diff --git a/core/java/android/net/NetworkIdentity.java b/core/java/android/net/NetworkIdentity.java
index d3b3599..fd118f3 100644
--- a/core/java/android/net/NetworkIdentity.java
+++ b/core/java/android/net/NetworkIdentity.java
@@ -58,21 +58,24 @@
     final String mNetworkId;
     final boolean mRoaming;
     final boolean mMetered;
+    final boolean mDefaultNetwork;
 
     public NetworkIdentity(
             int type, int subType, String subscriberId, String networkId, boolean roaming,
-            boolean metered) {
+            boolean metered, boolean defaultNetwork) {
         mType = type;
         mSubType = COMBINE_SUBTYPE_ENABLED ? SUBTYPE_COMBINED : subType;
         mSubscriberId = subscriberId;
         mNetworkId = networkId;
         mRoaming = roaming;
         mMetered = metered;
+        mDefaultNetwork = defaultNetwork;
     }
 
     @Override
     public int hashCode() {
-        return Objects.hash(mType, mSubType, mSubscriberId, mNetworkId, mRoaming, mMetered);
+        return Objects.hash(mType, mSubType, mSubscriberId, mNetworkId, mRoaming, mMetered,
+                mDefaultNetwork);
     }
 
     @Override
@@ -82,7 +85,8 @@
             return mType == ident.mType && mSubType == ident.mSubType && mRoaming == ident.mRoaming
                     && Objects.equals(mSubscriberId, ident.mSubscriberId)
                     && Objects.equals(mNetworkId, ident.mNetworkId)
-                    && mMetered == ident.mMetered;
+                    && mMetered == ident.mMetered
+                    && mDefaultNetwork == ident.mDefaultNetwork;
         }
         return false;
     }
@@ -109,6 +113,7 @@
             builder.append(", ROAMING");
         }
         builder.append(", metered=").append(mMetered);
+        builder.append(", defaultNetwork=").append(mDefaultNetwork);
         return builder.append("}").toString();
     }
 
@@ -153,6 +158,10 @@
         return mMetered;
     }
 
+    public boolean getDefaultNetwork() {
+        return mDefaultNetwork;
+    }
+
     /**
      * Scrub given IMSI on production builds.
      */
@@ -183,7 +192,8 @@
      * Build a {@link NetworkIdentity} from the given {@link NetworkState},
      * assuming that any mobile networks are using the current IMSI.
      */
-    public static NetworkIdentity buildNetworkIdentity(Context context, NetworkState state) {
+    public static NetworkIdentity buildNetworkIdentity(Context context, NetworkState state,
+            boolean defaultNetwork) {
         final int type = state.networkInfo.getType();
         final int subType = state.networkInfo.getSubtype();
 
@@ -216,7 +226,8 @@
             }
         }
 
-        return new NetworkIdentity(type, subType, subscriberId, networkId, roaming, metered);
+        return new NetworkIdentity(type, subType, subscriberId, networkId, roaming, metered,
+                defaultNetwork);
     }
 
     @Override
@@ -237,6 +248,9 @@
         if (res == 0) {
             res = Boolean.compare(mMetered, another.mMetered);
         }
+        if (res == 0) {
+            res = Boolean.compare(mDefaultNetwork, another.mDefaultNetwork);
+        }
         return res;
     }
 }
diff --git a/services/core/java/com/android/server/net/NetworkIdentitySet.java b/services/core/java/com/android/server/net/NetworkIdentitySet.java
index ee00fdc..68cd5e7 100644
--- a/services/core/java/com/android/server/net/NetworkIdentitySet.java
+++ b/services/core/java/com/android/server/net/NetworkIdentitySet.java
@@ -39,6 +39,7 @@
     private static final int VERSION_ADD_ROAMING = 2;
     private static final int VERSION_ADD_NETWORK_ID = 3;
     private static final int VERSION_ADD_METERED = 4;
+    private static final int VERSION_ADD_DEFAULT_NETWORK = 5;
 
     public NetworkIdentitySet() {
     }
@@ -76,12 +77,20 @@
                 metered = (type == TYPE_MOBILE);
             }
 
-            add(new NetworkIdentity(type, subType, subscriberId, networkId, roaming, metered));
+            final boolean defaultNetwork;
+            if (version >= VERSION_ADD_DEFAULT_NETWORK) {
+                defaultNetwork = in.readBoolean();
+            } else {
+                defaultNetwork = true;
+            }
+
+            add(new NetworkIdentity(type, subType, subscriberId, networkId, roaming, metered,
+                    defaultNetwork));
         }
     }
 
     public void writeToStream(DataOutputStream out) throws IOException {
-        out.writeInt(VERSION_ADD_METERED);
+        out.writeInt(VERSION_ADD_DEFAULT_NETWORK);
         out.writeInt(size());
         for (NetworkIdentity ident : this) {
             out.writeInt(ident.getType());
@@ -90,6 +99,7 @@
             writeOptionalString(out, ident.getNetworkId());
             out.writeBoolean(ident.getRoaming());
             out.writeBoolean(ident.getMetered());
+            out.writeBoolean(ident.getDefaultNetwork());
         }
     }
 
@@ -119,6 +129,20 @@
         return false;
     }
 
+    /** @return whether any {@link NetworkIdentity} in this set is considered on the default
+            network. */
+    public boolean areAllMembersOnDefaultNetwork() {
+        if (isEmpty()) {
+            return true;
+        }
+        for (NetworkIdentity ident : this) {
+            if (!ident.getDefaultNetwork()) {
+                return false;
+            }
+        }
+        return true;
+    }
+
     private static void writeOptionalString(DataOutputStream out, String value) throws IOException {
         if (value != null) {
             out.writeByte(1);
diff --git a/services/core/java/com/android/server/net/NetworkPolicyManagerService.java b/services/core/java/com/android/server/net/NetworkPolicyManagerService.java
index 5159c70..948e75e 100644
--- a/services/core/java/com/android/server/net/NetworkPolicyManagerService.java
+++ b/services/core/java/com/android/server/net/NetworkPolicyManagerService.java
@@ -1103,7 +1103,8 @@
             for (int subId : subIds) {
                 final String subscriberId = tele.getSubscriberId(subId);
                 final NetworkIdentity probeIdent = new NetworkIdentity(TYPE_MOBILE,
-                        TelephonyManager.NETWORK_TYPE_UNKNOWN, subscriberId, null, false, true);
+                        TelephonyManager.NETWORK_TYPE_UNKNOWN, subscriberId, null, false, true,
+                        true);
                 if (template.matches(probeIdent)) {
                     return true;
                 }
@@ -1304,7 +1305,7 @@
 
         // find and update the mobile NetworkPolicy for this subscriber id
         final NetworkIdentity probeIdent = new NetworkIdentity(TYPE_MOBILE,
-                TelephonyManager.NETWORK_TYPE_UNKNOWN, subscriberId, null, false, true);
+                TelephonyManager.NETWORK_TYPE_UNKNOWN, subscriberId, null, false, true, true);
         for (int i = mNetworkPolicy.size() - 1; i >= 0; i--) {
             final NetworkTemplate template = mNetworkPolicy.keyAt(i);
             if (template.matches(probeIdent)) {
@@ -1511,7 +1512,8 @@
             for (int subId : subIds) {
                 final String subscriberId = tm.getSubscriberId(subId);
                 final NetworkIdentity probeIdent = new NetworkIdentity(TYPE_MOBILE,
-                        TelephonyManager.NETWORK_TYPE_UNKNOWN, subscriberId, null, false, true);
+                        TelephonyManager.NETWORK_TYPE_UNKNOWN, subscriberId, null, false, true,
+                        true);
                 // Template is matched when subscriber id matches.
                 if (template.matches(probeIdent)) {
                     tm.setPolicyDataEnabled(enabled, subId);
@@ -1557,7 +1559,8 @@
         final ArrayMap<NetworkState, NetworkIdentity> identified = new ArrayMap<>();
         for (NetworkState state : states) {
             if (state.networkInfo != null && state.networkInfo.isConnected()) {
-                final NetworkIdentity ident = NetworkIdentity.buildNetworkIdentity(mContext, state);
+                final NetworkIdentity ident = NetworkIdentity.buildNetworkIdentity(mContext, state,
+                        true);
                 identified.put(state, ident);
             }
         }
@@ -1692,7 +1695,7 @@
     private boolean ensureActiveMobilePolicyAL(int subId, String subscriberId) {
         // Poke around to see if we already have a policy
         final NetworkIdentity probeIdent = new NetworkIdentity(TYPE_MOBILE,
-                TelephonyManager.NETWORK_TYPE_UNKNOWN, subscriberId, null, false, true);
+                TelephonyManager.NETWORK_TYPE_UNKNOWN, subscriberId, null, false, true, true);
         for (int i = mNetworkPolicy.size() - 1; i >= 0; i--) {
             final NetworkTemplate template = mNetworkPolicy.keyAt(i);
             if (template.matches(probeIdent)) {
diff --git a/services/core/java/com/android/server/net/NetworkStatsCollection.java b/services/core/java/com/android/server/net/NetworkStatsCollection.java
index 5f79769..961a451 100644
--- a/services/core/java/com/android/server/net/NetworkStatsCollection.java
+++ b/services/core/java/com/android/server/net/NetworkStatsCollection.java
@@ -17,6 +17,7 @@
 package com.android.server.net;
 
 import static android.net.NetworkStats.IFACE_ALL;
+import static android.net.NetworkStats.DEFAULT_NETWORK_NO;
 import static android.net.NetworkStats.DEFAULT_NETWORK_YES;
 import static android.net.NetworkStats.METERED_NO;
 import static android.net.NetworkStats.METERED_YES;
@@ -365,7 +366,8 @@
                 entry.uid = key.uid;
                 entry.set = key.set;
                 entry.tag = key.tag;
-                entry.defaultNetwork = DEFAULT_NETWORK_YES;
+                entry.defaultNetwork = key.ident.areAllMembersOnDefaultNetwork() ?
+                        DEFAULT_NETWORK_YES : DEFAULT_NETWORK_NO;
                 entry.metered = key.ident.isAnyMemberMetered() ? METERED_YES : METERED_NO;
                 entry.roaming = key.ident.isAnyMemberRoaming() ? ROAMING_YES : ROAMING_NO;
                 entry.rxBytes = historyEntry.rxBytes;
diff --git a/services/core/java/com/android/server/net/NetworkStatsService.java b/services/core/java/com/android/server/net/NetworkStatsService.java
index 84dd05d..78fd4b4 100644
--- a/services/core/java/com/android/server/net/NetworkStatsService.java
+++ b/services/core/java/com/android/server/net/NetworkStatsService.java
@@ -1061,7 +1061,9 @@
         for (NetworkState state : states) {
             if (state.networkInfo.isConnected()) {
                 final boolean isMobile = isNetworkTypeMobile(state.networkInfo.getType());
-                final NetworkIdentity ident = NetworkIdentity.buildNetworkIdentity(mContext, state);
+                final boolean isDefault = ArrayUtils.contains(mDefaultNetworks, state.network);
+                final NetworkIdentity ident = NetworkIdentity.buildNetworkIdentity(mContext, state,
+                        isDefault);
 
                 // Traffic occurring on the base interface is always counted for
                 // both total usage and UID details.
@@ -1081,7 +1083,8 @@
                         // Copy the identify from IMS one but mark it as metered.
                         NetworkIdentity vtIdent = new NetworkIdentity(ident.getType(),
                                 ident.getSubType(), ident.getSubscriberId(), ident.getNetworkId(),
-                                ident.getRoaming(), true);
+                                ident.getRoaming(), true /* metered */,
+                                true /* onDefaultNetwork */);
                         findOrCreateNetworkIdentitySet(mActiveIfaces, VT_INTERFACE).add(vtIdent);
                         findOrCreateNetworkIdentitySet(mActiveUidIfaces, VT_INTERFACE).add(vtIdent);
                     }
diff --git a/tests/net/java/com/android/server/net/NetworkStatsCollectionTest.java b/tests/net/java/com/android/server/net/NetworkStatsCollectionTest.java
index 9c10264..da0a48a 100644
--- a/tests/net/java/com/android/server/net/NetworkStatsCollectionTest.java
+++ b/tests/net/java/com/android/server/net/NetworkStatsCollectionTest.java
@@ -195,7 +195,7 @@
         final NetworkStats.Entry entry = new NetworkStats.Entry();
         final NetworkIdentitySet identSet = new NetworkIdentitySet();
         identSet.add(new NetworkIdentity(TYPE_MOBILE, TelephonyManager.NETWORK_TYPE_UNKNOWN,
-                TEST_IMSI, null, false, true));
+                TEST_IMSI, null, false, true, true));
 
         int myUid = Process.myUid();
         int otherUidInSameUser = Process.myUid() + 1;
@@ -447,7 +447,7 @@
         final NetworkStatsCollection large = new NetworkStatsCollection(HOUR_IN_MILLIS);
         final NetworkIdentitySet ident = new NetworkIdentitySet();
         ident.add(new NetworkIdentity(ConnectivityManager.TYPE_MOBILE, -1, TEST_IMSI, null,
-                false, true));
+                false, true, true));
         large.recordData(ident, UID_ALL, SET_ALL, TAG_NONE, TIME_A, TIME_B,
                 new NetworkStats.Entry(12_730_893_164L, 1, 0, 0, 0));
 
diff --git a/tests/net/java/com/android/server/net/NetworkStatsObserversTest.java b/tests/net/java/com/android/server/net/NetworkStatsObserversTest.java
index b12cfd1..185c3eb 100644
--- a/tests/net/java/com/android/server/net/NetworkStatsObserversTest.java
+++ b/tests/net/java/com/android/server/net/NetworkStatsObserversTest.java
@@ -226,6 +226,15 @@
         Mockito.verifyZeroInteractions(mockBinder);
     }
 
+    private NetworkIdentitySet makeTestIdentSet() {
+        NetworkIdentitySet identSet = new NetworkIdentitySet();
+        identSet.add(new NetworkIdentity(
+                TYPE_MOBILE, TelephonyManager.NETWORK_TYPE_UNKNOWN,
+                IMSI_1, null /* networkId */, false /* roaming */, true /* metered */,
+                true /* defaultNetwork */));
+        return identSet;
+    }
+
     @Test
     public void testUpdateStats_initialSample_doesNotNotify() throws Exception {
         DataUsageRequest inputRequest = new DataUsageRequest(
@@ -237,10 +246,7 @@
         assertTrue(Objects.equals(sTemplateImsi1, request.template));
         assertEquals(THRESHOLD_BYTES, request.thresholdInBytes);
 
-        NetworkIdentitySet identSet = new NetworkIdentitySet();
-        identSet.add(new NetworkIdentity(
-                TYPE_MOBILE, TelephonyManager.NETWORK_TYPE_UNKNOWN,
-                IMSI_1, null /* networkId */, false /* roaming */, true /* metered */));
+        NetworkIdentitySet identSet = makeTestIdentSet();
         mActiveIfaces.put(TEST_IFACE, identSet);
 
         // Baseline
@@ -265,10 +271,7 @@
         assertTrue(Objects.equals(sTemplateImsi1, request.template));
         assertEquals(THRESHOLD_BYTES, request.thresholdInBytes);
 
-        NetworkIdentitySet identSet = new NetworkIdentitySet();
-        identSet.add(new NetworkIdentity(
-                TYPE_MOBILE, TelephonyManager.NETWORK_TYPE_UNKNOWN,
-                IMSI_1, null /* networkId */, false /* roaming */, true /* metered */));
+        NetworkIdentitySet identSet = makeTestIdentSet();
         mActiveIfaces.put(TEST_IFACE, identSet);
 
         // Baseline
@@ -300,10 +303,7 @@
         assertTrue(Objects.equals(sTemplateImsi1, request.template));
         assertEquals(THRESHOLD_BYTES, request.thresholdInBytes);
 
-        NetworkIdentitySet identSet = new NetworkIdentitySet();
-        identSet.add(new NetworkIdentity(
-                TYPE_MOBILE, TelephonyManager.NETWORK_TYPE_UNKNOWN,
-                IMSI_1, null /* networkId */, false /* roaming */, true /* metered */));
+        NetworkIdentitySet identSet = makeTestIdentSet();
         mActiveIfaces.put(TEST_IFACE, identSet);
 
         // Baseline
@@ -336,10 +336,7 @@
         assertTrue(Objects.equals(sTemplateImsi1, request.template));
         assertEquals(THRESHOLD_BYTES, request.thresholdInBytes);
 
-        NetworkIdentitySet identSet = new NetworkIdentitySet();
-        identSet.add(new NetworkIdentity(
-                TYPE_MOBILE, TelephonyManager.NETWORK_TYPE_UNKNOWN,
-                IMSI_1, null /* networkId */, false /* roaming */, true /* metered */));
+        NetworkIdentitySet identSet = makeTestIdentSet();
         mActiveUidIfaces.put(TEST_IFACE, identSet);
 
         // Baseline
@@ -374,10 +371,7 @@
         assertTrue(Objects.equals(sTemplateImsi1, request.template));
         assertEquals(THRESHOLD_BYTES, request.thresholdInBytes);
 
-        NetworkIdentitySet identSet = new NetworkIdentitySet();
-        identSet.add(new NetworkIdentity(
-                TYPE_MOBILE, TelephonyManager.NETWORK_TYPE_UNKNOWN,
-                IMSI_1, null /* networkId */, false /* roaming */, true /* metered */));
+        NetworkIdentitySet identSet = makeTestIdentSet();
         mActiveUidIfaces.put(TEST_IFACE, identSet);
 
         // Baseline
@@ -411,10 +405,7 @@
         assertTrue(Objects.equals(sTemplateImsi1, request.template));
         assertEquals(THRESHOLD_BYTES, request.thresholdInBytes);
 
-        NetworkIdentitySet identSet = new NetworkIdentitySet();
-        identSet.add(new NetworkIdentity(
-                TYPE_MOBILE, TelephonyManager.NETWORK_TYPE_UNKNOWN,
-                IMSI_1, null /* networkId */, false /* roaming */, true /* metered */));
+        NetworkIdentitySet identSet = makeTestIdentSet();
         mActiveUidIfaces.put(TEST_IFACE, identSet);
 
         // Baseline
@@ -449,10 +440,7 @@
         assertTrue(Objects.equals(sTemplateImsi1, request.template));
         assertEquals(THRESHOLD_BYTES, request.thresholdInBytes);
 
-        NetworkIdentitySet identSet = new NetworkIdentitySet();
-        identSet.add(new NetworkIdentity(
-                TYPE_MOBILE, TelephonyManager.NETWORK_TYPE_UNKNOWN,
-                IMSI_1, null /* networkId */, false /* roaming */, true /* metered */));
+        NetworkIdentitySet identSet = makeTestIdentSet();
         mActiveUidIfaces.put(TEST_IFACE, identSet);
 
         // Baseline