sgsn: Use random TEID and Charging Identifier

Change-Id: I39934396372b057eaf5446e9185e83a1d56c153c
diff --git a/sgsn/SGSN_Tests.ttcn b/sgsn/SGSN_Tests.ttcn
index eb7fd14..ff5340e 100644
--- a/sgsn/SGSN_Tests.ttcn
+++ b/sgsn/SGSN_Tests.ttcn
@@ -769,6 +769,7 @@
 	octetstring		apn optional,			/* APN name */
 	ProtocolConfigOptionsV	pco optional,			/* protoco config opts */
 	OCT1			exp_rej_cause optional,		/* expected SM reject cause */
+	OCT1			gtp_resp_cause,			/* GTP response cause */
 	OCT4			chg_id,				/* GTP Charging Identifier */
 
 	OCT4			ggsn_tei_c,			/* GGSN TEI Control*/
@@ -880,11 +881,12 @@
 	apn := omit,
 	pco := omit,
 	exp_rej_cause := omit,
-	chg_id := '00000001'O,
+	gtp_resp_cause := int2oct(128, 1),
+	chg_id := f_rnd_octstring(4),
 
 	/* FIXME: make below dynamic !! */
-	ggsn_tei_c := '00010000'O,
-	ggsn_tei_u := '00020000'O,
+	ggsn_tei_c := f_rnd_octstring(4),
+	ggsn_tei_u := f_rnd_octstring(4),
 	ggsn_ip_c := f_inet_addr(ggsn_ip),
 	ggsn_ip_u := f_inet_addr(ggsn_ip),