diff --git a/bsc/BSC_Tests_CBSP.ttcn b/bsc/BSC_Tests_CBSP.ttcn
index 8b7954da7..20006dc32 100644
--- a/bsc/BSC_Tests_CBSP.ttcn
+++ b/bsc/BSC_Tests_CBSP.ttcn
@@ -68,6 +68,15 @@ private template (value) OCT2 bssmap_lac(GsmCgiAbstract cgi) := ts_BSSMAP_CI_LAC
 private template (value) OCT2 bssmap_ci(GsmCgiAbstract cgi) := ts_BSSMAP_CI_CI(cgi.ci);
 
 type component cbsp_test_CT extends test_CT, CBSP_Adapter_CT {
+	var uint16_t g_cbsp_msg_id := 0;
+	var uint16_t g_cbsp_ser_no := 0;
+}
+
+private function f_g_cbsp_next_msg_id_ser_no() runs on cbsp_test_CT
+{
+	g_cbsp_msg_id := g_cbsp_msg_id + 1;
+	g_cbsp_ser_no := g_cbsp_ser_no + 1;
+	log("g_cbsp_msg_id=", g_cbsp_msg_id, "  g_cbsp_ser_no=", g_cbsp_ser_no);
 }
 
 private altstep as_IgnRSL(template RSL_Message tr) runs on cbsp_test_CT {
@@ -108,7 +117,7 @@ private function f_cbsp_init_client() runs on cbsp_test_CT {
 	setverdict(pass);
 }
 
-private function f_cbsp_init_server(float guard_timeout := 30.0) runs on cbsp_test_CT {
+private function f_cbsp_init_server(uint16_t cbsp_msg_id, uint16_t cbsp_ser_no, float guard_timeout := 30.0) runs on cbsp_test_CT {
 	var ASP_Event asp_evt;
 	timer T := 10.0;
 
@@ -126,6 +135,10 @@ private function f_cbsp_init_server(float guard_timeout := 30.0) runs on cbsp_te
 		}
 	}
 	f_expect_cbsp_restart();
+
+	g_cbsp_msg_id := cbsp_msg_id;
+	g_cbsp_ser_no := cbsp_ser_no;
+	log("g_cbsp_msg_id=", g_cbsp_msg_id, "  g_cbsp_ser_no=", g_cbsp_ser_no);
 }
 private function f_expect_cbsp_restart() runs on cbsp_test_CT {
 	interleave {
@@ -353,13 +366,13 @@ testcase TC_cbsp_bsc_server() runs on cbsp_test_CT {
 
 /* Test if BSC (client) is connecting to CBC (server) */
 testcase TC_cbsp_bsc_client() runs on cbsp_test_CT {
-	f_cbsp_init_server();
+	f_cbsp_init_server(0, 0);
 	setverdict(pass);
 }
 
 /* Test if a BSS-global RESET is executed successfully */
 testcase TC_cbsp_reset_bss() runs on cbsp_test_CT {
-	f_cbsp_init_server();
+	f_cbsp_init_server(0, 0);
 
 	f_cbsp_reset_bss(0);
 	setverdict(pass);
@@ -368,7 +381,7 @@ testcase TC_cbsp_reset_bss() runs on cbsp_test_CT {
 testcase TC_cbsp_write() runs on cbsp_test_CT {
 	var template (value) CBSP_PDU tx;
 	var CBSP_IEs pages := {f_gen_page()};
-	f_cbsp_init_server();
+	f_cbsp_init_server(0, 0);
 
 	tx := ts_CBSP_WRITE_CBS(msg_id:=23,  new_ser_nr:=42, cell_list:=ts_BSSMAP_CIL_BSS,
 				channel_ind:=0, category:=CBSP_CATEG_NORMAL,
@@ -384,10 +397,10 @@ function f_tc_cbsp_write_bss(integer payload_len := -1, template (present) integ
 	var CBSP_IEs pages := {f_gen_page(payload_len := payload_len)};
 	var template (value) BSSMAP_FIELD_CellIdentificationList cell_list;
 	cell_list := ts_BSSMAP_CIL_BSS;
-	f_cbsp_write(1, 1001, cell_list, content:=pages,
+	f_cbsp_write(g_cbsp_msg_id, g_cbsp_ser_no, cell_list, content:=pages,
 		     success_list:=tr_BSSMAP_CIL_CGI({?,?,?}), fail_list:={?});
 
-	var template RSL_Message tr := f_page2rsl(pages[0], 1, 1001, expect_blocks := expect_blocks);
+	var template RSL_Message tr := f_page2rsl(pages[0], g_cbsp_msg_id, g_cbsp_ser_no, expect_blocks := expect_blocks);
 	log("RSL[0,1,2] EXPECTING ", tr_ASP_RSL_UD(tr));
 	interleave {
 	[] IPA_RSL[0].receive(tr_ASP_RSL_UD(tr)) { log("Got SMSCB CMD on RSL[0]"); }
@@ -395,9 +408,12 @@ function f_tc_cbsp_write_bss(integer payload_len := -1, template (present) integ
 	[] IPA_RSL[2].receive(tr_ASP_RSL_UD(tr)) { log("Got SMSCB CMD on RSL[2]"); }
 	}
 	setverdict(pass);
+
+	/* Make the next test run (if any) use different msg_id and ser_no */
+	f_g_cbsp_next_msg_id_ser_no();
 }
 testcase TC_cbsp_write_bss() runs on cbsp_test_CT {
-	f_cbsp_init_server(guard_timeout := 60.0);
+	f_cbsp_init_server(1001, 1501, guard_timeout := 60.0);
 	/* In the SMSCB message, there is a head followed by payload,
 	 * and the resulting data is segmented in blocks of 22 octets (<= 4 blocks).
 	 *
@@ -427,10 +443,10 @@ testcase TC_cbsp_write_bts_cgi() runs on cbsp_test_CT {
 	var CBSP_IEs pages := {f_gen_page()};
 	var template (value) BSSMAP_FIELD_CellIdentificationList cell_list;
 	cell_list := ts_BSSMAP_CIL_CGI({bssmap_cgi(mp_cgi_bts0)});
-	f_cbsp_init_server();
-	f_cbsp_write(2, 1002, cell_list, content:=pages,
+	f_cbsp_init_server(2001, 2501);
+	f_cbsp_write(g_cbsp_msg_id, g_cbsp_ser_no, cell_list, content:=pages,
 		     success_list:=cell_list, fail_list:=omit);
-	var template RSL_Message tr := f_page2rsl(pages[0], 1, 1001);
+	var template RSL_Message tr := f_page2rsl(pages[0], g_cbsp_msg_id, g_cbsp_ser_no);
 	IPA_RSL[0].receive(tr_ASP_RSL_UD(tr));
 	f_sleep(5.0);
 }
@@ -440,8 +456,8 @@ testcase TC_cbsp_write_bts_no_cbch() runs on cbsp_test_CT {
 	var CBSP_IEs pages := {f_gen_page()};
 	var template (value) BSSMAP_FIELD_CellIdentificationList cell_list;
 	cell_list := ts_BSSMAP_CIL_CGI({bssmap_cgi(mp_cgi_bts3)});
-	f_cbsp_init_server();
-	f_cbsp_write(3, 1003, cell_list, content:=pages,
+	f_cbsp_init_server(3001, 3501);
+	f_cbsp_write(g_cbsp_msg_id, g_cbsp_ser_no, cell_list, content:=pages,
 		     success_list:=omit, fail_list:={?});
 	f_sleep(5.0);
 }
@@ -451,8 +467,8 @@ testcase TC_cbsp_write_unknown_bts() runs on cbsp_test_CT {
 	var CBSP_IEs pages := {f_gen_page()};
 	var template (value) BSSMAP_FIELD_CellIdentificationList cell_list;
 	cell_list := ts_BSSMAP_CIL_CGI({ts_BSSMAP_CI_CGI(mp_cgi_bts0.mcc, mp_cgi_bts1.mnc, 22222, 33333)});
-	f_cbsp_init_server();
-	f_cbsp_write(4, 1004, cell_list, content:=pages,
+	f_cbsp_init_server(4001, 4501);
+	f_cbsp_write(g_cbsp_msg_id, g_cbsp_ser_no, cell_list, content:=pages,
 		     success_list:=omit, fail_list:={?});
 	f_sleep(5.0);
 }
@@ -462,10 +478,10 @@ testcase TC_cbsp_write_lac_ci() runs on cbsp_test_CT {
 	var CBSP_IEs pages := {f_gen_page()};
 	var template (value) BSSMAP_FIELD_CellIdentificationList cell_list;
 	cell_list := ts_BSSMAP_CIL_LAC_CI({bssmap_lac_ci(mp_cgi_bts0)});
-	f_cbsp_init_server();
-	f_cbsp_write(5, 1005, cell_list, content:=pages,
+	f_cbsp_init_server(5001, 5501);
+	f_cbsp_write(g_cbsp_msg_id, g_cbsp_ser_no, cell_list, content:=pages,
 		     success_list:=?, fail_list:=omit);
-	IPA_RSL[0].receive(tr_ASP_RSL_UD(f_page2rsl(pages[0], 5, 1005)));
+	IPA_RSL[0].receive(tr_ASP_RSL_UD(f_page2rsl(pages[0], g_cbsp_msg_id, g_cbsp_ser_no)));
 	f_sleep(5.0);
 }
 
@@ -474,10 +490,10 @@ testcase TC_cbsp_write_ci() runs on cbsp_test_CT {
 	var CBSP_IEs pages := {f_gen_page()};
 	var template (value) BSSMAP_FIELD_CellIdentificationList cell_list;
 	cell_list := ts_BSSMAP_CIL_CI({bssmap_ci(mp_cgi_bts0)});
-	f_cbsp_init_server();
-	f_cbsp_write(6, 1006, cell_list, content:=pages,
+	f_cbsp_init_server(6001, 6501);
+	f_cbsp_write(g_cbsp_msg_id, g_cbsp_ser_no, cell_list, content:=pages,
 		     success_list:=?, fail_list:=omit);
-	IPA_RSL[0].receive(tr_ASP_RSL_UD(f_page2rsl(pages[0], 6, 1006)));
+	IPA_RSL[0].receive(tr_ASP_RSL_UD(f_page2rsl(pages[0], g_cbsp_msg_id, g_cbsp_ser_no)));
 	f_sleep(5.0);
 }
 
@@ -486,10 +502,10 @@ testcase TC_cbsp_write_lai() runs on cbsp_test_CT {
 	var CBSP_IEs pages := {f_gen_page()};
 	var template (value) BSSMAP_FIELD_CellIdentificationList cell_list;
 	cell_list := ts_BSSMAP_CIL_LAI({bssmap_lai(mp_cgi_bts0)});
-	f_cbsp_init_server();
-	f_cbsp_write(7, 1007, cell_list, content:=pages,
+	f_cbsp_init_server(7001, 7501);
+	f_cbsp_write(g_cbsp_msg_id, g_cbsp_ser_no, cell_list, content:=pages,
 		     success_list:=?, fail_list:=omit);
-	IPA_RSL[0].receive(tr_ASP_RSL_UD(f_page2rsl(pages[0], 7, 1007)));
+	IPA_RSL[0].receive(tr_ASP_RSL_UD(f_page2rsl(pages[0], g_cbsp_msg_id, g_cbsp_ser_no)));
 	f_sleep(5.0);
 }
 
@@ -498,10 +514,10 @@ testcase TC_cbsp_write_lac() runs on cbsp_test_CT {
 	var CBSP_IEs pages := {f_gen_page()};
 	var template (value) BSSMAP_FIELD_CellIdentificationList cell_list;
 	cell_list := ts_BSSMAP_CIL_LAC({bssmap_lac(mp_cgi_bts0)});
-	f_cbsp_init_server();
-	f_cbsp_write(8, 1008, cell_list, content:=pages,
+	f_cbsp_init_server(8001, 8501);
+	f_cbsp_write(g_cbsp_msg_id, g_cbsp_ser_no, cell_list, content:=pages,
 		     success_list:=?, fail_list:=omit);
-	var template RSL_Message tr := f_page2rsl(pages[0], 8, 1008);
+	var template RSL_Message tr := f_page2rsl(pages[0], g_cbsp_msg_id, g_cbsp_ser_no);
 	interleave {
 	[] IPA_RSL[0].receive(tr_ASP_RSL_UD(tr));
 	[] IPA_RSL[1].receive(tr_ASP_RSL_UD(tr));
@@ -514,11 +530,19 @@ testcase TC_cbsp_write_then_replace() runs on cbsp_test_CT {
 	var CBSP_IEs pages := {f_gen_page()};
 	var template (value) BSSMAP_FIELD_CellIdentificationList cell_list;
 	cell_list := ts_BSSMAP_CIL_LAC_CI({bssmap_lac_ci(mp_cgi_bts0)});
-	f_cbsp_init_server();
-	f_cbsp_write(9, 1009, cell_list, num_bcast_req:=10, content:=pages,
+	f_cbsp_init_server(9001, 9501);
+	f_cbsp_write(g_cbsp_msg_id, g_cbsp_ser_no, cell_list, num_bcast_req:=10, content:=pages,
 		     success_list:=?, fail_list:=omit);
-	f_cbsp_replace(9, 2009, 1009, cell_list, content:=pages,
+
+	/* FIXME: expect CBSP message */
+
+	/* Replace: keep the same msg_id, use a new ser_no */
+	var uint16_t old_ser_no := g_cbsp_ser_no;
+	g_cbsp_ser_no := g_cbsp_ser_no + 1;
+	f_cbsp_replace(g_cbsp_msg_id, g_cbsp_ser_no, old_ser_no, cell_list, content:=pages,
 		       success_list:=?, fail_list:=omit);
+
+	/* FIXME: expect CBSP message */
 }
 
 /* Replace a message that doesn't exist: failure */
@@ -526,8 +550,8 @@ testcase TC_cbsp_replace_nonexist() runs on cbsp_test_CT {
 	var CBSP_IEs pages := {f_gen_page()};
 	var template (value) BSSMAP_FIELD_CellIdentificationList cell_list;
 	cell_list := ts_BSSMAP_CIL_LAC_CI({bssmap_lac_ci(mp_cgi_bts0)});
-	f_cbsp_init_server();
-	f_cbsp_replace(10, 2010, 1010, cell_list, content:=pages,
+	f_cbsp_init_server(10001, 10501);
+	f_cbsp_replace(10, 10023, 10042, cell_list, content:=pages,
 		       success_list:=omit, fail_list:=?);
 }
 
@@ -537,8 +561,8 @@ testcase TC_cbsp_write_too_many() runs on cbsp_test_CT {
 	var CBSP_IEs pages := {f_gen_page(), f_gen_page(), f_gen_page()};
 	var template (value) BSSMAP_FIELD_CellIdentificationList cell_list;
 	cell_list := ts_BSSMAP_CIL_LAC_CI({bssmap_lac_ci(mp_cgi_bts0)});
-	f_cbsp_init_server();
-	f_cbsp_write(11, 1011, cell_list, rep_period:=1, content:=pages,
+	f_cbsp_init_server(11001, 11501);
+	f_cbsp_write(g_cbsp_msg_id, g_cbsp_ser_no, cell_list, rep_period:=1, content:=pages,
 		     success_list:=omit, fail_list:=?);
 }
 
@@ -547,17 +571,17 @@ testcase TC_cbsp_kill_nonexist() runs on cbsp_test_CT {
 	var CBSP_IEs pages := {f_gen_page()};
 	var template (value) BSSMAP_FIELD_CellIdentificationList cell_list;
 	cell_list := ts_BSSMAP_CIL_LAC_CI({bssmap_lac_ci(mp_cgi_bts0)});
-	f_cbsp_init_server();
-	f_cbsp_kill(12, 1012, 0, cell_list, success_list:=omit, fail_list:=?);
+	f_cbsp_init_server(12001, 12501);
+	f_cbsp_kill(g_cbsp_msg_id, g_cbsp_ser_no, 0, cell_list, success_list:=omit, fail_list:=?);
 }
 /* Write a message, then kill it */
 testcase TC_cbsp_write_then_kill() runs on cbsp_test_CT {
 	var CBSP_IEs pages := {f_gen_page()};
 	var template (value) BSSMAP_FIELD_CellIdentificationList cell_list;
 	cell_list := ts_BSSMAP_CIL_LAC_CI({bssmap_lac_ci(mp_cgi_bts0)});
-	f_cbsp_init_server();
-	f_cbsp_write(13, 1013, cell_list, content:=pages, success_list:=?, fail_list:=omit);
-	f_cbsp_kill(13, 1013, 0, cell_list, success_list:=?, fail_list:=omit);
+	f_cbsp_init_server(13001, 13501);
+	f_cbsp_write(g_cbsp_msg_id, g_cbsp_ser_no, cell_list, content:=pages, success_list:=?, fail_list:=omit);
+	f_cbsp_kill(g_cbsp_msg_id, g_cbsp_ser_no, 0, cell_list, success_list:=?, fail_list:=omit);
 }
 
 /* Write a message, then reset all messages */
@@ -565,8 +589,8 @@ testcase TC_cbsp_write_then_reset() runs on cbsp_test_CT {
 	var CBSP_IEs pages := {f_gen_page()};
 	var template (value) BSSMAP_FIELD_CellIdentificationList cell_list;
 	cell_list := ts_BSSMAP_CIL_LAC_CI({bssmap_lac_ci(mp_cgi_bts0)});
-	f_cbsp_init_server();
-	f_cbsp_write(14, 1014, cell_list, content:=pages, success_list:=?, fail_list:=omit);
+	f_cbsp_init_server(14001, 14501);
+	f_cbsp_write(g_cbsp_msg_id, g_cbsp_ser_no, cell_list, content:=pages, success_list:=?, fail_list:=omit);
 	f_cbsp_reset_bss(0);
 }
 
@@ -585,14 +609,14 @@ testcase TC_cbsp_emerg_write_bts_cgi_dchan() runs on cbsp_test_CT {
 	var ASP_RSL_Unitdata rx_rsl_ud;
 
 	cell_list := ts_BSSMAP_CIL_CGI({bssmap_cgi(mp_cgi_bts0)});
-	f_cbsp_init_server();
+	f_cbsp_init_server(15001, 15501);
 
 	/* first establish a dedicated channel */
 	var DchanTuple dt := f_est_dchan('23'O, 23, '00010203040506'O);
 
 	/* then send ETWS PN */
-	f_cbsp_write_emerg(15, 1015, cell_list);
-	var template (present) octetstring tr_apdu := f_gen_etws_pn(1015, 15);
+	f_cbsp_write_emerg(g_cbsp_msg_id, g_cbsp_ser_no, cell_list);
+	var template (present) octetstring tr_apdu := f_gen_etws_pn(g_cbsp_msg_id, g_cbsp_ser_no);
 	timer T := 5.0;
 	T.start;
 	alt {
@@ -627,10 +651,10 @@ testcase TC_cbsp_emerg_write_bts_cgi_cchan() runs on cbsp_test_CT {
 	var ASP_RSL_Unitdata rx_rsl_ud;
 
 	cell_list := ts_BSSMAP_CIL_CGI({bssmap_cgi(mp_cgi_bts0)});
-	f_cbsp_init_server();
+	f_cbsp_init_server(16001, 16501);
 
-	f_cbsp_write_emerg(16, 1016, cell_list);
-	var template (present) octetstring tr_apdu := f_gen_etws_pn(1016, 16);
+	f_cbsp_write_emerg(g_cbsp_msg_id, g_cbsp_ser_no, cell_list);
+	var template (present) octetstring tr_apdu := f_gen_etws_pn(g_cbsp_msg_id, g_cbsp_ser_no);
 	timer T := 5.0;
 	T.start;
 	alt {
@@ -656,12 +680,12 @@ testcase TC_cbsp_emerg_write_bts_cgi_cchan_disable() runs on cbsp_test_CT {
 	var ASP_RSL_Unitdata rx_rsl_ud;
 
 	cell_list := ts_BSSMAP_CIL_CGI({bssmap_cgi(mp_cgi_bts0)});
-	f_cbsp_init_server();
+	f_cbsp_init_server(17001, 17501);
 
-	f_cbsp_write_emerg(16, 1016, cell_list);
+	f_cbsp_write_emerg(g_cbsp_msg_id, g_cbsp_ser_no, cell_list);
 
 	/* first expect the PN to be enabled */
-	var template (present) octetstring tr_apdu := f_gen_etws_pn(1016, 16);
+	var template (present) octetstring tr_apdu := f_gen_etws_pn(g_cbsp_msg_id, g_cbsp_ser_no);
 	timer T := 5.0;
 	T.start;
 	alt {