diff --git a/core/src/com/cloud/agent/api/PingRoutingWithNwGroupsCommand.java b/core/src/com/cloud/agent/api/PingRoutingWithNwGroupsCommand.java
index 9b51f1de3de..8f8f186d03d 100644
--- a/core/src/com/cloud/agent/api/PingRoutingWithNwGroupsCommand.java
+++ b/core/src/com/cloud/agent/api/PingRoutingWithNwGroupsCommand.java
@@ -18,22 +18,91 @@ version.
  */
 package com.cloud.agent.api;
 
+import java.lang.reflect.Type;
 import java.util.HashMap;
+import java.util.Iterator;
+import java.util.List;
 import java.util.Map;
 
-import com.cloud.host.Host.Type;
+import com.cloud.agent.api.SecStorageFirewallCfgCommand.PortConfig;
+import com.cloud.agent.transport.Request;
+import com.cloud.host.Host;
 import com.cloud.utils.Pair;
 import com.cloud.vm.State;
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+import com.google.gson.JsonArray;
+import com.google.gson.JsonDeserializationContext;
+import com.google.gson.JsonDeserializer;
+import com.google.gson.JsonElement;
+import com.google.gson.JsonNull;
+import com.google.gson.JsonParseException;
+import com.google.gson.JsonPrimitive;
+import com.google.gson.JsonSerializationContext;
+import com.google.gson.JsonSerializer;
+import com.google.gson.reflect.TypeToken;
 
 
 public class PingRoutingWithNwGroupsCommand extends PingRoutingCommand {
 	HashMap<String, Pair<Long, Long>> newGroupStates;
 
+	public static class NwGroupsCommandTypeAdaptor implements JsonDeserializer<Pair<Long, Long>>, JsonSerializer<Pair<Long,Long>> {
+		static final GsonBuilder s_gBuilder;
+	    static {
+	        s_gBuilder = Request.initBuilder();
+	    }
+
+	    public NwGroupsCommandTypeAdaptor() {
+	    }
+	    
+		@Override
+		public JsonElement serialize(Pair<Long, Long> src,
+				java.lang.reflect.Type typeOfSrc, JsonSerializationContext context) {
+	        JsonArray array = new JsonArray();
+	        Gson json = s_gBuilder.create();
+	        if(src.first() != null) {
+	        	array.add(json.toJsonTree(src.first()));
+	        } else {
+	        	array.add(new JsonNull());
+	        }
+	        
+	        if (src.second() != null) {
+	        	array.add(json.toJsonTree(src.second()));
+	        } else {
+	        	array.add(new JsonNull());
+	        }
+	        
+	        return array;
+		}
+
+		@Override
+		public Pair<Long, Long> deserialize(JsonElement json,
+				java.lang.reflect.Type type, JsonDeserializationContext context)
+				throws JsonParseException {
+			Pair<Long, Long> pairs = new Pair<Long, Long>(null, null);
+			JsonArray array = json.getAsJsonArray();
+			if (array.size() != 2) {
+				return pairs;
+			}
+			JsonElement element = array.get(0);
+			if (!element.isJsonNull()) {
+				pairs.first(element.getAsLong());
+			}
+
+			element = array.get(1);
+			if (!element.isJsonNull()) {
+				pairs.second(element.getAsLong());
+			}
+
+			return pairs;
+		}
+		
+	}
 	protected PingRoutingWithNwGroupsCommand() {
 		super();
 	}
 
-	public PingRoutingWithNwGroupsCommand(Type type, long id, Map<String, State> states, HashMap<String, Pair<Long, Long>> nwGrpStates) {
+	public PingRoutingWithNwGroupsCommand(Host.Type type, long id, Map<String, State> states, HashMap<String, Pair<Long, Long>> nwGrpStates) {
 		super(type, id, states);
 		newGroupStates = nwGrpStates;
 	}
@@ -45,5 +114,4 @@ public class PingRoutingWithNwGroupsCommand extends PingRoutingCommand {
 	public void setNewGroupStates(HashMap<String, Pair<Long, Long>> newGroupStates) {
 		this.newGroupStates = newGroupStates;
 	}
-
 }
diff --git a/core/src/com/cloud/agent/transport/Request.java b/core/src/com/cloud/agent/transport/Request.java
index dea1322f6d7..c8a3e22ad73 100755
--- a/core/src/com/cloud/agent/transport/Request.java
+++ b/core/src/com/cloud/agent/transport/Request.java
@@ -25,11 +25,13 @@ import org.apache.log4j.Logger;
 
 import com.cloud.agent.api.Answer;
 import com.cloud.agent.api.Command;
+import com.cloud.agent.api.PingRoutingWithNwGroupsCommand;
 import com.cloud.agent.api.SecStorageFirewallCfgCommand;
 import com.cloud.agent.api.SecStorageFirewallCfgCommand.PortConfig;
 import com.cloud.exception.UnsupportedVersionException;
 import com.cloud.storage.VolumeVO;
 import com.cloud.utils.NumbersUtil;
+import com.cloud.utils.Pair;
 import com.cloud.utils.exception.CloudRuntimeException;
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
@@ -85,6 +87,7 @@ public class Request {
         final Type listType = new TypeToken<List<VolumeVO>>() {}.getType();
         s_gBuilder.registerTypeAdapter(listType, new VolListTypeAdaptor());
         s_gBuilder.registerTypeAdapter(new TypeToken<List<PortConfig>>() {}.getType(), new SecStorageFirewallCfgCommand.PortConfigListTypeAdaptor());
+        s_gBuilder.registerTypeAdapter(new TypeToken<Pair<Long, Long>>() {}.getType(), new PingRoutingWithNwGroupsCommand.NwGroupsCommandTypeAdaptor());
         s_logger.info("Builder inited.");
     }
 
diff --git a/core/src/com/cloud/serializer/GsonHelper.java b/core/src/com/cloud/serializer/GsonHelper.java
index 2b815795512..efde449c4c4 100644
--- a/core/src/com/cloud/serializer/GsonHelper.java
+++ b/core/src/com/cloud/serializer/GsonHelper.java
@@ -23,9 +23,11 @@ import java.util.List;
 
 import com.cloud.agent.api.Answer;
 import com.cloud.agent.api.Command;
+import com.cloud.agent.api.PingRoutingWithNwGroupsCommand;
 import com.cloud.agent.transport.ArrayTypeAdaptor;
 import com.cloud.agent.transport.VolListTypeAdaptor;
 import com.cloud.storage.VolumeVO;
+import com.cloud.utils.Pair;
 import com.google.gson.GsonBuilder;
 import com.google.gson.reflect.TypeToken;
 
diff --git a/utils/src/com/cloud/utils/Pair.java b/utils/src/com/cloud/utils/Pair.java
index 0d06a2b30c8..994c175c495 100755
--- a/utils/src/com/cloud/utils/Pair.java
+++ b/utils/src/com/cloud/utils/Pair.java
@@ -21,6 +21,10 @@ public class Pair<T, U> {
     T t;
     U u;
     
+    protected Pair() {
+    	
+    }
+    
     public Pair(T t, U u) {
         this.t = t;
         this.u = u;