diff --git a/core/AmSession.cpp b/core/AmSession.cpp
index 92d68314..d67a6794 100644
--- a/core/AmSession.cpp
+++ b/core/AmSession.cpp
@@ -241,6 +241,15 @@ void AmSession::setUri(const string& uri)
   sdp.uri = uri;
 }
 
+void AmSession::setLocalTag()
+{
+  if (dlg.local_tag.empty()) {
+    dlg.local_tag = getNewId();
+    DBG("AmSession::setLocalTag() - session id set to %s\n", 
+	dlg.local_tag.c_str());
+  }
+}
+
 void AmSession::setLocalTag(const string& tag)
 {
   DBG("AmSession::setLocalTag(%s)\n",tag.c_str());
diff --git a/core/AmSession.h b/core/AmSession.h
index 8a35a804..a6a7aac8 100644
--- a/core/AmSession.h
+++ b/core/AmSession.h
@@ -286,6 +286,9 @@ public:
   /** Gets the Session's local tag */
   const string& getLocalTag() const;
 
+  /** Sets the Session's local tag if not set already */
+  void setLocalTag();
+
   /** Sets the Session's local tag */
   void setLocalTag(const string& tag);
 
diff --git a/core/AmSessionContainer.cpp b/core/AmSessionContainer.cpp
index f755406f..819f5147 100644
--- a/core/AmSessionContainer.cpp
+++ b/core/AmSessionContainer.cpp
@@ -233,22 +233,18 @@ void AmSessionContainer::startSessionUAS(AmSipRequest& req)
       AmSession* session;
       if((session = createSession(req)) != 0){
 
-	string local_tag = AmSession::getNewId();
-	session->setLocalTag(local_tag);
+	// update session's local tag (ID) if not already set
+	session->setLocalTag();
+	const string& local_tag = session->getLocalTag();
+	// by default each session is in its own callgroup
 	session->setCallgroup(local_tag);
 	session->start();
 
 	addSession_unsafe(req.callid,req.from_tag,local_tag,session);
 	session->postEvent(new AmSipRequestEvent(req));
       }
-      //else
-      //throw AmSession::Exception(500,"internal error");
     }
   } 
-  //     catch(const AmSession::SessionTimerException& e){
-  //  	ERROR("%i %s\n",e.code,e.reason.c_str());
-  // 	AmSipDialog::reply_error(req,e.code,e.reason,e.getErrorHeaders());
-  //     }
   catch(const AmSession::Exception& e){
     ERROR("%i %s\n",e.code,e.reason.c_str());
     AmSipDialog::reply_error(req,e.code,e.reason);