diff --git a/openbsc/include/openbsc/sgsn.h b/openbsc/include/openbsc/sgsn.h
new file mode 100644
index 0000000..2dc53c1
--- /dev/null
+++ b/openbsc/include/openbsc/sgsn.h
@@ -0,0 +1,30 @@
+#ifndef _SGSN_H
+#define _SGSN_H
+
+#include <sys/types.h>
+
+#include <osmocore/msgb.h>
+
+#include <openbsc/gprs_ns.h>
+
+struct sgsn_config {
+	/* parsed from config file */
+	u_int32_t nsip_listen_ip;
+	u_int16_t nsip_listen_port;
+
+	/* misc */
+	struct gprs_ns_inst *nsi;
+};
+
+
+/* sgsn_vty.c */
+
+int sgsn_vty_init(void);
+int sgsn_parse_config(const char *config_file, struct sgsn_config *cfg);
+
+/* sgsn.c */
+
+/* Main input function for Gb proxy */
+int sgsn_rcvmsg(struct msgb *msg, struct gprs_nsvc *nsvc, uint16_t ns_bvci);
+
+#endif
diff --git a/openbsc/src/Makefile.am b/openbsc/src/Makefile.am
index 6e4e506..18245ed 100644
--- a/openbsc/src/Makefile.am
+++ b/openbsc/src/Makefile.am
@@ -3,7 +3,7 @@
 AM_LDFLAGS = $(LIBOSMOCORE_LIBS)
 
 sbin_PROGRAMS = bsc_hack bs11_config ipaccess-find ipaccess-config \
-                isdnsync bsc_mgcp ipaccess-proxy osmo-gb_proxy
+                isdnsync bsc_mgcp ipaccess-proxy osmo-gbproxy osmo-sgsn
 noinst_LIBRARIES = libbsc.a libmsc.a libvty.a libsccp.a libsgsn.a
 noinst_HEADERS = vty/cardshell.h
 
@@ -33,7 +33,7 @@
 libsccp_a_SOURCES = sccp/sccp.c
 
 bsc_hack_SOURCES = bsc_hack.c bsc_init.c vty_interface.c vty_interface_layer3.c
-bsc_hack_LDADD = libmsc.a libbsc.a libmsc.a libsgsn.a libvty.a -ldl -ldbi $(LIBCRYPT)
+bsc_hack_LDADD = libmsc.a libbsc.a libmsc.a libvty.a -ldl -ldbi $(LIBCRYPT)
 
 bs11_config_SOURCES = bs11_config.c abis_nm.c gsm_data.c debug.c \
 		      rs232.c bts_siemens_bs11.c
@@ -51,6 +51,10 @@
 
 ipaccess_proxy_SOURCES = ipaccess/ipaccess-proxy.c debug.c
 
-osmo_gb_proxy_SOURCES = gb_proxy.c gb_proxy_main.c gb_proxy_vty.c \
+osmo_gbproxy_SOURCES = gb_proxy.c gb_proxy_main.c gb_proxy_vty.c \
 			gprs_ns.c socket.c debug.c
-osmo_gb_proxy_LDADD = libvty.a
+osmo_gbproxy_LDADD = libvty.a
+
+osmo_sgsn_SOURCES = sgsn_main.c sgsn_vty.c \
+			socket.c debug.c
+osmo_sgsn_LDADD = libvty.a libsgsn.a
diff --git a/openbsc/src/gb_proxy_main.c b/openbsc/src/gb_proxy_main.c
index 8f03060..fe72e02 100644
--- a/openbsc/src/gb_proxy_main.c
+++ b/openbsc/src/gb_proxy_main.c
@@ -64,7 +64,7 @@
 	"This is free software: you are free to change and redistribute it.\n"
 	"There is NO WARRANTY, to the extent permitted by law.\n";
 
-static char *config_file = "gb_proxy.cfg";
+static char *config_file = "osmo_gbproxy.cfg";
 static struct gbproxy_config gbcfg;
 
 /* Pointer to the SGSN peer */
diff --git a/openbsc/src/gprs_bssgp.c b/openbsc/src/gprs_bssgp.c
index a2181b1..ab6d1a0 100644
--- a/openbsc/src/gprs_bssgp.c
+++ b/openbsc/src/gprs_bssgp.c
@@ -138,6 +138,25 @@
 	return gprs_ns_sendmsg(bssgp_nsi, msg);
 }
 
+/* Chapter 8.4 BVC-Reset Procedure */
+static int bssgp_rx_bvc_reset(struct msgb *msg, struct tlv_parsed *tp,	
+			      uint16_t ns_bvci)
+{
+	uint8_t bvci;
+	int rc;
+
+	bvci = ntohs(*(u_int16_t *)TLVP_VAL(tp, BSSGP_IE_BVCI));
+	DEBUGPC(DGPRS, "BVCI=%u, cause=%s\n", bvci,
+		bssgp_cause_str(*TLVP_VAL(tp, BSSGP_IE_CAUSE)));
+
+	/* When we receive a BVC-RESET PDU (at least of a PTP BVCI), the BSS
+	 * informs us about its RAC + Cell ID, so we can create a mapping */
+
+	rc = bssgp_tx_simple_bvci(BSSGP_PDUT_BVC_RESET_ACK,
+				  msgb_nsei(msg), bvci, ns_bvci);
+	return 0;
+}
+
 /* Uplink unit-data */
 static int bssgp_rx_ul_ud(struct msgb *msg, u_int16_t bvci)
 {
@@ -157,10 +176,12 @@
 	    !TLVP_PRESENT(&tp, BSSGP_IE_LLC_PDU))
 		return -EIO;
 
+#if 0 //FIXME
 	/* Determine the BTS based on the Cell ID */
 	bts = gsm48_bts_by_ra_id(bsc_gsmnet,
 				 TLVP_VAL(&tp, BSSGP_IE_CELL_ID),
 				 TLVP_LEN(&tp, BSSGP_IE_CELL_ID));
+#endif
 	if (bts)
 		msg->trx = bts->c0;
 
@@ -229,6 +250,7 @@
 	return bssgp_tx_fc_bvc_ack(msgb_nsei(msg), *TLVP_VAL(tp, BSSGP_IE_TAG),
 				   ns_bvci);
 }
+
 /* We expect msg->l3h to point to the BSSGP header */
 int gprs_bssgp_rcvmsg(struct msgb *msg, u_int16_t ns_bvci)
 {
@@ -311,11 +333,7 @@
 		if (!TLVP_PRESENT(&tp, BSSGP_IE_BVCI) ||
 		    !TLVP_PRESENT(&tp, BSSGP_IE_CAUSE))
 			goto err_mand_ie;
-		bvci = ntohs(*(u_int16_t *)TLVP_VAL(&tp, BSSGP_IE_BVCI));
-		DEBUGPC(DGPRS, "BVCI=%u, cause=%s\n", bvci,
-			bssgp_cause_str(*TLVP_VAL(&tp, BSSGP_IE_CAUSE)));
-		rc = bssgp_tx_simple_bvci(BSSGP_PDUT_BVC_RESET_ACK,
-					  msgb_nsei(msg), bvci, ns_bvci);
+		rc = bssgp_rx_bvc_reset(msg, &tp, ns_bvci);
 		break;
 	case BSSGP_PDUT_STATUS:
 		/* Some exception has occurred */
diff --git a/openbsc/src/gprs_sgsn.c b/openbsc/src/gprs_sgsn.c
index 3f7f61e..9844f88 100644
--- a/openbsc/src/gprs_sgsn.c
+++ b/openbsc/src/gprs_sgsn.c
@@ -94,35 +94,3 @@
 
 	return ctx;
 }
-
-/* call-back function for the NS protocol */
-static int gprs_ns_cb(enum gprs_ns_evt event, struct gprs_nsvc *nsvc,
-		      struct msgb *msg, u_int16_t bvci)
-{
-	int rc = 0;
-
-	switch (event) {
-	case GPRS_NS_EVT_UNIT_DATA:
-		/* hand the message into the BSSGP implementation */
-		rc = gprs_bssgp_rcvmsg(msg, bvci);
-		break;
-	default:
-		LOGP(DGPRS, LOGL_ERROR, "SGSN: Unknown event %u from NS\n", event);
-		if (msg)
-			talloc_free(msg);
-		rc = -EIO;
-		break;
-	}
-	return rc;
-}
-
-int sgsn_init(void)
-{
-	struct gprs_ns_inst *nsi;
-
-	nsi = gprs_ns_instantiate(&gprs_ns_cb);
-	if (!nsi)
-		return -EIO;
-
-	return nsip_listen(nsi, 23000);
-}
diff --git a/openbsc/src/gsm_04_08_gprs.c b/openbsc/src/gsm_04_08_gprs.c
index ffc3303..db439da 100644
--- a/openbsc/src/gsm_04_08_gprs.c
+++ b/openbsc/src/gsm_04_08_gprs.c
@@ -153,7 +153,7 @@
 	aa->att_result = 1;	/* GPRS only */
 	aa->ra_upd_timer = GPRS_TMR_MINUTE | 10;
 	aa->radio_prio = 4;	/* lowest */
-	gsm48_ra_id_by_bts(aa->ra_id.digits, old_msg->trx->bts);
+	//FIXME gsm48_ra_id_by_bts(aa->ra_id.digits, old_msg->trx->bts);
 
 	/* Option: P-TMSI signature, allocated P-TMSI, MS ID, ... */
 	return gsm48_gmm_sendmsg(msg, 0);
@@ -227,7 +227,7 @@
 	DEBUGP(DMM, "GMM IDENTITY RESPONSE: mi_type=0x%02x MI(%s) ",
 		mi_type, mi_string);
 
-	gprs_ra_id_by_bts(&ra_id, msg->trx->bts);
+	//FIXME gprs_ra_id_by_bts(&ra_id, msg->trx->bts);
 	ctx = sgsn_mm_ctx_by_tlli(msgb_tlli(msg), &ra_id);
 	if (!ctx) {
 		DEBUGP(DMM, "from unknown TLLI 0x%08x?!?\n", msgb_tlli(msg));
@@ -289,7 +289,7 @@
 	 * with a foreign TLLI (P-TMSI that was allocated to the MS before),
 	 * or with random TLLI. */
 
-	gprs_ra_id_by_bts(&ra_id, msg->trx->bts);
+	//FIXME gprs_ra_id_by_bts(&ra_id, msg->trx->bts);
 
 	/* MS network capability 10.5.5.12 */
 	msnc_len = *cur++;
@@ -391,7 +391,7 @@
 	rua->force_stby = 0;	/* not indicated */
 	rua->upd_result = 0;	/* RA updated */
 	rua->ra_upd_timer = GPRS_TMR_MINUTE | 10;
-	gsm48_ra_id_by_bts(rua->ra_id.digits, old_msg->trx->bts);
+	//FIXME gsm48_ra_id_by_bts(rua->ra_id.digits, old_msg->trx->bts);
 
 	/* Option: P-TMSI signature, allocated P-TMSI, MS ID, ... */
 	return gsm48_gmm_sendmsg(msg, 0);
diff --git a/openbsc/src/osmo_gbproxy.cfg b/openbsc/src/osmo_gbproxy.cfg
new file mode 100644
index 0000000..f2ef141
--- /dev/null
+++ b/openbsc/src/osmo_gbproxy.cfg
@@ -0,0 +1,13 @@
+!
+! OpenBSC configuration saved from vty
+!   !
+!
+line vty
+ no login
+!
+gbproxy
+  nsip bss local port 23000
+  nsip sgsn remote ip 192.168.100.239
+  nsip sgsn remote port 23000
+  nsip sgsn nsei 1
+  nsip sgsn nsvci 11
diff --git a/openbsc/src/osmo_sgsn.cfg b/openbsc/src/osmo_sgsn.cfg
new file mode 100644
index 0000000..f39e853
--- /dev/null
+++ b/openbsc/src/osmo_sgsn.cfg
@@ -0,0 +1,9 @@
+!
+! OpenBSC configuration saved from vty
+!   !
+!
+line vty
+ no login
+!
+sgsn
+  nsip local port 23000
diff --git a/openbsc/src/sgsn_main.c b/openbsc/src/sgsn_main.c
new file mode 100644
index 0000000..5c56ca7
--- /dev/null
+++ b/openbsc/src/sgsn_main.c
@@ -0,0 +1,141 @@
+/* GPRS SGSN Implementation */
+
+/* (C) 2010 by Harald Welte <laforge@gnumonks.org>
+ * (C) 2010 by On Waves
+ * All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ */
+
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <getopt.h>
+#include <errno.h>
+#include <sys/fcntl.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+
+#include <osmocore/talloc.h>
+#include <osmocore/select.h>
+
+#include <openbsc/signal.h>
+#include <openbsc/debug.h>
+#include <openbsc/telnet_interface.h>
+#include <openbsc/vty.h>
+#include <openbsc/sgsn.h>
+#include <openbsc/gprs_ns.h>
+#include <openbsc/gprs_bssgp.h>
+
+#include "../bscconfig.h"
+
+/* this is here for the vty... it will never be called */
+void subscr_put() { abort(); }
+
+#define _GNU_SOURCE
+#include <getopt.h>
+
+void *tall_bsc_ctx;
+
+struct gprs_ns_inst *sgsn_nsi;
+
+const char *openbsc_version = "Osmocom NSIP Proxy " PACKAGE_VERSION;
+const char *openbsc_copyright =
+	"Copyright (C) 2010 Harald Welte and On-Waves\n"
+	"Contributions by Daniel Willmann, Jan Lübbe, Stefan Schmidt\n"
+	"Dieter Spaar, Andreas Eversberg, Holger Freyther\n\n"
+	"License GPLv2+: GNU GPL version 2 or later <http://gnu.org/licenses/gpl.html>\n"
+	"This is free software: you are free to change and redistribute it.\n"
+	"There is NO WARRANTY, to the extent permitted by law.\n";
+
+static char *config_file = "osmo_sgsn.cfg";
+static struct sgsn_config sgcfg;
+
+/* call-back function for the NS protocol */
+static int sgsn_ns_cb(enum gprs_ns_evt event, struct gprs_nsvc *nsvc,
+		      struct msgb *msg, u_int16_t bvci)
+{
+	int rc = 0;
+
+	switch (event) {
+	case GPRS_NS_EVT_UNIT_DATA:
+		/* hand the message into the BSSGP implementation */
+		rc = gprs_bssgp_rcvmsg(msg, bvci);
+		break;
+	default:
+		LOGP(DGPRS, LOGL_ERROR, "SGSN: Unknown event %u from NS\n", event);
+		if (msg)
+			talloc_free(msg);
+		rc = -EIO;
+		break;
+	}
+	return rc;
+}
+
+
+int main(int argc, char **argv)
+{
+	struct gsm_network dummy_network;
+	struct log_target *stderr_target;
+	struct sockaddr_in sin;
+	int rc;
+
+	tall_bsc_ctx = talloc_named_const(NULL, 0, "osmo_sgsn");
+
+	log_init(&log_info);
+	stderr_target = log_target_create_stderr();
+	log_add_target(stderr_target);
+	log_set_all_filter(stderr_target, 1);
+
+	telnet_init(&dummy_network, 4245);
+	rc = sgsn_parse_config(config_file, &sgcfg);
+	if (rc < 0) {
+		LOGP(DGPRS, LOGL_FATAL, "Cannot parse config file\n");
+		exit(2);
+	}
+
+	sgsn_nsi = gprs_ns_instantiate(&sgsn_ns_cb);
+	if (!sgsn_nsi) {
+		LOGP(DGPRS, LOGL_ERROR, "Unable to instantiate NS\n");
+		exit(1);
+	}
+	sgcfg.nsi = sgsn_nsi;
+	nsip_listen(sgsn_nsi, sgcfg.nsip_listen_port);
+
+	while (1) {
+		rc = bsc_select_main(0);
+		if (rc < 0)
+			exit(3);
+	}
+
+	exit(0);
+}
+
+struct gsm_network;
+int bsc_vty_init(struct gsm_network *dummy)
+{
+	cmd_init(1);
+	vty_init();
+
+	openbsc_vty_add_cmds();
+        sgsn_vty_init();
+	return 0;
+}
+
diff --git a/openbsc/src/sgsn_vty.c b/openbsc/src/sgsn_vty.c
new file mode 100644
index 0000000..ec18fcb
--- /dev/null
+++ b/openbsc/src/sgsn_vty.c
@@ -0,0 +1,146 @@
+/*
+ * (C) 2010 by Harald Welte <laforge@gnumonks.org>
+ * (C) 2010 by On-Waves
+ * All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ */
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+
+#include <osmocore/talloc.h>
+
+#include <openbsc/debug.h>
+#include <openbsc/sgsn.h>
+#include <openbsc/gprs_ns.h>
+
+#include <vty/command.h>
+#include <vty/vty.h>
+
+static struct sgsn_config *g_cfg = NULL;
+
+static struct cmd_node sgsn_node = {
+	SGSN_NODE,
+	"%s(sgsn)#",
+	1,
+};
+
+static int config_write_sgsn(struct vty *vty)
+{
+	struct in_addr ia;
+
+	vty_out(vty, "sgsn%s", VTY_NEWLINE);
+
+	if (g_cfg->nsip_listen_ip) {
+		ia.s_addr = htonl(g_cfg->nsip_listen_ip);
+		vty_out(vty, "  nsip local ip %s%s", inet_ntoa(ia),
+			VTY_NEWLINE);
+	}
+	vty_out(vty, "  nsip local port %u%s", g_cfg->nsip_listen_port,
+		VTY_NEWLINE);
+
+	return CMD_SUCCESS;
+}
+
+DEFUN(show_sgsn, show_sgsn_cmd, "show sgsn",
+      SHOW_STR "Display information about the SGSN")
+{
+	/* FIXME: iterate over list of NS-VC's and display their state */
+	struct gprs_ns_inst *nsi = g_cfg->nsi;
+	struct gprs_nsvc *nsvc;
+
+	llist_for_each_entry(nsvc, &nsi->gprs_nsvcs, list) {
+		vty_out(vty, "NSEI %5u, NS-VC %5u, %s-mode, %s %s%s",
+			nsvc->nsei, nsvc->nsvci,
+			nsvc->remote_end_is_sgsn ? "BSS" : "SGSN",
+			nsvc->state & NSE_S_ALIVE ? "ALIVE" : "DEAD",
+			nsvc->state & NSE_S_BLOCKED ? "BLOCKED" : "UNBLOCKED",
+			VTY_NEWLINE);
+		if (nsvc->nsi->ll == GPRS_NS_LL_UDP)
+			vty_out(vty, "  remote peer %s:%u%s",
+				inet_ntoa(nsvc->ip.bts_addr.sin_addr),
+				ntohs(nsvc->ip.bts_addr.sin_port), VTY_NEWLINE);
+	}
+
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_sgsn,
+      cfg_sgsn_cmd,
+      "sgsn",
+      "Configure the SGSN")
+{
+	vty->node = SGSN_NODE;
+	return CMD_SUCCESS;
+}
+
+
+DEFUN(cfg_nsip_local_ip,
+      cfg_nsip_local_ip_cmd,
+      "nsip local ip A.B.C.D",
+      "Set the IP address on which we listen for BSS connects")
+{
+	struct in_addr ia;
+
+	inet_aton(argv[0], &ia);
+	g_cfg->nsip_listen_ip = ntohl(ia.s_addr);
+
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_nsip_local_port,
+      cfg_nsip_local_port_cmd,
+      "nsip local port <0-65534>",
+      "Set the UDP port on which we listen for BSS connects")
+{
+	unsigned int port = atoi(argv[0]);
+
+	g_cfg->nsip_listen_port = port;
+	return CMD_SUCCESS;
+}
+
+
+
+
+int sgsn_vty_init(void)
+{
+	install_element(VIEW_NODE, &show_sgsn_cmd);
+
+	install_element(CONFIG_NODE, &cfg_sgsn_cmd);
+	install_node(&sgsn_node, config_write_sgsn);
+	install_default(SGSN_NODE);
+	install_element(SGSN_NODE, &cfg_nsip_local_ip_cmd);
+	install_element(SGSN_NODE, &cfg_nsip_local_port_cmd);
+
+	return 0;
+}
+
+int sgsn_parse_config(const char *config_file, struct sgsn_config *cfg)
+{
+	int rc;
+
+	g_cfg = cfg;
+	rc = vty_read_config_file(config_file);
+	if (rc < 0) {
+		fprintf(stderr, "Failed to parse the config file: '%s'\n", config_file);
+		return rc;
+	}
+
+	return 0;
+}