diff -urN asterisk-1.4.9.orig/channels/chan_iax2.c asterisk-1.4.9/channels/chan_iax2.c
--- asterisk-1.4.9.orig/channels/chan_iax2.c	2007-07-24 12:32:20.000000000 -0400
+++ asterisk-1.4.9/channels/chan_iax2.c	2007-07-31 16:25:40.000000000 -0400
@@ -1866,12 +1866,27 @@
 static void __attempt_transmit(void *data)
 {
 	/* Attempt to transmit the frame to the remote peer...
-	   Called without iaxsl held. */
-	struct iax_frame *f = data;
-	int freeme=0;
-	int callno = f->callno;
-	/* Make sure this call is still active */
-	if (callno) 
+	Called without iaxsl held. */
+	struct iax_frame *f;
+	//int freeme = 0;
+	int callno = 0;
+	int found = 0;
+	
+	/* Check if data is still a valid frame -- if it is, it should be in the queue*/
+	AST_LIST_LOCK(&iaxq.queue);
+	AST_LIST_TRAVERSE_SAFE_BEGIN(&iaxq.queue, f, list) {
+		if (f == data) {
+			found = 1;
+			callno = f->callno;
+			break;
+		}
+	}
+	AST_LIST_TRAVERSE_SAFE_END
+			AST_LIST_UNLOCK(&iaxq.queue);
+	if (!found)
+		return;
+	
+	/* The frame is valid,, process it */	if (callno) 
 		ast_mutex_lock(&iaxsl[callno]);
 	if (callno && iaxs[callno]) {
 		if ((f->retries < 0) /* Already ACK'd */ ||
@@ -1908,7 +1923,7 @@
 					}
 
 				}
-				freeme++;
+				//freeme++;
 		} else {
 			/* Update it if it needs it */
 			update_packet(f);
@@ -1927,21 +1942,21 @@
 	} else {
 		/* Make sure it gets freed */
 		f->retries = -1;
-		freeme++;
+		//freeme++;
 	}
 	if (callno)
 		ast_mutex_unlock(&iaxsl[callno]);
 	/* Do not try again */
-	if (freeme) {
-		/* Don't attempt delivery, just remove it from the queue */
-		AST_LIST_LOCK(&iaxq.queue);
-		AST_LIST_REMOVE(&iaxq.queue, f, list);
-		iaxq.count--;
-		AST_LIST_UNLOCK(&iaxq.queue);
-		f->retrans = -1;
-		/* Free the IAX frame */
-		iax2_frame_free(f);
-	}
+//	if (freeme) {
+//		/* Don't attempt delivery, just remove it from the queue */
+//		AST_LIST_LOCK(&iaxq.queue);
+//		AST_LIST_REMOVE(&iaxq.queue, f, list);
+//		iaxq.count--;
+//		AST_LIST_UNLOCK(&iaxq.queue);
+//		f->retrans = -1;
+//		/* Free the IAX frame */
+//		iax2_frame_free(f);
+//	}
 }
 
 static int attempt_transmit(void *data)
@@ -5938,13 +5953,18 @@
 	AST_LIST_TRAVERSE(&iaxq.queue, f, list) {
 		/* Send a copy immediately */
 		if ((f->callno == callno) && iaxs[f->callno] &&
-			((unsigned char ) (f->oseqno - last) < 128)) {
-			send_packet(f);
+				   ((unsigned char)(f->oseqno - last) < 128)) {
+			if (f->dcallno != iaxs[f->callno]->peercallno )
+			{
+				ast_log(LOG_WARNING, "Callno inconsistency detected: callno=%d, peercallno=%d, f->dcallno=%d, f->retries=%d, f->retrans=%d\n", callno, iaxs[f->callno]->peercallno, f->dcallno, f->retries, f->retrans);
+			} else if ( f->retries == -1 ) {
+				ast_log(LOG_WARNING, "NO LONGER retransmitting frame with -1 retries (src %d, dest %d, retrans %d)\n", f->callno, f->dcallno, f->retrans);
+			} else 
+				send_packet(f);
 		}
 	}
 	AST_LIST_UNLOCK(&iaxq.queue);
 }
-
 static void __iax2_poke_peer_s(void *data)
 {
 	struct iax2_peer *peer = data;
@@ -8317,9 +8337,23 @@
 		count = 0;
 		wakeup = -1;
 		AST_LIST_TRAVERSE_SAFE_BEGIN(&iaxq.queue, f, list) {
-			if (f->sentyet)
+			if (f->sentyet) {
+				/* Remove frames marked for cleanup */
+				if (f->retries < 0) {
+					unsigned short callno = f->callno;
+					/* Attempt to lock the call pvt -- if we fail, try again later */
+					if (ast_mutex_trylock(&iaxsl[callno])) {
+						wakeup = 1;
+						continue;
+					}
+					AST_LIST_REMOVE_CURRENT(&iaxq.queue, list);
+					iaxq.count--;
+					iax2_frame_free(f);
+					ast_mutex_unlock(&iaxsl[callno]);
+				}
 				continue;
-			
+			}
+		
 			/* Try to lock the pvt, if we can't... don't fret - defer it till later */
 			if (ast_mutex_trylock(&iaxsl[f->callno])) {
 				wakeup = 1;