Index: channels/chan_sip.c
===================================================================
--- channels/chan_sip.c	(revision 102141)
+++ channels/chan_sip.c	(arbetskopia)
@@ -899,6 +899,10 @@
 	int attendedtransfer;				/*!< Attended or blind transfer? */
 	int localtransfer;				/*!< Transfer to local domain? */
 	enum referstatus status;			/*!< REFER status */
+	int notify_cseq;				/*!< Cseq of unanswered NOTIFY */
+	char *next_notify;				/*!< Next notify to send */
+	int next_cseq;					/*!< Cseq to use */
+	int next_terminate;				/*!< Terminate flag of next message */
 };
 
 /*! \brief sip_pvt: PVT structures are used for each SIP dialog, ie. a call, a registration, a subscribe  */
@@ -3086,6 +3090,10 @@
 		ast_rtp_destroy(p->vrtp);
 	if (p->udptl)
 		ast_udptl_destroy(p->udptl);
+
+	if (p->refer && p->refer->next_notify)
+		free(p->refer->next_notify);
+
 	if (p->refer)
 		free(p->refer);
 	if (p->route) {
@@ -7337,6 +7345,18 @@
 	struct sip_request req;
 	char tmp[SIPBUFSIZE/2];
 
+	/* Check if we already have an open NOTIFY transaction. If so, then cache this. 
+		Overwrite previous message if we have multiple messages on queue. */
+	if (p->refer && p->refer->notify_cseq) {
+		if (p->refer->next_notify)
+			free(p->refer->next_notify);
+		p->refer->next_notify = ast_strdup(message);
+		p->refer->next_cseq = cseq;
+		p->refer->next_terminate = terminate;
+		if (option_debug > 2)
+			ast_log(LOG_DEBUG, "Queueing Refer NOTIFY message due to open transaction.\n");
+	}
+
 	reqprep(&req, p, SIP_NOTIFY, 0, 1);
 	snprintf(tmp, sizeof(tmp), "refer;id=%d", cseq);
 	add_header(&req, "Event", tmp);
@@ -7353,6 +7373,8 @@
 		initialize_initreq(p, &req);
 
 	p->lastnoninvite = p->ocseq;
+	if (p->refer)
+		p->refer->notify_cseq = p->ocseq;
 
 	return send_request(p, &req, XMIT_RELIABLE, p->ocseq);
 }
@@ -12633,8 +12655,16 @@
 					if (!p->refer) {
 						ast_log(LOG_WARNING, "Notify answer on an owned channel? - %s\n", p->owner->name);
 						ast_queue_hangup(p->owner);
-					} else if (option_debug > 3) 
-						ast_log(LOG_DEBUG, "Got OK on REFER Notify message\n");
+					} else {
+						if (option_debug > 3) 
+							ast_log(LOG_DEBUG, "Got OK on REFER Notify message\n");
+						p->refer->notify_cseq = 0;	/* No pending NOTIFY's */
+						if (p->refer->next_notify) {	/* If we have a queued notify, send it now */
+							transmit_notify_with_sipfrag(p, p->refer->next_cseq, p->refer->next_notify, p->refer->next_terminate);
+							free(p->refer->next_notify);
+							p->refer->next_notify = NULL;
+						}
+					}
 				} else {
 					if (p->subscribed == NONE) 
 						ast_set_flag(&p->flags[0], SIP_NEEDDESTROY);