diff --git a/openbsc/src/gprs_sgsn.c b/openbsc/src/gprs_sgsn.c
index 477e448..3f7f61e 100644
--- a/openbsc/src/gprs_sgsn.c
+++ b/openbsc/src/gprs_sgsn.c
@@ -26,7 +26,10 @@
 #include <osmocore/talloc.h>
 #include <osmocore/timer.h>
 #include <openbsc/gsm_subscriber.h>
+#include <openbsc/debug.h>
 #include <openbsc/gprs_sgsn.h>
+#include <openbsc/gprs_ns.h>
+#include <openbsc/gprs_bssgp.h>
 
 static LLIST_HEAD(sgsn_mm_ctxts);
 
@@ -91,3 +94,35 @@
 
 	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);
+}