Index: channels/chan_sip.c
===================================================================
--- channels/chan_sip.c	(revision 78241)
+++ channels/chan_sip.c	(working copy)
@@ -2013,6 +2013,8 @@
 		siptimer_a = pkt->timer_t1 * 2;
 
 	/* Schedule retransmission */
+	if (pkt->retransid > -1)
+		ast_sched_del(sched, pkt->retransid);
 	pkt->retransid = ast_sched_add_variable(sched, siptimer_a, retrans_pkt, pkt, 1);
 	if (option_debug > 3 && sipdebug)
 		ast_log(LOG_DEBUG, "*** SIP TIMER: Initalizing retransmit timer on packet: Id  #%d\n", pkt->retransid);
@@ -2954,6 +2956,8 @@
 			p->invitestate = INV_CALLING;
 
 			/* Initialize auto-congest time */
+			if (p->initid > -1)
+				ast_sched_del(sched, p->initid);
 			p->initid = ast_sched_add(sched, p->maxtime ? (p->maxtime * 4) : SIP_TRANS_TIMEOUT, auto_congest, p);
 		}
 	}
@@ -12270,7 +12274,9 @@
 		r->refresh= (int) expires_ms / 1000;
 
 		/* Schedule re-registration before we expire */
-		r->expire=ast_sched_add(sched, expires_ms, sip_reregister, r); 
+		if (r->expire > -1)
+			ast_sched_del(sched, r->expire);
+		r->expire = ast_sched_add(sched, expires_ms, sip_reregister, r); 
 		ASTOBJ_UNREF(r, sip_registry_destroy);
 	}
 	return 1;
@@ -15424,6 +15430,8 @@
 	peer->lastms = -1;
 	ast_device_state_changed("SIP/%s", peer->name);
 	/* Try again quickly */
+	if (peer->pokeexpire > -1)
+		ast_sched_del(sched, peer->pokeexpire);
 	peer->pokeexpire = ast_sched_add(sched, DEFAULT_FREQ_NOTOK, sip_poke_peer_s, peer);
 	return 0;
 }
@@ -15487,8 +15495,11 @@
 	gettimeofday(&peer->ps, NULL);
 	if (xmitres == XMIT_ERROR)
 		sip_poke_noanswer(peer);	/* Immediately unreachable, network problems */
-	else
+	else {
+		if (peer->pokeexpire > -1)
+			ast_sched_del(sched, peer->pokeexpire);
 		peer->pokeexpire = ast_sched_add(sched, DEFAULT_MAXMS * 2, sip_poke_noanswer, peer);
+	}
 
 	return 0;
 }