diff --git a/include/osmocom/msc/gsm_data.h b/include/osmocom/msc/gsm_data.h
index f3e1b94..6f0aca4 100644
--- a/include/osmocom/msc/gsm_data.h
+++ b/include/osmocom/msc/gsm_data.h
@@ -20,7 +20,8 @@
 
 #include "gsm_data_shared.h"
 
-
+/* TS 48.008 DLCI containing DCCH/ACCH + SAPI */
+#define OMSC_LINKID_CB(__msgb)   (__msgb)->cb[3]
 
 /** annotations for msgb ownership */
 #define __uses
diff --git a/include/osmocom/msc/transaction.h b/include/osmocom/msc/transaction.h
index 272fb3b..63b1cc5 100644
--- a/include/osmocom/msc/transaction.h
+++ b/include/osmocom/msc/transaction.h
@@ -31,6 +31,9 @@
 	/* The current transaction ID */
 	uint8_t transaction_id;
 
+	/* The DLCI (DCCH/ACCH + SAPI) of this transaction */
+	uint8_t dlci;
+
 	/* To whom we belong, unique identifier of remote MM entity */
 	struct vlr_subscr *vsub;
 
diff --git a/src/libmsc/a_iface.c b/src/libmsc/a_iface.c
index 2b1baf0..6f2000e 100644
--- a/src/libmsc/a_iface.c
+++ b/src/libmsc/a_iface.c
@@ -145,14 +145,13 @@
 	struct gsm_subscriber_connection *conn;
 	struct msgb *msg_resp;
 
-	/* FIXME: Set this to some meaninful value! */
-	uint8_t link_id = 0x00;
+	uint8_t link_id = OMSC_LINKID_CB(msg);
 	OSMO_ASSERT(msg);
 	conn = (struct gsm_subscriber_connection *)msg->dst;
 	OSMO_ASSERT(conn);
 	OSMO_ASSERT(conn->a.scu);
 
-	LOGPCONN(conn, LOGL_DEBUG, "Passing DTAP message from MSC to BSC\n");
+	LOGPCONN(conn, LOGL_DEBUG, "Passing DTAP message (DLCI=0x%02x) from MSC to BSC\n", link_id);
 
 	msg->l3h = msg->data;
 	msg_resp = gsm0808_create_dtap(msg, link_id);
diff --git a/src/libmsc/a_iface_bssap.c b/src/libmsc/a_iface_bssap.c
index 1665e23..d0d6bc0 100644
--- a/src/libmsc/a_iface_bssap.c
+++ b/src/libmsc/a_iface_bssap.c
@@ -610,6 +610,7 @@
 {
 	struct gsm_network *network = a_conn_info->network;
 	struct gsm_subscriber_connection *conn;
+	struct dtap_header *dtap = (struct dtap_header *) msg->l2h;
 
 	conn = subscr_conn_lookup_a(network, a_conn_info->conn_id);
 	if (!conn) {
@@ -620,6 +621,7 @@
 
 	/* msc_dtap expects the dtap payload in l3h */
 	msg->l3h = msg->l2h + 3;
+	OMSC_LINKID_CB(msg) = dtap->link_id;
 
 	/* Forward dtap payload into the msc */
 	msc_dtap(conn, conn->a.conn_id, msg);
diff --git a/src/libmsc/gsm_04_08.c b/src/libmsc/gsm_04_08.c
index a90ff17..e5ddb44 100644
--- a/src/libmsc/gsm_04_08.c
+++ b/src/libmsc/gsm_04_08.c
@@ -164,6 +164,7 @@
 	 * work that the caller no longer has to do */
 	if (trans) {
 		gh->proto_discr = trans->protocol | (trans->transaction_id << 4);
+		OMSC_LINKID_CB(msg) = trans->dlci;
 	}
 
 	return msc_tx_dtap(conn, msg);
@@ -3110,6 +3111,7 @@
 
 		/* Assign conn */
 		trans->conn = msc_subscr_conn_get(conn, MSC_CONN_USE_TRANS_CC);
+		trans->dlci = 0x00; /* SAPI=0, not SACCH */
 		vlr_subscr_put(vsub);
 	} else {
 		/* update the subscriber we deal with */
@@ -3262,6 +3264,7 @@
 		}
 		/* Assign transaction */
 		trans->conn = msc_subscr_conn_get(conn, MSC_CONN_USE_TRANS_CC);
+		trans->dlci = OMSC_LINKID_CB(msg); /* DLCI as received from BSC */
 		cm_service_request_concludes(conn, msg);
 	}
 
diff --git a/src/libmsc/gsm_04_11.c b/src/libmsc/gsm_04_11.c
index f82aa6d..aa60490 100644
--- a/src/libmsc/gsm_04_11.c
+++ b/src/libmsc/gsm_04_11.c
@@ -137,6 +137,7 @@
 	/* Outgoing needs the highest bit set */
 	gh->proto_discr = trans->protocol | (trans->transaction_id<<4);
 	gh->msg_type = msg_type;
+	OMSC_LINKID_CB(msg) = trans->dlci;
 
 	DEBUGP(DLSMS, "sending CP message (trans=%x)\n", trans->transaction_id);
 
@@ -947,6 +948,7 @@
 			gsm411_rl_recv, gsm411_mn_send);
 
 		trans->conn = msc_subscr_conn_get(conn, MSC_CONN_USE_TRANS_SMS);
+		trans->dlci = OMSC_LINKID_CB(msg); /* DLCI as received from BSC */
 
 		new_trans = 1;
 		cm_service_request_concludes(conn, msg);
@@ -1029,6 +1031,8 @@
 	trans->sms.sms = sms;
 
 	trans->conn = msc_subscr_conn_get(conn, MSC_CONN_USE_TRANS_SMS);
+	trans->dlci = 0x03;
+	/* FIXME: specify SACCH in case we already have active TCH */
 
 	/* Hardcode SMSC Originating Address for now */
 	data = (uint8_t *)msgb_put(msg, 8);