diff --git a/openbsc/include/openbsc/gsm_data.h b/openbsc/include/openbsc/gsm_data.h
index a14e59f..620b6e4 100644
--- a/openbsc/include/openbsc/gsm_data.h
+++ b/openbsc/include/openbsc/gsm_data.h
@@ -106,6 +106,12 @@
 	uint8_t last_seen_nr;
 };
 
+enum ran_type {
+       RAN_UNKNOWN,
+       RAN_GERAN_A,	/* 2G / A-interface */
+       RAN_UTRAN_IU,	/* 3G / Iu-interface (IuCS or IuPS) */
+};
+
 /* active radio connection of a mobile subscriber */
 struct gsm_subscriber_connection {
 	struct llist_head entry;
@@ -148,6 +154,8 @@
 	struct osmo_timer_list T10; /* BSC */
 	struct gsm_lchan *secondary_lchan; /* BSC */
 
+	/* connected via 2G or 3G? */
+	enum ran_type via_ran;
 };
 
 
diff --git a/openbsc/src/libbsc/bsc_api.c b/openbsc/src/libbsc/bsc_api.c
index 7a48296..54978e5 100644
--- a/openbsc/src/libbsc/bsc_api.c
+++ b/openbsc/src/libbsc/bsc_api.c
@@ -251,6 +251,7 @@
 	conn->network = net;
 	conn->lchan = lchan;
 	conn->bts = lchan->ts->trx->bts;
+	conn->via_ran = RAN_GERAN_A;
 	lchan->conn = conn;
 	llist_add_tail(&conn->entry, &net->subscr_conns);
 	return conn;
diff --git a/openbsc/src/libmsc/gsm_04_08.c b/openbsc/src/libmsc/gsm_04_08.c
index 3cc86ba..fff902d 100644
--- a/openbsc/src/libmsc/gsm_04_08.c
+++ b/openbsc/src/libmsc/gsm_04_08.c
@@ -1235,7 +1235,7 @@
 	       osmo_hexdump_nospc(res, res_len));
 
 	/* Future: vlr_sub_rx_auth_resp(conn->vsub, is_r99,
-	 *				conn->via_iface == IFACE_IU,
+	 *				conn->via_ran == RAN_UTRAN_IU,
 	 *				res, res_len);
 	 */