diff --git a/msc/BSC_ConnectionHandler.ttcn b/msc/BSC_ConnectionHandler.ttcn
index 1dd4d05..e951400 100644
--- a/msc/BSC_ConnectionHandler.ttcn
+++ b/msc/BSC_ConnectionHandler.ttcn
@@ -70,7 +70,11 @@
 	OCT1	kc_support,
 	boolean expect_tmsi,
 	boolean	expect_auth,
-	boolean	expect_ciph
+	boolean	expect_ciph,
+	boolean expect_imei,
+	boolean expect_imei_early,
+	GSUP_IMEIResult check_imei_result,
+	boolean check_imei_error
 }
 
 type record BSC_ConnHdlrPars {
@@ -433,6 +437,82 @@
 	}
 }
 
+function f_mm_imei() runs on BSC_ConnHdlr
+{
+	var PDU_DTAP_MT dtap_mt;
+	var GSUP_PDU gsup_msg;
+	var MobileL3_CommonIE_Types.MobileIdentityLV mi;
+
+	if (not g_pars.net.expect_imei) {
+		return
+	}
+
+	/* MSC <-> BSC: ID req/rsp for IMEI */
+	alt {
+	[] BSSAP.receive(tr_PDU_DTAP_MT(tr_ML3_MT_MM_ID_Req(CM_ID_TYPE_IMEI))) {
+		mi := valueof(ts_MI_IMEI_LV(g_pars.imei));
+		BSSAP.send(ts_PDU_DTAP_MO(ts_ML3_MO_MM_ID_Rsp(mi)));
+		}
+	[] BSSAP.receive(tr_PDU_DTAP_MT(?)) -> value dtap_mt {
+		setverdict(fail, "Expected ID REQ for IMEI DTAP MT message, but got: ", dtap_mt);
+		mtc.stop;
+		}
+	}
+
+	/* MSC <-> HLR: Check IMEI req/res/err */
+	alt {
+	[g_pars.net.check_imei_error] GSUP.receive(tr_GSUP_CHECK_IMEI_REQ(g_pars.imsi, g_pars.imei)) {
+		GSUP.send(ts_GSUP_CHECK_IMEI_ERR(g_pars.imsi, 96 /* Invalid Mandatory Information */));
+		}
+	[not g_pars.net.check_imei_error] GSUP.receive(tr_GSUP_CHECK_IMEI_REQ(g_pars.imsi, g_pars.imei)) {
+		GSUP.send(ts_GSUP_CHECK_IMEI_RES(g_pars.imsi, g_pars.net.check_imei_result));
+		}
+	[] GSUP.receive(?) -> value gsup_msg {
+		setverdict(fail, "Expected CHECK IMEI REQ GSUP message (with IMEI:", g_pars.imei, " and IMSI: ",
+			   g_pars.imsi, "), but got: ", gsup_msg);
+		mtc.stop;
+		}
+	}
+}
+
+function f_mm_imei_early() runs on BSC_ConnHdlr
+{
+	var PDU_DTAP_MT dtap_mt;
+	var GSUP_PDU gsup_msg;
+	var MobileL3_CommonIE_Types.MobileIdentityLV mi;
+
+	if (not g_pars.net.expect_imei_early) {
+		return
+	}
+
+	/* MSC <-> BSC: ID req/rsp for IMEISV */
+	alt {
+	[] BSSAP.receive(tr_PDU_DTAP_MT(tr_ML3_MT_MM_ID_Req(CM_ID_TYPE_IMEISV))) {
+		mi := valueof(ts_MI_IMEISV_LV(g_pars.imei));
+		BSSAP.send(ts_PDU_DTAP_MO(ts_ML3_MO_MM_ID_Rsp(mi)));
+		}
+	[] BSSAP.receive(tr_PDU_DTAP_MT(?)) -> value dtap_mt {
+		setverdict(fail, "Expected ID REQ for IMEISV DTAP MT message, but got: ", dtap_mt);
+		mtc.stop;
+		}
+	}
+
+	/* MSC <-> HLR: Check IMEI req/res/err */
+	alt {
+	[g_pars.net.check_imei_error] GSUP.receive(tr_GSUP_CHECK_IMEI_REQ(g_pars.imsi, g_pars.imei)) {
+		GSUP.send(ts_GSUP_CHECK_IMEI_ERR(g_pars.imsi, 96 /* Invalid Mandatory Information */));
+		}
+	[not g_pars.net.check_imei_error] GSUP.receive(tr_GSUP_CHECK_IMEI_REQ(g_pars.imsi, g_pars.imei)) {
+		GSUP.send(ts_GSUP_CHECK_IMEI_RES(g_pars.imsi, g_pars.net.check_imei_result));
+		}
+	[] GSUP.receive(?) -> value gsup_msg {
+		setverdict(fail, "Expected CHECK IMEI REQ GSUP message (with IMEI:", g_pars.imei, " and IMSI: ",
+			   g_pars.imsi, "), but got: ", gsup_msg);
+		mtc.stop;
+		}
+	}
+}
+
 function f_mm_common() runs on BSC_ConnHdlr
 {
 	f_mm_auth();
@@ -508,8 +588,10 @@
 		f_ranap_initial_ue(l3_lu);
 	}
 
+	f_mm_imei_early();
 	f_mm_common();
 	f_msc_lu_hlr();
+	f_mm_imei();
 	f_accept_reject_lu();
 	/* FIXME: there could be pending SMS or other common procedures by the MSC, let's ignore them */
 	f_expect_clear();