diff --git a/jingle/extension/source/org/jivesoftware/smackx/jingle/JingleSession.java b/jingle/extension/source/org/jivesoftware/smackx/jingle/JingleSession.java
index 2b4e87965..f84ab9efc 100644
--- a/jingle/extension/source/org/jivesoftware/smackx/jingle/JingleSession.java
+++ b/jingle/extension/source/org/jivesoftware/smackx/jingle/JingleSession.java
@@ -299,6 +299,7 @@ public abstract class JingleSession extends JingleNegotiator {
 
     /**
      * Overides JingleNegiociator Method to add listener capabilities
+     *
      * @param newState new State
      */
     protected void setState(State newState) {
@@ -880,7 +881,7 @@ public abstract class JingleSession extends JingleNegotiator {
     protected void removePacketListener() {
         if (packetListener != null) {
             getConnection().removePacketListener(packetListener);
-            
+
             System.out.println("REMOVE PACKET LISTENER");
         }
     }
@@ -1063,6 +1064,10 @@ public abstract class JingleSession extends JingleNegotiator {
         if (jingleMediaManager != null) {
             jingleMediaSession = jingleMediaManager.createMediaSession(pt, rc, lc);
             if (jingleMediaSession != null) {
+
+                rc.removeCandidateEcho();
+                lc.removeCandidateEcho();
+
                 jingleMediaSession.startTrasmit();
                 jingleMediaSession.startReceive();
             }
diff --git a/jingle/extension/source/org/jivesoftware/smackx/jingle/nat/ICECandidate.java b/jingle/extension/source/org/jivesoftware/smackx/jingle/nat/ICECandidate.java
index 33b2a03ef..1e9424a93 100644
--- a/jingle/extension/source/org/jivesoftware/smackx/jingle/nat/ICECandidate.java
+++ b/jingle/extension/source/org/jivesoftware/smackx/jingle/nat/ICECandidate.java
@@ -51,6 +51,10 @@
  */
 package org.jivesoftware.smackx.jingle.nat;
 
+import java.net.InetAddress;
+import java.net.UnknownHostException;
+import java.util.List;
+
 /**
  * ICE Transport candidate.
  * <p/>
@@ -235,6 +239,60 @@ public class ICECandidate extends TransportCandidate implements Comparable {
         this.type = type;
     }
 
+    /**
+     * Check if a transport candidate is usable. The transport resolver should
+     * check if the transport candidate the other endpoint has provided is
+     * usable.
+     * <p/>
+     * ICE Candidate can check connectivity using UDP echo Test.
+     */
+    public void check(final List<TransportCandidate> localCandidates) {
+        //TODO candidate is being checked trigger
+        //candidatesChecking.add(cand);
+
+        Thread checkThread = new Thread(new Runnable() {
+            public void run() {
+                boolean isUsable = false;
+
+                for (TransportCandidate candidate : localCandidates) {
+                    CandidateEcho echo = candidate.getCandidateEcho();
+                    if (echo != null) {
+                        try {
+                            InetAddress address = InetAddress.getByName(getIp());
+                            if (echo.test(address, getPort())) isUsable = true;
+                            if (isUsable) break;
+                        }
+                        catch (UnknownHostException e) {
+                            e.printStackTrace();
+                        }
+                    }
+                }
+
+                if (isUsable) {
+                    System.out.println("Checked using UDP Echo:" + getLocalIp());
+                    triggerCandidateChecked(isUsable);
+                    return;
+                }
+
+                InetAddress candAddress;
+                try {
+                    candAddress = InetAddress.getByName(getIp());
+                    isUsable = candAddress.isReachable(TransportResolver.CHECK_TIMEOUT);
+                }
+                catch (Exception e) {
+                    isUsable = false;
+                }
+                triggerCandidateChecked(isUsable);
+
+                //TODO candidate is being checked trigger
+                //candidatesChecking.remove(cand);
+            }
+        }, "Transport candidate check");
+
+        checkThread.setName("Transport candidate test");
+        checkThread.start();
+    }
+
     /*
     * (non-Javadoc)
     *
diff --git a/jingle/extension/source/org/jivesoftware/smackx/jingle/nat/ICEResolver.java b/jingle/extension/source/org/jivesoftware/smackx/jingle/nat/ICEResolver.java
index 0ddc2fb9b..e4c52be2d 100644
--- a/jingle/extension/source/org/jivesoftware/smackx/jingle/nat/ICEResolver.java
+++ b/jingle/extension/source/org/jivesoftware/smackx/jingle/nat/ICEResolver.java
@@ -80,6 +80,12 @@ public class ICEResolver extends TransportResolver {
                     TransportCandidate transportCandidate = new ICECandidate(candidate.getAddress().getInetAddress().getHostAddress(), 1, candidate.getNetwork(), "1", candidate.getPort(), "1", candidate.getPriority(), typeString);
                     transportCandidate.setLocalIp(candidate.getBase().getAddress().getInetAddress().getHostAddress());
                     transportCandidate.setPort(getFreePort());
+                    try {
+                        transportCandidate.addCandidateEcho();
+                    }
+                    catch (SocketException e) {
+                        e.printStackTrace();
+                    }
                     this.addCandidate(transportCandidate);
 
                     System.out.println("C: " + candidate.getAddress().getInetAddress() + "|" + candidate.getBase().getAddress().getInetAddress() + " p:" + candidate.getPriority());
diff --git a/jingle/extension/source/org/jivesoftware/smackx/jingle/nat/TransportCandidate.java b/jingle/extension/source/org/jivesoftware/smackx/jingle/nat/TransportCandidate.java
index dcb8a6ccb..f4202cad1 100644
--- a/jingle/extension/source/org/jivesoftware/smackx/jingle/nat/TransportCandidate.java
+++ b/jingle/extension/source/org/jivesoftware/smackx/jingle/nat/TransportCandidate.java
@@ -104,7 +104,8 @@ public abstract class TransportCandidate {
     }
 
     public void removeCandidateEcho() {
-        candidateEcho.cancel();
+        if (candidateEcho != null)
+            candidateEcho.cancel();
         candidateEcho = null;
         echoThread = null;
     }
@@ -370,7 +371,7 @@ public abstract class TransportCandidate {
      * <p/>
      * Subclasses should provide better methods if they can...
      */
-    public void check() {
+    public void check(final List<TransportCandidate> localCandidates) {
         //TODO candidate is being checked trigger
         //candidatesChecking.add(cand);
 
@@ -402,7 +403,7 @@ public abstract class TransportCandidate {
      *
      * @param result The result.
      */
-    private void triggerCandidateChecked(boolean result) {
+    void triggerCandidateChecked(boolean result) {
 
         for (TransportResolverListener.Checker trl : getListenersList()) {
             trl.candidateChecked(this, result);
@@ -461,7 +462,7 @@ public abstract class TransportCandidate {
             super(ip, port, generation);
         }
     }
-   
+
     /**
      * Type-safe enum for the transportElement protocol
      */
diff --git a/jingle/extension/source/org/jivesoftware/smackx/jingle/nat/TransportNegotiator.java b/jingle/extension/source/org/jivesoftware/smackx/jingle/nat/TransportNegotiator.java
index cbcd79017..3a2d30700 100644
--- a/jingle/extension/source/org/jivesoftware/smackx/jingle/nat/TransportNegotiator.java
+++ b/jingle/extension/source/org/jivesoftware/smackx/jingle/nat/TransportNegotiator.java
@@ -219,7 +219,7 @@ public abstract class TransportNegotiator extends JingleNegotiator {
             }
 
         });
-        offeredCandidate.check();
+        offeredCandidate.check(resolver.getCandidatesList());
     }
 
     /**
diff --git a/jingle/extension/test/org/jivesoftware/smackx/jingle/nat/BasicResolverTest.java b/jingle/extension/test/org/jivesoftware/smackx/jingle/nat/BasicResolverTest.java
index 16fc889db..f00db201c 100644
--- a/jingle/extension/test/org/jivesoftware/smackx/jingle/nat/BasicResolverTest.java
+++ b/jingle/extension/test/org/jivesoftware/smackx/jingle/nat/BasicResolverTest.java
@@ -2,6 +2,8 @@ package org.jivesoftware.smackx.jingle.nat;
 
 import org.jivesoftware.smack.test.SmackTestCase;
 
+import java.util.ArrayList;
+
 public class BasicResolverTest extends SmackTestCase {
 
 	private int counter;
@@ -54,7 +56,7 @@ public class BasicResolverTest extends SmackTestCase {
             }
         });
 		
-		tc.check();
+		tc.check(new ArrayList<TransportCandidate>());
 		
 		try {
 			Thread.sleep(TransportResolver.CHECK_TIMEOUT);
@@ -83,7 +85,7 @@ public class BasicResolverTest extends SmackTestCase {
             }
         });
 		
-		tc.check();
+		tc.check(new ArrayList<TransportCandidate>());
 		
 		try {
 			Thread.sleep(TransportResolver.CHECK_TIMEOUT);