diff --git a/core/java/android/net/INetworkStatsService.aidl b/core/java/android/net/INetworkStatsService.aidl
index 95e7f6031c..90e3ffd550 100644
--- a/core/java/android/net/INetworkStatsService.aidl
+++ b/core/java/android/net/INetworkStatsService.aidl
@@ -18,6 +18,7 @@ package android.net;
 
 import android.net.DataUsageRequest;
 import android.net.INetworkStatsSession;
+import android.net.Network;
 import android.net.NetworkStats;
 import android.net.NetworkStatsHistory;
 import android.net.NetworkTemplate;
@@ -53,7 +54,7 @@ interface INetworkStatsService {
     void setUidForeground(int uid, boolean uidForeground);
 
     /** Force update of ifaces. */
-    void forceUpdateIfaces();
+    void forceUpdateIfaces(in Network[] defaultNetworks);
     /** Force update of statistics. */
     void forceUpdate();
 
diff --git a/core/java/android/net/NetworkIdentity.java b/core/java/android/net/NetworkIdentity.java
index d3b35998be..fd118f3401 100644
--- a/core/java/android/net/NetworkIdentity.java
+++ b/core/java/android/net/NetworkIdentity.java
@@ -58,21 +58,24 @@ public class NetworkIdentity implements Comparable<NetworkIdentity> {
     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 @@ public class NetworkIdentity implements Comparable<NetworkIdentity> {
             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 @@ public class NetworkIdentity implements Comparable<NetworkIdentity> {
             builder.append(", ROAMING");
         }
         builder.append(", metered=").append(mMetered);
+        builder.append(", defaultNetwork=").append(mDefaultNetwork);
         return builder.append("}").toString();
     }
 
@@ -153,6 +158,10 @@ public class NetworkIdentity implements Comparable<NetworkIdentity> {
         return mMetered;
     }
 
+    public boolean getDefaultNetwork() {
+        return mDefaultNetwork;
+    }
+
     /**
      * Scrub given IMSI on production builds.
      */
@@ -183,7 +192,8 @@ public class NetworkIdentity implements Comparable<NetworkIdentity> {
      * 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 @@ public class NetworkIdentity implements Comparable<NetworkIdentity> {
             }
         }
 
-        return new NetworkIdentity(type, subType, subscriberId, networkId, roaming, metered);
+        return new NetworkIdentity(type, subType, subscriberId, networkId, roaming, metered,
+                defaultNetwork);
     }
 
     @Override
@@ -237,6 +248,9 @@ public class NetworkIdentity implements Comparable<NetworkIdentity> {
         if (res == 0) {
             res = Boolean.compare(mMetered, another.mMetered);
         }
+        if (res == 0) {
+            res = Boolean.compare(mDefaultNetwork, another.mDefaultNetwork);
+        }
         return res;
     }
 }
diff --git a/core/java/android/net/NetworkStats.java b/core/java/android/net/NetworkStats.java
index 171adc054b..a85f80e38d 100644
--- a/core/java/android/net/NetworkStats.java
+++ b/core/java/android/net/NetworkStats.java
@@ -82,6 +82,13 @@ public class NetworkStats implements Parcelable {
     /** {@link #roaming} value where roaming data is accounted. */
     public static final int ROAMING_YES = 1;
 
+    /** {@link #onDefaultNetwork} value to account for all default network states. */
+    public static final int DEFAULT_NETWORK_ALL = -1;
+    /** {@link #onDefaultNetwork} value to account for usage while not the default network. */
+    public static final int DEFAULT_NETWORK_NO = 0;
+    /** {@link #onDefaultNetwork} value to account for usage while the default network. */
+    public static final int DEFAULT_NETWORK_YES = 1;
+
     /** Denotes a request for stats at the interface level. */
     public static final int STATS_PER_IFACE = 0;
     /** Denotes a request for stats at the interface and UID level. */
@@ -102,6 +109,7 @@ public class NetworkStats implements Parcelable {
     private int[] tag;
     private int[] metered;
     private int[] roaming;
+    private int[] defaultNetwork;
     private long[] rxBytes;
     private long[] rxPackets;
     private long[] txBytes;
@@ -125,6 +133,12 @@ public class NetworkStats implements Parcelable {
          * getSummary().
          */
         public int roaming;
+        /**
+         * Note that this is only populated w/ the default value when read from /proc or written
+         * to disk. We merge in the correct value when reporting this value to clients of
+         * getSummary().
+         */
+        public int defaultNetwork;
         public long rxBytes;
         public long rxPackets;
         public long txBytes;
@@ -142,18 +156,27 @@ public class NetworkStats implements Parcelable {
 
         public Entry(String iface, int uid, int set, int tag, long rxBytes, long rxPackets,
                 long txBytes, long txPackets, long operations) {
-            this(iface, uid, set, tag, METERED_NO, ROAMING_NO, rxBytes, rxPackets, txBytes,
-                    txPackets, operations);
+            this(iface, uid, set, tag, METERED_NO, ROAMING_NO, DEFAULT_NETWORK_NO,
+                    rxBytes, rxPackets, txBytes, txPackets, operations);
+        }
+
+        // TODO: fix the the telephony code to pass DEFAULT_NETWORK_YES and remove this constructor.
+        public Entry(String iface, int uid, int set, int tag, int metered, int roaming,
+                 long rxBytes, long rxPackets, long txBytes, long txPackets, long operations) {
+            this(iface, uid, set, tag, metered, roaming, DEFAULT_NETWORK_YES, rxBytes, rxPackets,
+                    txBytes, txPackets, operations);
         }
 
         public Entry(String iface, int uid, int set, int tag, int metered, int roaming,
-                 long rxBytes, long rxPackets, long txBytes, long txPackets, long operations) {
+                 int defaultNetwork, long rxBytes, long rxPackets, long txBytes, long txPackets,
+                 long operations) {
             this.iface = iface;
             this.uid = uid;
             this.set = set;
             this.tag = tag;
             this.metered = metered;
             this.roaming = roaming;
+            this.defaultNetwork = defaultNetwork;
             this.rxBytes = rxBytes;
             this.rxPackets = rxPackets;
             this.txBytes = txBytes;
@@ -187,6 +210,7 @@ public class NetworkStats implements Parcelable {
             builder.append(" tag=").append(tagToString(tag));
             builder.append(" metered=").append(meteredToString(metered));
             builder.append(" roaming=").append(roamingToString(roaming));
+            builder.append(" defaultNetwork=").append(defaultNetworkToString(defaultNetwork));
             builder.append(" rxBytes=").append(rxBytes);
             builder.append(" rxPackets=").append(rxPackets);
             builder.append(" txBytes=").append(txBytes);
@@ -200,7 +224,8 @@ public class NetworkStats implements Parcelable {
             if (o instanceof Entry) {
                 final Entry e = (Entry) o;
                 return uid == e.uid && set == e.set && tag == e.tag && metered == e.metered
-                        && roaming == e.roaming && rxBytes == e.rxBytes && rxPackets == e.rxPackets
+                        && roaming == e.roaming && defaultNetwork == e.defaultNetwork
+                        && rxBytes == e.rxBytes && rxPackets == e.rxPackets
                         && txBytes == e.txBytes && txPackets == e.txPackets
                         && operations == e.operations && iface.equals(e.iface);
             }
@@ -209,7 +234,7 @@ public class NetworkStats implements Parcelable {
 
         @Override
         public int hashCode() {
-            return Objects.hash(uid, set, tag, metered, roaming, iface);
+            return Objects.hash(uid, set, tag, metered, roaming, defaultNetwork, iface);
         }
     }
 
@@ -224,6 +249,7 @@ public class NetworkStats implements Parcelable {
             this.tag = new int[initialSize];
             this.metered = new int[initialSize];
             this.roaming = new int[initialSize];
+            this.defaultNetwork = new int[initialSize];
             this.rxBytes = new long[initialSize];
             this.rxPackets = new long[initialSize];
             this.txBytes = new long[initialSize];
@@ -238,6 +264,7 @@ public class NetworkStats implements Parcelable {
             this.tag = EmptyArray.INT;
             this.metered = EmptyArray.INT;
             this.roaming = EmptyArray.INT;
+            this.defaultNetwork = EmptyArray.INT;
             this.rxBytes = EmptyArray.LONG;
             this.rxPackets = EmptyArray.LONG;
             this.txBytes = EmptyArray.LONG;
@@ -256,6 +283,7 @@ public class NetworkStats implements Parcelable {
         tag = parcel.createIntArray();
         metered = parcel.createIntArray();
         roaming = parcel.createIntArray();
+        defaultNetwork = parcel.createIntArray();
         rxBytes = parcel.createLongArray();
         rxPackets = parcel.createLongArray();
         txBytes = parcel.createLongArray();
@@ -274,6 +302,7 @@ public class NetworkStats implements Parcelable {
         dest.writeIntArray(tag);
         dest.writeIntArray(metered);
         dest.writeIntArray(roaming);
+        dest.writeIntArray(defaultNetwork);
         dest.writeLongArray(rxBytes);
         dest.writeLongArray(rxPackets);
         dest.writeLongArray(txBytes);
@@ -308,10 +337,11 @@ public class NetworkStats implements Parcelable {
 
     @VisibleForTesting
     public NetworkStats addValues(String iface, int uid, int set, int tag, int metered, int roaming,
-            long rxBytes, long rxPackets, long txBytes, long txPackets, long operations) {
+            int defaultNetwork, long rxBytes, long rxPackets, long txBytes, long txPackets,
+            long operations) {
         return addValues(new Entry(
-                iface, uid, set, tag, metered, roaming, rxBytes, rxPackets, txBytes, txPackets,
-                operations));
+                iface, uid, set, tag, metered, roaming, defaultNetwork, rxBytes, rxPackets,
+                txBytes, txPackets, operations));
     }
 
     /**
@@ -327,6 +357,7 @@ public class NetworkStats implements Parcelable {
             tag = Arrays.copyOf(tag, newLength);
             metered = Arrays.copyOf(metered, newLength);
             roaming = Arrays.copyOf(roaming, newLength);
+            defaultNetwork = Arrays.copyOf(defaultNetwork, newLength);
             rxBytes = Arrays.copyOf(rxBytes, newLength);
             rxPackets = Arrays.copyOf(rxPackets, newLength);
             txBytes = Arrays.copyOf(txBytes, newLength);
@@ -341,6 +372,7 @@ public class NetworkStats implements Parcelable {
         tag[size] = entry.tag;
         metered[size] = entry.metered;
         roaming[size] = entry.roaming;
+        defaultNetwork[size] = entry.defaultNetwork;
         rxBytes[size] = entry.rxBytes;
         rxPackets[size] = entry.rxPackets;
         txBytes[size] = entry.txBytes;
@@ -362,6 +394,7 @@ public class NetworkStats implements Parcelable {
         entry.tag = tag[i];
         entry.metered = metered[i];
         entry.roaming = roaming[i];
+        entry.defaultNetwork = defaultNetwork[i];
         entry.rxBytes = rxBytes[i];
         entry.rxPackets = rxPackets[i];
         entry.txBytes = txBytes[i];
@@ -416,7 +449,7 @@ public class NetworkStats implements Parcelable {
      */
     public NetworkStats combineValues(Entry entry) {
         final int i = findIndex(entry.iface, entry.uid, entry.set, entry.tag, entry.metered,
-                entry.roaming);
+                entry.roaming, entry.defaultNetwork);
         if (i == -1) {
             // only create new entry when positive contribution
             addValues(entry);
@@ -444,10 +477,12 @@ public class NetworkStats implements Parcelable {
     /**
      * Find first stats index that matches the requested parameters.
      */
-    public int findIndex(String iface, int uid, int set, int tag, int metered, int roaming) {
+    public int findIndex(String iface, int uid, int set, int tag, int metered, int roaming,
+            int defaultNetwork) {
         for (int i = 0; i < size; i++) {
             if (uid == this.uid[i] && set == this.set[i] && tag == this.tag[i]
                     && metered == this.metered[i] && roaming == this.roaming[i]
+                    && defaultNetwork == this.defaultNetwork[i]
                     && Objects.equals(iface, this.iface[i])) {
                 return i;
             }
@@ -461,7 +496,7 @@ public class NetworkStats implements Parcelable {
      */
     @VisibleForTesting
     public int findIndexHinted(String iface, int uid, int set, int tag, int metered, int roaming,
-            int hintIndex) {
+            int defaultNetwork, int hintIndex) {
         for (int offset = 0; offset < size; offset++) {
             final int halfOffset = offset / 2;
 
@@ -475,6 +510,7 @@ public class NetworkStats implements Parcelable {
 
             if (uid == this.uid[i] && set == this.set[i] && tag == this.tag[i]
                     && metered == this.metered[i] && roaming == this.roaming[i]
+                    && defaultNetwork == this.defaultNetwork[i]
                     && Objects.equals(iface, this.iface[i])) {
                 return i;
             }
@@ -489,7 +525,8 @@ public class NetworkStats implements Parcelable {
      */
     public void spliceOperationsFrom(NetworkStats stats) {
         for (int i = 0; i < size; i++) {
-            final int j = stats.findIndex(iface[i], uid[i], set[i], tag[i], metered[i], roaming[i]);
+            final int j = stats.findIndex(iface[i], uid[i], set[i], tag[i], metered[i], roaming[i],
+                    defaultNetwork[i]);
             if (j == -1) {
                 operations[i] = 0;
             } else {
@@ -581,6 +618,7 @@ public class NetworkStats implements Parcelable {
         entry.tag = TAG_NONE;
         entry.metered = METERED_ALL;
         entry.roaming = ROAMING_ALL;
+        entry.defaultNetwork = DEFAULT_NETWORK_ALL;
         entry.rxBytes = 0;
         entry.rxPackets = 0;
         entry.txBytes = 0;
@@ -677,6 +715,7 @@ public class NetworkStats implements Parcelable {
             entry.tag = left.tag[i];
             entry.metered = left.metered[i];
             entry.roaming = left.roaming[i];
+            entry.defaultNetwork = left.defaultNetwork[i];
             entry.rxBytes = left.rxBytes[i];
             entry.rxPackets = left.rxPackets[i];
             entry.txBytes = left.txBytes[i];
@@ -685,7 +724,7 @@ public class NetworkStats implements Parcelable {
 
             // find remote row that matches, and subtract
             final int j = right.findIndexHinted(entry.iface, entry.uid, entry.set, entry.tag,
-                    entry.metered, entry.roaming, i);
+                    entry.metered, entry.roaming, entry.defaultNetwork, i);
             if (j != -1) {
                 // Found matching row, subtract remote value.
                 entry.rxBytes -= right.rxBytes[j];
@@ -725,6 +764,7 @@ public class NetworkStats implements Parcelable {
         entry.tag = TAG_NONE;
         entry.metered = METERED_ALL;
         entry.roaming = ROAMING_ALL;
+        entry.defaultNetwork = DEFAULT_NETWORK_ALL;
         entry.operations = 0L;
 
         for (int i = 0; i < size; i++) {
@@ -755,6 +795,7 @@ public class NetworkStats implements Parcelable {
         entry.tag = TAG_NONE;
         entry.metered = METERED_ALL;
         entry.roaming = ROAMING_ALL;
+        entry.defaultNetwork = DEFAULT_NETWORK_ALL;
 
         for (int i = 0; i < size; i++) {
             // skip specific tags, since already counted in TAG_NONE
@@ -802,6 +843,7 @@ public class NetworkStats implements Parcelable {
             pw.print(" tag="); pw.print(tagToString(tag[i]));
             pw.print(" metered="); pw.print(meteredToString(metered[i]));
             pw.print(" roaming="); pw.print(roamingToString(roaming[i]));
+            pw.print(" defaultNetwork="); pw.print(defaultNetworkToString(defaultNetwork[i]));
             pw.print(" rxBytes="); pw.print(rxBytes[i]);
             pw.print(" rxPackets="); pw.print(rxPackets[i]);
             pw.print(" txBytes="); pw.print(txBytes[i]);
@@ -900,6 +942,22 @@ public class NetworkStats implements Parcelable {
         }
     }
 
+    /**
+     * Return text description of {@link #defaultNetwork} value.
+     */
+    public static String defaultNetworkToString(int defaultNetwork) {
+        switch (defaultNetwork) {
+            case DEFAULT_NETWORK_ALL:
+                return "ALL";
+            case DEFAULT_NETWORK_NO:
+                return "NO";
+            case DEFAULT_NETWORK_YES:
+                return "YES";
+            default:
+                return "UNKNOWN";
+        }
+    }
+
     @Override
     public String toString() {
         final CharArrayWriter writer = new CharArrayWriter();
@@ -1055,6 +1113,7 @@ public class NetworkStats implements Parcelable {
                 tmpEntry.set = set[i];
                 tmpEntry.metered = metered[i];
                 tmpEntry.roaming = roaming[i];
+                tmpEntry.defaultNetwork = defaultNetwork[i];
                 combineValues(tmpEntry);
                 if (tag[i] == TAG_NONE) {
                     moved.add(tmpEntry);
@@ -1075,6 +1134,7 @@ public class NetworkStats implements Parcelable {
         moved.iface = underlyingIface;
         moved.metered = METERED_ALL;
         moved.roaming = ROAMING_ALL;
+        moved.defaultNetwork = DEFAULT_NETWORK_ALL;
         combineValues(moved);
 
         // Caveat: if the vpn software uses tag, the total tagged traffic may be greater than
@@ -1085,13 +1145,13 @@ public class NetworkStats implements Parcelable {
         // roaming data after applying these adjustments, by checking the NetworkIdentity of the
         // underlying iface.
         int idxVpnBackground = findIndex(underlyingIface, tunUid, SET_DEFAULT, TAG_NONE,
-                METERED_NO, ROAMING_NO);
+                METERED_NO, ROAMING_NO, DEFAULT_NETWORK_NO);
         if (idxVpnBackground != -1) {
             tunSubtract(idxVpnBackground, this, moved);
         }
 
         int idxVpnForeground = findIndex(underlyingIface, tunUid, SET_FOREGROUND, TAG_NONE,
-                METERED_NO, ROAMING_NO);
+                METERED_NO, ROAMING_NO, DEFAULT_NETWORK_NO);
         if (idxVpnForeground != -1) {
             tunSubtract(idxVpnForeground, this, moved);
         }
diff --git a/core/java/com/android/internal/net/NetworkStatsFactory.java b/core/java/com/android/internal/net/NetworkStatsFactory.java
index 5eda81baa3..02cd09f78a 100644
--- a/core/java/com/android/internal/net/NetworkStatsFactory.java
+++ b/core/java/com/android/internal/net/NetworkStatsFactory.java
@@ -219,7 +219,7 @@ public class NetworkStatsFactory {
             }
 
             NetworkStats.Entry adjust =
-                    new NetworkStats.Entry(baseIface, 0, 0, 0, 0L, 0L, 0L, 0L, 0L);
+                    new NetworkStats.Entry(baseIface, 0, 0, 0, 0, 0, 0, 0L, 0L, 0L, 0L, 0L);
             // Subtract any 464lat traffic seen for the root UID on the current base interface.
             adjust.rxBytes -= (entry.rxBytes + entry.rxPackets * IPV4V6_HEADER_DELTA);
             adjust.txBytes -= (entry.txBytes + entry.txPackets * IPV4V6_HEADER_DELTA);
diff --git a/core/jni/com_android_internal_net_NetworkStatsFactory.cpp b/core/jni/com_android_internal_net_NetworkStatsFactory.cpp
index 0cb6935990..d254de65f7 100644
--- a/core/jni/com_android_internal_net_NetworkStatsFactory.cpp
+++ b/core/jni/com_android_internal_net_NetworkStatsFactory.cpp
@@ -45,6 +45,7 @@ static struct {
     jfieldID tag;
     jfieldID metered;
     jfieldID roaming;
+    jfieldID defaultNetwork;
     jfieldID rxBytes;
     jfieldID rxPackets;
     jfieldID txBytes;
@@ -246,6 +247,9 @@ static int readNetworkStatsDetail(JNIEnv* env, jclass clazz, jobject stats,
     ScopedIntArrayRW roaming(env, get_int_array(env, stats,
             gNetworkStatsClassInfo.roaming, size, grow));
     if (roaming.get() == NULL) return -1;
+    ScopedIntArrayRW defaultNetwork(env, get_int_array(env, stats,
+            gNetworkStatsClassInfo.defaultNetwork, size, grow));
+    if (defaultNetwork.get() == NULL) return -1;
     ScopedLongArrayRW rxBytes(env, get_long_array(env, stats,
             gNetworkStatsClassInfo.rxBytes, size, grow));
     if (rxBytes.get() == NULL) return -1;
@@ -269,7 +273,7 @@ static int readNetworkStatsDetail(JNIEnv* env, jclass clazz, jobject stats,
         uid[i] = lines[i].uid;
         set[i] = lines[i].set;
         tag[i] = lines[i].tag;
-        // Metered and Roaming are populated in Java-land by inspecting the iface properties.
+        // Metered, roaming and defaultNetwork are populated in Java-land.
         rxBytes[i] = lines[i].rxBytes;
         rxPackets[i] = lines[i].rxPackets;
         txBytes[i] = lines[i].txBytes;
@@ -285,6 +289,8 @@ static int readNetworkStatsDetail(JNIEnv* env, jclass clazz, jobject stats,
         env->SetObjectField(stats, gNetworkStatsClassInfo.tag, tag.getJavaArray());
         env->SetObjectField(stats, gNetworkStatsClassInfo.metered, metered.getJavaArray());
         env->SetObjectField(stats, gNetworkStatsClassInfo.roaming, roaming.getJavaArray());
+        env->SetObjectField(stats, gNetworkStatsClassInfo.defaultNetwork,
+                defaultNetwork.getJavaArray());
         env->SetObjectField(stats, gNetworkStatsClassInfo.rxBytes, rxBytes.getJavaArray());
         env->SetObjectField(stats, gNetworkStatsClassInfo.rxPackets, rxPackets.getJavaArray());
         env->SetObjectField(stats, gNetworkStatsClassInfo.txBytes, txBytes.getJavaArray());
@@ -318,6 +324,7 @@ int register_com_android_internal_net_NetworkStatsFactory(JNIEnv* env) {
     gNetworkStatsClassInfo.tag = GetFieldIDOrDie(env, clazz, "tag", "[I");
     gNetworkStatsClassInfo.metered = GetFieldIDOrDie(env, clazz, "metered", "[I");
     gNetworkStatsClassInfo.roaming = GetFieldIDOrDie(env, clazz, "roaming", "[I");
+    gNetworkStatsClassInfo.defaultNetwork = GetFieldIDOrDie(env, clazz, "defaultNetwork", "[I");
     gNetworkStatsClassInfo.rxBytes = GetFieldIDOrDie(env, clazz, "rxBytes", "[J");
     gNetworkStatsClassInfo.rxPackets = GetFieldIDOrDie(env, clazz, "rxPackets", "[J");
     gNetworkStatsClassInfo.txBytes = GetFieldIDOrDie(env, clazz, "txBytes", "[J");
diff --git a/services/core/java/com/android/server/net/NetworkIdentitySet.java b/services/core/java/com/android/server/net/NetworkIdentitySet.java
index ee00fdc333..68cd5e7aed 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 @@ public class NetworkIdentitySet extends HashSet<NetworkIdentity> implements
     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 @@ public class NetworkIdentitySet extends HashSet<NetworkIdentity> implements
                 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 @@ public class NetworkIdentitySet extends HashSet<NetworkIdentity> implements
             writeOptionalString(out, ident.getNetworkId());
             out.writeBoolean(ident.getRoaming());
             out.writeBoolean(ident.getMetered());
+            out.writeBoolean(ident.getDefaultNetwork());
         }
     }
 
@@ -119,6 +129,20 @@ public class NetworkIdentitySet extends HashSet<NetworkIdentity> implements
         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/NetworkStatsCollection.java b/services/core/java/com/android/server/net/NetworkStatsCollection.java
index 4ceb592af0..961a451778 100644
--- a/services/core/java/com/android/server/net/NetworkStatsCollection.java
+++ b/services/core/java/com/android/server/net/NetworkStatsCollection.java
@@ -17,6 +17,8 @@
 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;
 import static android.net.NetworkStats.ROAMING_NO;
@@ -364,6 +366,8 @@ public class NetworkStatsCollection implements FileRotator.Reader {
                 entry.uid = key.uid;
                 entry.set = key.set;
                 entry.tag = key.tag;
+                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 db61ef5cd9..78fd4b4923 100644
--- a/services/core/java/com/android/server/net/NetworkStatsService.java
+++ b/services/core/java/com/android/server/net/NetworkStatsService.java
@@ -25,6 +25,7 @@ import static android.content.Intent.ACTION_USER_REMOVED;
 import static android.content.Intent.EXTRA_UID;
 import static android.net.ConnectivityManager.ACTION_TETHER_STATE_CHANGED;
 import static android.net.ConnectivityManager.isNetworkTypeMobile;
+import static android.net.NetworkStats.DEFAULT_NETWORK_ALL;
 import static android.net.NetworkStats.IFACE_ALL;
 import static android.net.NetworkStats.METERED_ALL;
 import static android.net.NetworkStats.ROAMING_ALL;
@@ -83,6 +84,7 @@ import android.net.INetworkManagementEventObserver;
 import android.net.INetworkStatsService;
 import android.net.INetworkStatsSession;
 import android.net.LinkProperties;
+import android.net.Network;
 import android.net.NetworkCapabilities;
 import android.net.NetworkIdentity;
 import android.net.NetworkInfo;
@@ -231,14 +233,24 @@ public class NetworkStatsService extends INetworkStatsService.Stub {
     private final Object mStatsLock = new Object();
 
     /** Set of currently active ifaces. */
+    @GuardedBy("mStatsLock")
     private final ArrayMap<String, NetworkIdentitySet> mActiveIfaces = new ArrayMap<>();
+
     /** Set of currently active ifaces for UID stats. */
+    @GuardedBy("mStatsLock")
     private final ArrayMap<String, NetworkIdentitySet> mActiveUidIfaces = new ArrayMap<>();
+
     /** Current default active iface. */
     private String mActiveIface;
+
     /** Set of any ifaces associated with mobile networks since boot. */
+    @GuardedBy("mStatsLock")
     private String[] mMobileIfaces = new String[0];
 
+    /** Set of all ifaces currently used by traffic that does not explicitly specify a Network. */
+    @GuardedBy("mStatsLock")
+    private Network[] mDefaultNetworks = new Network[0];
+
     private final DropBoxNonMonotonicObserver mNonMonotonicObserver =
             new DropBoxNonMonotonicObserver();
 
@@ -666,9 +678,9 @@ public class NetworkStatsService extends INetworkStatsService.Stub {
         final NetworkStatsHistory.Entry entry = history.getValues(start, end, now, null);
 
         final NetworkStats stats = new NetworkStats(end - start, 1);
-        stats.addValues(new NetworkStats.Entry(IFACE_ALL, UID_ALL, SET_ALL, TAG_NONE, METERED_ALL,
-                ROAMING_ALL, entry.rxBytes, entry.rxPackets, entry.txBytes, entry.txPackets,
-                entry.operations));
+        stats.addValues(new NetworkStats.Entry(IFACE_ALL, UID_ALL, SET_ALL, TAG_NONE,
+                METERED_ALL, ROAMING_ALL, DEFAULT_NETWORK_ALL, entry.rxBytes, entry.rxPackets,
+                entry.txBytes, entry.txPackets, entry.operations));
         return stats;
     }
 
@@ -779,13 +791,13 @@ public class NetworkStatsService extends INetworkStatsService.Stub {
     }
 
     @Override
-    public void forceUpdateIfaces() {
+    public void forceUpdateIfaces(Network[] defaultNetworks) {
         mContext.enforceCallingOrSelfPermission(READ_NETWORK_USAGE_HISTORY, TAG);
         assertBandwidthControlEnabled();
 
         final long token = Binder.clearCallingIdentity();
         try {
-            updateIfaces();
+            updateIfaces(defaultNetworks);
         } finally {
             Binder.restoreCallingIdentity(token);
         }
@@ -996,11 +1008,11 @@ public class NetworkStatsService extends INetworkStatsService.Stub {
         }
     };
 
-    private void updateIfaces() {
+    private void updateIfaces(Network[] defaultNetworks) {
         synchronized (mStatsLock) {
             mWakeLock.acquire();
             try {
-                updateIfacesLocked();
+                updateIfacesLocked(defaultNetworks);
             } finally {
                 mWakeLock.release();
             }
@@ -1013,7 +1025,7 @@ public class NetworkStatsService extends INetworkStatsService.Stub {
      * are active on a single {@code iface}, they are combined under a single
      * {@link NetworkIdentitySet}.
      */
-    private void updateIfacesLocked() {
+    private void updateIfacesLocked(Network[] defaultNetworks) {
         if (!mSystemReady) return;
         if (LOGV) Slog.v(TAG, "updateIfacesLocked()");
 
@@ -1040,12 +1052,18 @@ public class NetworkStatsService extends INetworkStatsService.Stub {
         // Rebuild active interfaces based on connected networks
         mActiveIfaces.clear();
         mActiveUidIfaces.clear();
+        if (defaultNetworks != null) {
+            // Caller is ConnectivityService. Update the list of default networks.
+            mDefaultNetworks = defaultNetworks;
+        }
 
         final ArraySet<String> mobileIfaces = new ArraySet<>();
         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.
@@ -1065,7 +1083,8 @@ public class NetworkStatsService extends INetworkStatsService.Stub {
                         // 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);
                     }
@@ -1511,7 +1530,7 @@ public class NetworkStatsService extends INetworkStatsService.Stub {
                     return true;
                 }
                 case MSG_UPDATE_IFACES: {
-                    mService.updateIfaces();
+                    mService.updateIfaces(null);
                     return true;
                 }
                 case MSG_REGISTER_GLOBAL_ALERT: {