diff --git a/src/libmsc/gsm_04_08.c b/src/libmsc/gsm_04_08.c
index 646e9a0..980f668 100644
--- a/src/libmsc/gsm_04_08.c
+++ b/src/libmsc/gsm_04_08.c
@@ -326,10 +326,6 @@
 
  	lu = (struct gsm48_loc_upd_req *) gh->data;
 
-	mi_type = lu->mi[0] & GSM_MI_TYPE_MASK;
-
-	gsm48_mi_to_string(mi_string, sizeof(mi_string), lu->mi, lu->mi_len);
-
 	if (ran_conn_is_establishing_auth_ciph(conn)) {
 		LOG_RAN_CONN_CAT(conn, DMM, LOGL_ERROR,
 				 "Cannot accept another LU, conn already busy establishing authenticity;"
@@ -346,7 +342,8 @@
 		return -EINVAL;
 	}
 
-	ran_conn_update_id(conn, COMPLETE_LAYER3_LU, mi_string);
+	conn->complete_layer3_type = COMPLETE_LAYER3_LU;
+	ran_conn_update_id_from_mi(conn, lu->mi, lu->mi_len);
 
 	LOG_RAN_CONN_CAT(conn, DMM, LOGL_DEBUG, "LOCATION UPDATING REQUEST: MI=%s LU-type=%s\n",
 			 osmo_mi_name(lu->mi, lu->mi_len), osmo_lu_type_name(lu->type));
@@ -373,6 +370,8 @@
 	/* TODO: 10.5.7.8 Device properties */
 	/* TODO: 10.5.1.15 MS network feature support */
 
+	mi_type = lu->mi[0] & GSM_MI_TYPE_MASK;
+	gsm48_mi_to_string(mi_string, sizeof(mi_string), lu->mi, lu->mi_len);
 	switch (mi_type) {
 	case GSM_MI_TYPE_IMSI:
 		tmsi = GSM_RESERVED_TMSI;
@@ -677,7 +676,7 @@
 		conn->received_cm_service_request = true;
 		ran_conn_get(conn, RAN_CONN_USE_CM_SERVICE);
 	}
-	ran_conn_update_id(conn, conn->complete_layer3_type, mi_string);
+	ran_conn_update_id(conn);
 	return conn->network->vlr->ops.tx_cm_serv_acc(conn);
 }
 
@@ -696,8 +695,6 @@
 {
 	struct gsm_network *net = conn->network;
 	uint8_t mi_type;
-	char mi_string[GSM48_MI_SIZE];
-
 	struct gsm48_hdr *gh = msgb_l3(msg);
 	struct gsm48_service_request *req =
 			(struct gsm48_service_request *)gh->data;
@@ -734,12 +731,12 @@
 		/* or should we accept and note down the service request anyway? */
 	}
 
-	gsm48_mi_to_string(mi_string, sizeof(mi_string), mi, mi_len);
+	conn->complete_layer3_type = COMPLETE_LAYER3_CM_SERVICE_REQ;
+	ran_conn_update_id_from_mi(conn, mi, mi_len);
+	LOG_RAN_CONN_CAT(conn, DMM, LOGL_DEBUG, "Rx CM SERVICE REQUEST cm_service_type=0x%02x\n",
+			 req->cm_service_type);
 
-	mi_type = mi[0] & GSM_MI_TYPE_MASK;
-	LOG_RAN_CONN_CAT(conn, DMM, LOGL_DEBUG, "Rx CM SERVICE REQUEST cm_service_type=0x%02x MI(%s)=%s\n",
-			 req->cm_service_type, gsm48_mi_type_name(mi_type), mi_string);
-
+	mi_type = (mi && mi_len) ? (mi[0] & GSM_MI_TYPE_MASK) : GSM_MI_TYPE_NONE;
 	switch (mi_type) {
 	case GSM_MI_TYPE_IMSI:
 	case GSM_MI_TYPE_TMSI:
@@ -753,7 +750,7 @@
 		}
 		/* fall-through for non-emergency setup */
 	default:
-		LOG_RAN_CONN(conn, LOGL_ERROR, "mi_type is not expected: %d\n", mi_type);
+		LOG_RAN_CONN(conn, LOGL_ERROR, "MI type is not expected: %s\n", gsm48_mi_type_name(mi_type));
 		return msc_gsm48_tx_mm_serv_rej(conn,
 						GSM48_REJECT_INCORRECT_MESSAGE);
 	}
@@ -772,9 +769,6 @@
 	if (ran_conn_is_accepted(conn))
 		return cm_serv_reuse_conn(conn, mi_p);
 
-
-	ran_conn_update_id(conn, COMPLETE_LAYER3_CM_SERVICE_REQ, mi_string);
-
 	osmo_signal_dispatch(SS_SUBSCR, S_SUBSCR_IDENTITY, mi_p);
 
 	is_utran = (conn->via_ran == OSMO_RAT_UTRAN_IU);
@@ -1142,25 +1136,15 @@
 {
 	struct gsm_network *net = conn->network;
 	struct gsm48_hdr *gh = msgb_l3(msg);
-	struct gsm48_pag_resp *resp;
 	uint8_t classmark2_len = gh->data[1];
 	uint8_t *classmark2 = gh->data+2;
 	uint8_t *mi_lv = classmark2 + classmark2_len;
-	uint8_t mi_type;
-	char mi_string[GSM48_MI_SIZE];
 	struct osmo_location_area_id lai;
 	bool is_utran;
 
 	lai.plmn = conn->network->plmn;
 	lai.lac = conn->lac;
 
-	resp = (struct gsm48_pag_resp *) &gh->data[0];
-
-	if (gsm48_paging_extract_mi(resp, msgb_l3len(msg) - sizeof(*gh), mi_string, &mi_type) <= 0) {
-		LOGP(DRR, LOGL_ERROR, "PAGING RESPONSE: invalid Mobile Identity\n");
-		return -EINVAL;
-	}
-
 	if (ran_conn_is_establishing_auth_ciph(conn)) {
 		LOGP(DMM, LOGL_ERROR,
 		     "Ignoring Paging Response, conn already busy establishing authenticity\n");
@@ -1172,8 +1156,9 @@
 		return 0;
 	}
 
-	ran_conn_update_id(conn, COMPLETE_LAYER3_PAGING_RESP, mi_string);
-	LOG_RAN_CONN_CAT(conn, DRR, LOGL_DEBUG, "PAGING RESPONSE: MI(%s)=%s\n", gsm48_mi_type_name(mi_type), mi_string);
+	conn->complete_layer3_type = COMPLETE_LAYER3_PAGING_RESP;
+	ran_conn_update_id_from_mi(conn, mi_lv + 1, *mi_lv);
+	LOG_RAN_CONN_CAT(conn, DRR, LOGL_DEBUG, "PAGING RESPONSE\n");
 
 	is_utran = (conn->via_ran == OSMO_RAT_UTRAN_IU);
 	vlr_proc_acc_req(conn->fi,
@@ -1734,6 +1719,7 @@
 {
 	LOGVSUBP(LOGL_NOTICE, subscr, "VLR: update for IMSI=%s (MSISDN=%s, used=%d)\n",
 		 subscr->imsi, subscr->msisdn, subscr->use_count);
+	ran_conn_update_id_for_vsub(subscr);
 }
 
 static void update_classmark(const struct gsm_classmark *src, struct gsm_classmark *dst)
@@ -1777,6 +1763,7 @@
 	 * associated with the conn: merge the new Classmark into vsub->classmark. Don't overwrite valid
 	 * vsub->classmark with unset classmark, though. */
 	update_classmark(&conn->temporary_classmark, &conn->vsub->classmark);
+	ran_conn_update_id(conn);
 	return 0;
 }
 
diff --git a/src/libmsc/iu_dummy.c b/src/libmsc/iu_dummy.c
index 3f11d94..277ec07 100644
--- a/src/libmsc/iu_dummy.c
+++ b/src/libmsc/iu_dummy.c
@@ -91,8 +91,9 @@
 
 uint32_t iu_get_conn_id(const struct ranap_ue_conn_ctx *ue)
 {
-	LOGP(DLGLOBAL, LOGL_INFO, "iu_get_conn_id() dummy called, returning BOGUS value\n");
-	return 23;
+	/* There is a bogus conn_id in the bogus struct ranap_ue_conn_ctx, managed for unit testing of Iu even in the
+	 * absence of libosmo-ranap (when built without Iu support). */
+	return ue->conn_id;
 }
 
 #endif
diff --git a/src/libmsc/ran_conn.c b/src/libmsc/ran_conn.c
index 714907f..dca8ce0 100644
--- a/src/libmsc/ran_conn.c
+++ b/src/libmsc/ran_conn.c
@@ -491,22 +491,31 @@
 	.timer_cb = ran_conn_fsm_timeout,
 };
 
-char *ran_conn_get_conn_id(struct ran_conn *conn)
+/* Return statically allocated string of the ran_conn RAT type and id. */
+const char *ran_conn_get_conn_id(struct ran_conn *conn)
 {
-	char *id;
+	static char id[42];
+	int rc;
+	uint32_t conn_id;
 
 	switch (conn->via_ran) {
 	case OSMO_RAT_GERAN_A:
-		id = talloc_asprintf(conn, "GERAN_A-%08x", conn->a.conn_id);
+		conn_id = conn->a.conn_id;
 		break;
 	case OSMO_RAT_UTRAN_IU:
-		id = talloc_asprintf(conn, "UTRAN_IU-%08x", iu_get_conn_id(conn->iu.ue_ctx));
+		conn_id = iu_get_conn_id(conn->iu.ue_ctx);
 		break;
 	default:
-		LOGP(DMM, LOGL_ERROR, "RAN of conn %p unknown!\n", conn);
-		return NULL;
+		return "ran-unknown";
 	}
 
+	rc = snprintf(id, sizeof(id), "%s-%u", osmo_rat_type_name(conn->via_ran), conn_id);
+	/* < 0 is error, == 0 is empty, >= size means truncation. Not really expecting this to catch on in any practical
+	 * situation. */
+	if (rc <= 0 || rc >= sizeof(id)) {
+		LOGP(DMM, LOGL_ERROR, "Error with conn id; rc=%d\n", rc);
+		return "conn-id-error";
+	}
 	return id;
 }
 
@@ -684,12 +693,57 @@
 	{ 0, NULL }
 };
 
-void ran_conn_update_id(struct ran_conn *conn,
-			       enum complete_layer3_type from, const char *id)
+static void _ran_conn_update_id(struct ran_conn *conn, const char *subscr_identity)
 {
-       conn->complete_layer3_type = from;
-       osmo_fsm_inst_update_id_f(conn->fi, "%s:%s", complete_layer3_type_name(from), id);
-       LOGPFSML(conn->fi, LOGL_DEBUG, "Updated ID\n");
+	struct vlr_subscr *vsub = conn->vsub;
+
+	if (osmo_fsm_inst_update_id_f(conn->fi, "%s:%s:%s",
+				      subscr_identity,
+				      ran_conn_get_conn_id(conn),
+				      complete_layer3_type_name(conn->complete_layer3_type))
+	    != 0)
+		return; /* osmo_fsm_inst_update_id_f() will log an error. */
+
+	if (vsub) {
+		if (vsub->lu_fsm)
+			osmo_fsm_inst_update_id(vsub->lu_fsm, conn->fi->id);
+		if (vsub->auth_fsm)
+			osmo_fsm_inst_update_id(vsub->auth_fsm, conn->fi->id);
+		if (vsub->proc_arq_fsm)
+			osmo_fsm_inst_update_id(vsub->proc_arq_fsm, conn->fi->id);
+	}
+
+	LOGPFSML(conn->fi, LOGL_DEBUG, "Updated ID\n");
+}
+
+/* Compose an ID almost like gsm48_mi_to_string(), but print the MI type along, and print a TMSI as hex. */
+void ran_conn_update_id_from_mi(struct ran_conn *conn, const uint8_t *mi, uint8_t mi_len)
+{
+	_ran_conn_update_id(conn, osmo_mi_name(mi, mi_len));
+}
+
+/* Update ran_conn->fi id string from current conn->vsub and conn->complete_layer3_type. */
+void ran_conn_update_id(struct ran_conn *conn)
+{
+	_ran_conn_update_id(conn, vlr_subscr_name(conn->vsub));
+}
+
+/* Iterate all ran_conn instances that are relevant for this subscriber, and update FSM ID strings for all of the FSM
+ * instances. */
+void ran_conn_update_id_for_vsub(struct vlr_subscr *for_vsub)
+{
+	struct gsm_network *network;
+	struct ran_conn *conn;
+	if (!for_vsub)
+		return;
+
+	network = for_vsub->vlr->user_ctx;
+	OSMO_ASSERT(network);
+
+	llist_for_each_entry(conn, &network->ran_conns, entry) {
+		if (conn->vsub == for_vsub)
+			ran_conn_update_id(conn);
+	}
 }
 
 static void rx_close_complete(struct ran_conn *conn, const char *label, bool *flag)
diff --git a/src/libvlr/vlr.c b/src/libvlr/vlr.c
index b0e7f79..887602c 100644
--- a/src/libvlr/vlr.c
+++ b/src/libvlr/vlr.c
@@ -81,20 +81,34 @@
 /* return static buffer with printable name of VLR subscriber */
 const char *vlr_subscr_name(const struct vlr_subscr *vsub)
 {
-	static char buf[32];
+	static char buf[128];
+	char imsi[23] = "";
+	char msisdn[25] = "";
+	char tmsi[23] = "";
+	char tmsi_new[23] = "";
+	bool present = false;
 	if (!vsub)
 		return "unknown";
-	if (vsub->msisdn[0])
-		snprintf(buf, sizeof(buf), "MSISDN:%s", vsub->msisdn);
-	else if (vsub->imsi[0])
-		snprintf(buf, sizeof(buf), "IMSI:%s", vsub->imsi);
-	else if (vsub->tmsi != GSM_RESERVED_TMSI)
-		snprintf(buf, sizeof(buf), "TMSI:0x%08x", vsub->tmsi);
-	else if (vsub->tmsi_new != GSM_RESERVED_TMSI)
-		snprintf(buf, sizeof(buf), "TMSI(new):0x%08x", vsub->tmsi_new);
-	else
+	if (vsub->imsi[0]) {
+		snprintf(imsi, sizeof(imsi), "IMSI-%s", vsub->imsi);
+		present = true;
+	}
+	if (vsub->msisdn[0]) {
+		snprintf(msisdn, sizeof(msisdn), "%sMSISDN-%s", present? ":" : "", vsub->msisdn);
+		present = true;
+	}
+	if (vsub->tmsi != GSM_RESERVED_TMSI) {
+		snprintf(tmsi, sizeof(tmsi), "%sTMSI-0x%08X", present? ":" : "", vsub->tmsi);
+		present = true;
+	}
+	if (vsub->tmsi_new != GSM_RESERVED_TMSI) {
+		snprintf(tmsi_new, sizeof(tmsi_new), "%sTMSInew-0x%08X", present? ":" : "", vsub->tmsi_new);
+		present = true;
+	}
+	if (!present)
 		return "unknown";
-	buf[sizeof(buf)-1] = '\0';
+
+	snprintf(buf, sizeof(buf), "%s%s%s%s", imsi, msisdn, tmsi, tmsi_new);
 	return buf;
 }
 
@@ -329,6 +343,7 @@
 			continue;
 
 		vsub->tmsi_new = tmsi;
+		vsub->vlr->ops.subscr_update(vsub);
 		return 0;
 	}
 
diff --git a/src/libvlr/vlr_lu_fsm.c b/src/libvlr/vlr_lu_fsm.c
index b00f8ce..8640d2b 100644
--- a/src/libvlr/vlr_lu_fsm.c
+++ b/src/libvlr/vlr_lu_fsm.c
@@ -547,6 +547,7 @@
 
 	vsub->tmsi = vsub->tmsi_new;
 	vsub->tmsi_new = GSM_RESERVED_TMSI;
+	vsub->vlr->ops.subscr_update(vsub);
 
 	vlr_lu_compl_fsm_success(fi);
 }