diff --git a/core/java/android/net/ConnectivityManager.java b/core/java/android/net/ConnectivityManager.java
index 2242e9e8e1..ce6f697be6 100644
--- a/core/java/android/net/ConnectivityManager.java
+++ b/core/java/android/net/ConnectivityManager.java
@@ -163,6 +163,12 @@ public class ConnectivityManager {
      */
     public static final String EXTRA_ERRORED_TETHER = "erroredArray";
 
+    /**
+     * The absence of APN..
+     * @hide
+     */
+    public static final int TYPE_NONE        = -1;
+
     /**
      * The Default Mobile data connection.  When active, all data traffic
      * will use this connection by default.
diff --git a/services/java/com/android/server/ConnectivityService.java b/services/java/com/android/server/ConnectivityService.java
index aa3dfa6201..e6f443a54b 100644
--- a/services/java/com/android/server/ConnectivityService.java
+++ b/services/java/com/android/server/ConnectivityService.java
@@ -466,12 +466,10 @@ public class ConnectivityService extends IConnectivityManager.Stub {
         INetworkManagementService nmService = INetworkManagementService.Stub.asInterface(b);
 
         mTethering = new Tethering(mContext, nmService, mHandler.getLooper());
-        mTetheringConfigValid = (((mNetTrackers[ConnectivityManager.TYPE_MOBILE_DUN] != null) ||
-                                  !mTethering.isDunRequired()) &&
-                                 (mTethering.getTetherableUsbRegexs().length != 0 ||
+        mTetheringConfigValid = ((mTethering.getTetherableUsbRegexs().length != 0 ||
                                   mTethering.getTetherableWifiRegexs().length != 0 ||
                                   mTethering.getTetherableBluetoothRegexs().length != 0) &&
-                                 mTethering.getUpstreamIfaceRegexs().length != 0);
+                                 mTethering.getUpstreamIfaceTypes().length != 0);
 
         mVpn = new Vpn(mContext, new VpnCallback());
 
@@ -1576,12 +1574,6 @@ public class ConnectivityService extends IConnectivityManager.Stub {
                 }
                 addPrivateDnsRoutes(mNetTrackers[netType]);
             }
-
-            /** Notify TetheringService if interface name has been changed. */
-            if (TextUtils.equals(mNetTrackers[netType].getNetworkInfo().getReason(),
-                                 Phone.REASON_LINK_PROPERTIES_CHANGED)) {
-                handleTetherIfaceChange(netType);
-            }
         } else {
             if (mNetConfigs[netType].isDefault()) {
                 removeDefaultRoute(mNetTrackers[netType]);
@@ -2412,14 +2404,6 @@ public class ConnectivityService extends IConnectivityManager.Stub {
         }
     }
 
-    private void handleTetherIfaceChange(int type) {
-        String iface = mNetTrackers[type].getLinkProperties().getInterfaceName();
-
-        if (isTetheringSupported()) {
-            mTethering.handleTetherIfaceChange(iface);
-        }
-    }
-
     private void log(String s) {
         Slog.d(TAG, s);
     }