diff --git a/include/osmocom/bsc/gsm_data.h b/include/osmocom/bsc/gsm_data.h
index c730d96..04dc696 100644
--- a/include/osmocom/bsc/gsm_data.h
+++ b/include/osmocom/bsc/gsm_data.h
@@ -25,6 +25,7 @@
 #include <osmocom/gsm/protocol/gsm_12_21.h>
 #include <osmocom/abis/e1_input.h>
 #include <osmocom/bsc/meas_rep.h>
+#include <osmocom/bsc/bsc_msg_filter.h>
 
 struct mgcp_client_conf;
 struct mgcp_client;
@@ -80,6 +81,12 @@
 	uint8_t classmark3[14]; /* if cm3 gets extended by spec, it will be truncated */
 };
 
+enum subscr_sccp_state {
+	SUBSCR_SCCP_ST_NONE,
+	SUBSCR_SCCP_ST_WAIT_CONN_CONF,
+	SUBSCR_SCCP_ST_CONNECTED
+};
+
 /* active radio connection of a mobile subscriber */
 struct gsm_subscriber_connection {
 	/* global linked list of subscriber_connections */
@@ -88,9 +95,6 @@
 	/* libbsc subscriber information (if available) */
 	struct bsc_subscr *bsub;
 
-	/* SCCP connection associatd with this subscriber_connection */
-	struct osmo_bsc_sccp_con *sccp_con;
-
 	/* back pointers */
 	struct gsm_network *network;
 
@@ -121,6 +125,47 @@
 	 * capabilities, which the MSC is required to translate into the codec list. */
 	struct gsm0808_speech_codec_list codec_list;
 	bool codec_list_present;
+
+	/* flag to prevent multiple simultaneous ciphering commands */
+	int ciphering_handled;
+
+	/* state related to welcome USSD */
+	uint8_t new_subscriber;
+
+	/* state related to osmo_bsc_filter.c */
+	struct bsc_filter_state filter_state;
+
+	/* SCCP connection associatd with this subscriber_connection */
+	struct {
+		/* for advanced ping/pong */
+		int send_ping;
+
+		/* SCCP connection realted */
+		struct bsc_msc_data *msc;
+
+		/* Sigtran connection ID */
+		int conn_id;
+		enum subscr_sccp_state state;
+	} sccp;
+
+	/* for audio handling */
+	struct {
+		uint16_t cic;
+		uint32_t rtp_ip;
+		int rtp_port;
+		/* RTP address of the remote end (assigned by MSC through assignment request) */
+		struct sockaddr_storage aoip_rtp_addr_remote;
+
+		/* Local RTP address (reported back to the MSC by us with the
+		 * assignment complete message) */
+		struct sockaddr_storage aoip_rtp_addr_local;
+
+		/* storage to keep states of the MGCP connection handler, the
+		* handler is created when an assignment request is received
+		* and is terminated when the assignment complete message is
+		* sent */
+		struct mgcp_ctx *mgcp_ctx;
+	} user_plane;
 };
 
 
diff --git a/include/osmocom/bsc/osmo_bsc.h b/include/osmocom/bsc/osmo_bsc.h
index 485c836..678ac41 100644
--- a/include/osmocom/bsc/osmo_bsc.h
+++ b/include/osmocom/bsc/osmo_bsc.h
@@ -16,59 +16,14 @@
 };
 
 struct bsc_msc_data;
-struct bsc_msc_connection;
-
-struct osmo_bsc_sccp_con {
-	/* list_head anchoring us to gsm_network.subscr_conns */
-	struct llist_head entry;
-
-	/* flag to prevent multiple simultaneous ciphering commands */
-	int ciphering_handled;
-
-	/* for audio handling */
-	struct {
-		uint16_t cic;
-		uint32_t rtp_ip;
-		int rtp_port;
-		/* RTP address of the remote end (assigned by MSC through assignment request) */
-		struct sockaddr_storage aoip_rtp_addr_remote;
-
-		/* Local RTP address (reported back to the MSC by us with the
-		 * assignment complete message) */
-		struct sockaddr_storage aoip_rtp_addr_local;
-
-		/* storage to keep states of the MGCP connection handler, the
-		* handler is created when an assignment request is received
-		* and is terminated when the assignment complete message is
-		* sent */
-		struct mgcp_ctx *mgcp_ctx;
-	} user_plane;
-
-	/* for advanced ping/pong */
-	int send_ping;
-
-	/* SCCP connection realted */
-	struct bsc_msc_data *msc;
-
-	/* back-pointer to subscriber connection */
-	struct gsm_subscriber_connection *conn;
-	/* state related to welcome USSD */
-	uint8_t new_subscriber;
-
-	/* state related to osmo_bsc_filter.c */
-	struct bsc_filter_state filter_state;
-
-	/* Sigtran connection ID */
-	int conn_id;
-};
 
 struct bsc_api *osmo_bsc_api();
 
-int bsc_queue_for_msc(struct osmo_bsc_sccp_con *conn, struct msgb *msg);
-int bsc_open_connection(struct osmo_bsc_sccp_con *sccp, struct msgb *msg);
+int bsc_queue_for_msc(struct gsm_subscriber_connection *conn, struct msgb *msg);
+int bsc_open_connection(struct gsm_subscriber_connection *sccp, struct msgb *msg);
 enum bsc_con bsc_create_new_connection(struct gsm_subscriber_connection *conn,
 				       struct bsc_msc_data *msc, int send_ping);
-int bsc_delete_connection(struct osmo_bsc_sccp_con *sccp);
+int bsc_delete_connection(struct gsm_subscriber_connection *sccp);
 
 struct bsc_msc_data *bsc_find_msc(struct gsm_subscriber_connection *conn, struct msgb *);
 int bsc_scan_bts_msg(struct gsm_subscriber_connection *conn, struct msgb *msg);
@@ -76,7 +31,7 @@
 int bsc_send_welcome_ussd(struct gsm_subscriber_connection *conn);
 
 int bsc_handle_udt(struct bsc_msc_data *msc, struct msgb *msg, unsigned int length);
-int bsc_handle_dt(struct osmo_bsc_sccp_con *conn, struct msgb *msg, unsigned int len);
+int bsc_handle_dt(struct gsm_subscriber_connection *conn, struct msgb *msg, unsigned int len);
 
 int bsc_ctrl_cmds_install();
 
diff --git a/include/osmocom/bsc/osmo_bsc_mgcp.h b/include/osmocom/bsc/osmo_bsc_mgcp.h
index dc2ba34..15039f7 100644
--- a/include/osmocom/bsc/osmo_bsc_mgcp.h
+++ b/include/osmocom/bsc/osmo_bsc_mgcp.h
@@ -43,7 +43,7 @@
 	/* Copy of the pointer and the data with context information
 	 * needed to process the AoIP and MGCP requests (system data) */
 	struct mgcp_client *mgcp;
-	struct osmo_bsc_sccp_con *conn;
+	struct gsm_subscriber_connection *conn;
 	enum gsm48_chan_mode chan_mode;
 	bool full_rate;
 	struct gsm_lchan *lchan;
@@ -54,7 +54,8 @@
 
 void mgcp_init(struct gsm_network *net);
 
-struct mgcp_ctx *mgcp_assignm_req(void *ctx, struct mgcp_client *mgcp, struct osmo_bsc_sccp_con *conn,
+struct mgcp_ctx *mgcp_assignm_req(void *ctx, struct mgcp_client *mgcp,
+				  struct gsm_subscriber_connection *conn,
 				  enum gsm48_chan_mode chan_mode, bool full_rate);
 void mgcp_clear_complete(struct mgcp_ctx *mgcp_ctx, struct msgb *resp);
 void mgcp_ass_complete(struct mgcp_ctx *mgcp_ctx, struct gsm_lchan *lchan);
diff --git a/include/osmocom/bsc/osmo_bsc_sigtran.h b/include/osmocom/bsc/osmo_bsc_sigtran.h
index 8964903..5cb7230 100644
--- a/include/osmocom/bsc/osmo_bsc_sigtran.h
+++ b/include/osmocom/bsc/osmo_bsc_sigtran.h
@@ -28,15 +28,15 @@
 enum bsc_con osmo_bsc_sigtran_new_conn(struct gsm_subscriber_connection *conn, struct bsc_msc_data *msc);
 
 /* Open a new connection oriented sigtran connection */
-int osmo_bsc_sigtran_open_conn(const struct osmo_bsc_sccp_con *conn, struct msgb *msg);
+int osmo_bsc_sigtran_open_conn(struct gsm_subscriber_connection *conn, struct msgb *msg);
 
 /* Send data to MSC */
-int osmo_bsc_sigtran_send(const struct osmo_bsc_sccp_con *conn, struct msgb *msg);
+int osmo_bsc_sigtran_send(struct gsm_subscriber_connection *conn, struct msgb *msg);
 
 /* Delete a connection from the list with open connections
  * (called by osmo_bsc_api.c on failing open connections and
  * locally, when a connection is closed by the MSC */
-int osmo_bsc_sigtran_del_conn(struct osmo_bsc_sccp_con *sccp);
+int osmo_bsc_sigtran_del_conn(struct gsm_subscriber_connection *sccp);
 
 /* Initalize osmo sigtran backhaul */
 int osmo_bsc_sigtran_init(struct llist_head *mscs);