diff --git a/mgw/MGCP_Test.ttcn b/mgw/MGCP_Test.ttcn
index c4f97a8..5575f7a 100644
--- a/mgw/MGCP_Test.ttcn
+++ b/mgw/MGCP_Test.ttcn
@@ -1693,14 +1693,14 @@
 
 	/* Create one connection in loopback mode, test if the RTP packets are
 	 * actually reflected */
-	function f_TC_one_crcx_loopback_rtp(boolean one_phase := true) runs on dummy_CT {
+	function f_TC_one_crcx_loopback_rtp(charstring local_ip, charstring remote_ip, boolean one_phase := true) runs on dummy_CT {
 		var RtpFlowData flow;
 		var MgcpEndpoint ep := c_mgw_ep_rtpbridge & "1@" & c_mgw_domain;
 		var MgcpCallId call_id := '1225'H;
 		var RtpemStats stats;
 
 		f_init(ep);
-		flow := valueof(t_RtpFlow(mp_local_ipv4, mp_remote_ipv4, 111, "GSM-HR-08/8000/1"));
+		flow := valueof(t_RtpFlow(local_ip, remote_ip, 111, "GSM-HR-08/8000/1"));
 		flow.em.portnr := 10000;
 		f_flow_create(RTPEM[0], ep, call_id, "loopback", flow, one_phase := one_phase);
 
@@ -1725,7 +1725,7 @@
 	/* Create one connection in loopback mode, test if the RTP packets are
 	 * actually reflected */
 	testcase TC_one_crcx_loopback_rtp() runs on dummy_CT {
-		 f_TC_one_crcx_loopback_rtp(one_phase := true)
+		 f_TC_one_crcx_loopback_rtp(mp_local_ipv4, mp_remote_ipv4, one_phase := true)
 	}
 
 	/* Same as above, but we will intenionally not tell the MGW where to
@@ -1733,7 +1733,7 @@
 	 * loopback mode, so the MGW should take the originating address from
 	 * the incoming RTP packet and send it back to the source */
 	testcase TC_one_crcx_loopback_rtp_implicit() runs on dummy_CT {
-		 f_TC_one_crcx_loopback_rtp(one_phase := false)
+		 f_TC_one_crcx_loopback_rtp(mp_local_ipv6, mp_remote_ipv6, one_phase := false)
 	}