diff --git a/core/AmB2BSession.cpp b/core/AmB2BSession.cpp
index f69ec88e..bd7a937f 100644
--- a/core/AmB2BSession.cpp
+++ b/core/AmB2BSession.cpp
@@ -510,6 +510,13 @@ void AmB2BSession::onSessionTimeout() {
   AmSession::onSessionTimeout();
 }
 
+void AmB2BSession::onNoAck(unsigned int cseq)
+{
+  DBG("OnNoAck(%u): terminate other leg.\n",cseq);
+  terminateOtherLeg();
+  AmSession::onNoAck(cseq);
+}
+
 void AmB2BSession::saveSessionDescription(const string& content_type,
 					  const string& body) {
   DBG("saving session description (%s, %.*s...)\n",
diff --git a/core/AmB2BSession.h b/core/AmB2BSession.h
index 525e4bfa..57f5037c 100644
--- a/core/AmB2BSession.h
+++ b/core/AmB2BSession.h
@@ -185,6 +185,7 @@ class AmB2BSession: public AmSession
   void onInvite2xx(const AmSipReply& reply);
 
   void onSessionTimeout();
+  void onNoAck(unsigned int cseq);
 
   /** send re-INVITE with established session description 
    *  @return 0 on success