diff --git a/core/java/android/net/IConnectivityManager.aidl b/core/java/android/net/IConnectivityManager.aidl
index fb01283..95a2f2e 100644
--- a/core/java/android/net/IConnectivityManager.aidl
+++ b/core/java/android/net/IConnectivityManager.aidl
@@ -31,6 +31,7 @@
 import android.net.ProxyInfo;
 import android.os.Bundle;
 import android.os.IBinder;
+import android.os.INetworkActivityListener;
 import android.os.Messenger;
 import android.os.ParcelFileDescriptor;
 import android.os.PersistableBundle;
@@ -233,4 +234,10 @@
                 in PersistableBundle extras);
 
     void systemReady();
+
+    void registerNetworkActivityListener(in INetworkActivityListener l);
+
+    void unregisterNetworkActivityListener(in INetworkActivityListener l);
+
+    boolean isDefaultNetworkActive();
 }
diff --git a/services/core/java/com/android/server/ConnectivityService.java b/services/core/java/com/android/server/ConnectivityService.java
index 414d75b..52df42f 100644
--- a/services/core/java/com/android/server/ConnectivityService.java
+++ b/services/core/java/com/android/server/ConnectivityService.java
@@ -146,6 +146,7 @@
 import android.os.Handler;
 import android.os.HandlerThread;
 import android.os.IBinder;
+import android.os.INetworkActivityListener;
 import android.os.INetworkManagementService;
 import android.os.Looper;
 import android.os.Message;
@@ -2340,6 +2341,31 @@
     }
 
     /**
+     * Start listening for default data network activity state changes.
+     */
+    @Override
+    public void registerNetworkActivityListener(@NonNull INetworkActivityListener l) {
+        // TODO: Replace network activity listener registry in ConnectivityManager from NMS to here
+    }
+
+    /**
+     * Stop listening for default data network activity state changes.
+     */
+    @Override
+    public void unregisterNetworkActivityListener(@NonNull INetworkActivityListener l) {
+        // TODO: Replace network activity listener registry in ConnectivityManager from NMS to here
+    }
+
+    /**
+     * Check whether the default network radio is currently active.
+     */
+    @Override
+    public boolean isDefaultNetworkActive() {
+        // TODO: Replace isNetworkActive() in NMS.
+        return false;
+    }
+
+    /**
      * Setup data activity tracking for the given network.
      *
      * Every {@code setupDataActivityTracking} should be paired with a