diff --git a/include/openbsc/Makefile.am b/include/openbsc/Makefile.am
index 995f02d..25709f1 100644
--- a/include/openbsc/Makefile.am
+++ b/include/openbsc/Makefile.am
@@ -2,6 +2,8 @@
 	abis_nm.h \
 	abis_om2000.h \
 	abis_rsl.h \
+	a_iface.h \
+	a_iface_bssap.h \
 	arfcn_range_encode.h \
 	auth.h \
 	bsc_msc.h \
@@ -66,8 +68,10 @@
 	openbscdefines.h \
 	osmo_bsc.h \
 	osmo_bsc_grace.h \
+	a_reset.h \
 	osmo_bsc_rf.h \
 	osmo_msc.h \
+	osmo_bsc_sigtran.h \
 	bsc_msc_data.h \
 	osmux.h \
 	paging.h \
diff --git a/include/openbsc/a_iface.h b/include/openbsc/a_iface.h
new file mode 100644
index 0000000..149f1c7
--- /dev/null
+++ b/include/openbsc/a_iface.h
@@ -0,0 +1,76 @@
+/* (C) 2017 by Sysmocom s.f.m.c. GmbH
+ * All Rights Reserved
+ *
+ * Author: Philipp Maier
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#pragma once
+
+#include <openbsc/a_reset.h>
+
+/* A struct to keep a context information about the BSCs we are associated with */
+struct bsc_context {
+	struct llist_head list;
+
+	/* Holds a copy of the sccp address of the BSC,
+	 * this address will become known as soon as
+	 * a remote BSC tries to make a connection or
+	 * sends a RESET request via UNIDATA */
+	struct osmo_sccp_addr bsc_addr;
+
+	/* Holds a copy of the our local MSC address,
+	 * this will be the sccp-address that is associated
+	 * with the A interface */
+	struct osmo_sccp_addr msc_addr;
+
+	/* A pointer to the reset handler FSM, the
+	 * state machine is allocated when the BSC
+	 * is registerd. */
+	struct a_reset_ctx *reset;
+
+	/* A pointer to the sccp_user that is associated
+	 * with the A interface. We need this information
+	 * to send the resets and to send paging requests */
+	struct osmo_sccp_user *sccp_user;
+};
+
+/* Initalize A interface connection between to MSC and BSC */
+int a_init(struct osmo_sccp_instance *sccp, struct gsm_network *network);
+
+/* Send DTAP message via A-interface */
+int a_iface_tx_dtap(struct msgb *msg);
+
+/* Send Cipher mode command via A-interface */
+int a_iface_tx_cipher_mode(const struct gsm_subscriber_connection *conn,
+			   int cipher, const const uint8_t *key, int len, int include_imeisv);
+
+/* Page a subscriber via A-interface */
+int a_iface_tx_paging(const char *imsi, uint32_t tmsi, uint16_t lac);
+
+/* Send assignment request via A-interface */
+int a_iface_tx_assignment(const struct gsm_trans *trans);
+
+/* Send clear command via A-interface */
+int a_iface_tx_clear_cmd(struct gsm_subscriber_connection *conn);
+
+/* Clear all subscriber connections on a specified BSC
+ * (Helper function for a_iface_bssap.c) */
+void a_clear_all(struct osmo_sccp_user *scu, const struct osmo_sccp_addr *bsc_addr);
+
+/* Delete info of a closed connection from the active connection list
+ * (Helper function for a_iface_bssap.c) */
+void a_delete_bsc_con(uint32_t conn_id);
diff --git a/include/openbsc/a_iface_bssap.h b/include/openbsc/a_iface_bssap.h
new file mode 100644
index 0000000..237c618
--- /dev/null
+++ b/include/openbsc/a_iface_bssap.h
@@ -0,0 +1,41 @@
+/* (C) 2017 by sysmocom s.f.m.c. GmbH
+ * All Rights Reserved
+ *
+ * Author: Philipp Maier
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#pragma once
+
+/* Note: The structs and functions presented in this header file are intended
+ * to be used only by a_iface.c. */
+
+/* A structure to hold tha most basic information about a sigtran connection
+ * we use this struct internally here to pass connection data around */
+struct a_conn_info {
+	struct osmo_sccp_addr *msc_addr;
+	struct osmo_sccp_addr *bsc_addr;
+	uint32_t conn_id;
+	struct gsm_network *network;
+	struct a_reset_ctx *reset;
+};
+
+/* Receive incoming connection less data messages via sccp */
+void sccp_rx_udt(struct osmo_sccp_user *scu, const struct a_conn_info *a_conn_info, struct msgb *msg);
+
+/* Receive incoming connection oriented data messages via sccp */
+int sccp_rx_dt(struct osmo_sccp_user *scu, const struct a_conn_info *a_conn_info, struct msgb *msg);
+
diff --git a/include/openbsc/a_reset.h b/include/openbsc/a_reset.h
new file mode 100644
index 0000000..7aaab06
--- /dev/null
+++ b/include/openbsc/a_reset.h
@@ -0,0 +1,63 @@
+/* (C) 2017 by sysmocom s.f.m.c. GmbH
+ * All Rights Reserved
+ *
+ * Author: Philipp Maier
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#pragma once
+
+
+
+/* Reset context data (callbacks, state machine etc...) */
+struct a_reset_ctx {
+
+	/* FSM instance, which handles the reset procedure */
+	struct osmo_fsm_inst *fsm;
+
+	/* Connection failure counter. When this counter
+	 * reaches a certain threshold, the reset procedure
+	 * will be triggered */
+	int conn_loss_counter;
+
+	/* A human readable name to display in the logs */
+	char name[256];
+
+	/* Callback function to be called when a connection
+	 * failure is detected and a rest must occur */
+	void (*cb)(void *priv);
+
+	/* Privated data for the callback function */
+	void *priv;
+};
+
+/* Create and start state machine which handles the reset/reset-ack procedure */
+struct a_reset_ctx *a_reset_alloc(const void *ctx, const char *name, void *cb, void *priv);
+
+/* Tear down state machine */
+void a_reset_free(struct a_reset_ctx *reset);
+
+/* Confirm that we sucessfully received a reset acknowlege message */
+void a_reset_ack_confirm(struct a_reset_ctx *reset);
+
+/* Report a failed connection */
+void a_reset_conn_fail(struct a_reset_ctx *reset);
+
+/* Report a successful connection */
+void a_reset_conn_success(struct a_reset_ctx *reset);
+
+/* Check if we have a connection to a specified msc */
+bool a_reset_conn_ready(struct a_reset_ctx *reset);
diff --git a/include/openbsc/bsc_msc.h b/include/openbsc/bsc_msc.h
index 39258d3..380eb17 100644
--- a/include/openbsc/bsc_msc.h
+++ b/include/openbsc/bsc_msc.h
@@ -24,6 +24,8 @@
 
 #include <osmocom/core/write_queue.h>
 #include <osmocom/core/timer.h>
+#include <osmocom/sigtran/sccp_sap.h>
+#include <openbsc/a_reset.h>
 
 #include <netinet/in.h>
 
@@ -37,6 +39,7 @@
 
 
 struct bsc_msc_connection {
+	/* FIXME: Remove stuff that is no longer needed! */
 	struct osmo_wqueue write_queue;
 	int is_connected;
 	int is_authenticated;
@@ -52,6 +55,15 @@
 	struct osmo_timer_list timeout_timer;
 
 	struct msgb *pending_msg;
+
+	/* Sigtran connection data */
+	struct osmo_sccp_instance *sccp;
+	struct osmo_sccp_user *sccp_user;
+	struct osmo_sccp_addr g_calling_addr;
+	struct osmo_sccp_addr g_called_addr;
+	struct a_reset_ctx *reset;
+
+	int conn_id_counter;
 };
 
 struct bsc_msc_connection *bsc_msc_create(void *ctx, struct llist_head *dest);
diff --git a/include/openbsc/bsc_msc_data.h b/include/openbsc/bsc_msc_data.h
index 38e87cf..4a283d1 100644
--- a/include/openbsc/bsc_msc_data.h
+++ b/include/openbsc/bsc_msc_data.h
@@ -32,6 +32,14 @@
 #include <osmocom/core/timer.h>
 #include <osmocom/gsm/protocol/gsm_04_08.h>
 
+
+#include <osmocom/sigtran/osmo_ss7.h>
+#include <osmocom/sigtran/sccp_sap.h>
+#include <osmocom/sigtran/sccp_helpers.h>
+#include <osmocom/sigtran/protocol/sua.h>
+#include <osmocom/sigtran/protocol/m3ua.h>
+#include <osmocom/core/fsm.h>
+
 #include <regex.h>
 
 struct osmo_bsc_rf;
@@ -103,6 +111,30 @@
 	char *ussd_grace_txt;
 
 	char *acc_lst_name;
+
+	/* Sigtran connection data */
+	struct {
+		uint32_t cs7_instance;
+		bool cs7_instance_valid;
+		struct osmo_sccp_instance *sccp;
+		struct osmo_sccp_user *sccp_user;
+
+		/* Holds a copy of the our local MSC address,
+		 * this will be the sccp-address that is associated
+		 * with the A interface of this particular BSC,
+		 * this address is filled up by the VTY interface */
+		struct osmo_sccp_addr bsc_addr;
+		char *bsc_addr_name;
+
+		/* Holds a copy of the MSC address. This is the
+		 * address of the MSC that handles the calls of
+		 * this BSC. The address is configured via the
+		 * VTY interface */
+		struct osmo_sccp_addr msc_addr;
+		char *msc_addr_name;
+
+		struct a_reset_ctx *reset;
+	} a;
 };
 
 /*
diff --git a/include/openbsc/debug.h b/include/openbsc/debug.h
index de00b29..65e197d 100644
--- a/include/openbsc/debug.h
+++ b/include/openbsc/debug.h
@@ -40,6 +40,7 @@
 	DPCU,
 	DVLR,
 	DIUCS,
+	DSIGTRAN,
 	Debug_LastEntry,
 };
 
diff --git a/include/openbsc/gsm_04_08.h b/include/openbsc/gsm_04_08.h
index 6d6ead1..ca251b0 100644
--- a/include/openbsc/gsm_04_08.h
+++ b/include/openbsc/gsm_04_08.h
@@ -80,4 +80,6 @@
 
 int gsm48_multirate_config(uint8_t *lv, const struct amr_multirate_conf *mr, const struct amr_mode *modes);
 
+int gsm48_tch_rtp_create(struct gsm_trans *trans);
+
 #endif
diff --git a/include/openbsc/gsm_data.h b/include/openbsc/gsm_data.h
index f4de381..43fc6d3 100644
--- a/include/openbsc/gsm_data.h
+++ b/include/openbsc/gsm_data.h
@@ -12,12 +12,14 @@
 #include <osmocom/core/stats.h>
 
 #include <osmocom/crypt/auth.h>
+#include <osmocom/sigtran/sccp_sap.h>
 
 #include <openbsc/common.h>
 #include <openbsc/rest_octets.h>
 #include <openbsc/common_cs.h>
 #include <openbsc/mgcpgw_client.h>
 
+
 /** annotations for msgb ownership */
 #define __uses
 
@@ -193,14 +195,33 @@
 	uint16_t lac;
 	struct gsm_encr encr;
 
+	struct {
+		unsigned int mgcp_rtp_endpoint;
+		uint16_t port_subscr;
+		uint16_t port_cn;
+	} rtp;
+
 	/* which Iu-CS connection, if any. */
 	struct {
 		struct ue_conn_ctx *ue_ctx;
-		unsigned int mgcp_rtp_endpoint;
-		uint16_t mgcp_rtp_port_ue;
-		uint16_t mgcp_rtp_port_cn;
 		uint8_t rab_id;
 	} iu;
+
+	struct {
+		/* A pointer to the SCCP user that handles
+		 * the SCCP connections for this subscriber
+		 * connection */
+		struct osmo_sccp_user *scu;
+
+		/* The address of the BSC that is associated
+		 * with this subscriber connection */
+		struct osmo_sccp_addr bsc_addr;
+
+		/* The connection identifier that is used
+		 * to reference the SCCP connection that is
+		 * associated with this subscriber connection */
+		int conn_id;
+	} a;
 };
 
 
@@ -470,8 +491,20 @@
 	} mgcpgw;
 
 	struct {
+		/* CS7 instance id number (set via VTY) */
+		uint32_t cs7_instance;
 		enum nsap_addr_enc rab_assign_addr_enc;
+		struct osmo_sccp_instance *sccp;
 	} iu;
+
+	struct {
+		/* CS7 instance id number (set via VTY) */
+		uint32_t cs7_instance;
+		/* A list with the context information about
+		 * all BSCs we have connections with */
+		struct llist_head bscs;
+		struct osmo_sccp_instance *sccp;
+	} a;
 };
 
 struct osmo_esme;
diff --git a/include/openbsc/gsm_data_shared.h b/include/openbsc/gsm_data_shared.h
index 60da2e5..bed46d2 100644
--- a/include/openbsc/gsm_data_shared.h
+++ b/include/openbsc/gsm_data_shared.h
@@ -252,6 +252,16 @@
 		uint8_t speech_mode;
 #ifdef ROLE_BSC
 		struct rtp_socket *rtp_socket;
+
+		/* info we need to postpone the AoIP
+		 * assignment completed message */
+		struct {
+			uint8_t rr_cause;
+			uint8_t chosen_channel;
+			uint8_t encr_alg_id;
+			uint8_t speech_mode;
+			bool valid;
+		} ass_compl;
 #else
 		struct osmo_rtp_socket *rtp_socket;
 #endif
diff --git a/include/openbsc/iu.h b/include/openbsc/iu.h
index 5b29830..08e4cd0 100644
--- a/include/openbsc/iu.h
+++ b/include/openbsc/iu.h
@@ -5,13 +5,15 @@
 
 #include <osmocom/core/linuxlist.h>
 #include <osmocom/gsm/gsm48.h>
+#include <osmocom/sigtran/sccp_sap.h>
 
 #include <openbsc/common.h>
 
 struct sgsn_pdp_ctx;
 struct msgb;
-struct osmo_sccp_link;
 struct gsm_auth_tuple;
+struct osmo_sccp_addr;
+struct osmo_ss7_instance;
 
 struct RANAP_RAB_SetupOrModifiedItemIEs_s;
 struct RANAP_GlobalRNC_ID;
@@ -23,7 +25,10 @@
 
 struct ue_conn_ctx {
 	struct llist_head list;
-	struct osmo_sccp_link *link;
+	/* TODO: It's not needed to store the full SCCP address for each
+	 * UE.  Rather than that, a pointer to the RNC should be far
+	 * sufficient */
+	struct osmo_sccp_addr sccp_addr;
 	uint32_t conn_id;
 	int integrity_active;
 	struct gprs_ra_id ra_id;
@@ -53,11 +58,9 @@
 typedef int (* iu_rab_ass_resp_cb_t )(struct ue_conn_ctx *ue_ctx, uint8_t rab_id,
 		struct RANAP_RAB_SetupOrModifiedItemIEs_s *setup_ies);
 
-int iu_init(void *ctx, const char *listen_addr, uint16_t listen_port,
+int iu_init(void *ctx, struct osmo_sccp_instance *sccp,
 	    iu_recv_cb_t iu_recv_cb, iu_event_cb_t iu_event_cb);
 
-void iu_link_del(struct osmo_sccp_link *link);
-
 int iu_tx(struct msgb *msg, uint8_t sapi);
 
 int iu_page_cs(const char *imsi, const uint32_t *tmsi, uint16_t lac);
diff --git a/include/openbsc/mgcpgw_client.h b/include/openbsc/mgcpgw_client.h
index b353db0..b1b5fd4 100644
--- a/include/openbsc/mgcpgw_client.h
+++ b/include/openbsc/mgcpgw_client.h
@@ -3,11 +3,11 @@
 #include <stdint.h>
 
 #include <osmocom/core/linuxlist.h>
+#include <osmocom/core/write_queue.h>
 
 enum mgcp_connection_mode;
 
 struct msgb;
-struct mgcpgw_client;
 struct vty;
 
 #define MGCPGW_CLIENT_LOCAL_ADDR_DEFAULT "0.0.0.0"
@@ -24,6 +24,9 @@
 	int local_port;
 	const char *remote_addr;
 	int remote_port;
+	uint16_t first_endpoint;
+	uint16_t last_endpoint;
+	uint16_t bts_base;
 };
 
 struct mgcp_response_head {
@@ -38,6 +41,20 @@
 	uint16_t audio_port;
 };
 
+struct mgcpgw_client {
+	struct mgcpgw_client_conf actual;
+	uint32_t remote_addr;
+	struct osmo_wqueue wq;
+	mgcp_trans_id_t next_trans_id;
+	struct llist_head responses_pending;
+	struct llist_head inuse_endpoints;
+};
+
+struct mgcp_inuse_endpoint {
+	struct llist_head entry;
+	uint16_t id;
+};
+
 /* Invoked when an MGCP response is received or sending failed.  When the
  * response is passed as NULL, this indicates failure during transmission. */
 typedef void (* mgcp_response_cb_t )(struct mgcp_response *response, void *priv);
@@ -61,7 +78,11 @@
 uint16_t mgcpgw_client_remote_port(struct mgcpgw_client *mgcp);
 uint32_t mgcpgw_client_remote_addr_n(struct mgcpgw_client *mgcp);
 
-unsigned int mgcpgw_client_next_endpoint(struct mgcpgw_client *client);
+/* Find and seize an unsused endpoint id */
+int mgcpgw_client_next_endpoint(struct mgcpgw_client *client);
+
+/* Release a seized endpoint id to make it available again for other calls */
+void mgcpgw_client_release_endpoint(uint16_t id, struct mgcpgw_client *client);
 
 int mgcp_response_parse_params(struct mgcp_response *r);
 
@@ -76,6 +97,9 @@
 			   uint16_t rtp_endpoint, const char *rtp_conn_addr,
 			   uint16_t rtp_port, enum mgcp_connection_mode mode);
 
+struct msgb *mgcp_msg_dlcx(struct mgcpgw_client *mgcp, uint16_t rtp_endpoint,
+			   unsigned int call_id);
+
 void mgcpgw_client_vty_init(int node, struct mgcpgw_client_conf *conf);
 int mgcpgw_client_config_write(struct vty *vty, const char *indent);
 
diff --git a/include/openbsc/msc_ifaces.h b/include/openbsc/msc_ifaces.h
index 2965c72..a1071ae 100644
--- a/include/openbsc/msc_ifaces.h
+++ b/include/openbsc/msc_ifaces.h
@@ -28,20 +28,6 @@
 /* Each main linkage must implement this function (see comment above). */
 extern int iu_tx(struct msgb *msg, uint8_t sapi);
 
-/* So far this is a dummy implemented in libmsc/a_iface.c. When A-interface
- * gets implemented, it should be in a separate lib (like libiu), this function
- * should move there, and the following comment should remain here: "
- * Each main linkage must implement this function (see comment above).
- * " */
-extern int a_tx(struct msgb *msg);
-
-/* So far this is a dummy implemented in libmsc/a_iface.c. When A-interface
- * gets implemented, it should be in a separate lib (like libiu), this function
- * should move there, and the following comment should remain here: "
- * Each main linkage must implement this function (see comment above).
- * " */
-extern int a_page(const char *imsi, uint32_t tmsi, uint16_t lac);
-
 int msc_tx_dtap(struct gsm_subscriber_connection *conn,
 		struct msgb *msg);
 
@@ -49,10 +35,8 @@
 int msc_gsm48_tx_mm_serv_rej(struct gsm_subscriber_connection *conn,
 			     enum gsm48_reject_value value);
 
-/* TODO: specific to A interface, move this away */
-int msc_gsm0808_tx_cipher_mode(struct gsm_subscriber_connection *conn, int cipher,
-			       const uint8_t *key, int len, int include_imeisv);
-
 int msc_tx_common_id(struct gsm_subscriber_connection *conn);
 int msc_call_assignment(struct gsm_trans *trans);
 int msc_call_bridge(struct gsm_trans *trans1, struct gsm_trans *trans2);
+void msc_call_release(struct gsm_trans *trans);
+int msc_call_connect(struct gsm_trans *trans, uint16_t port, uint32_t ip);
diff --git a/include/openbsc/osmo_bsc.h b/include/openbsc/osmo_bsc.h
index 9e688fd..5ebea50 100644
--- a/include/openbsc/osmo_bsc.h
+++ b/include/openbsc/osmo_bsc.h
@@ -26,6 +26,7 @@
 
 	/* for audio handling */
 	uint16_t cic;
+	uint32_t rtp_ip;
 	int rtp_port;
 
 	/* for advanced ping/pong */
@@ -44,6 +45,9 @@
 	uint8_t new_subscriber;
 
 	struct bsc_filter_state filter_state;
+
+	/* Sigtran connection ID */
+	int conn_id;
 };
 
 struct bsc_api *osmo_bsc_api();
@@ -60,7 +64,7 @@
 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_dt1(struct osmo_bsc_sccp_con *conn, struct msgb *msg, unsigned int len);
+int bsc_handle_dt(struct osmo_bsc_sccp_con *conn, struct msgb *msg, unsigned int len);
 
 int bsc_ctrl_cmds_install();
 
diff --git a/include/openbsc/osmo_bsc_reset.h b/include/openbsc/osmo_bsc_reset.h
new file mode 100644
index 0000000..578f763
--- /dev/null
+++ b/include/openbsc/osmo_bsc_reset.h
@@ -0,0 +1,34 @@
+/* (C) 2017 by sysmocom s.f.m.c. GmbH
+ * All Rights Reserved
+ *
+ * Author: Philipp Maier
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+/* Create and start state machine which handles the reset/reset-ack procedure */
+void start_reset_fsm(struct bsc_msc_data *msc);
+
+/* Confirm that we sucessfully received a reset acknowlege message */
+void reset_ack_confirm(struct bsc_msc_data *msc);
+
+/* Report a failed connection */
+void report_conn_fail(struct bsc_msc_data *msc);
+
+/* Report a successful connection */
+void report_conn_success(struct bsc_msc_data *msc);
+
+/* Check if we have a connection to a specified msc */
+bool sccp_conn_ready(struct bsc_msc_data *msc);
diff --git a/include/openbsc/osmo_bsc_sigtran.h b/include/openbsc/osmo_bsc_sigtran.h
new file mode 100644
index 0000000..fbcfcb3
--- /dev/null
+++ b/include/openbsc/osmo_bsc_sigtran.h
@@ -0,0 +1,48 @@
+/* (C) 2017 by Sysmocom s.f.m.c. GmbH
+ * All Rights Reserved
+ *
+ * Author: Philipp Maier
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#pragma once
+
+#include <openbsc/gsm_data.h>
+#include <openbsc/bsc_msc_data.h>
+
+/* Allocate resources to make a new connection oriented sigtran connection
+ * (not the connection ittself!) */
+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);
+
+/* Send data to MSC */
+int osmo_bsc_sigtran_send(const struct osmo_bsc_sccp_con *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);
+
+/* Initalize osmo sigtran backhaul */
+int osmo_bsc_sigtran_init(struct llist_head *mscs);
+
+/* Close all open sigtran connections and channels */
+void osmo_bsc_sigtran_reset(const struct bsc_msc_data *msc);
+
+/* Send reset-ack to MSC */
+void osmo_bsc_sigtran_tx_reset_ack(const struct bsc_msc_data *msc);
diff --git a/include/openbsc/osmo_msc.h b/include/openbsc/osmo_msc.h
index bc96f1d..cdfd27f 100644
--- a/include/openbsc/osmo_msc.h
+++ b/include/openbsc/osmo_msc.h
@@ -63,6 +63,8 @@
 int msc_vlr_alloc(struct gsm_network *net);
 int msc_vlr_start(struct gsm_network *net);
 
+void msc_sapi_n_reject(struct gsm_subscriber_connection *conn, int dlci);
+int msc_clear_request(struct gsm_subscriber_connection *conn, uint32_t cause);
 int msc_compl_l3(struct gsm_subscriber_connection *conn,
 		 struct msgb *msg, uint16_t chosen_channel);
 void msc_dtap(struct gsm_subscriber_connection *conn, uint8_t link_id,
@@ -70,6 +72,11 @@
 void msc_cipher_mode_compl(struct gsm_subscriber_connection *conn,
 			   struct msgb *msg, uint8_t alg_id);
 void msc_rx_sec_mode_compl(struct gsm_subscriber_connection *conn);
+void msc_classmark_chg(struct gsm_subscriber_connection *conn,
+		       const uint8_t *cm2, uint8_t cm2_len,
+		       const uint8_t *cm3, uint8_t cm3_len);
+void msc_assign_fail(struct gsm_subscriber_connection *conn,
+		     uint8_t cause, uint8_t *rr_cause);
 
 void msc_subscr_conn_init(void);
 bool msc_subscr_conn_is_accepted(struct gsm_subscriber_connection *conn);
diff --git a/include/openbsc/transaction.h b/include/openbsc/transaction.h
index 713d878..4930fbd 100644
--- a/include/openbsc/transaction.h
+++ b/include/openbsc/transaction.h
@@ -46,6 +46,16 @@
 	/* is thats one paging? */
 	struct subscr_request *paging_request;
 
+	/* bearer capabilities (rate and codec) */
+	struct gsm_mncc_bearer_cap bearer_cap;
+
+	/* status of the assignment, true when done */
+	bool assignment_done;
+
+	/* if true, TCH_RTP_CREATE is sent after the
+	 * assignment is done */
+	bool tch_rtp_create;
+
 	union {
 		struct {