diff --git a/core/java/android/net/ConnectivityManager.java b/core/java/android/net/ConnectivityManager.java
index 6ff1a339fb..cda9f77c0e 100644
--- a/core/java/android/net/ConnectivityManager.java
+++ b/core/java/android/net/ConnectivityManager.java
@@ -328,6 +328,18 @@ public class ConnectivityManager {
     /** {@hide} */
     public static final int MAX_NETWORK_TYPE = TYPE_WIFI_P2P;
 
+    /**
+     * If you want to set the default network preference,you can directly
+     * change the networkAttributes array in framework's config.xml.
+     *
+     * @deprecated Since we support so many more networks now, the single
+     *             network default network preference can't really express
+     *             the heirarchy.  Instead, the default is defined by the
+     *             networkAttributes in config.xml.  You can determine
+     *             the current value by calling {@link getNetworkPreference()}
+     *             from an App.
+     */
+    @Deprecated
     public static final int DEFAULT_NETWORK_PREFERENCE = TYPE_WIFI;
 
     /**
diff --git a/services/java/com/android/server/ConnectivityService.java b/services/java/com/android/server/ConnectivityService.java
index 4c22ae8cb3..8c5ff04241 100644
--- a/services/java/com/android/server/ConnectivityService.java
+++ b/services/java/com/android/server/ConnectivityService.java
@@ -412,8 +412,6 @@ public class ConnectivityService extends IConnectivityManager.Stub {
                 ConnectivityManager.MAX_NETWORK_TYPE+1];
         mCurrentLinkProperties = new LinkProperties[ConnectivityManager.MAX_NETWORK_TYPE+1];
 
-        mNetworkPreference = getPersistedNetworkPreference();
-
         mRadioAttributes = new RadioAttributes[ConnectivityManager.MAX_RADIO_TYPE+1];
         mNetConfigs = new NetworkConfig[ConnectivityManager.MAX_NETWORK_TYPE+1];
 
@@ -495,6 +493,21 @@ public class ConnectivityService extends IConnectivityManager.Stub {
             }
         }
 
+        // Update mNetworkPreference according to user mannually first then overlay config.xml
+        mNetworkPreference = getPersistedNetworkPreference();
+        if (mNetworkPreference == -1) {
+            for (int n : mPriorityList) {
+                if (mNetConfigs[n].isDefault() && ConnectivityManager.isNetworkTypeValid(n)) {
+                    mNetworkPreference = n;
+                    break;
+                }
+            }
+            if (mNetworkPreference == -1) {
+                throw new IllegalStateException(
+                        "You should set at least one default Network in config.xml!");
+            }
+        }
+
         mNetRequestersPids = new ArrayList[ConnectivityManager.MAX_NETWORK_TYPE+1];
         for (int i : mPriorityList) {
             mNetRequestersPids[i] = new ArrayList();
@@ -726,11 +739,8 @@ public class ConnectivityService extends IConnectivityManager.Stub {
 
         final int networkPrefSetting = Settings.Global
                 .getInt(cr, Settings.Global.NETWORK_PREFERENCE, -1);
-        if (networkPrefSetting != -1) {
-            return networkPrefSetting;
-        }
 
-        return ConnectivityManager.DEFAULT_NETWORK_PREFERENCE;
+        return networkPrefSetting;
     }
 
     /**