diff --git a/mgw/MGCP_Test.ttcn b/mgw/MGCP_Test.ttcn
index dd8d25b..d5858ec 100644
--- a/mgw/MGCP_Test.ttcn
+++ b/mgw/MGCP_Test.ttcn
@@ -9,8 +9,15 @@
 		port MGCP_CODEC_PT MGCP;
 		var boolean initialized := false;
 		var ConnectionId g_conn_id := -1;
+		var integer g_trans_id;
 	};
 
+	function get_next_trans_id() runs on dummy_CT return MgcpTransId {
+		var MgcpTransId tid := int2str(g_trans_id);
+		g_trans_id := g_trans_id + 1;
+		return tid;
+	}
+
 	modulepar {
 		PortNumber mp_local_udp_port := 2727;
 		charstring mp_local_ip := "127.0.0.1";
@@ -25,6 +32,7 @@
 		}
 		initialized := true;
 
+		g_trans_id := float2int(rnd()*65535.0);
 		map(self:MGCP, system:MGCP_CODEC_PT);
 		res := f_IPL4_connect(MGCP, mp_remote_ip, mp_remote_udp_port, mp_local_ip, mp_local_udp_port, 0, { udp := {} });
 		g_conn_id := res.connId;