork(getLocalRoutesFor(mIfaceName, addedPrefixes));
+                addRoutesToNetworkAndLinkProperties(INetd.LOCAL_NET_ID,
+                        getLocalRoutesFor(mIfaceName, addedPrefixes));
             }
         }
     }
@@ -1114,7 +1123,8 @@
             }
 
             try {
-                NetdUtils.tetherInterface(mNetd, mIfaceName, asIpPrefix(mIpv4Address));
+                NetdUtils.tetherInterface(mNetd, INetd.LOCAL_NET_ID, mIfaceName,
+                        asIpPrefix(mIpv4Address));
             } catch (RemoteException | ServiceSpecificException | IllegalStateException e) {
                 mLog.e("Error Tethering", e);
                 mLastError = TETHER_ERROR_TETHER_IFACE_ERROR;
@@ -1213,14 +1223,14 @@
                 return;
             }
 
-            // Remove deprecated routes from local network.
-            removeRoutesFromLocalNetwork(
-                    Collections.singletonList(getDirectConnectedRoute(deprecatedLinkAddress)));
+            // Remove deprecated routes from downstream network.
+            removeRoutesFromNetworkAndLinkProperties(INetd.LOCAL_NET_ID,
+                    List.of(getDirectConnectedRoute(deprecatedLinkAddress)));
             mLinkProperties.removeLinkAddress(deprecatedLinkAddress);
 
-            // Add new routes to local network.
-            addRoutesToLocalNetwork(
-                    Collections.singletonList(getDirectConnectedRoute(mIpv4Address)));
+            // Add new routes to downstream network.
+            addRoutesToNetworkAndLinkProperties(INetd.LOCAL_NET_ID,
+                    List.of(getDirectConnectedRoute(mIpv4Address)));
             mLinkProperties.addLinkAddress(mIpv4Address);
 
             // Update local DNS caching server with new IPv4 address, otherwise, dnsmasq doesn't
diff --git a/staticlibs/client-libs/netd/com/android/net/module/util/NetdUtils.java b/staticlibs/client-libs/netd/com/android/net/module/util/NetdUtils.java
index d99eedc..553a24b 100644
--- a/staticlibs/client-libs/netd/com/android/net/module/util/NetdUtils.java
+++ b/staticlibs/client-libs/netd/com/android/net/module/util/NetdUtils.java
@@ -149,17 +149,17 @@
     }
 
     /** Setup interface for tethering. */
-    public static void tetherInterface(final INetd netd, final String iface, final IpPrefix dest)
-            throws RemoteException, ServiceSpecificException {
-        tetherInterface(netd, iface, dest, 20 /* maxAttempts */, 50 /* pollingIntervalMs */);
+    public static void tetherInterface(final INetd netd, int netId, final String iface,
+            final IpPrefix dest) throws RemoteException, ServiceSpecificException {
+        tetherInterface(netd, netId, iface, dest, 20 /* maxAttempts */, 50 /* pollingIntervalMs */);
     }
 
     /** Setup interface with configurable retries for tethering. */
-    public static void tetherInterface(final INetd netd, final String iface, final IpPrefix dest,
-            int maxAttempts, int pollingIntervalMs)
+    public static void tetherInterface(final INetd netd, int netId, final String iface,
+            final IpPrefix dest, int maxAttempts, int pollingIntervalMs)
             throws RemoteException, ServiceSpecificException {
         netd.tetherInterfaceAdd(iface);
-        networkAddInterface(netd, iface, maxAttempts, pollingIntervalMs);
+        networkAddInterface(netd, netId, iface, maxAttempts, pollingIntervalMs);
         // Activate a route to dest and IPv6 link local.
         modifyRoute(netd, ModifyOperation.ADD, INetd.LOCAL_NET_ID,
                 new RouteInfo(dest, null, iface, RTN_UNICAST));
@@ -174,12 +174,12 @@
      * in use in netd because the ConnectivityService thread hasn't processed the disconnect yet.
      * See b/158269544 for detail.
      */
-    private static void networkAddInterface(final INetd netd, final String iface,
+    private static void networkAddInterface(final INetd netd, int netId, final String iface,
             int maxAttempts, int pollingIntervalMs)
             throws ServiceSpecificException, RemoteException {
         for (int i = 1; i <= maxAttempts; i++) {
             try {
-                netd.networkAddInterface(INetd.LOCAL_NET_ID, iface);
+                netd.networkAddInterface(netId, iface);
                 return;
             } catch (ServiceSpecificException e) {
                 if (e.errorCode == EBUSY && i < maxAttempts) {
@@ -203,28 +203,29 @@
         }
     }
 
-    /** Add |routes| to local network. */
-    public static void addRoutesToLocalNetwork(final INetd netd, final String iface,
+    /** Add |routes| to the given network. */
+    public static void addRoutesToNetwork(final INetd netd, int netId, final String iface,
             final List<RouteInfo> routes) {
 
         for (RouteInfo route : routes) {
             if (!route.isDefaultRoute()) {
-                modifyRoute(netd, ModifyOperation.ADD, INetd.LOCAL_NET_ID, route);
+                modifyRoute(netd, ModifyOperation.ADD, netId, route);
             }
         }
 
         // IPv6 link local should be activated always.
-        modifyRoute(netd, ModifyOperation.ADD, INetd.LOCAL_NET_ID,
+        modifyRoute(netd, ModifyOperation.ADD, netId,
                 new RouteInfo(new IpPrefix("fe80::/64"), null, iface, RTN_UNICAST));
     }
 
-    /** Remove routes from local network. */
-    public static int removeRoutesFromLocalNetwork(final INetd netd, final List<RouteInfo> routes) {
+    /** Remove routes from the given network. */
+    public static int removeRoutesFromNetwork(final INetd netd, int netId,
+            final List<RouteInfo> routes) {
         int failures = 0;
 
         for (RouteInfo route : routes) {
             try {
-                modifyRoute(netd, ModifyOperation.REMOVE, INetd.LOCAL_NET_ID, route);
+                modifyRoute(netd, ModifyOperation.REMOVE, netId, route);
             } catch (IllegalStateException e) {
                 failures++;
             }
diff --git a/staticlibs/client-libs/tests/unit/src/com/android/net/module/util/NetdUtilsTest.java b/staticlibs/client-libs/tests/unit/src/com/android/net/module/util/NetdUtilsTest.java
index 5069672..ab90a50 100644
--- a/staticlibs/client-libs/tests/unit/src/com/android/net/module/util/NetdUtilsTest.java
+++ b/staticlibs/client-libs/tests/unit/src/com/android/net/module/util/NetdUtilsTest.java
@@ -163,7 +163,7 @@
         setNetworkAddInterfaceOutcome(new ServiceSpecificException(expectedCode), expectedTries);
 
         try {
-            NetdUtils.tetherInterface(mNetd, IFACE, TEST_IPPREFIX, 20, 0);
+            NetdUtils.tetherInterface(mNetd, LOCAL_NET_ID, IFACE, TEST_IPPREFIX, 20, 0);
             fail("Expect throw ServiceSpecificException");
         } catch (ServiceSpecificException e) {
             assertEquals(e.errorCode, expectedCode);
@@ -177,7 +177,7 @@
         setNetworkAddInterfaceOutcome(new RemoteException(), expectedTries);
 
         try {
-            NetdUtils.tetherInterface(mNetd, IFACE, TEST_IPPREFIX, 20, 0);
+            NetdUtils.tetherInterface(mNetd, LOCAL_NET_ID, IFACE, TEST_IPPREFIX, 20, 0);
             fail("Expect throw RemoteException");
         } catch (RemoteException e) { }
 
@@ -195,7 +195,7 @@
     private void verifyTetherInterfaceSucceeds(int expectedTries) throws Exception {
         setNetworkAddInterfaceOutcome(null, expectedTries);
 
-        NetdUtils.tetherInterface(mNetd, IFACE, TEST_IPPREFIX);
+        NetdUtils.tetherInterface(mNetd, LOCAL_NET_ID, IFACE, TEST_IPPREFIX);
         verify(mNetd).tetherInterfaceAdd(IFACE);
         verify(mNetd, times(expectedTries)).networkAddInterface(LOCAL_NET_ID, IFACE);
         verify(mNetd, times(2)).networkAddRoute(eq(LOCAL_NET_ID), eq(IFACE), any(), any());