diff --git a/include/openbsc/Makefile.am b/include/openbsc/Makefile.am
index 25709f1..89e0338 100644
--- a/include/openbsc/Makefile.am
+++ b/include/openbsc/Makefile.am
@@ -49,9 +49,9 @@
 	handover.h \
 	handover_decision.h \
 	ipaccess.h \
-	iu.h \
 	iucs.h \
 	iucs_ranap.h \
+	iu_dummy.h \
 	meas_feed.h \
 	meas_rep.h \
 	mgcp.h \
diff --git a/include/openbsc/gprs_sgsn.h b/include/openbsc/gprs_sgsn.h
index 4e49c08..57995e0 100644
--- a/include/openbsc/gprs_sgsn.h
+++ b/include/openbsc/gprs_sgsn.h
@@ -117,7 +117,7 @@
 	uint16_t pdp_status;
 };
 
-struct ue_conn_ctx;
+struct ranap_ue_conn_ctx;
 
 /* According to TS 03.60, Table 5: SGSN MM and PDP Contexts */
 /* Extended by 3GPP TS 23.060, Table 6: SGSN MM and PDP Contexts */
@@ -159,7 +159,7 @@
 		/* CSG Subscription Data */
 		/* LIPA Allowed */
 		/* Voice Support Match Indicator */
-		struct ue_conn_ctx	*ue_ctx;
+		struct ranap_ue_conn_ctx	*ue_ctx;
 		struct service_info	service;
 	} iu;
 	/* VLR number */
diff --git a/include/openbsc/gsm_data.h b/include/openbsc/gsm_data.h
index 43fc6d3..6079900 100644
--- a/include/openbsc/gsm_data.h
+++ b/include/openbsc/gsm_data.h
@@ -30,7 +30,7 @@
 struct bsc_subscr;
 struct vlr_instance;
 struct vlr_subscr;
-struct ue_conn_ctx;
+struct ranap_ue_conn_ctx;
 
 #define OBSC_LINKID_CB(__msgb)	(__msgb)->cb[3]
 
@@ -203,7 +203,7 @@
 
 	/* which Iu-CS connection, if any. */
 	struct {
-		struct ue_conn_ctx *ue_ctx;
+		struct ranap_ue_conn_ctx *ue_ctx;
 		uint8_t rab_id;
 	} iu;
 
@@ -493,7 +493,7 @@
 	struct {
 		/* CS7 instance id number (set via VTY) */
 		uint32_t cs7_instance;
-		enum nsap_addr_enc rab_assign_addr_enc;
+		int rab_assign_addr_enc;
 		struct osmo_sccp_instance *sccp;
 	} iu;
 
diff --git a/include/openbsc/iu.h b/include/openbsc/iu.h
deleted file mode 100644
index 08e4cd0..0000000
--- a/include/openbsc/iu.h
+++ /dev/null
@@ -1,77 +0,0 @@
-#pragma once
-
-#include <stdbool.h>
-#include <stdint.h>
-
-#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 gsm_auth_tuple;
-struct osmo_sccp_addr;
-struct osmo_ss7_instance;
-
-struct RANAP_RAB_SetupOrModifiedItemIEs_s;
-struct RANAP_GlobalRNC_ID;
-struct RANAP_Cause;
-
-/* Debugging switches from asn1c and osmo-iuh */
-extern int asn_debug;
-extern int asn1_xer_print;
-
-struct ue_conn_ctx {
-	struct llist_head list;
-	/* 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;
-	enum nsap_addr_enc rab_assign_addr_enc;
-};
-
-enum iu_event_type {
-	IU_EVENT_RAB_ASSIGN,
-	IU_EVENT_SECURITY_MODE_COMPLETE,
-	IU_EVENT_IU_RELEASE, /* An actual Iu Release message was received */
-	IU_EVENT_LINK_INVALIDATED, /* A SUA link was lost or closed down */
-};
-
-extern const struct value_string iu_event_type_names[];
-static inline const char *iu_event_type_str(enum iu_event_type e)
-{
-	return get_value_string(iu_event_type_names, e);
-}
-
-/* Implementations of iu_recv_cb_t shall find the ue_conn_ctx in msg->dst. */
-typedef int (* iu_recv_cb_t )(struct msgb *msg, struct gprs_ra_id *ra_id,
-			      uint16_t *sai);
-
-typedef int (* iu_event_cb_t )(struct ue_conn_ctx *ue_ctx,
-			       enum iu_event_type type, void *data);
-
-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, struct osmo_sccp_instance *sccp,
-	    iu_recv_cb_t iu_recv_cb, iu_event_cb_t iu_event_cb);
-
-int iu_tx(struct msgb *msg, uint8_t sapi);
-
-int iu_page_cs(const char *imsi, const uint32_t *tmsi, uint16_t lac);
-int iu_page_ps(const char *imsi, const uint32_t *ptmsi, uint16_t lac, uint8_t rac);
-
-int iu_rab_act(struct ue_conn_ctx *ue_ctx, struct msgb *msg);
-int iu_rab_deact(struct ue_conn_ctx *ue_ctx, uint8_t rab_id);
-int iu_tx_sec_mode_cmd(struct ue_conn_ctx *uectx, struct gsm_auth_tuple *tp,
-		       int send_ck, int new_key);
-int iu_tx_common_id(struct ue_conn_ctx *ue_ctx, const char *imsi);
-int iu_tx_release(struct ue_conn_ctx *ctx, const struct RANAP_Cause *cause);
-
-void iu_vty_init(int iu_parent_node, enum nsap_addr_enc *rab_assign_addr_enc);
-int iu_vty_config_write(struct vty *vty, const char *indent);
diff --git a/include/openbsc/iu_dummy.h b/include/openbsc/iu_dummy.h
new file mode 100644
index 0000000..d5e1428
--- /dev/null
+++ b/include/openbsc/iu_dummy.h
@@ -0,0 +1,51 @@
+/* Trivial switch-off of external Iu dependencies,
+ * allowing to run full unit tests even when built without Iu support. */
+
+/*
+ * (C) 2016,2017 by sysmocom s.f.m.c. GmbH <info@sysmocom.de>
+ *
+ * Author: Neels Hofmeyr <nhofmeyr@sysmocom.de>
+ *
+ * All Rights Reserved
+ *
+ * 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/>.
+ *
+ */
+
+#include <stdint.h>
+#include <stdbool.h>
+
+#include <osmocom/core/linuxlist.h>
+
+struct msgb;
+struct gsm_auth_tuple;
+struct RANAP_Cause;
+struct osmo_auth_vector;
+
+struct ranap_ue_conn_ctx {
+	struct llist_head list;
+	uint32_t conn_id;
+};
+
+int ranap_iu_tx(struct msgb *msg, uint8_t sapi);
+int ranap_iu_tx_sec_mode_cmd(struct ranap_ue_conn_ctx *uectx, struct osmo_auth_vector *vec,
+			     int send_ck);
+int ranap_iu_page_cs(const char *imsi, const uint32_t *tmsi, uint16_t lac);
+int ranap_iu_page_ps(const char *imsi, const uint32_t *ptmsi, uint16_t lac, uint8_t rac);
+struct msgb *ranap_new_msg_rab_assign_voice(uint8_t rab_id, uint32_t rtp_ip,
+					    uint16_t rtp_port,
+					    bool use_x213_nsap);
+int ranap_iu_rab_act(struct ranap_ue_conn_ctx *ue_ctx, struct msgb *msg);
+int ranap_iu_tx_common_id(struct ranap_ue_conn_ctx *uectx, const char *imsi);
+int ranap_iu_tx_release(struct ranap_ue_conn_ctx *ctx, const struct RANAP_Cause *cause);
diff --git a/include/openbsc/iucs.h b/include/openbsc/iucs.h
index fb61a5c..b7d6064 100644
--- a/include/openbsc/iucs.h
+++ b/include/openbsc/iucs.h
@@ -4,4 +4,4 @@
 			uint16_t *lac);
 
 struct gsm_subscriber_connection *subscr_conn_lookup_iu(struct gsm_network *network,
-							struct ue_conn_ctx *ue);
+							struct ranap_ue_conn_ctx *ue);
diff --git a/include/openbsc/iucs_ranap.h b/include/openbsc/iucs_ranap.h
index 748de23..c2ff5f9 100644
--- a/include/openbsc/iucs_ranap.h
+++ b/include/openbsc/iucs_ranap.h
@@ -1,7 +1,7 @@
 #pragma once
 
 struct gsm_network;
-struct ue_conn_ctx;
+struct ranap_ue_conn_ctx;
 
 int iucs_rx_ranap_event(struct gsm_network *network,
-			struct ue_conn_ctx *ue_ctx, int type, void *data);
+			struct ranap_ue_conn_ctx *ue_ctx, int type, void *data);
diff --git a/include/openbsc/sgsn.h b/include/openbsc/sgsn.h
index 57b2978..f371dc6 100644
--- a/include/openbsc/sgsn.h
+++ b/include/openbsc/sgsn.h
@@ -112,7 +112,7 @@
 	} dcomp_v42bis;
 
 	struct {
-		enum nsap_addr_enc rab_assign_addr_enc;
+		int rab_assign_addr_enc;
 	} iu;
 };