diff --git a/openbsc/include/openbsc/gprs_gsup_client.h b/openbsc/include/openbsc/gprs_gsup_client.h
index 9537db4..ccfa388 100644
--- a/openbsc/include/openbsc/gprs_gsup_client.h
+++ b/openbsc/include/openbsc/gprs_gsup_client.h
@@ -23,6 +23,8 @@
 
 #include <osmocom/core/timer.h>
 
+#include <openbsc/oap.h>
+
 #define GPRS_GSUP_RECONNECT_INTERVAL 10
 #define GPRS_GSUP_PING_INTERVAL 20
 
@@ -38,6 +40,8 @@ struct gprs_gsup_client {
 	gprs_gsup_read_cb_t	read_cb;
 	void			*data;
 
+	struct oap_state	oap_state;
+
 	struct osmo_timer_list	ping_timer;
 	struct osmo_timer_list	connect_timer;
 	int			is_connected;
@@ -46,7 +50,8 @@ struct gprs_gsup_client {
 
 struct gprs_gsup_client *gprs_gsup_client_create(const char *ip_addr,
 						 unsigned int tcp_port,
-						 gprs_gsup_read_cb_t read_cb);
+						 gprs_gsup_read_cb_t read_cb,
+						 struct oap_config *oap_config);
 
 void gprs_gsup_client_destroy(struct gprs_gsup_client *gsupc);
 int gprs_gsup_client_send(struct gprs_gsup_client *gsupc, struct msgb *msg);
diff --git a/openbsc/include/openbsc/sgsn.h b/openbsc/include/openbsc/sgsn.h
index d4f9913..2b1b97c 100644
--- a/openbsc/include/openbsc/sgsn.h
+++ b/openbsc/include/openbsc/sgsn.h
@@ -6,6 +6,7 @@
 
 #include <osmocom/gprs/gprs_ns.h>
 #include <openbsc/gprs_sgsn.h>
+#include <openbsc/oap.h>
 
 #include <ares.h>
 
@@ -61,6 +62,8 @@ struct sgsn_config {
 	} timers;
 
 	int dynamic_lookup;
+
+	struct oap_config oap;
 };
 
 struct sgsn_instance {
diff --git a/openbsc/src/gprs/gprs_gsup_client.c b/openbsc/src/gprs/gprs_gsup_client.c
index 1f9e34c..a332fa7 100644
--- a/openbsc/src/gprs/gprs_gsup_client.c
+++ b/openbsc/src/gprs/gprs_gsup_client.c
@@ -108,6 +108,20 @@ static void gsup_client_send(struct gprs_gsup_client *gsupc, int proto_ext, stru
 	/* msg_tx is now queued and will be freed. */
 }
 
+static void gsup_client_oap_register(struct gprs_gsup_client *gsupc)
+{
+	struct msgb *msg_tx;
+	int rc;
+	rc = oap_register(&gsupc->oap_state, &msg_tx);
+
+	if ((rc < 0) || (!msg_tx)) {
+		LOGP(DGPRS, LOGL_ERROR, "GSUP OAP set up, but cannot register.\n");
+		return;
+	}
+
+	gsup_client_send(gsupc, IPAC_PROTO_EXT_OAP, msg_tx);
+}
+
 static void gsup_client_updown_cb(struct ipa_client_conn *link, int up)
 {
 	struct gprs_gsup_client *gsupc = link->data;
@@ -120,6 +134,9 @@ static void gsup_client_updown_cb(struct ipa_client_conn *link, int up)
 	if (up) {
 		start_test_procedure(gsupc);
 
+		if (gsupc->oap_state.state == OAP_INITIALIZED)
+			gsup_client_oap_register(gsupc);
+
 		osmo_timer_del(&gsupc->connect_timer);
 	} else {
 		osmo_timer_del(&gsupc->ping_timer);
@@ -129,6 +146,22 @@ static void gsup_client_updown_cb(struct ipa_client_conn *link, int up)
 	}
 }
 
+static int gsup_client_oap_handle(struct gprs_gsup_client *gsupc, struct msgb *msg_rx)
+{
+	int rc;
+	struct msgb *msg_tx;
+
+	rc = oap_handle(&gsupc->oap_state, msg_rx, &msg_tx);
+	msgb_free(msg_rx);
+	if (rc < 0)
+		return rc;
+
+	if (msg_tx)
+		gsup_client_send(gsupc, IPAC_PROTO_EXT_OAP, msg_tx);
+
+	return 0;
+}
+
 static int gsup_client_read_cb(struct ipa_client_conn *link, struct msgb *msg)
 {
 	struct ipaccess_head *hh = (struct ipaccess_head *) msg->data;
@@ -168,16 +201,24 @@ static int gsup_client_read_cb(struct ipa_client_conn *link, struct msgb *msg)
 	if (hh->proto != IPAC_PROTO_OSMO)
 		goto invalid;
 
-	if (!he || msgb_l2len(msg) < sizeof(*he) ||
-	    he->proto != IPAC_PROTO_EXT_GSUP)
+	if (!he || msgb_l2len(msg) < sizeof(*he))
 		goto invalid;
 
 	msg->l2h = &he->data[0];
 
-	OSMO_ASSERT(gsupc->read_cb != NULL);
-	gsupc->read_cb(gsupc, msg);
+	if (he->proto == IPAC_PROTO_EXT_GSUP) {
+		OSMO_ASSERT(gsupc->read_cb != NULL);
+		gsupc->read_cb(gsupc, msg);
+		/* expecting read_cb() to free msg */
+	}
+	else
+	if (he->proto == IPAC_PROTO_EXT_OAP) {
+		return gsup_client_oap_handle(gsupc, msg);
+		/* gsup_client_oap_handle frees msg */
+	}
+	else
+		goto invalid;
 
-	/* Not freeing msg here, because that must be done by the read_cb. */
 	return 0;
 
 invalid:
@@ -222,7 +263,8 @@ static void start_test_procedure(struct gprs_gsup_client *gsupc)
 
 struct gprs_gsup_client *gprs_gsup_client_create(const char *ip_addr,
 						 unsigned int tcp_port,
-						 gprs_gsup_read_cb_t read_cb)
+						 gprs_gsup_read_cb_t read_cb,
+						 struct oap_config *oap_config)
 {
 	struct gprs_gsup_client *gsupc;
 	int rc;
@@ -230,6 +272,10 @@ struct gprs_gsup_client *gprs_gsup_client_create(const char *ip_addr,
 	gsupc = talloc_zero(tall_bsc_ctx, struct gprs_gsup_client);
 	OSMO_ASSERT(gsupc);
 
+	rc = oap_init(oap_config, &gsupc->oap_state);
+	if (rc != 0)
+		goto failed;
+
 	gsupc->link = ipa_client_conn_create(gsupc,
 					     /* no e1inp */ NULL,
 					     0,
diff --git a/openbsc/src/gprs/gprs_subscriber.c b/openbsc/src/gprs/gprs_subscriber.c
index 8231e8c..3467293 100644
--- a/openbsc/src/gprs/gprs_subscriber.c
+++ b/openbsc/src/gprs/gprs_subscriber.c
@@ -63,7 +63,8 @@ int gprs_subscr_init(struct sgsn_instance *sgi)
 
 	sgi->gsup_client = gprs_gsup_client_create(
 		addr_str, sgi->cfg.gsup_server_port,
-		&gsup_read_cb);
+		&gsup_read_cb,
+		&sgi->cfg.oap);
 
 	if (!sgi->gsup_client)
 		return -1;
diff --git a/openbsc/tests/sgsn/Makefile.am b/openbsc/tests/sgsn/Makefile.am
index 3c202dd..24504c2 100644
--- a/openbsc/tests/sgsn/Makefile.am
+++ b/openbsc/tests/sgsn/Makefile.am
@@ -28,6 +28,8 @@ sgsn_test_LDADD = \
 	$(top_builddir)/src/gprs/gprs_utils.o \
 	$(top_builddir)/src/gprs/gprs_subscriber.o \
 	$(top_builddir)/src/gprs/gsm_04_08_gprs.o \
+	$(top_builddir)/src/gprs/oap.o \
+	$(top_builddir)/src/gprs/oap_messages.o \
 	$(top_builddir)/src/libcommon/libcommon.a \
 	$(LIBOSMOABIS_LIBS) \
 	$(LIBOSMOCORE_LIBS) \
