diff --git a/services/core/java/com/android/server/ConnectivityService.java b/services/core/java/com/android/server/ConnectivityService.java
index 9e8ab4f..fe2fc1b 100644
--- a/services/core/java/com/android/server/ConnectivityService.java
+++ b/services/core/java/com/android/server/ConnectivityService.java
@@ -68,6 +68,7 @@
 import android.net.CaptivePortal;
 import android.net.ConnectionInfo;
 import android.net.ConnectivityDiagnosticsManager.ConnectivityReport;
+import android.net.ConnectivityDiagnosticsManager.DataStallReport;
 import android.net.ConnectivityManager;
 import android.net.ICaptivePortal;
 import android.net.IConnectivityDiagnosticsCallback;
@@ -3009,6 +3010,21 @@
         }
 
         @Override
+        public void notifyDataStallSuspected(
+                long timestampMillis, int detectionMethod, PersistableBundle extras) {
+            final Message msg =
+                    mConnectivityDiagnosticsHandler.obtainMessage(
+                            ConnectivityDiagnosticsHandler.EVENT_DATA_STALL_SUSPECTED,
+                            detectionMethod, mNetId, timestampMillis);
+            msg.setData(new Bundle(extras));
+
+            // NetworkStateTrackerHandler currently doesn't take any actions based on data
+            // stalls so send the message directly to ConnectivityDiagnosticsHandler and avoid
+            // the cost of going through two handlers.
+            mConnectivityDiagnosticsHandler.sendMessage(msg);
+        }
+
+        @Override
         public int getInterfaceVersion() {
             return this.VERSION;
         }
@@ -7559,6 +7575,16 @@
          */
         private static final int EVENT_NETWORK_TESTED = ConnectivityService.EVENT_NETWORK_TESTED;
 
+        /**
+         * Event for NetworkMonitor to inform ConnectivityService that a potential data stall has
+         * been detected on the network.
+         * obj = Long the timestamp (in millis) for when the suspected data stall was detected.
+         * arg1 = {@link DataStallReport#DetectionMethod} indicating the detection method.
+         * arg2 = NetID.
+         * data = PersistableBundle of extras passed from NetworkMonitor.
+         */
+        private static final int EVENT_DATA_STALL_SUSPECTED = 4;
+
         private ConnectivityDiagnosticsHandler(Looper looper) {
             super(looper);
         }
@@ -7589,6 +7615,17 @@
                     handleNetworkTestedWithExtras(reportEvent, extras);
                     break;
                 }
+                case EVENT_DATA_STALL_SUSPECTED: {
+                    final NetworkAgentInfo nai = getNetworkAgentInfoForNetId(msg.arg2);
+                    if (nai == null) break;
+
+                    // This is safe because NetworkMonitorCallbacks#notifyDataStallSuspected
+                    // receives a PersistableBundle and converts it to the Bundle in the incoming
+                    // Message.
+                    final PersistableBundle extras = new PersistableBundle(msg.getData());
+                    handleDataStallSuspected(nai, (long) msg.obj, msg.arg1, extras);
+                    break;
+                }
             }
         }
     }
@@ -7718,6 +7755,22 @@
         }
     }
 
+    private void handleDataStallSuspected(
+            @NonNull NetworkAgentInfo nai, long timestampMillis, int detectionMethod,
+            @NonNull PersistableBundle extras) {
+        final DataStallReport report =
+                new DataStallReport(nai.network, timestampMillis, detectionMethod, extras);
+        final List<IConnectivityDiagnosticsCallback> results =
+                getMatchingPermissionedCallbacks(nai);
+        for (final IConnectivityDiagnosticsCallback cb : results) {
+            try {
+                cb.onDataStallSuspected(report);
+            } catch (RemoteException ex) {
+                loge("Error invoking onDataStallSuspected", ex);
+            }
+        }
+    }
+
     private List<IConnectivityDiagnosticsCallback> getMatchingPermissionedCallbacks(
             @NonNull NetworkAgentInfo nai) {
         final List<IConnectivityDiagnosticsCallback> results = new ArrayList<>();
diff --git a/tests/net/java/com/android/server/ConnectivityServiceTest.java b/tests/net/java/com/android/server/ConnectivityServiceTest.java
index 8162843..760ebf6 100644
--- a/tests/net/java/com/android/server/ConnectivityServiceTest.java
+++ b/tests/net/java/com/android/server/ConnectivityServiceTest.java
@@ -24,6 +24,7 @@
 import static android.content.pm.PackageManager.PERMISSION_DENIED;
 import static android.content.pm.PackageManager.PERMISSION_GRANTED;
 import static android.net.ConnectivityDiagnosticsManager.ConnectivityReport;
+import static android.net.ConnectivityDiagnosticsManager.DataStallReport;
 import static android.net.ConnectivityManager.ACTION_CAPTIVE_PORTAL_SIGN_IN;
 import static android.net.ConnectivityManager.CONNECTIVITY_ACTION;
 import static android.net.ConnectivityManager.CONNECTIVITY_ACTION_SUPL;
@@ -570,6 +571,9 @@
                 | NETWORK_VALIDATION_RESULT_PARTIAL;
         private static final int VALIDATION_RESULT_INVALID = 0;
 
+        private static final long DATA_STALL_TIMESTAMP = 10L;
+        private static final int DATA_STALL_DETECTION_METHOD = 1;
+
         private INetworkMonitor mNetworkMonitor;
         private INetworkMonitorCallbacks mNmCallbacks;
         private int mNmValidationResult = VALIDATION_RESULT_BASE;
@@ -577,6 +581,7 @@
         private int mProbesSucceeded;
         private String mNmValidationRedirectUrl = null;
         private PersistableBundle mValidationExtras = PersistableBundle.EMPTY;
+        private PersistableBundle mDataStallExtras = PersistableBundle.EMPTY;
         private boolean mNmProvNotificationRequested = false;
 
         private final ConditionVariable mNetworkStatusReceived = new ConditionVariable();
@@ -804,6 +809,11 @@
         public void expectPreventReconnectReceived() {
             expectPreventReconnectReceived(TIMEOUT_MS);
         }
+
+        void notifyDataStallSuspected() throws Exception {
+            mNmCallbacks.notifyDataStallSuspected(
+                    DATA_STALL_TIMESTAMP, DATA_STALL_DETECTION_METHOD, mDataStallExtras);
+        }
     }
 
     /**
@@ -6625,4 +6635,35 @@
         verify(mConnectivityDiagnosticsCallback, timeout(TIMEOUT_MS))
                 .onConnectivityReport(any(ConnectivityReport.class));
     }
+
+    @Test
+    public void testConnectivityDiagnosticsCallbackOnDataStallSuspected() throws Exception {
+        final NetworkRequest request = new NetworkRequest.Builder().build();
+        when(mConnectivityDiagnosticsCallback.asBinder()).thenReturn(mIBinder);
+
+        mServiceContext.setPermission(
+                android.Manifest.permission.NETWORK_STACK, PERMISSION_GRANTED);
+
+        mService.registerConnectivityDiagnosticsCallback(
+                mConnectivityDiagnosticsCallback, request, mContext.getPackageName());
+
+        // Block until all other events are done processing.
+        HandlerUtilsKt.waitForIdle(mCsHandlerThread, TIMEOUT_MS);
+
+        // Connect the cell agent verify that it notifies TestNetworkCallback that it is available
+        final TestNetworkCallback callback = new TestNetworkCallback();
+        mCm.registerDefaultNetworkCallback(callback);
+        mCellNetworkAgent = new TestNetworkAgentWrapper(TRANSPORT_CELLULAR);
+        mCellNetworkAgent.connect(true);
+        callback.expectAvailableThenValidatedCallbacks(mCellNetworkAgent);
+        callback.assertNoCallback();
+
+        // Trigger notifyDataStallSuspected() on the INetworkMonitorCallbacks instance in the
+        // cellular network agent
+        mCellNetworkAgent.notifyDataStallSuspected();
+
+        // Wait for onDataStallSuspected to fire
+        verify(mConnectivityDiagnosticsCallback, timeout(TIMEOUT_MS))
+                .onDataStallSuspected(any(DataStallReport.class));
+    }
 }