diff --git a/sip/SIP_Tests.ttcn b/sip/SIP_Tests.ttcn
index de2f498..f690dc7 100644
--- a/sip/SIP_Tests.ttcn
+++ b/sip/SIP_Tests.ttcn
@@ -17,9 +17,10 @@
 
 import from SIP_Emulation all;
 import from SIPmsg_Types all;
+import from SIP_Templates all;
 
 modulepar {
-	//charstring mp_local_host := "127.0.0.2;
+	charstring mp_local_host := "127.0.0.2";
 	charstring mp_osmosip_host := "127.0.0.1";
 	integer mp_osmosip_port_ctrl := -1; /* RFU */
 	charstring mp_mncc := "/tmp/mncc";
@@ -38,7 +39,48 @@
 }
 
 type record ConnHdlrPars {
-	float t_guard
+	float t_guard,
+	CallPars g_cp optional
+}
+
+type record CallPars {
+	boolean is_mo,
+	charstring calling,
+	charstring called,
+
+	uint32_t mncc_call_id optional,
+
+	CallParsComputed comp optional
+}
+
+type record CallParsComputed {
+	CallidString sip_call_id,
+	SipAddr sip_url_ext,
+	SipAddr sip_url_gsm,
+	charstring sip_body,
+	integer sip_seq_nr
+}
+
+private template (value) CallPars t_CallPars(boolean is_mo) := {
+	is_mo := is_mo,
+	calling := "12345",
+	called := "98766",
+	mncc_call_id := omit,
+	comp := omit
+}
+
+private function f_CallPars_compute(inout CallPars cp) {
+	if (cp.is_mo) {
+		cp.comp.sip_url_ext := valueof(ts_SipAddr(cp.called, mp_local_host, 5060));
+		cp.comp.sip_url_gsm := valueof(ts_SipAddr(cp.calling, mp_osmosip_host, 5060));
+		cp.mncc_call_id := f_rnd_int(429496725);
+	} else {
+		cp.comp.sip_url_ext := valueof(ts_SipAddr(cp.calling, mp_local_host, 5060));
+		cp.comp.sip_url_gsm := valueof(ts_SipAddr(cp.called, mp_osmosip_host, 5060));
+		cp.comp.sip_call_id := hex2str(f_rnd_hexstring(15));
+	}
+	cp.comp.sip_seq_nr := f_rnd_int(4294967295);
+	cp.comp.sip_body := "";
 }
 
 
@@ -105,67 +147,246 @@
 
 
 template (value) ConnHdlrPars t_Pars := {
-	t_guard := 30.0
+	t_guard := 30.0,
+	g_cp := omit
 }
 
-private function f_TC_mo_setup(charstring id) runs on ConnHdlr {
+/* Establish a mobile terminated call described in 'cp' */
+function f_establish_mt(inout CallPars cp) runs on ConnHdlr {
+	var template SipAddr sip_addr_gsm := tr_SipAddr_from_val(cp.comp.sip_url_gsm);
+	var template SipAddr sip_addr_ext := tr_SipAddr_from_val(cp.comp.sip_url_ext);
 	var PDU_SIP_Request sip_req;
+	var MNCC_PDU mncc;
 
-	var MNCC_number dst := valueof(ts_MNCC_number("01234567"));
-	var MNCC_number src := valueof(ts_MNCC_number("112"));
+	/* Ask MNCC_Emulation to "expect" a call to the given called number */
+	f_create_mncc_expect(cp.called);
 
-	f_create_sip_expect(valueof(ts_SIP_Url("+01234567")));
+	/* OSC <- SIP: A party sends SIP invite for a MT-call into OSC */
+	SIP.send(ts_SIP_INVITE(cp.comp.sip_call_id, cp.comp.sip_url_ext, cp.comp.sip_url_gsm,
+				cp.comp.sip_seq_nr, cp.comp.sip_body));
+	/* MSC <- OSC: OSC generates MNCC_SETUP_REQ from INVITE */
+	MNCC.receive(tr_MNCC_SETUP_req) -> value mncc {
+		cp.mncc_call_id := mncc.u.signal.callref;
+		}
+	/* OSC -> SIP */
+	SIP.receive(tr_SIP_Response(cp.comp.sip_call_id, sip_addr_ext, sip_addr_gsm, *,
+				    "INVITE", 100, ?, "Trying", *));
 
-	log("sending mncc setup");
-	MNCC.send(ts_MNCC_SETUP_ind(2342, dst, src, "262420123456789"));
+	/* MSC -> OSC: After MS sends CALL CONF in response to SETUP */
+	MNCC.send(ts_MNCC_CALL_CONF_ind(cp.mncc_call_id));
+	/* MSC <- OSC: OSC asks MSC to create RTP socket */
+	MNCC.receive(tr_MNCC_RTP_CREATE(cp.mncc_call_id));
+	MNCC.send(ts_MNCC_RTP_CREATE(cp.mncc_call_id));
 
-	MNCC.receive(tr_MNCC_RTP_CREATE(2342));
-	MNCC.send(ts_MNCC_RTP_CREATE(2342));
+	/* MSC -> OSC: After MS is ringing and sent CC ALERTING */
+	MNCC.send(ts_MNCC_ALERT_ind(cp.mncc_call_id));
+	SIP.clear;
+	SIP.receive(tr_SIP_Response(cp.comp.sip_call_id, sip_addr_ext, sip_addr_gsm, *,
+				    "INVITE", 180, ?, "Ringing", *));
 
-	SIP.receive(PDU_SIP_Request:?) -> value sip_req {
-		log(sip_req);
+	/* MSC -> OSC: After MT user has picked up and sent CC CONNECT */
+	MNCC.send(ts_MNCC_SETUP_CNF(cp.mncc_call_id));
+
+	SIP.clear;
+	interleave {
+	/* MSC <- OSC: OSC asks MSC to connect its RTP stream to remote end */
+	[] MNCC.receive(tr_MNCC_RTP_CONNECT(cp.mncc_call_id)) {}
+	/* OSC -> SIP: OSC confirms call establishment to SIP side */
+	[] SIP.receive(tr_SIP_Response(cp.comp.sip_call_id, sip_addr_ext, sip_addr_gsm, ?,
+					"INVITE", 200, ?, "OK", ?)) {}
 	}
+	/* OSC <- SIP: SIP world acknowledges "200 OK" */
+	SIP.send(ts_SIP_ACK(cp.comp.sip_call_id, cp.comp.sip_url_ext, cp.comp.sip_url_gsm,
+			    cp.comp.sip_seq_nr, omit));
+	/* MSC <- OSC: OSC sends SETUP COMPL to MNCC (which triggers CC CONNECT ACK */
+	MNCC.receive(tr_MNCC_SETUP_COMPL_req(cp.mncc_call_id));
 }
 
-testcase TC_mo_setup() runs on test_CT {
+/* Establish a mobile originated call described in 'cp' */
+function f_establish_mo(inout CallPars cp) runs on ConnHdlr {
+	var MNCC_number dst := valueof(ts_MNCC_number(cp.called, GSM48_TON_UNKNOWN));
+	var MNCC_number src := valueof(ts_MNCC_number(cp.calling, GSM48_TON_UNKNOWN));
+	var template SipAddr sip_addr_gsm := tr_SipAddr_from_val(cp.comp.sip_url_gsm);
+	var template SipAddr sip_addr_ext := tr_SipAddr_from_val(cp.comp.sip_url_ext);
+	var PDU_SIP_Request sip_req;
+	var integer seq_nr;
+
+	f_create_sip_expect(cp.comp.sip_url_ext.addr.nameAddr.addrSpec);
+
+	/* MSC -> OSC: MSC sends SETUP.ind after CC SETUP was received from MS */
+	MNCC.send(ts_MNCC_SETUP_ind(cp.mncc_call_id, dst, src, "262420123456789"));
+	/* MSC <- OSC: Create GSM side RTP socket */
+	MNCC.receive(tr_MNCC_RTP_CREATE(cp.mncc_call_id)) {
+		var MNCC_PDU mncc := valueof(ts_MNCC_RTP_CREATE(cp.mncc_call_id));
+		mncc.u.rtp.payload_msg_type := oct2int('0300'O);
+		MNCC.send(mncc);	/* FIXME: port/ip */
+		}
+	/* OSC -> SIP: Send INVITE with GSM side IP/Port in SDP */
+	SIP.receive(tr_SIP_INVITE(?, sip_addr_gsm, sip_addr_ext, ?, ?)) -> value sip_req {
+		cp.comp.sip_url_gsm.params := sip_req.msgHeader.fromField.fromParams;
+		cp.comp.sip_call_id := sip_req.msgHeader.callId.callid;
+		seq_nr := sip_req.msgHeader.cSeq.seqNumber;
+		}
+	/* OSC <- SIP: Notify call is proceeding */
+	SIP.send(ts_SIP_Response(cp.comp.sip_call_id, cp.comp.sip_url_gsm, cp.comp.sip_url_ext,
+				 "INVITE", 100, seq_nr, "Trying", sip_req.msgHeader.via));
+	/* MSC <- OSC: "100 Trying" translated to MNCC_CALL_PROC_REQ */
+	MNCC.receive(tr_MNCC_CALL_PROC_req(cp.mncc_call_id));
+
+	/* OSC <- SIP: SIP-terminated user is ringing now */
+	SIP.send(ts_SIP_Response(cp.comp.sip_call_id, cp.comp.sip_url_gsm, cp.comp.sip_url_ext,
+				 "INVITE", 180, seq_nr, "Ringing", sip_req.msgHeader.via));
+
+	/* MSC <- OSC: "180 Ringing" translated to MNCC_ALERT_REQ */
+	MNCC.receive(tr_MNCC_ALERT_req(cp.mncc_call_id)) {}
+
+	/* OSC <- SIP: SIP-terminated user has accepted the call */
+	SIP.send(ts_SIP_Response(cp.comp.sip_call_id, cp.comp.sip_url_gsm, cp.comp.sip_url_ext,
+				 "INVITE", 200, seq_nr, "OK", sip_req.msgHeader.via,
+				 cp.comp.sip_body));
+	MNCC.receive(tr_MNCC_RTP_CONNECT(cp.mncc_call_id));
+	/* MSC <- OSC: "200 OK" translated to MNCC_SETUP_RSP */
+	MNCC.receive(tr_MNCC_SETUP_rsp(cp.mncc_call_id));
+
+	/* MSC -> OSC: CC CONNECT ACK was received from MS */
+	MNCC.send(ts_MNCC_SETUP_COMPL_ind(cp.mncc_call_id));
+	/* OSC -> SIP: Acknowledge the call */
+	SIP.receive(tr_SIP_ACK(cp.comp.sip_call_id, sip_addr_gsm, sip_addr_ext, ?, omit));
+}
+
+/* Release call from the mobile side */
+function f_release_mobile(inout CallPars cp) runs on ConnHdlr {
+	var template SipAddr sip_addr_gsm := tr_SipAddr_from_val(cp.comp.sip_url_gsm);
+	var template SipAddr sip_addr_ext := tr_SipAddr_from_val(cp.comp.sip_url_ext);
+	var PDU_SIP_Request sip_req;
+	SIP.clear;
+	/* MSC -> OSC: Simulate a CC DISCONNET from the MT user */
+	MNCC.send(ts_MNCC_DISC_ind(cp.mncc_call_id, ts_MNCC_cause(0)));
+	/* OSC -> SIP: Expect BYE from OSC to SIP side */
+	SIP.receive(tr_SIP_BYE(cp.comp.sip_call_id, sip_addr_gsm, sip_addr_ext, ?, *)) -> value sip_req {
+		cp.comp.sip_url_gsm.params := sip_req.msgHeader.fromField.fromParams;
+	}
+	/* OSC <- SIP: Acknowledge the BYE */
+	SIP.send(ts_SIP_Response(cp.comp.sip_call_id, cp.comp.sip_url_gsm, cp.comp.sip_url_ext,
+					 "BYE", 200, sip_req.msgHeader.cSeq.seqNumber, "OK",
+					 sip_req.msgHeader.via));
+	/* MSC <- OSC: Send REL_REQ to MSC, triggers CC RELEASE REQ to MS */
+	MNCC.receive(tr_MNCC_REL_req(cp.mncc_call_id)); // CAUSE?
+	/* MSC -> OSC: MS has responded with CC CLEAR COMPL, triggers MNCC_REL_CNF */
+	MNCC.send(ts_MNCC_REL_cnf(cp.mncc_call_id, ts_MNCC_cause(0)));
+}
+
+/* Release call from the SIP side */
+function f_release_sip(inout CallPars cp) runs on ConnHdlr {
+	var template SipAddr sip_addr_gsm := tr_SipAddr_from_val(cp.comp.sip_url_gsm);
+	var template SipAddr sip_addr_ext := tr_SipAddr_from_val(cp.comp.sip_url_ext);
+	/* OSC <- SIP: SIP-side sends a BYE to OSC */
+	SIP.send(ts_SIP_BYE(cp.comp.sip_call_id, cp.comp.sip_url_ext, cp.comp.sip_url_gsm,
+			    cp.comp.sip_seq_nr, omit));
+	/* MSC <- OSC: Expect OSC to cause MNCC Disconnect Request */
+	MNCC.receive(tr_MNCC_DISC_req(cp.mncc_call_id));
+	/* MSC -> OSC: Indicate GSM side release */
+	MNCC.send(ts_MNCC_REL_ind(cp.mncc_call_id, ts_MNCC_cause(0)));
+	/* OSC -> SIP: Confirmation to SIP side */
+	SIP.receive(tr_SIP_Response(cp.comp.sip_call_id, sip_addr_ext, sip_addr_gsm, *,
+				    "BYE", 200, cp.comp.sip_seq_nr, "OK", omit));
+}
+
+/* Successful MT Call, which is subsequently released by GSM side */
+private function f_TC_mt_success_rel_gsm(charstring id) runs on ConnHdlr {
+	var CallPars cp := valueof(t_CallPars(false));
+	f_CallPars_compute(cp);
+	cp.comp.sip_body := "v=0\r\no=Osmocom 0 0 IN IP4 0.0.0.0\r\ns=GSM Call\r\nc=IN IP4 0.0.0.0\r\nt=0 0\r\nm=audio 0 RTP/AVP 0\r\na=rtpmap:0 GSM/8000\r\n";
+	f_sleep(3.0)
+
+	f_establish_mt(cp);
+	/* now call is fully established */
+	f_sleep(2.0);
+	f_release_mobile(cp);
+	setverdict(pass);
+}
+testcase TC_mt_success_rel_gsm() runs on test_CT {
 	var ConnHdlrPars pars;
 	var ConnHdlr vc_conn;
-
 	f_init();
-
 	pars := valueof(t_Pars);
-	vc_conn := f_start_handler(refers(f_TC_mo_setup), pars);
+	vc_conn := f_start_handler(refers(f_TC_mt_success_rel_gsm), pars);
+	vc_conn.done;
+}
+
+/* Successful MT Call, which is subsequently released by SIP side */
+private function f_TC_mt_success_rel_sip(charstring id) runs on ConnHdlr {
+	var CallPars cp := valueof(t_CallPars(false));
+	f_CallPars_compute(cp);
+	cp.comp.sip_body := "v=0\r\no=Osmocom 0 0 IN IP4 0.0.0.0\r\ns=GSM Call\r\nc=IN IP4 0.0.0.0\r\nt=0 0\r\nm=audio 0 RTP/AVP 0\r\na=rtpmap:0 GSM/8000\r\n";
+	f_sleep(3.0)
+
+	f_establish_mt(cp);
+	/* now call is fully established */
+	f_sleep(2.0);
+	f_release_sip(cp);
+	setverdict(pass);
+}
+testcase TC_mt_success_rel_sip() runs on test_CT {
+	var ConnHdlrPars pars;
+	var ConnHdlr vc_conn;
+	f_init();
+	pars := valueof(t_Pars);
+	vc_conn := f_start_handler(refers(f_TC_mt_success_rel_sip), pars);
 	vc_conn.done;
 }
 
 
+/* Successful MO Call, which is subsequently released by GSM side */
+private function f_TC_mo_success_rel_gsm(charstring id) runs on ConnHdlr {
+	var CallPars cp := valueof(t_CallPars(true));
+	f_CallPars_compute(cp);
+	cp.comp.sip_body := "v=0\r\no=Osmocom 0 0 IN IP4 0.0.0.0\r\ns=GSM Call\r\nc=IN IP4 0.0.0.0\r\nt=0 0\r\nm=audio 0 RTP/AVP 0\r\na=rtpmap:0 GSM/8000\r\n";
+	f_sleep(3.0)
 
-
-
-/* SIP specifics */
-
-const integer c_SIP_PORT := 5060;
-
-template (value) SIP_comm_adress ts_SipAddr(charstring rhost,
-					    template (omit) charstring lhost := omit,
-					    integer rport := c_SIP_PORT,
-					    integer lport := c_SIP_PORT,
-					    SIP_com_prot prot := UDP_E) := {
-	remote_host := rhost,
-	remote_port := rport,
-	local_host := lhost,
-	local_port := lport,
-	protocol := prot
+	f_establish_mo(cp);
+	/* now call is fully established */
+	f_sleep(2.0);
+	f_release_mobile(cp);
+	setverdict(pass);
+}
+testcase TC_mo_success_rel_gsm() runs on test_CT {
+	var ConnHdlrPars pars;
+	var ConnHdlr vc_conn;
+	f_init();
+	pars := valueof(t_Pars);
+	vc_conn := f_start_handler(refers(f_TC_mo_success_rel_gsm), pars);
+	vc_conn.done;
 }
 
-template (value) ASP_SIP_open ts_SIP_open(SIP_comm_adress addr) := {
-	addr := addr
-}
+/* Successful MO Call, which is subsequently released by SIP side */
+private function f_TC_mo_success_rel_sip(charstring id) runs on ConnHdlr {
+	var CallPars cp := valueof(t_CallPars(true));
+	f_CallPars_compute(cp);
+	cp.comp.sip_body := "v=0\r\no=Osmocom 0 0 IN IP4 0.0.0.0\r\ns=GSM Call\r\nc=IN IP4 0.0.0.0\r\nt=0 0\r\nm=audio 0 RTP/AVP 0\r\na=rtpmap:0 GSM/8000\r\n";
+	f_sleep(3.0)
 
+	f_establish_mo(cp);
+	/* now call is fully established */
+	f_sleep(2.0);
+	f_release_sip(cp);
+	setverdict(pass);
+}
+testcase TC_mo_success_rel_sip() runs on test_CT {
+	var ConnHdlrPars pars;
+	var ConnHdlr vc_conn;
+	f_init();
+	pars := valueof(t_Pars);
+	vc_conn := f_start_handler(refers(f_TC_mo_success_rel_sip), pars);
+	vc_conn.done;
+}
 
 
 control {
-	execute( TC_mo_setup() );
+	execute( TC_mt_success_rel_gsm() );
+	execute( TC_mt_success_rel_sip() );
+	execute( TC_mo_success_rel_gsm() );
+	execute( TC_mo_success_rel_sip() );
 }