diff --git a/framework/src/android/net/NetworkCapabilities.java b/framework/src/android/net/NetworkCapabilities.java
index c82cd3b..73fbd61 100644
--- a/framework/src/android/net/NetworkCapabilities.java
+++ b/framework/src/android/net/NetworkCapabilities.java
@@ -131,6 +131,7 @@
         mPrivateDnsBroken = false;
         mRequestorUid = Process.INVALID_UID;
         mRequestorPackageName = null;
+        mSubIds = new ArraySet<>();
     }
 
     /**
@@ -159,6 +160,7 @@
         mPrivateDnsBroken = nc.mPrivateDnsBroken;
         mRequestorUid = nc.mRequestorUid;
         mRequestorPackageName = nc.mRequestorPackageName;
+        mSubIds = new ArraySet<>(nc.mSubIds);
     }
 
     /**
@@ -1655,6 +1657,7 @@
         combineSSIDs(nc);
         combineRequestor(nc);
         combineAdministratorUids(nc);
+        combineSubIds(nc);
     }
 
     /**
@@ -1674,8 +1677,9 @@
                 && satisfiedBySpecifier(nc)
                 && (onlyImmutable || satisfiedBySignalStrength(nc))
                 && (onlyImmutable || satisfiedByUids(nc))
-                && (onlyImmutable || satisfiedBySSID(nc)))
-                && (onlyImmutable || satisfiedByRequestor(nc));
+                && (onlyImmutable || satisfiedBySSID(nc))
+                && (onlyImmutable || satisfiedByRequestor(nc))
+                && (onlyImmutable || satisfiedBySubIds(nc)));
     }
 
     /**
@@ -1771,7 +1775,8 @@
                 && equalsOwnerUid(that)
                 && equalsPrivateDnsBroken(that)
                 && equalsRequestor(that)
-                && equalsAdministratorUids(that);
+                && equalsAdministratorUids(that)
+                && equalsSubIds(that);
     }
 
     @Override
@@ -1793,7 +1798,8 @@
                 + Objects.hashCode(mPrivateDnsBroken) * 47
                 + Objects.hashCode(mRequestorUid) * 53
                 + Objects.hashCode(mRequestorPackageName) * 59
-                + Arrays.hashCode(mAdministratorUids) * 61;
+                + Arrays.hashCode(mAdministratorUids) * 61
+                + Objects.hashCode(mSubIds) * 67;
     }
 
     @Override
@@ -1827,6 +1833,7 @@
         dest.writeInt(mOwnerUid);
         dest.writeInt(mRequestorUid);
         dest.writeString(mRequestorPackageName);
+        dest.writeIntArray(CollectionUtils.toIntArray(mSubIds));
     }
 
     public static final @android.annotation.NonNull Creator<NetworkCapabilities> CREATOR =
@@ -1850,6 +1857,11 @@
                 netCap.mOwnerUid = in.readInt();
                 netCap.mRequestorUid = in.readInt();
                 netCap.mRequestorPackageName = in.readString();
+                netCap.mSubIds = new ArraySet<>();
+                final int[] subIdInts = Objects.requireNonNull(in.createIntArray());
+                for (int i = 0; i < subIdInts.length; i++) {
+                    netCap.mSubIds.add(subIdInts[i]);
+                }
                 return netCap;
             }
             @Override
@@ -1933,11 +1945,14 @@
             sb.append(" SSID: ").append(mSSID);
         }
 
-
         if (mPrivateDnsBroken) {
             sb.append(" PrivateDnsBroken");
         }
 
+        if (!mSubIds.isEmpty()) {
+            sb.append(" SubscriptionIds: ").append(mSubIds);
+        }
+
         sb.append("]");
         return sb.toString();
     }
@@ -2251,6 +2266,68 @@
     }
 
     /**
+     * Set of the subscription IDs that identifies the network or request, empty if none.
+     */
+    @NonNull
+    private ArraySet<Integer> mSubIds = new ArraySet<>();
+
+    /**
+     * Sets the subscription ID set that associated to this network or request.
+     *
+     * @hide
+     */
+    @NonNull
+    public NetworkCapabilities setSubIds(@NonNull Set<Integer> subIds) {
+        mSubIds = new ArraySet(Objects.requireNonNull(subIds));
+        return this;
+    }
+
+    /**
+     * Gets the subscription ID set that associated to this network or request.
+     * @hide
+     * @return
+     */
+    @NonNull
+    public Set<Integer> getSubIds() {
+        return new ArraySet<>(mSubIds);
+    }
+
+    /**
+     * Tests if the subscription ID set of this network is the same as that of the passed one.
+     */
+    private boolean equalsSubIds(@NonNull NetworkCapabilities nc) {
+        return Objects.equals(mSubIds, nc.mSubIds);
+    }
+
+    /**
+     * Check if the subscription ID set requirements of this object are matched by the passed one.
+     * If specified in the request, the passed one need to have at least one subId and at least
+     * one of them needs to be in the request set.
+     */
+    private boolean satisfiedBySubIds(@NonNull NetworkCapabilities nc) {
+        if (mSubIds.isEmpty()) return true;
+        if (nc.mSubIds.isEmpty()) return false;
+        for (final Integer subId : nc.mSubIds) {
+            if (mSubIds.contains(subId)) return true;
+        }
+        return false;
+    }
+
+    /**
+     * Combine subscription ID set of the capabilities.
+     *
+     * <p>This is only legal if the subscription Ids are equal.
+     *
+     * <p>If both subscription IDs are not equal, they belong to different subscription
+     * (or no subscription). In this case, it would not make sense to add them together.
+     */
+    private void combineSubIds(@NonNull NetworkCapabilities nc) {
+        if (!Objects.equals(mSubIds, nc.mSubIds)) {
+            throw new IllegalStateException("Can't combine two subscription ID sets");
+        }
+    }
+
+    /**
      * Builder class for NetworkCapabilities.
      *
      * This class is mainly for for {@link NetworkAgent} instances to use. Many fields in
@@ -2556,6 +2633,20 @@
         }
 
         /**
+         * Set the subscription ID set.
+         *
+         * @param subIds a set that represent the subscription IDs. Empty if clean up.
+         * @return this builder.
+         *
+         * @hide
+         */
+        @NonNull
+        public Builder setSubIds(@NonNull final Set<Integer> subIds) {
+            mCaps.setSubIds(subIds);
+            return this;
+        }
+
+        /**
          * Builds the instance of the capabilities.
          *
          * @return the built instance of NetworkCapabilities.
diff --git a/framework/src/android/net/NetworkRequest.java b/framework/src/android/net/NetworkRequest.java
index 17a8ee1..65ca1b2 100644
--- a/framework/src/android/net/NetworkRequest.java
+++ b/framework/src/android/net/NetworkRequest.java
@@ -456,6 +456,23 @@
             }
             nc.addCapability(NET_CAPABILITY_NOT_VCN_MANAGED);
         }
+
+        /**
+         * Sets the optional subscription ID set.
+         * <p>
+         * This specify the subscription IDs requirement.
+         * A network will satisfy this request only if it matches one of the subIds in this set.
+         * An empty set matches all networks, including those without a subId.
+         *
+         * @param subIds A {@code Set} that represents subscription IDs.
+         *
+         * @hide
+         */
+        @NonNull
+        public Builder setSubIds(@NonNull Set<Integer> subIds) {
+            mNetworkCapabilities.setSubIds(subIds);
+            return this;
+        }
     }
 
     // implement the Parcelable interface
diff --git a/tests/net/common/java/android/net/NetworkCapabilitiesTest.java b/tests/net/common/java/android/net/NetworkCapabilitiesTest.java
index e84b992..0dfec75 100644
--- a/tests/net/common/java/android/net/NetworkCapabilitiesTest.java
+++ b/tests/net/common/java/android/net/NetworkCapabilitiesTest.java
@@ -28,6 +28,7 @@
 import static android.net.NetworkCapabilities.NET_CAPABILITY_NOT_METERED;
 import static android.net.NetworkCapabilities.NET_CAPABILITY_NOT_RESTRICTED;
 import static android.net.NetworkCapabilities.NET_CAPABILITY_NOT_ROAMING;
+import static android.net.NetworkCapabilities.NET_CAPABILITY_NOT_VCN_MANAGED;
 import static android.net.NetworkCapabilities.NET_CAPABILITY_NOT_VPN;
 import static android.net.NetworkCapabilities.NET_CAPABILITY_OEM_PAID;
 import static android.net.NetworkCapabilities.NET_CAPABILITY_OEM_PRIVATE;
@@ -44,6 +45,10 @@
 import static android.net.NetworkCapabilities.UNRESTRICTED_CAPABILITIES;
 import static android.os.Process.INVALID_UID;
 
+import static com.android.modules.utils.build.SdkLevel.isAtLeastR;
+import static com.android.modules.utils.build.SdkLevel.isAtLeastS;
+import static com.android.testutils.MiscAsserts.assertEmpty;
+import static com.android.testutils.MiscAsserts.assertThrows;
 import static com.android.testutils.ParcelUtils.assertParcelSane;
 import static com.android.testutils.ParcelUtils.assertParcelingIsLossless;
 import static com.android.testutils.ParcelUtils.parcelingRoundTrip;
@@ -67,7 +72,6 @@
 
 import androidx.test.runner.AndroidJUnit4;
 
-import com.android.modules.utils.build.SdkLevel;
 import com.android.testutils.CompatUtil;
 import com.android.testutils.DevSdkIgnoreRule;
 import com.android.testutils.DevSdkIgnoreRule.IgnoreUpTo;
@@ -85,6 +89,9 @@
 public class NetworkCapabilitiesTest {
     private static final String TEST_SSID = "TEST_SSID";
     private static final String DIFFERENT_TEST_SSID = "DIFFERENT_TEST_SSID";
+    private static final int TEST_SUBID1 = 1;
+    private static final int TEST_SUBID2 = 2;
+    private static final int TEST_SUBID3 = 3;
 
     @Rule
     public DevSdkIgnoreRule mDevSdkIgnoreRule = new DevSdkIgnoreRule();
@@ -92,14 +99,6 @@
     private DiscoverySession mDiscoverySession = Mockito.mock(DiscoverySession.class);
     private PeerHandle mPeerHandle = Mockito.mock(PeerHandle.class);
 
-    private boolean isAtLeastR() {
-        return SdkLevel.isAtLeastR();
-    }
-
-    private boolean isAtLeastS() {
-        return SdkLevel.isAtLeastS();
-    }
-
     @Test
     public void testMaybeMarkCapabilitiesRestricted() {
         // verify EIMS is restricted
@@ -305,7 +304,9 @@
             .setUids(uids)
             .addCapability(NET_CAPABILITY_EIMS)
             .addCapability(NET_CAPABILITY_NOT_METERED);
-        if (isAtLeastR()) {
+        if (isAtLeastS()) {
+            netCap.setSubIds(Set.of(TEST_SUBID1, TEST_SUBID2));
+        } else if (isAtLeastR()) {
             netCap.setOwnerUid(123);
             netCap.setAdministratorUids(new int[] {5, 11});
         }
@@ -380,7 +381,7 @@
 
     private void testParcelSane(NetworkCapabilities cap) {
         if (isAtLeastS()) {
-            assertParcelSane(cap, 16);
+            assertParcelSane(cap, 17);
         } else if (isAtLeastR()) {
             assertParcelSane(cap, 15);
         } else {
@@ -614,6 +615,20 @@
         assertFalse(nc2.appliesToUid(12));
         assertTrue(nc1.appliesToUid(22));
         assertTrue(nc2.appliesToUid(22));
+
+        // Verify the subscription id list can be combined only when they are equal.
+        if (isAtLeastS()) {
+            nc1.setSubIds(Set.of(TEST_SUBID1, TEST_SUBID2));
+            nc2.setSubIds(Set.of(TEST_SUBID2));
+            assertThrows(IllegalStateException.class, () -> nc2.combineCapabilities(nc1));
+
+            nc2.setSubIds(Set.of());
+            assertThrows(IllegalStateException.class, () -> nc2.combineCapabilities(nc1));
+
+            nc2.setSubIds(Set.of(TEST_SUBID2, TEST_SUBID1));
+            nc2.combineCapabilities(nc1);
+            assertEquals(Set.of(TEST_SUBID2, TEST_SUBID1), nc2.getSubIds());
+        }
     }
 
     @Test @IgnoreUpTo(Build.VERSION_CODES.Q)
@@ -762,6 +777,24 @@
         nc1.setUids(uidRange(10, 13));
         nc2.set(nc1);  // Overwrites, as opposed to combineCapabilities
         assertEquals(nc1, nc2);
+
+        if (isAtLeastS()) {
+            assertThrows(NullPointerException.class, () -> nc1.setSubIds(null));
+            nc1.setSubIds(Set.of());
+            nc2.set(nc1);
+            assertEquals(nc1, nc2);
+
+            nc1.setSubIds(Set.of(TEST_SUBID1));
+            nc2.set(nc1);
+            assertEquals(nc1, nc2);
+
+            nc2.setSubIds(Set.of(TEST_SUBID2, TEST_SUBID1));
+            nc2.set(nc1);
+            assertEquals(nc1, nc2);
+
+            nc2.setSubIds(Set.of(TEST_SUBID3, TEST_SUBID2));
+            assertNotEquals(nc1, nc2);
+        }
     }
 
     @Test
@@ -842,6 +875,50 @@
         } catch (NullPointerException expected) { }
     }
 
+    private static NetworkCapabilities capsWithSubIds(Integer ... subIds) {
+        // Since the NetworkRequest would put NOT_VCN_MANAGED capabilities in general, for
+        // every NetworkCapabilities that simulates networks needs to add it too in order to
+        // satisfy these requests.
+        final NetworkCapabilities nc = new NetworkCapabilities.Builder()
+                .addCapability(NET_CAPABILITY_NOT_VCN_MANAGED)
+                .setSubIds(new ArraySet<>(subIds)).build();
+        assertEquals(new ArraySet<>(subIds), nc.getSubIds());
+        return nc;
+    }
+
+    @Test @IgnoreUpTo(Build.VERSION_CODES.R)
+    public void testSubIds() throws Exception {
+        final NetworkCapabilities ncWithoutId = capsWithSubIds();
+        final NetworkCapabilities ncWithId = capsWithSubIds(TEST_SUBID1);
+        final NetworkCapabilities ncWithOtherIds = capsWithSubIds(TEST_SUBID1, TEST_SUBID3);
+        final NetworkCapabilities ncWithoutRequestedIds = capsWithSubIds(TEST_SUBID3);
+
+        final NetworkRequest requestWithoutId = new NetworkRequest.Builder().build();
+        assertEmpty(requestWithoutId.networkCapabilities.getSubIds());
+        final NetworkRequest requestWithIds = new NetworkRequest.Builder()
+                .setSubIds(Set.of(TEST_SUBID1, TEST_SUBID2)).build();
+        assertEquals(Set.of(TEST_SUBID1, TEST_SUBID2),
+                requestWithIds.networkCapabilities.getSubIds());
+
+        assertFalse(requestWithIds.canBeSatisfiedBy(ncWithoutId));
+        assertTrue(requestWithIds.canBeSatisfiedBy(ncWithOtherIds));
+        assertFalse(requestWithIds.canBeSatisfiedBy(ncWithoutRequestedIds));
+        assertTrue(requestWithIds.canBeSatisfiedBy(ncWithId));
+        assertTrue(requestWithoutId.canBeSatisfiedBy(ncWithoutId));
+        assertTrue(requestWithoutId.canBeSatisfiedBy(ncWithId));
+    }
+
+    @Test @IgnoreUpTo(Build.VERSION_CODES.R)
+    public void testEqualsSubIds() throws Exception {
+        assertEquals(capsWithSubIds(), capsWithSubIds());
+        assertNotEquals(capsWithSubIds(), capsWithSubIds(TEST_SUBID1));
+        assertEquals(capsWithSubIds(TEST_SUBID1), capsWithSubIds(TEST_SUBID1));
+        assertNotEquals(capsWithSubIds(TEST_SUBID1), capsWithSubIds(TEST_SUBID2));
+        assertNotEquals(capsWithSubIds(TEST_SUBID1), capsWithSubIds(TEST_SUBID2, TEST_SUBID1));
+        assertEquals(capsWithSubIds(TEST_SUBID1, TEST_SUBID2),
+                capsWithSubIds(TEST_SUBID2, TEST_SUBID1));
+    }
+
     @Test
     public void testLinkBandwidthKbps() {
         final NetworkCapabilities nc = new NetworkCapabilities();
@@ -1022,5 +1099,11 @@
             fail("Should not set null into NetworkCapabilities.Builder");
         } catch (NullPointerException expected) { }
         assertEquals(nc, new NetworkCapabilities.Builder(nc).build());
+
+        if (isAtLeastS()) {
+            final NetworkCapabilities nc2 = new NetworkCapabilities.Builder()
+                    .setSubIds(Set.of(TEST_SUBID1)).build();
+            assertEquals(Set.of(TEST_SUBID1), nc2.getSubIds());
+        }
     }
 }