diff --git a/apps/announce_transfer/AnnounceTransfer.cpp b/apps/announce_transfer/AnnounceTransfer.cpp
index 1bea3e3b..34e2b79f 100644
--- a/apps/announce_transfer/AnnounceTransfer.cpp
+++ b/apps/announce_transfer/AnnounceTransfer.cpp
@@ -181,7 +181,7 @@ void AnnounceTransferDialog::onSipRequest(const AmSipRequest& req)
 
 }
 
-void AnnounceTransferDialog::onSipReply(const AmSipReply& rep, int old_dlg_status) {
+void AnnounceTransferDialog::onSipReply(const AmSipReply& rep, int old_dlg_status, const string& trans_method) {
   if ((status==Transfering ||status==Hangup)  && 
       dlg.get_uac_trans_method(rep.cseq) == "REFER") {
     if (rep.code >= 300) {
@@ -191,7 +191,7 @@ void AnnounceTransferDialog::onSipReply(const AmSipReply& rep, int old_dlg_statu
     }
   }
 
-  AmSession::onSipReply(rep, old_dlg_status);
+  AmSession::onSipReply(rep, old_dlg_status, trans_method);
 }
 
 void AnnounceTransferDialog::onBye(const AmSipRequest& req)
diff --git a/apps/announce_transfer/AnnounceTransfer.h b/apps/announce_transfer/AnnounceTransfer.h
index b2840401..8849e3f3 100644
--- a/apps/announce_transfer/AnnounceTransfer.h
+++ b/apps/announce_transfer/AnnounceTransfer.h
@@ -72,7 +72,7 @@ public:
   void startSession();
   void onBye(const AmSipRequest& req);
   void onSipRequest(const AmSipRequest& req);
-    void onSipReply(const AmSipReply& rep, int old_dlg_status);
+  void onSipReply(const AmSipReply& rep, int old_dlg_status, const string& trans_method);
   void onDtmf(int event, int duration_msec) {}
 
   void process(AmEvent* event);
diff --git a/apps/auth_b2b/AuthB2B.cpp b/apps/auth_b2b/AuthB2B.cpp
index 9de578c7..45f76a49 100644
--- a/apps/auth_b2b/AuthB2B.cpp
+++ b/apps/auth_b2b/AuthB2B.cpp
@@ -314,15 +314,15 @@ inline UACAuthCred* AuthB2BCalleeSession::getCredentials() {
   return &credentials;
 }
 
-void AuthB2BCalleeSession::onSipReply(const AmSipReply& reply, int old_dlg_status) {
+void AuthB2BCalleeSession::onSipReply(const AmSipReply& reply, int old_dlg_status, const string& trans_method) {
   if (NULL == auth) {    
-      AmB2BCalleeSession::onSipReply(reply,old_dlg_status);
+    AmB2BCalleeSession::onSipReply(reply,old_dlg_status,trans_method);
     return;
   }
   
   unsigned int cseq_before = dlg.cseq;
-  if (!auth->onSipReply(reply, old_dlg_status)) {
-      AmB2BCalleeSession::onSipReply(reply,old_dlg_status);
+  if (!auth->onSipReply(reply, old_dlg_status,trans_method)) {
+    AmB2BCalleeSession::onSipReply(reply,old_dlg_status,trans_method);
   } else {
     if (cseq_before != dlg.cseq) {
       DBG("uac_auth consumed reply with cseq %d and resent with cseq %d; "
diff --git a/apps/auth_b2b/AuthB2B.h b/apps/auth_b2b/AuthB2B.h
index 5619a881..7bca232b 100644
--- a/apps/auth_b2b/AuthB2B.h
+++ b/apps/auth_b2b/AuthB2B.h
@@ -95,7 +95,7 @@ class AuthB2BCalleeSession
   AmSessionEventHandler* auth;
 
  protected:
-  void onSipReply(const AmSipReply& reply, int old_dlg_status);
+  void onSipReply(const AmSipReply& reply, int old_dlg_status, const string& trans_method);
   void onSendRequest(const string& method, const string& content_type,
 		     const string& body, string& hdrs, int flags, unsigned int cseq);
 
diff --git a/apps/conference/Conference.cpp b/apps/conference/Conference.cpp
index b1b39928..f2ccce0f 100644
--- a/apps/conference/Conference.cpp
+++ b/apps/conference/Conference.cpp
@@ -862,10 +862,10 @@ void ConferenceDialog::onSipRequest(const AmSipRequest& req)
   return;
 }
 
-void ConferenceDialog::onSipReply(const AmSipReply& reply, int old_dlg_status)
+void ConferenceDialog::onSipReply(const AmSipReply& reply, int old_dlg_status, const string& trans_method)
 {
   int status = dlg.getStatus();
-  AmSession::onSipReply(reply,old_dlg_status);
+  AmSession::onSipReply(reply, old_dlg_status, trans_method);
 
   DBG("ConferenceDialog::onSipReply: code = %i, reason = %s\n, status = %i\n",
       reply.code,reply.reason.c_str(),dlg.getStatus());
diff --git a/apps/conference/Conference.h b/apps/conference/Conference.h
index ce284b04..ab00af83 100644
--- a/apps/conference/Conference.h
+++ b/apps/conference/Conference.h
@@ -153,7 +153,8 @@ public:
   void onBye(const AmSipRequest& req);
 
   void onSipRequest(const AmSipRequest& req);
-  void onSipReply(const AmSipReply& reply, int old_dlg_status);
+  void onSipReply(const AmSipReply& reply, int old_dlg_status,
+		  const string& trans_method);
 
 #ifdef WITH_SAS_TTS
   void onZRTPEvent(zrtp_event_t event, zrtp_stream_ctx_t *stream_ctx);
diff --git a/apps/dsm/DSMCall.cpp b/apps/dsm/DSMCall.cpp
index 49b3e7d3..9d0fcf7c 100644
--- a/apps/dsm/DSMCall.cpp
+++ b/apps/dsm/DSMCall.cpp
@@ -287,7 +287,7 @@ void DSMCall::onSipRequest(const AmSipRequest& req) {
   AmB2BCallerSession::onSipRequest(req);  
 }
 
-void DSMCall::onSipReply(const AmSipReply& reply, int old_dlg_status) {
+void DSMCall::onSipReply(const AmSipReply& reply, int old_dlg_status, const string& trans_method) {
 
   if (checkVar(DSM_ENABLE_REPLY_EVENTS, DSM_TRUE)) {
     map<string, string> params;
@@ -318,7 +318,7 @@ void DSMCall::onSipReply(const AmSipReply& reply, int old_dlg_status) {
     }
   }
 
-  AmB2BCallerSession::onSipReply(reply,old_dlg_status);
+  AmB2BCallerSession::onSipReply(reply,old_dlg_status,trans_method);
 
   if ((old_dlg_status < AmSipDialog::Connected) && 
       (dlg.getStatus() == AmSipDialog::Disconnected)) {
diff --git a/apps/dsm/DSMCall.h b/apps/dsm/DSMCall.h
index a7794d7b..c3208588 100644
--- a/apps/dsm/DSMCall.h
+++ b/apps/dsm/DSMCall.h
@@ -83,7 +83,7 @@ public:
   void onDtmf(int event, int duration_msec);
 
   void onSipRequest(const AmSipRequest& req);
-  void onSipReply(const AmSipReply& reply, int old_dlg_status);
+  void onSipReply(const AmSipReply& reply, int old_dlg_status, const string& trans_method);
 
   void process(AmEvent* event);
 
diff --git a/apps/examples/b2b_connect/b2b_connect.cpp b/apps/examples/b2b_connect/b2b_connect.cpp
index bde20ab0..62ee1f27 100644
--- a/apps/examples/b2b_connect/b2b_connect.cpp
+++ b/apps/examples/b2b_connect/b2b_connect.cpp
@@ -286,8 +286,10 @@ inline UACAuthCred* b2b_connectCalleeSession::getCredentials() {
   return &credentials;
 }
 
-void b2b_connectCalleeSession::onSipReply(const AmSipReply& reply, int old_dlg_status) {
-  AmB2ABCalleeSession::onSipReply(reply, old_dlg_status);
+void b2b_connectCalleeSession::onSipReply(const AmSipReply& reply,
+					  int old_dlg_status,
+					  const string& trans_method) {
+  AmB2ABCalleeSession::onSipReply(reply, old_dlg_status, trans_method);
  
   if ((old_dlg_status == AmSipDialog::Pending)&&
       (dlg.getStatus() == AmSipDialog::Disconnected)) {
diff --git a/apps/examples/b2b_connect/b2b_connect.h b/apps/examples/b2b_connect/b2b_connect.h
index 83d39bc2..b7722743 100644
--- a/apps/examples/b2b_connect/b2b_connect.h
+++ b/apps/examples/b2b_connect/b2b_connect.h
@@ -88,7 +88,8 @@ class b2b_connectCalleeSession
   AmSipRequest invite_req;
 
  protected:
-  void onSipReply(const AmSipReply& reply, int old_dlg_status);
+  void onSipReply(const AmSipReply& reply, int old_dlg_status,
+		  const string& trans_method);
  
 public:
   b2b_connectCalleeSession(const string& other_tag, 
diff --git a/apps/gateway/GWSession.cpp b/apps/gateway/GWSession.cpp
index 38e2482e..5720d33a 100644
--- a/apps/gateway/GWSession.cpp
+++ b/apps/gateway/GWSession.cpp
@@ -90,7 +90,7 @@ void GWSession::onSipRequest(const AmSipRequest& req)
   }
 }
 
-void GWSession::onSipReply(const AmSipReply& reply, int old_dlg_status) {
+void GWSession::onSipReply(const AmSipReply& reply, int old_dlg_status, const string& trans_method) {
     int status = dlg.getStatus();
     DBG("GWSession::onSipReply: code = %i, reason = %s\n, status = %i\n",  
 	reply.code,reply.reason.c_str(),dlg.getStatus());
@@ -99,7 +99,7 @@ void GWSession::onSipReply(const AmSipReply& reply, int old_dlg_status) {
 	int ret=((mISDNChannel*)m_OtherLeg)->hangup();
     }
     DBG("GWSession::onSipReply calling parent\n");
-    AmSession::onSipReply(reply, old_dlg_status);
+    AmSession::onSipReply(reply, old_dlg_status, trans_method);
 }
 
 void GWSession::on_stop() {
diff --git a/apps/gateway/GWSession.h b/apps/gateway/GWSession.h
index 535a6cfa..8126f782 100644
--- a/apps/gateway/GWSession.h
+++ b/apps/gateway/GWSession.h
@@ -33,7 +33,7 @@ static    GWSession* CallFromOutside(std::string &fromnumber, std::string &tonum
   void onBye(const AmSipRequest& req);
 //virtual void onSipEvent(AmSipEvent* sip_ev);
   void onSipRequest(const AmSipRequest& req);
-  void onSipReply(const AmSipReply& reply, int old_dlg_status);
+  void onSipReply(const AmSipReply& reply, int old_dlg_status, const string& trans_method);
 //virtual void onRtpTimeout();
 //virtual void onSendRequest(const string& method, const string& content_type, const string& body, string& hdrs, int flags, unsigned int cseq);
 //virtual void onSendReply(const AmSipRequest& req, unsigned int code,const string& reason,const string& content_type, const string& body,string& hdrs,int flags)
diff --git a/apps/ivr/Ivr.cpp b/apps/ivr/Ivr.cpp
index 89f31b33..37a66b32 100644
--- a/apps/ivr/Ivr.cpp
+++ b/apps/ivr/Ivr.cpp
@@ -749,11 +749,11 @@ void safe_Py_DECREF(PyObject* pyo) {
   Py_DECREF(pyo);
 }
 
-void IvrDialog::onSipReply(const AmSipReply& r, int old_dlg_status) {
+void IvrDialog::onSipReply(const AmSipReply& r, int old_dlg_status, const string& trans_method) {
   PyObject* pyo = getPySipReply(r);
   callPyEventHandler("onSipReply","(O)", pyo);
   safe_Py_DECREF(pyo);
-  AmB2BSession::onSipReply(r,old_dlg_status);
+  AmB2BSession::onSipReply(r,old_dlg_status,trans_method);
 }
 
 void IvrDialog::onSipRequest(const AmSipRequest& r){
diff --git a/apps/ivr/Ivr.h b/apps/ivr/Ivr.h
index b2ba8f6d..bd87c720 100644
--- a/apps/ivr/Ivr.h
+++ b/apps/ivr/Ivr.h
@@ -149,7 +149,7 @@ class IvrDialog : public AmB2BCallerSession
   void onOtherBye(const AmSipRequest& req);
   bool onOtherReply(const AmSipReply& r);
 
-  void onSipReply(const AmSipReply& r,int old_dlg_status);
+  void onSipReply(const AmSipReply& r,int old_dlg_status, const string& trans_method);
   void onSipRequest(const AmSipRequest& r);
 
   void onRtpTimeout();
diff --git a/apps/registrar_client/SIPRegistrarClient.cpp b/apps/registrar_client/SIPRegistrarClient.cpp
index 914bb930..770a4f44 100644
--- a/apps/registrar_client/SIPRegistrarClient.cpp
+++ b/apps/registrar_client/SIPRegistrarClient.cpp
@@ -369,9 +369,9 @@ bool SIPRegistration::registerExpired(time_t now_sec) {
   return ((reg_begin+reg_expires) < (unsigned int)now_sec);	
 }
 
-void SIPRegistration::onSipReply(const AmSipReply& reply, int old_dlg_status)
+void SIPRegistration::onSipReply(const AmSipReply& reply, int old_dlg_status, const string& trans_method)
 {
-  if ((seh!=NULL) && seh->onSipReply(reply, old_dlg_status)) 
+  if ((seh!=NULL) && seh->onSipReply(reply, old_dlg_status, trans_method))
     return;
 
   waiting_result = false;
@@ -498,7 +498,7 @@ void SIPRegistrarClient::onRemoveRegistration(SIPRemoveRegistrationEvent* new_re
 void SIPRegistrarClient::on_stop() { }
 
 
-bool SIPRegistrarClient::onSipReply(const AmSipReply& rep) {
+bool SIPRegistrarClient::onSipReply(const AmSipReply& rep, int old_dlg_status, const string& trans_method) {
   DBG("got reply with tag '%s'\n", rep.local_tag.c_str());
 	
   if (instance()->hasRegistration(rep.local_tag)) {
diff --git a/apps/registrar_client/SIPRegistrarClient.h b/apps/registrar_client/SIPRegistrarClient.h
index e79af3bf..5bcfef00 100644
--- a/apps/registrar_client/SIPRegistrarClient.h
+++ b/apps/registrar_client/SIPRegistrarClient.h
@@ -124,7 +124,7 @@ class SIPRegistration : public AmSipDialogEventHandler,
   // CredentialHolder	
   UACAuthCred* getCredentials() { return &cred; }
 
-  void onSipReply(const AmSipReply& reply, int old_dlg_status);
+  void onSipReply(const AmSipReply& reply, int old_dlg_status, const string& trans_method);
   void onSipRequest(const AmSipRequest& req) {}
   void onInvite2xx(const AmSipReply&) {}
   void onNoAck(unsigned int) {}
@@ -192,7 +192,7 @@ class SIPRegistrarClient  : public AmThread,
   void invoke(const string& method, 
 	      const AmArg& args, AmArg& ret);
 	
-  bool onSipReply(const AmSipReply& rep);
+  bool onSipReply(const AmSipReply& rep, int old_dlg_status, const string& trans_method);
   int onLoad();
 	
   void run();
diff --git a/apps/sst_b2b/SSTB2B.cpp b/apps/sst_b2b/SSTB2B.cpp
index bd8425c7..05271215 100644
--- a/apps/sst_b2b/SSTB2B.cpp
+++ b/apps/sst_b2b/SSTB2B.cpp
@@ -132,25 +132,10 @@ void SSTB2BDialog::onInvite(const AmSipRequest& req)
   recvd_req.insert(std::make_pair(req.cseq,req));
   
   set_sip_relay_only(true);
-  DBG("##### connecting to <%s>",req.r_uri.c_str());
+  DBG("##### connecting to <%s> #####\n",req.r_uri.c_str());
   connectCallee("<" + req.r_uri + ">", req.r_uri, true);
 }
 
-void SSTB2BDialog::sendReinvite(bool updateSDP, const string& headers) {
-  if (sip_relay_only) {
-    // we send empty reinvite 
-    DBG("sending empty reinvite in callee session\n");
-    dlg.reinvite(headers, "", ""); 
-  } else {
-    AmB2BCallerSession::sendReinvite(updateSDP, headers);
-  }
-
-  // // we send empty reinvite
-  // dlg.reinvite(headers, "", "");
-  // we send reinvite with the last body we got from the other side
-  // last_otherleg_content_type, last_otherleg_body);
-}
-
 void SSTB2BDialog::process(AmEvent* ev)
 {
   AmB2BCallerSession::process(ev);
@@ -171,7 +156,8 @@ void SSTB2BDialog::onSipRequest(const AmSipRequest& req) {
   AmB2BCallerSession::onSipRequest(req);
 }
 
-void SSTB2BDialog::onSipReply(const AmSipReply& reply, int old_dlg_status) 
+void SSTB2BDialog::onSipReply(const AmSipReply& reply, int old_dlg_status,
+			      const string& trans_method)
 {
   TransMap::iterator t = relayed_req.find(reply.cseq);
   bool fwd = t != relayed_req.end();
@@ -179,10 +165,10 @@ void SSTB2BDialog::onSipReply(const AmSipReply& reply, int old_dlg_status)
   DBG("onSipReply: %i %s (fwd=%i)\n",reply.code,reply.reason.c_str(),fwd);
   DBG("onSipReply: content-type = %s\n",reply.content_type.c_str());
   if (fwd) {
-      CALL_EVENT_H(onSipReply,reply, old_dlg_status);
+      CALL_EVENT_H(onSipReply,reply, old_dlg_status, trans_method);
   }
 
-  AmB2BCallerSession::onSipReply(reply,old_dlg_status);
+  AmB2BCallerSession::onSipReply(reply,old_dlg_status, trans_method);
 }
 
 bool SSTB2BDialog::onOtherReply(const AmSipReply& reply)
@@ -344,7 +330,8 @@ void SSTB2BCalleeSession::onSipRequest(const AmSipRequest& req) {
   AmB2BCalleeSession::onSipRequest(req);
 }
 
-void SSTB2BCalleeSession::onSipReply(const AmSipReply& reply, int old_dlg_status) 
+void SSTB2BCalleeSession::onSipReply(const AmSipReply& reply, int old_dlg_status,
+				     const string& trans_method)
 {
   // call event handlers where it is not done 
   TransMap::iterator t = relayed_req.find(reply.cseq);
@@ -352,17 +339,17 @@ void SSTB2BCalleeSession::onSipReply(const AmSipReply& reply, int old_dlg_status
   DBG("onSipReply: %i %s (fwd=%i)\n",reply.code,reply.reason.c_str(),fwd);
   DBG("onSipReply: content-type = %s\n",reply.content_type.c_str());
   if(fwd) {
-      CALL_EVENT_H(onSipReply,reply, old_dlg_status);
+    CALL_EVENT_H(onSipReply,reply, old_dlg_status, trans_method);
   }
 
   if (NULL == auth) {    
-      AmB2BCalleeSession::onSipReply(reply,old_dlg_status);
+    AmB2BCalleeSession::onSipReply(reply,old_dlg_status, trans_method);
     return;
   }
   
   unsigned int cseq_before = dlg.cseq;
-  if (!auth->onSipReply(reply, old_dlg_status)) {
-      AmB2BCalleeSession::onSipReply(reply,old_dlg_status);
+  if (!auth->onSipReply(reply, old_dlg_status, trans_method)) {
+      AmB2BCalleeSession::onSipReply(reply, old_dlg_status, trans_method);
   } else {
     if (cseq_before != dlg.cseq) {
       DBG("uac_auth consumed reply with cseq %d and resent with cseq %d; "
@@ -390,13 +377,3 @@ void SSTB2BCalleeSession::onSendRequest(const string& method, const string& cont
 				     body, hdrs, flags, cseq);
 }
 
-void SSTB2BCalleeSession::sendReinvite(bool updateSDP, const string& headers) {
-  if (sip_relay_only) {
-    // we send empty reinvite 
-    DBG("sending empty reinvite in callee session\n");
-    dlg.reinvite(headers, "", ""); 
-  } else {
-    AmB2BCalleeSession::sendReinvite(updateSDP, headers);
-  }
-}
-
diff --git a/apps/sst_b2b/SSTB2B.h b/apps/sst_b2b/SSTB2B.h
index 2d6aa0f0..69a2aaf6 100644
--- a/apps/sst_b2b/SSTB2B.h
+++ b/apps/sst_b2b/SSTB2B.h
@@ -90,10 +90,9 @@ class SSTB2BDialog : public AmB2BCallerSession
   void onInvite(const AmSipRequest& req);
   void onCancel();
 
-  void sendReinvite(bool updateSDP, const string& headers);
-
  protected:
-    void onSipReply(const AmSipReply& reply, int old_dlg_status);
+  void onSipReply(const AmSipReply& reply, int old_dlg_status,
+		  const string& trans_method);
   void onSipRequest(const AmSipRequest& req);  
 
  protected:
@@ -115,7 +114,8 @@ class SSTB2BCalleeSession
 
  protected:
   void onSipRequest(const AmSipRequest& req);
-    void onSipReply(const AmSipReply& reply, int old_dlg_status);
+  void onSipReply(const AmSipReply& reply, int old_dlg_status,
+		  const string& trans_method);
   void onSendRequest(const string& method, const string& content_type,
 		     const string& body, string& hdrs, int flags, unsigned int cseq);
 
@@ -128,7 +128,5 @@ class SSTB2BCalleeSession
   inline UACAuthCred* getCredentials();
   
   void setAuthHandler(AmSessionEventHandler* h) { auth = h; }
-
-  void sendReinvite(bool updateSDP, const string& headers);
 };
 #endif                           
diff --git a/apps/webconference/WebConferenceDialog.cpp b/apps/webconference/WebConferenceDialog.cpp
index 229d44cc..0fe4d85c 100644
--- a/apps/webconference/WebConferenceDialog.cpp
+++ b/apps/webconference/WebConferenceDialog.cpp
@@ -173,11 +173,11 @@ void WebConferenceDialog::onSessionStart(const AmSipReply& rep) {
   connectConference(dlg.user);
 }
 
-void WebConferenceDialog::onSipReply(const AmSipReply& reply, int old_dlg_status) 
+void WebConferenceDialog::onSipReply(const AmSipReply& reply, int old_dlg_status, const string& trans_method)
 {
   //int status = dlg.getStatus();
 
-  AmSession::onSipReply(reply,old_dlg_status);
+  AmSession::onSipReply(reply,old_dlg_status,trans_method);
 
   DBG("reply: %u %s, old_dlg_status = %s, status = %s\n",
       reply.code, reply.reason.c_str(),
diff --git a/apps/webconference/WebConferenceDialog.h b/apps/webconference/WebConferenceDialog.h
index 203dee43..ea36c26b 100644
--- a/apps/webconference/WebConferenceDialog.h
+++ b/apps/webconference/WebConferenceDialog.h
@@ -94,7 +94,7 @@ public:
   ~WebConferenceDialog();
 
   void process(AmEvent* ev);
-  void onSipReply(const AmSipReply& reply, int old_dlg_status);
+  void onSipReply(const AmSipReply& reply, int old_dlg_status, const string& trans_method);
   void onSessionStart(const AmSipRequest& req);
   void onSessionStart(const AmSipReply& rep);
   void onEarlySessionStart(const AmSipReply& rep);
diff --git a/core/AmB2ABSession.cpp b/core/AmB2ABSession.cpp
index 89e7d7c5..82c95d76 100644
--- a/core/AmB2ABSession.cpp
+++ b/core/AmB2ABSession.cpp
@@ -353,13 +353,13 @@ void AmB2ABCalleeSession::onSessionStart(const AmSipReply& rep) {
   relayEvent(new B2ABConnectAudioEvent());
 }
 
-void AmB2ABCalleeSession::onSipReply(const AmSipReply& rep, int old_dlg_status) {
-
-    int status_before = old_dlg_status;//dlg.getStatus();
-    AmB2ABSession::onSipReply(rep, old_dlg_status);
+void AmB2ABCalleeSession::onSipReply(const AmSipReply& rep,
+				     int old_dlg_status,
+				     const string& trans_method) {
+  AmB2ABSession::onSipReply(rep, old_dlg_status, trans_method);
   int status = dlg.getStatus();
  
-  if ((status_before == AmSipDialog::Pending)&&
+  if ((old_dlg_status == AmSipDialog::Pending)&&
       (status == AmSipDialog::Disconnected)) {
 	  
     DBG("callee session creation failed. notifying caller session.\n");
diff --git a/core/AmB2ABSession.h b/core/AmB2ABSession.h
index ad05edb0..1827e5c6 100644
--- a/core/AmB2ABSession.h
+++ b/core/AmB2ABSession.h
@@ -247,7 +247,8 @@ class AmB2ABCalleeSession: public AmB2ABSession
 
   void onEarlySessionStart(const AmSipReply& rep);
   void onSessionStart(const AmSipReply& rep);
-  void onSipReply(const AmSipReply& rep, int old_dlg_status);	
+  void onSipReply(const AmSipReply& rep, int old_dlg_status,
+		  const string& trans_method);
 
  protected:
   void onB2ABEvent(B2ABEvent* ev);
diff --git a/core/AmB2BSession.cpp b/core/AmB2BSession.cpp
index 27439fdd..671147a9 100644
--- a/core/AmB2BSession.cpp
+++ b/core/AmB2BSession.cpp
@@ -90,6 +90,16 @@ void AmB2BSession::onB2BEvent(B2BEvent* ev)
       assert(req_ev);
 
       if(req_ev->forward){
+	if (req_ev->req.method == SIP_METH_INVITE &&
+	    dlg.getUACInvTransPending()) {
+	  // don't relay INVITE if INV trans pending
+	  AmSipReply n_reply;
+	  n_reply.code = 491;
+	  n_reply.reason = "Request Pending";
+	  n_reply.cseq = req_ev->req.cseq;
+	  relayEvent(new B2BSipReplyEvent(n_reply, true, SIP_METH_INVITE));
+	  return;
+	}
 
 	relaySip(req_ev->req);
       }
@@ -106,19 +116,21 @@ void AmB2BSession::onB2BEvent(B2BEvent* ev)
       B2BSipReplyEvent* reply_ev = dynamic_cast<B2BSipReplyEvent*>(ev);
       assert(reply_ev);
 
-      DBG("B2BSipReply: %i %s (fwd=%i)\n",reply_ev->reply.code,
-	  reply_ev->reply.reason.c_str(),reply_ev->forward);
+      DBG("B2BSipReply: %i %s (fwd=%s)\n",reply_ev->reply.code,
+	  reply_ev->reply.reason.c_str(),reply_ev->forward?"true":"false");
       DBG("B2BSipReply: content-type = %s\n",reply_ev->reply.content_type.c_str());
 
       if(reply_ev->forward){
 
-        std::map<int,AmSipRequest>::iterator t_req = recvd_req.find(reply_ev->reply.cseq);
+        std::map<int,AmSipRequest>::iterator t_req =
+	  recvd_req.find(reply_ev->reply.cseq);
+
 	if (t_req != recvd_req.end()) {
 	  relaySip(t_req->second,reply_ev->reply);
 		
 	  if(reply_ev->reply.code >= 200){
 
-	    if( (t_req->second.method == "INVITE") &&
+	    if( (t_req->second.method == SIP_METH_INVITE) &&
 		(reply_ev->reply.code == 487)){
 	      
 	      terminateLeg();
@@ -129,6 +141,24 @@ void AmB2BSession::onB2BEvent(B2BEvent* ev)
 	  ERROR("Request with CSeq %u not found in recvd_req.\n",
 		reply_ev->reply.cseq);
 	}
+      } else {
+	// check whether not-forwarded (locally initiated)
+	// INV/UPD transaction changed session in other leg
+	if (SIP_IS_200_CLASS(reply_ev->reply.code) &&
+	    (!reply_ev->reply.body.empty()) &&
+	    (reply_ev->reply.method == SIP_METH_INVITE ||
+	     reply_ev->reply.method == SIP_METH_UPDATE)) {
+	  if (updateSessionDescription(reply_ev->reply.content_type,
+				       reply_ev->reply.body)) {
+	    if (dlg.getUACInvTransPending()) {
+	      DBG("changed session, but UAC INVITE trans pending\n");
+	      // todo(?): save until trans is finished?
+	      return;
+	    }
+	    DBG("session description changed - refreshing\n");
+	    sendEstablishedReInvite();
+	  }
+	}
       }
     }
     return;
@@ -137,44 +167,6 @@ void AmB2BSession::onB2BEvent(B2BEvent* ev)
     terminateLeg();
     break;
 
-  case B2BMsgBody:
-    {
-      if (!sip_relay_only) {
-	ERROR("relayed message body received but not in sip_relay_only mode\n");
-	return;
-      }
-
-      B2BMsgBodyEvent* body_ev = dynamic_cast<B2BMsgBodyEvent*>(ev);
-      assert(body_ev);
-
-      DBG("received B2B Msg body event; is_offer=%s, r_cseq=%d\n",
-	  body_ev->is_offer?"true":"false", body_ev->r_cseq);
-      
-      if (body_ev->is_offer) {
-	// send INVITE with SDP
-	trans_ticket tt; // empty transaction ticket
-	relayed_body_req[dlg.cseq] = AmSipTransaction("INVITE", body_ev->r_cseq, tt);
-	if (dlg.reinvite("", body_ev->content_type, body_ev->body)) {
-	  ERROR("sending reinvite with relayed body\n");
-	  relayed_body_req.erase(dlg.cseq);
-	  // TODO?: relay error back instead?
-	  // tear down:
-	  DBG("error sending reinvite - terminating this and the other leg\n");
-	  terminateOtherLeg();	   
-	  terminateLeg();
-	}
-      } else {
-	// is_answer - send 200 ACK
-	// todo: use that from uas_trans? 
-	trans_ticket tt; // not used for ACK
-	AmSipTransaction trans("INVITE", body_ev->r_cseq, tt);
-	if (dlg.send_200_ack(trans, body_ev->content_type, body_ev->body, 
-			     "" /* hdrs - todo */, SIP_FLAGS_VERBATIM)) {
-	  ERROR("sending ACK with SDP\n");
-	}
-      }
-      return; 
-    }; break;
   }
 
   //ERROR("unknown event caught\n");
@@ -189,7 +181,6 @@ void AmB2BSession::onSipRequest(const AmSipRequest& req)
   if(!fwd)
     AmSession::onSipRequest(req);
   else {
-    //dlg.updateStatus(req);
     updateRefreshMethod(req.hdrs);
     recvd_req.insert(std::make_pair(req.cseq,req));
   }
@@ -197,73 +188,33 @@ void AmB2BSession::onSipRequest(const AmSipRequest& req)
   relayEvent(new B2BSipRequestEvent(req,fwd));
 }
 
-void AmB2BSession::onSipReply(const AmSipReply& reply, int old_dlg_status)
+void AmB2BSession::onSipReply(const AmSipReply& reply,
+			      int old_dlg_status,
+			      const string& trans_method)
 {
-  updateRefreshMethod(reply.hdrs);
-
   TransMap::iterator t = relayed_req.find(reply.cseq);
   bool fwd = (t != relayed_req.end()) && (reply.code != 100);
 
-  DBG("onSipReply: %i %s (fwd=%i)\n",reply.code,reply.reason.c_str(),fwd);
+  DBG("onSipReply: %s -> %i %s (fwd=%s)\n",
+      trans_method.c_str(), reply.code,reply.reason.c_str(),fwd?"true":"false");
   DBG("onSipReply: content-type = %s\n",reply.content_type.c_str());
   if(fwd) {
+    updateRefreshMethod(reply.hdrs);
+
     AmSipReply n_reply = reply;
     n_reply.cseq = t->second.cseq;
     
-    //dlg.updateStatus(reply, false);
-    relayEvent(new B2BSipReplyEvent(n_reply,true));
+    relayEvent(new B2BSipReplyEvent(n_reply, true, t->second.method));
 
     if(reply.code >= 200) {
-      if ((reply.code < 300) && (t->second.method == "INVITE")) {
+      if ((reply.code < 300) && (t->second.method == SIP_METH_INVITE)) {
 	DBG("not removing relayed INVITE transaction yet...\n");
       } else 
 	relayed_req.erase(t);
     }
   } else {
-    string trans_method = dlg.get_uac_trans_method(reply.cseq);
-
-    bool relay_body = 
-      // is a reply to request we sent, 
-      // even though we are in sip_relay_only  mode
-      (sip_relay_only && 
-       // positive reply
-       (200 <= reply.code) && (reply.code < 300) &&
-       // with body
-       !reply.body.empty() &&
-       trans_method == SIP_METH_INVITE);
-    
-    if (relay_body) {
-      // is it an answer to a relayed body, or an answer to empty re-INVITE? 
-      TransMap::iterator rel_body_it = relayed_body_req.find(reply.cseq);
-      bool is_offer =  (rel_body_it == relayed_body_req.end());
-      // answer to empty re-INVITE we have sent
-      relayEvent(new B2BMsgBodyEvent(reply.content_type, reply.body, 
-				     is_offer, is_offer ? reply.cseq : rel_body_it->second.cseq));
-
-      if (is_offer) {	
-	// onSipReply from AmSession without do_200_ack in dlg.updateStatus(reply)
-	// todo (?): add do_200_ack flag to AmSession::onSipReply and call AmSession::onSipReply
-	CALL_EVENT_H(onSipReply,reply,old_dlg_status);
-	
-	//int status = dlg.getStatus();
-	//dlg.updateStatus(reply, false);
-	
-	if (old_dlg_status != dlg.getStatus())
-	  DBG("Dialog status changed %s -> %s (stopped=%s) \n", 
-	      AmSipDialog::status2str[old_dlg_status], 
-	      AmSipDialog::status2str[dlg.getStatus()],
-	      getStopped() ? "true" : "false");
-	else 
-	  DBG("Dialog status stays %s (stopped=%s)\n", AmSipDialog::status2str[old_dlg_status], 
-	      getStopped() ? "true" : "false");
-      } else {
-	relayed_body_req.erase(rel_body_it);
-	AmSession::onSipReply(reply, old_dlg_status);
-      }      
-    } else {
-      AmSession::onSipReply(reply, old_dlg_status);
-    }
-    relayEvent(new B2BSipReplyEvent(reply,false));
+    AmSession::onSipReply(reply, old_dlg_status, trans_method);
+    relayEvent(new B2BSipReplyEvent(reply, false, trans_method));
   }
 }
 
@@ -325,12 +276,97 @@ void AmB2BSession::onSessionTimeout() {
   AmSession::onSessionTimeout();
 }
 
+void AmB2BSession::saveSessionDescription(const string& content_type,
+					  const string& body) {
+  DBG("saving session description (%s, %.*s...)\n",
+      content_type.c_str(), 50, body.c_str());
+  established_content_type = content_type;
+  established_body = body;
+
+  const char* cmp_body_begin = body.c_str();
+  size_t cmp_body_length = body.length();
+  if (content_type == SIP_APPLICATION_SDP) {
+    // for SDP, skip v and o line
+    // (o might change even if SDP unchanged)
+#define skip_line						\
+    while (cmp_body_length-- && *cmp_body_begin != '\n')	\
+      cmp_body_begin++;						\
+    cmp_body_begin++;						\
+
+    skip_line;
+    skip_line;
+  }
+
+  body_hash = hashlittle(cmp_body_begin, cmp_body_length, 0);
+}
+
+bool AmB2BSession::updateSessionDescription(const string& content_type,
+					    const string& body) {
+  const char* cmp_body_begin = body.c_str();
+  size_t cmp_body_length = body.length();
+  if (content_type == SIP_APPLICATION_SDP) {
+    // for SDP, skip v and o line
+    // (o might change even if SDP unchanged)
+    skip_line;
+    skip_line;
+  }
+
+#undef skip_line
+
+  uint32_t new_body_hash = hashlittle(cmp_body_begin, cmp_body_length, 0);
+
+  if (body_hash != new_body_hash) {
+    DBG("session description changed - saving (%s, %.*s...)\n",
+	content_type.c_str(), 50, body.c_str());
+    body_hash = new_body_hash;
+    established_content_type = content_type;
+    established_body = body;
+    return true;
+  }
+
+  return false;
+}
+
+int AmB2BSession::sendEstablishedReInvite() {
+  if (established_content_type.empty() || established_body.empty()) {
+    ERROR("trying to re-INVITE with saved description, but none saved\n");
+    return -1;
+  }
+
+  DBG("sending re-INVITE with saved session description\n");
+  return dlg.reinvite(get_100rel_hdr(reliable_1xx),
+		      established_content_type, established_body);
+}
+
+bool AmB2BSession::refresh() {
+  // not in B2B mode
+  if (other_id.empty() ||
+      // UPDATE as refresh handled like normal session
+      refresh_method == REFRESH_UPDATE) {
+    return AmSession::refresh();
+  }
+
+  // refresh with re-INVITE
+  if (dlg.getUACInvTransPending()) {
+    DBG("INVITE transaction pending - not refreshing now\n");
+    return false;
+  }
+  return sendEstablishedReInvite() == 0;
+}
+
 void AmB2BSession::relaySip(const AmSipRequest& req)
 {
   if (req.method != "ACK") {
     relayed_req[dlg.cseq] = AmSipTransaction(req.method,req.cseq,req.tt);
     dlg.sendRequest(req.method,req.content_type, req.body, req.hdrs, SIP_FLAGS_VERBATIM);
     // todo: relay error event back if sending fails
+
+    if ((req.method == SIP_METH_INVITE ||
+	 req.method == SIP_METH_UPDATE) &&
+	!req.body.empty()) {
+      saveSessionDescription(req.content_type, req.body);
+    }
+
   } else {
     //its a (200) ACK 
     TransMap::iterator t = relayed_req.begin(); 
@@ -344,9 +380,16 @@ void AmB2BSession::relaySip(const AmSipRequest& req)
       ERROR("transaction for ACK not found in relayed requests\n");
       return;
     }
+
     DBG("sending relayed ACK\n");
     dlg.send_200_ack(AmSipTransaction(t->second.method, t->first,t->second.tt), 
 		     req.content_type, req.body, req.hdrs, SIP_FLAGS_VERBATIM);
+
+    if (!req.body.empty() && t->second.method == SIP_METH_INVITE) {
+    // delayed SDP negotiation - save SDP
+      saveSessionDescription(req.content_type, req.body);
+    }
+
     relayed_req.erase(t);
   }
 }
@@ -356,6 +399,13 @@ void AmB2BSession::relaySip(const AmSipRequest& orig, const AmSipReply& reply)
   dlg.reply(orig,reply.code,reply.reason,
 	    reply.content_type,
 	    reply.body,reply.hdrs,SIP_FLAGS_VERBATIM);
+
+  if ((orig.method == SIP_METH_INVITE ||
+       orig.method == SIP_METH_UPDATE) &&
+      !reply.body.empty()) {
+    saveSessionDescription(reply.content_type, reply.body);
+  }
+
 }
 
 // 
@@ -411,7 +461,8 @@ void AmB2BCallerSession::onB2BEvent(B2BEvent* ev)
 	if ((!sip_relay_only) && sip_relay_early_media_sdp && 
 	    reply.code>=180 && reply.code<=183 && (!reply.body.empty())) {
 	  if (reinviteCaller(reply)) {
-	    ERROR("re-INVITEing caller for early session - stopping this and other leg\n");
+	    ERROR("re-INVITEing caller for early session - "
+		  "stopping this and other leg\n");
 	    terminateOtherLeg();
 	    terminateLeg();
 	  }
@@ -500,7 +551,9 @@ void AmB2BCallerSession::connectCallee(const string& remote_party,
 
 int AmB2BCallerSession::reinviteCaller(const AmSipReply& callee_reply)
 {
-  return dlg.sendRequest("INVITE",callee_reply.content_type,callee_reply.body, "", SIP_FLAGS_VERBATIM);
+  return dlg.sendRequest(SIP_METH_INVITE,
+			 callee_reply.content_type, callee_reply.body,
+			 "" /* hdrs */, SIP_FLAGS_VERBATIM);
 }
 
 void AmB2BCallerSession::createCalleeSession() {
@@ -572,12 +625,17 @@ void AmB2BCalleeSession::onB2BEvent(B2BEvent* ev)
     dlg.remote_uri   = co_ev->remote_uri;
 
     if (co_ev->relayed_invite) {
-      relayed_req[dlg.cseq] = AmSipTransaction("INVITE", co_ev->r_cseq, trans_ticket());
+      relayed_req[dlg.cseq] =
+	AmSipTransaction(SIP_METH_INVITE, co_ev->r_cseq, trans_ticket());
     }
 
-    dlg.sendRequest("INVITE",co_ev->content_type,co_ev->body,co_ev->hdrs,SIP_FLAGS_VERBATIM);
+    dlg.sendRequest(SIP_METH_INVITE, 
+		    co_ev->content_type, co_ev->body,
+		    co_ev->hdrs, SIP_FLAGS_VERBATIM);
     // todo: relay error event back if sending fails
 
+    saveSessionDescription(co_ev->content_type, co_ev->body);
+
     return;
   }    
 
diff --git a/core/AmB2BSession.h b/core/AmB2BSession.h
index 9b8d7dcb..1dc4e7a1 100644
--- a/core/AmB2BSession.h
+++ b/core/AmB2BSession.h
@@ -30,6 +30,7 @@
 
 #include "AmSession.h"
 #include "AmSipDialog.h"
+#include "sip/hash.h"
 
 enum { B2BTerminateLeg, 
        B2BConnectLeg, 
@@ -65,18 +66,20 @@ struct B2BSipRequestEvent: public B2BSipEvent
   B2BSipRequestEvent(const AmSipRequest& req, bool forward)
     : B2BSipEvent(B2BSipRequest,forward),
        req(req)
-  {}
+  { }
 };
 
 /** \brief SIP reply in B2B session */
 struct B2BSipReplyEvent: public B2BSipEvent
 {
   AmSipReply reply;
+  string trans_method;
 
-  B2BSipReplyEvent(const AmSipReply& reply, bool forward)
-    : B2BSipEvent(B2BSipReply,forward),
-       reply(reply)
-  {}
+ B2BSipReplyEvent(const AmSipReply& reply, bool forward,
+		  string trans_method)
+   : B2BSipEvent(B2BSipReply,forward),
+    reply(reply), trans_method(trans_method)
+  { }
 };
 
 /** \brief relay a message body to other leg in B2B session */
@@ -84,17 +87,10 @@ struct B2BMsgBodyEvent : public B2BEvent {
   string content_type;
   string body;
 
-  bool is_offer;
-  unsigned int r_cseq;
-
-  B2BMsgBodyEvent(const string& content_type, 
-	       const string& body, 
-	       bool is_offer,
-	       unsigned int r_cseq)
+  B2BMsgBodyEvent(const string& content_type,
+		  const string& body)
     : B2BEvent(B2BMsgBody),
-    content_type(content_type), body(body), 
-    is_offer(is_offer), r_cseq(r_cseq)  {
-  }
+    content_type(content_type), body(body) { }
   ~B2BMsgBodyEvent() { }
 };
 
@@ -124,7 +120,8 @@ struct B2BConnectEvent: public B2BEvent
 /**
  * \brief Base class for Sessions in B2BUA mode.
  * 
- * It has two legs: Callee- and caller-leg.
+ * It has two legs as independent sessions:
+ * Callee- and caller-leg.
  */
 class AmB2BSession: public AmSession
 {
@@ -134,32 +131,40 @@ class AmB2BSession: public AmSession
 
   /** Tell if the session should
    *  process SIP request itself
-   * or only relay them.
+   * or only relay them (B2B mode).
    */
   bool sip_relay_only;
 
   /** 
-   * Requests which
-   * have been relayed (sent)
+   * Requests which have been relayed 
+   * from the other leg and sent as SIP
    */
   TransMap relayed_req;
 
-  /** 
-   * Requests which have been originated 
-   * from local dialog but with 
-   * relayed body
-   */
-  TransMap relayed_body_req;
-
   /** Requests received for relaying */
   std::map<int,AmSipRequest> recvd_req;
 
+  /** content-type of established session */
+  string established_content_type;
+  /** body of established session */
+  string established_body;
+  /** hash of body (from o-line) */
+  uint32_t body_hash;
+  /** save current session description (SDP) */
+  void saveSessionDescription(const string& content_type, const string& body);
+  /** @return whether session has changed */
+  bool updateSessionDescription(const string& content_type, const string& body);
+
+  /** reset relation with other leg */
   void clear_other();
 
   /** Relay one event to the other side. */
   virtual void relayEvent(AmEvent* ev);
 
+  /** send a relayed SIP Request */
   void relaySip(const AmSipRequest& req);
+
+  /** send a relayed SIP Reply */
   void relaySip(const AmSipRequest& orig, const AmSipReply& reply);
 
   /** Terminate our leg and forget the other. */
@@ -170,18 +175,27 @@ class AmB2BSession: public AmSession
 
   /** @see AmSession */
   void onSipRequest(const AmSipRequest& req);
-  void onSipReply(const AmSipReply& reply, int old_dlg_status);
+  void onSipReply(const AmSipReply& reply,
+		  int old_dlg_status, const string& trans_method);
   void onInvite2xx(const AmSipReply& reply);
 
   void onSessionTimeout();
 
+  /** send re-INVITE with established session description 
+   *  @return 0 on success
+   */
+  int sendEstablishedReInvite();
+
+  /** do session refresh */
+  bool refresh();
+
   /** @see AmEventQueue */
   void process(AmEvent* event);
 
   /** B2BEvent handler */
   virtual void onB2BEvent(B2BEvent* ev);
 
-  // Other leg received a BYE
+  /** handle BYE on other leg */
   virtual void onOtherBye(const AmSipRequest& req);
 
   /** 
diff --git a/core/AmSession.cpp b/core/AmSession.cpp
index 5e340e58..060276e9 100644
--- a/core/AmSession.cpp
+++ b/core/AmSession.cpp
@@ -36,7 +36,6 @@
 #include "AmMediaProcessor.h"
 #include "AmDtmfDetector.h"
 #include "AmPlayoutBuffer.h"
-#include "AmSipHeaders.h"
 
 #ifdef WITH_ZRTP
 #include "AmZRTP.h"
@@ -774,9 +773,10 @@ void AmSession::onSipRequest(const AmSipRequest& req)
   }
 }
 
-void AmSession::onSipReply(const AmSipReply& reply, int old_dlg_status)
+void AmSession::onSipReply(const AmSipReply& reply,
+			   int old_dlg_status, const string& trans_method)
 {
-  CALL_EVENT_H(onSipReply,reply,old_dlg_status);
+  CALL_EVENT_H(onSipReply, reply, old_dlg_status, trans_method);
 
   updateRefreshMethod(reply.hdrs);
 
@@ -786,7 +786,8 @@ void AmSession::onSipReply(const AmSipReply& reply, int old_dlg_status)
 	AmSipDialog::status2str[dlg.getStatus()],
 	sess_stopped.get() ? "true" : "false");
   else 
-    DBG("Dialog status stays %s (stopped=%s)\n", AmSipDialog::status2str[old_dlg_status], 
+    DBG("Dialog status stays %s (stopped=%s)\n",
+	AmSipDialog::status2str[old_dlg_status], 
 	sess_stopped.get() ? "true" : "false");
 
 
@@ -953,7 +954,7 @@ void AmSession::onInvite(const AmSipRequest& req)
 
     acceptAudio(req.body,req.hdrs,&sdp_reply);
     if(dlg.reply(req,200,"OK",
-		 "application/sdp",sdp_reply) != 0)
+		 SIP_APPLICATION_SDP, sdp_reply) != 0)
       throw AmSession::Exception(500,"could not send response");
 	
   }catch(const AmSession::Exception& e){
@@ -1103,20 +1104,26 @@ void AmSession::updateRefreshMethod(const string& headers) {
   }
 }
 
-void AmSession::refresh() {
+bool AmSession::refresh() {
   if (refresh_method == REFRESH_UPDATE) {
     DBG("Refreshing session with UPDATE\n");
-    sendUpdate("", "", "");
+    return sendUpdate("", "", "") == 0;
   } else {
+
+    if (dlg.getUACInvTransPending()) {
+      DBG("INVITE transaction pending - not refreshing now\n");
+      return false;
+    }
+
     DBG("Refreshing session with re-INVITE\n");
-    sendReinvite(true);
+    return sendReinvite(true) == 0;
   }
 }
 
-void AmSession::sendUpdate(const string &cont_type, const string &body,
+int AmSession::sendUpdate(const string &cont_type, const string &body,
 			   const string &hdrs)
 {
-  dlg.update(cont_type, body, hdrs);
+  return dlg.update(cont_type, body, hdrs);
 }
 
 void AmSession::sendPrack(const string &sdp_offer, 
@@ -1141,32 +1148,16 @@ string AmSession::sid4dbg()
   return dbg;
 }
 
-static inline string get_100rel_hdr(unsigned char reliable_1xx)
-{
-  switch(reliable_1xx) {
-    case REL100_SUPPORTED: 
-      return SIP_HDR_COLSP(SIP_HDR_SUPPORTED) SIP_EXT_100REL CRLF;
-    case REL100_REQUIRE: 
-      return SIP_HDR_COLSP(SIP_HDR_REQUIRE) SIP_EXT_100REL CRLF;
-    default:
-      ERROR("BUG: unexpected reliability switch value of '%d'.\n",
-          reliable_1xx);
-    case 0:
-      break;
-  }
-  return "";
-}
-
-void AmSession::sendReinvite(bool updateSDP, const string& headers) 
+int AmSession::sendReinvite(bool updateSDP, const string& headers) 
 {
   if (updateSDP) {
     RTPStream()->setLocalIP(AmConfig::LocalIP);
     string sdp_body;
     sdp.genResponse(advertisedIP(), RTPStream()->getLocalPort(), sdp_body);
-    dlg.reinvite(headers + get_100rel_hdr(reliable_1xx), "application/sdp",
+    return dlg.reinvite(headers + get_100rel_hdr(reliable_1xx), SIP_APPLICATION_SDP,
         sdp_body);
   } else {
-    dlg.reinvite(headers + get_100rel_hdr(reliable_1xx), "", "");
+    return dlg.reinvite(headers + get_100rel_hdr(reliable_1xx), "", "");
   }
 }
 
@@ -1181,7 +1172,7 @@ int AmSession::sendInvite(const string& headers)
   // Generate SDP.
   string sdp_body;
   sdp.genRequest(advertisedIP(), RTPStream()->getLocalPort(), sdp_body);
-  return dlg.invite(headers + get_100rel_hdr(reliable_1xx), "application/sdp",
+  return dlg.invite(headers + get_100rel_hdr(reliable_1xx), SIP_APPLICATION_SDP,
       sdp_body);
 }
 
diff --git a/core/AmSession.h b/core/AmSession.h
index c3c174f5..fcd61ad2 100644
--- a/core/AmSession.h
+++ b/core/AmSession.h
@@ -34,6 +34,7 @@
 #include "AmRtpAudio.h"
 #include "AmDtmfDetector.h"
 #include "AmSipMsg.h"
+#include "AmSipHeaders.h"
 #include "AmSipDialog.h"
 #include "AmSipEvent.h"
 #include "AmApi.h"
@@ -360,13 +361,13 @@ public:
 			 string* sdp_reply);
 
   /** refresh the session - re-INVITE or UPDATE*/
-  virtual void refresh();
+  virtual bool refresh();
 
   /** send an UPDATE in the session */
-  virtual void sendUpdate(const string &cont_type, const string &body, const string &hdrs);
+  virtual int sendUpdate(const string &cont_type, const string &body, const string &hdrs);
 
   /** send a Re-INVITE (if connected) */
-  virtual void sendReinvite(bool updateSDP = true, const string& headers = "");
+  virtual int sendReinvite(bool updateSDP = true, const string& headers = "");
 
   /** send an INVITE */
   virtual int sendInvite(const string& headers = "");
@@ -521,7 +522,8 @@ public:
   virtual void onSipRequest(const AmSipRequest& req);
 
   /** Entry point for SIP Replies   */
-  virtual void onSipReply(const AmSipReply& reply, int old_dlg_status);
+  virtual void onSipReply(const AmSipReply& reply, int old_dlg_status,
+			      const string& trans_method);
 
   /** 2xx reply has been received for an INVITE transaction */
   virtual void onInvite2xx(const AmSipReply& reply);
@@ -586,6 +588,7 @@ public:
   // The IP address to put as c= in SDP bodies and to use for Contact:.
   string advertisedIP();
 
+  /** format session id for debugging */
   string sid4dbg();
 };
 
@@ -598,6 +601,22 @@ inline AmRtpAudio* AmSession::RTPStream() {
   return _rtp_str.get();
 }
 
+static inline string get_100rel_hdr(unsigned char reliable_1xx)
+{
+  switch(reliable_1xx) {
+    case REL100_SUPPORTED:
+      return SIP_HDR_COLSP(SIP_HDR_SUPPORTED) SIP_EXT_100REL CRLF;
+    case REL100_REQUIRE:
+      return SIP_HDR_COLSP(SIP_HDR_REQUIRE) SIP_EXT_100REL CRLF;
+    default:
+      ERROR("BUG: unexpected reliability switch value of '%d'.\n",
+          reliable_1xx);
+    case 0:
+      break;
+  }
+  return "";
+}
+
 #endif
 
 /** EMACS **
diff --git a/core/AmSessionEventHandler.cpp b/core/AmSessionEventHandler.cpp
index ed4cb0b6..3d8b88d6 100644
--- a/core/AmSessionEventHandler.cpp
+++ b/core/AmSessionEventHandler.cpp
@@ -43,7 +43,8 @@ bool AmSessionEventHandler::onSipRequest(const AmSipRequest&)
   return false;
 }
 
-bool AmSessionEventHandler::onSipReply(const AmSipReply& reply, int old_dlg_status)
+bool AmSessionEventHandler::onSipReply(const AmSipReply& reply, int old_dlg_status,
+				       const string& trans_method)
 {
   return false;
 }
diff --git a/core/AmSessionEventHandler.h b/core/AmSessionEventHandler.h
index 14e71338..ce3e381b 100644
--- a/core/AmSessionEventHandler.h
+++ b/core/AmSessionEventHandler.h
@@ -66,7 +66,8 @@ public:
   virtual bool process(AmEvent*);
 
   virtual bool onSipRequest(const AmSipRequest&);
-  virtual bool onSipReply(const AmSipReply&, int old_dlg_status);
+  virtual bool onSipReply(const AmSipReply&, int old_dlg_status,
+			  const string& trans_method);
   virtual bool onSipReqTimeout(const AmSipRequest &);
   virtual bool onSipRplTimeout(const AmSipRequest &, const AmSipReply &);
 
diff --git a/core/AmSipDialog.cpp b/core/AmSipDialog.cpp
index 2b6d3d22..96fb10f4 100644
--- a/core/AmSipDialog.cpp
+++ b/core/AmSipDialog.cpp
@@ -226,6 +226,7 @@ void AmSipDialog::updateStatus(const AmSipReply& reply)
 
   AmSipTransaction& t = t_it->second;
   int old_dlg_status = status;
+  string trans_method = t.method;
 
   // rfc3261 12.1
   // Dialog established only by 101-199 or 2xx 
@@ -240,7 +241,7 @@ void AmSipDialog::updateStatus(const AmSipReply& reply)
     remote_tag = reply.remote_tag;
   }
 
-  // allow route overwritting
+  // allow route overwriting
   if ((status < Connected) && !reply.route.empty()) {
       route = reply.route;
   }
@@ -250,7 +251,7 @@ void AmSipDialog::updateStatus(const AmSipReply& reply)
 
   switch(status){
   case Disconnecting:
-    if( t.method == "INVITE" ){
+    if (trans_method == SIP_METH_INVITE) {
 
       if(reply.code == 487){
 	// CANCEL accepted
@@ -270,7 +271,7 @@ void AmSipDialog::updateStatus(const AmSipReply& reply)
   case Disconnected:
     // only change status of dialog if reply 
     // to INVITE received
-    if(t.method == "INVITE"){ 
+    if (trans_method == SIP_METH_INVITE) { 
       if(reply.code < 200)
 	status = Pending;
       else if(reply.code >= 300)
@@ -289,7 +290,7 @@ void AmSipDialog::updateStatus(const AmSipReply& reply)
     // TODO: 
     // - place this somewhere else.
     //   (probably in AmSession...)
-    if((reply.code < 300) && (t.method == "INVITE")) {
+    if((reply.code < 300) && (trans_method == SIP_METH_INVITE)) {
 
 	if(hdl) {
 	    hdl->onInvite2xx(reply);
@@ -304,7 +305,7 @@ void AmSipDialog::updateStatus(const AmSipReply& reply)
   }
 
   if(hdl)
-      hdl->onSipReply(reply, old_dlg_status);
+    hdl->onSipReply(reply, old_dlg_status, trans_method);
 }
 
 void AmSipDialog::uasTimeout(AmSipTimeoutEvent* to_ev)
@@ -330,6 +331,19 @@ void AmSipDialog::uasTimeout(AmSipTimeoutEvent* to_ev)
   to_ev->processed = true;
 }
 
+bool AmSipDialog::getUACTransPending() {
+  return !uac_trans.empty();
+}
+
+bool AmSipDialog::getUACInvTransPending() {
+  for (TransMap::iterator it=uac_trans.begin();
+       it != uac_trans.end(); it++) {
+    if (it->second.method == "INVITE")
+      return true;
+  }
+  return false;
+}
+
 string AmSipDialog::getContactHdr()
 {
   if(contact_uri.empty()) {
diff --git a/core/AmSipDialog.h b/core/AmSipDialog.h
index e25104b1..aad81ca7 100644
--- a/core/AmSipDialog.h
+++ b/core/AmSipDialog.h
@@ -74,7 +74,8 @@ class AmSipDialogEventHandler
   virtual void onSipRequest(const AmSipRequest& req)=0;
 
   /** Hook called when a reply has been received */
-  virtual void onSipReply(const AmSipReply& reply, int old_dlg_status)=0;
+  virtual void onSipReply(const AmSipReply& reply, int old_dlg_status,
+			  const string& trans_method)=0;
 
   /** Hook called before a request is sent */
   virtual void onSendRequest(const string& method,
@@ -160,7 +161,11 @@ class AmSipDialog
   AmSipDialog(AmSipDialogEventHandler* h=0);
   ~AmSipDialog();
 
-  bool   getUACTransPending() { return !uac_trans.empty(); }
+  /** @return whether UAC transaction is pending */
+  bool   getUACTransPending();
+
+  /** @return whether INVITE transaction is pending */
+  bool   getUACInvTransPending();
   int    getStatus() { return status; }
   void   setStatus(int new_status);
 
@@ -174,6 +179,7 @@ class AmSipDialog
 
   void uasTimeout(AmSipTimeoutEvent* to_ev);
     
+  /** @return 0 on success */
   int reply(const AmSipRequest& req,
 	    unsigned int  code, 
 	    const string& reason,
@@ -182,34 +188,51 @@ class AmSipDialog
 	    const string& hdrs = "",
 	    int flags = 0);
 
+  /** @return 0 on success */
   int sendRequest(const string& method, 
 		  const string& content_type = "",
 		  const string& body = "",
 		  const string& hdrs = "",
 		  int flags = 0);
 
+  /** @return 0 on success */
   int send_200_ack(const AmSipTransaction& t,
 		   const string& content_type = "",
 		   const string& body = "",
 		   const string& hdrs = "",
 		   int flags = 0);
     
+  /** @return 0 on success */
   int bye(const string& hdrs = "");
+
+  /** @return 0 on success */
   int cancel();
+
+  /** @return 0 on success */
   int prack(const string &cont_type, 
             const string &body, 
             const string &hdrs);
+
+  /** @return 0 on success */
   int update(const string &cont_type, 
             const string &body, 
             const string &hdrs);
+
+  /** @return 0 on success */
   int reinvite(const string& hdrs,  
 	       const string& content_type,
 	       const string& body);
+
+  /** @return 0 on success */
   int invite(const string& hdrs,  
 	     const string& content_type,
 	     const string& body);
+
+  /** @return 0 on success */
   int refer(const string& refer_to,
 	    int expires = -1);
+
+  /** @return 0 on success */
   int transfer(const string& target);
   int drop();
 
diff --git a/core/AmSipHeaders.h b/core/AmSipHeaders.h
index cdc3d313..dc22b9c1 100644
--- a/core/AmSipHeaders.h
+++ b/core/AmSipHeaders.h
@@ -41,4 +41,8 @@
 #define SIP_EXT_100REL          "100rel"
 
 #define SIP_HDR_SESSION_EXPIRES_COMPACT "x"
+
+#define SIP_IS_200_CLASS(code)  ((code >= 200) && (code < 300))
+
+#define SIP_APPLICATION_SDP     "application/sdp"
 #endif /* __AMSIPHEADERS_H__ */
diff --git a/core/plug-in/session_timer/SessionTimer.cpp b/core/plug-in/session_timer/SessionTimer.cpp
index c6cd47ce..0e49b97d 100644
--- a/core/plug-in/session_timer/SessionTimer.cpp
+++ b/core/plug-in/session_timer/SessionTimer.cpp
@@ -77,7 +77,8 @@ bool SessionTimer::onSipRequest(const AmSipRequest& req)
   return false;
 }
 
-bool SessionTimer::onSipReply(const AmSipReply& reply, int old_dlg_status)
+bool SessionTimer::onSipReply(const AmSipReply& reply, int old_dlg_status,
+			      const string& trans_method)
 {
   updateTimer(s,reply);
   return false;
@@ -327,6 +328,15 @@ void SessionTimer::setTimers(AmSession* s)
   }
 }
 
+void SessionTimer::retryRefreshTimer(AmSession* s) {
+  DBG("Retrying session refresh timer: T-2s, tag '%s' \n",
+      s->getLocalTag().c_str());
+
+  UserTimer::instance()->
+    setTimer(ID_SESSION_REFRESH_TIMER, 2, s->getLocalTag());
+}
+
+
 void SessionTimer::removeTimers(AmSession* s) 
 {
   UserTimer::instance()->
@@ -342,7 +352,9 @@ void SessionTimer::onTimeoutEvent(AmTimeoutEvent* timeout_ev)
   if (timer_id == ID_SESSION_REFRESH_TIMER) {
     if (session_refresher == refresh_local) {
       DBG("Session Timer: initiating session refresh\n");
-      s->refresh();
+      if (!s->refresh()) {
+	retryRefreshTimer(s);
+      }
     } else {
       DBG("need session refresh but remote session is refresher\n");
     }
diff --git a/core/plug-in/session_timer/SessionTimer.h b/core/plug-in/session_timer/SessionTimer.h
index 0b179e81..92a0afa4 100644
--- a/core/plug-in/session_timer/SessionTimer.h
+++ b/core/plug-in/session_timer/SessionTimer.h
@@ -120,6 +120,7 @@ class SessionTimer: public AmSessionEventHandler
   void updateTimer(AmSession* s,const AmSipReply& reply);
     
   void setTimers(AmSession* s);
+  void retryRefreshTimer(AmSession* s);
   void removeTimers(AmSession* s);
 
   string getReplyHeaders(const AmSipRequest& req);
@@ -140,7 +141,8 @@ class SessionTimer: public AmSessionEventHandler
   virtual bool process(AmEvent*);
 
   virtual bool onSipRequest(const AmSipRequest&);
-  virtual bool onSipReply(const AmSipReply&, int old_dlg_status);
+  virtual bool onSipReply(const AmSipReply&, int old_dlg_status,
+			  const string& trans_method);
 
   virtual bool onSendRequest(const string& method, 
 			     const string& content_type,
diff --git a/core/plug-in/uac_auth/UACAuth.cpp b/core/plug-in/uac_auth/UACAuth.cpp
index d81d3721..af04b1f8 100644
--- a/core/plug-in/uac_auth/UACAuth.cpp
+++ b/core/plug-in/uac_auth/UACAuth.cpp
@@ -124,7 +124,7 @@ bool UACAuth::onSipRequest(const AmSipRequest& req)
   return false;
 }
 
-bool UACAuth::onSipReply(const AmSipReply& reply, int old_dlg_status)
+bool UACAuth::onSipReply(const AmSipReply& reply, int old_dlg_status, const string& trans_method)
 {
   bool processed = false;
   if (reply.code==407 || reply.code==401) {
diff --git a/core/plug-in/uac_auth/UACAuth.h b/core/plug-in/uac_auth/UACAuth.h
index 93af41d5..4c6eacf5 100644
--- a/core/plug-in/uac_auth/UACAuth.h
+++ b/core/plug-in/uac_auth/UACAuth.h
@@ -138,7 +138,7 @@ class UACAuth : public AmSessionEventHandler
   virtual bool process(AmEvent*);
   virtual bool onSipEvent(AmSipEvent*);
   virtual bool onSipRequest(const AmSipRequest&);
-  virtual bool onSipReply(const AmSipReply&, int old_dlg_status);
+  virtual bool onSipReply(const AmSipReply&, int old_dlg_status, const string& trans_method);
 	
   virtual bool onSendRequest(const string& method, 
 			     const string& content_type,