diff --git a/gprs_gb/NS_Emulation.ttcn b/gprs_gb/NS_Emulation.ttcn
index 99607a0..253c91e 100644
--- a/gprs_gb/NS_Emulation.ttcn
+++ b/gprs_gb/NS_Emulation.ttcn
@@ -102,9 +102,9 @@
 	}
 
 	modulepar {
-		PortNumber mp_local_udp_port := 23001;
+		PortNumber mp_local_udp_port := 23000;
 		charstring mp_local_ip := "127.0.0.1";
-		PortNumber mp_remote_udp_port := 23000;
+		PortNumber mp_remote_udp_port := 21000;
 		charstring mp_remote_ip := "127.0.0.1";
 		Nsvci mp_nsvci := 0;
 		Nsvci mp_nsei := 2342;