diff --git a/services/core/java/com/android/server/connectivity/Vpn.java b/services/core/java/com/android/server/connectivity/Vpn.java
index c1df335..e3262cf 100644
--- a/services/core/java/com/android/server/connectivity/Vpn.java
+++ b/services/core/java/com/android/server/connectivity/Vpn.java
@@ -22,7 +22,6 @@
 import static android.net.NetworkCapabilities.NET_CAPABILITY_NOT_METERED;
 import static android.net.NetworkCapabilities.NET_CAPABILITY_NOT_VPN;
 import static android.net.NetworkCapabilities.TRANSPORT_CELLULAR;
-import static android.net.NetworkCapabilities.TRANSPORT_VPN;
 import static android.net.RouteInfo.RTN_THROW;
 import static android.net.RouteInfo.RTN_UNREACHABLE;
 import static android.net.VpnManager.NOTIFICATION_CHANNEL_VPN;
@@ -280,15 +279,22 @@
     private static final int VPN_DEFAULT_SCORE = 101;
 
     /**
-     * The reset session timer for data stall. If a session has not successfully revalidated after
-     * the delay, the session will be torn down and restarted in an attempt to recover. Delay
+     * The recovery timer for data stall. If a session has not successfully revalidated after
+     * the delay, the session will perform MOBIKE or be restarted in an attempt to recover. Delay
      * counter is reset on successful validation only.
      *
+     * <p>The first {@code MOBIKE_RECOVERY_ATTEMPT} timers are used for performing MOBIKE.
+     * System will perform session reset for the remaining timers.
      * <p>If retries have exceeded the length of this array, the last entry in the array will be
      * used as a repeating interval.
      */
-    private static final long[] DATA_STALL_RESET_DELAYS_SEC = {30L, 60L, 120L, 240L, 480L, 960L};
-
+    // TODO: use ms instead to speed up the test.
+    private static final long[] DATA_STALL_RECOVERY_DELAYS_SEC =
+            {1L, 5L, 30L, 60L, 120L, 240L, 480L, 960L};
+    /**
+     * Maximum attempts to perform MOBIKE when the network is bad.
+     */
+    private static final int MAX_MOBIKE_RECOVERY_ATTEMPT = 2;
     /**
      * The initial token value of IKE session.
      */
@@ -393,7 +399,6 @@
     private final UserManager mUserManager;
 
     private final VpnProfileStore mVpnProfileStore;
-    protected boolean mDataStallSuspected = false;
 
     @VisibleForTesting
     VpnProfileStore getVpnProfileStore() {
@@ -686,14 +691,14 @@
         }
 
         /**
-         * Get the length of time to wait before resetting the ike session when a data stall is
-         * suspected.
+         * Get the length of time to wait before perform data stall recovery when the validation
+         * result is bad.
          */
-        public long getDataStallResetSessionSeconds(int count) {
-            if (count >= DATA_STALL_RESET_DELAYS_SEC.length) {
-                return DATA_STALL_RESET_DELAYS_SEC[DATA_STALL_RESET_DELAYS_SEC.length - 1];
+        public long getValidationFailRecoverySeconds(int count) {
+            if (count >= DATA_STALL_RECOVERY_DELAYS_SEC.length) {
+                return DATA_STALL_RECOVERY_DELAYS_SEC[DATA_STALL_RECOVERY_DELAYS_SEC.length - 1];
             } else {
-                return DATA_STALL_RESET_DELAYS_SEC[count];
+                return DATA_STALL_RECOVERY_DELAYS_SEC[count];
             }
         }
 
@@ -3052,7 +3057,6 @@
 
         @Nullable private IkeSessionWrapper mSession;
         @Nullable private IkeSessionConnectionInfo mIkeConnectionInfo;
-        @Nullable private VpnConnectivityDiagnosticsCallback mDiagnosticsCallback;
 
         // mMobikeEnabled can only be updated after IKE AUTH is finished.
         private boolean mMobikeEnabled = false;
@@ -3063,7 +3067,7 @@
          * <p>This variable controls the retry delay, and is reset when the VPN pass network
          * validation.
          */
-        private int mDataStallRetryCount = 0;
+        private int mValidationFailRetryCount = 0;
 
         /**
          * The number of attempts since the last successful connection.
@@ -3145,15 +3149,6 @@
                 mConnectivityManager.registerSystemDefaultNetworkCallback(mNetworkCallback,
                         new Handler(mLooper));
             }
-
-            // DiagnosticsCallback may return more than one alive VPNs, but VPN will filter based on
-            // Network object.
-            final NetworkRequest diagRequest = new NetworkRequest.Builder()
-                    .addTransportType(TRANSPORT_VPN)
-                    .removeCapability(NET_CAPABILITY_NOT_VPN).build();
-            mDiagnosticsCallback = new VpnConnectivityDiagnosticsCallback();
-            mConnectivityDiagnosticsManager.registerConnectivityDiagnosticsCallback(
-                    diagRequest, mExecutor, mDiagnosticsCallback);
         }
 
         private boolean isActiveNetwork(@Nullable Network network) {
@@ -3887,39 +3882,12 @@
             }
         }
 
-        class VpnConnectivityDiagnosticsCallback
-                extends ConnectivityDiagnosticsManager.ConnectivityDiagnosticsCallback {
-            // The callback runs in the executor thread.
-            @Override
-            public void onDataStallSuspected(
-                    ConnectivityDiagnosticsManager.DataStallReport report) {
-                synchronized (Vpn.this) {
-                    // Ignore stale runner.
-                    if (mVpnRunner != Vpn.IkeV2VpnRunner.this) return;
-
-                    // Handle the report only for current VPN network. If data stall is already
-                    // reported, ignoring the other reports. It means that the stall is not
-                    // recovered by MOBIKE and should be on the way to reset the ike session.
-                    if (mNetworkAgent != null
-                            && mNetworkAgent.getNetwork().equals(report.getNetwork())
-                            && !mDataStallSuspected) {
-                        Log.d(TAG, "Data stall suspected");
-
-                        // Trigger MOBIKE.
-                        maybeMigrateIkeSessionAndUpdateVpnTransportInfo(mActiveNetwork);
-                        mDataStallSuspected = true;
-                    }
-                }
-            }
-        }
-
         public void onValidationStatus(int status) {
             mEventChanges.log("[Validation] validation status " + status);
             if (status == NetworkAgent.VALIDATION_STATUS_VALID) {
                 // No data stall now. Reset it.
                 mExecutor.execute(() -> {
-                    mDataStallSuspected = false;
-                    mDataStallRetryCount = 0;
+                    mValidationFailRetryCount = 0;
                     if (mScheduledHandleDataStallFuture != null) {
                         Log.d(TAG, "Recovered from stall. Cancel pending reset action.");
                         mScheduledHandleDataStallFuture.cancel(false /* mayInterruptIfRunning */);
@@ -3930,8 +3898,21 @@
                 // Skip other invalid status if the scheduled recovery exists.
                 if (mScheduledHandleDataStallFuture != null) return;
 
+                if (mValidationFailRetryCount < MAX_MOBIKE_RECOVERY_ATTEMPT) {
+                    Log.d(TAG, "Validation failed");
+
+                    // Trigger MOBIKE to recover first.
+                    mExecutor.schedule(() -> {
+                        maybeMigrateIkeSessionAndUpdateVpnTransportInfo(mActiveNetwork);
+                    }, mDeps.getValidationFailRecoverySeconds(mValidationFailRetryCount++),
+                            TimeUnit.SECONDS);
+                    return;
+                }
+
+                // Data stall is not recovered by MOBIKE. Try to reset session to recover it.
                 mScheduledHandleDataStallFuture = mExecutor.schedule(() -> {
-                    if (mDataStallSuspected) {
+                    // Only perform the recovery when the network is still bad.
+                    if (mValidationFailRetryCount > 0) {
                         Log.d(TAG, "Reset session to recover stalled network");
                         // This will reset old state if it exists.
                         startIkeSession(mActiveNetwork);
@@ -3940,7 +3921,9 @@
                     // Reset mScheduledHandleDataStallFuture since it's already run on executor
                     // thread.
                     mScheduledHandleDataStallFuture = null;
-                }, mDeps.getDataStallResetSessionSeconds(mDataStallRetryCount++), TimeUnit.SECONDS);
+                    // TODO: compute the delay based on the last recovery timestamp
+                }, mDeps.getValidationFailRecoverySeconds(mValidationFailRetryCount++),
+                        TimeUnit.SECONDS);
             }
         }
 
@@ -4243,8 +4226,6 @@
             mCarrierConfigManager.unregisterCarrierConfigChangeListener(
                     mCarrierConfigChangeListener);
             mConnectivityManager.unregisterNetworkCallback(mNetworkCallback);
-            mConnectivityDiagnosticsManager.unregisterConnectivityDiagnosticsCallback(
-                    mDiagnosticsCallback);
             clearVpnNetworkPreference(mSessionKey);
 
             mExecutor.shutdown();
@@ -5231,7 +5212,7 @@
                 pw.println("MOBIKE " + (runner.mMobikeEnabled ? "enabled" : "disabled"));
                 pw.println("Profile: " + runner.mProfile);
                 pw.println("Token: " + runner.mCurrentToken);
-                if (mDataStallSuspected) pw.println("Data stall suspected");
+                pw.println("Validation failed retry count:" + runner.mValidationFailRetryCount);
                 if (runner.mScheduledHandleDataStallFuture != null) {
                     pw.println("Reset session scheduled");
                 }