Index: chan_sip.c
===================================================================
--- chan_sip.c	(revision 792)
+++ chan_sip.c	(working copy)
@@ -14370,6 +14370,16 @@
 	if (strcasecmp(args.param, "rtpqos"))
 		return 0;
 
+	if (args.type == NULL) {
+		ast_log(LOG_WARNING, "rtpqos: type must be specified\n");
+		return 0;
+	}
+
+	if (args.field == NULL) {
+		ast_log(LOG_WARNING, "rtpqos: field must be specified\n");
+		return 0;
+	}
+
 	memset(buf, 0, buflen);
 	memset(&qos, 0, sizeof(qos));