diff --git a/bts/BTS_Tests_OML.ttcn b/bts/BTS_Tests_OML.ttcn
index 40fb5cd..4a58312 100644
--- a/bts/BTS_Tests_OML.ttcn
+++ b/bts/BTS_Tests_OML.ttcn
@@ -696,30 +696,30 @@
 	IPA_OSMO_PCU.receive(tr_ASP_IPA_EV(ASP_IPA_EVENT_ID_RESP));
 	IPA_OSMO_PCU.receive(tr_ASP_IPA_EV(ASP_IPA_EVENT_ID_ACK));
 
-	IPA_OSMO_PCU.send(ts_PCUIF_CONTAINER(0, ts_PCUIF_CONT_OTHER(100, payloadReq)))
+	IPA_OSMO_PCU.send(ts_PCUIF_CONTAINER(0, ts_PCUIF_CONT_OTHER(PCU_IF_MSG_NEIGH_ADDR_REQ, payloadReq)))
 	T.start;
 	alt {
-	[] PCU.receive(t_SD_PCUIF(g_pcu_conn_id, tr_PCUIF_CONTAINER(0, tr_PCUIF_CONT_OTHER(100, payloadReq)))) {
+	[] PCU.receive(t_SD_PCUIF(g_pcu_conn_id, tr_PCUIF_CONTAINER(0, tr_PCUIF_CONT_OTHER(PCU_IF_MSG_NEIGH_ADDR_REQ, payloadReq)))) {
 		setverdict(pass);
 		}
 	[] PCU.receive(PCUIF_send_data:?) -> value pcu_sd_msg {
 		setverdict(fail, "Unexpected message received: ", pcu_sd_msg.data, " vs exp: ",
-			   t_SD_PCUIF(g_pcu_conn_id, tr_PCUIF_CONTAINER(0, tr_PCUIF_CONT_OTHER(100, payloadReq))));
+			   t_SD_PCUIF(g_pcu_conn_id, tr_PCUIF_CONTAINER(0, tr_PCUIF_CONT_OTHER(PCU_IF_MSG_NEIGH_ADDR_REQ, payloadReq))));
 	}
 	[] T.timeout { setverdict(fail, "Timeout waiting for ANR request on PCU inteface");}
 	}
 	T.stop;
 
 	/* Send back the response: */
-	PCU.send(t_SD_PCUIF(g_pcu_conn_id, ts_PCUIF_CONTAINER(0, ts_PCUIF_CONT_OTHER(100, payloadRep))))
+	PCU.send(t_SD_PCUIF(g_pcu_conn_id, ts_PCUIF_CONTAINER(0, ts_PCUIF_CONT_OTHER(PCU_IF_MSG_NEIGH_ADDR_REQ, payloadRep))))
 	T.start;
 	alt {
-	[] IPA_OSMO_PCU.receive(tr_PCUIF_CONTAINER(0, tr_PCUIF_CONT_OTHER(100, payloadRep))) {
+	[] IPA_OSMO_PCU.receive(tr_PCUIF_CONTAINER(0, tr_PCUIF_CONT_OTHER(PCU_IF_MSG_NEIGH_ADDR_REQ, payloadRep))) {
 		setverdict(pass);
 		}
 	[] IPA_OSMO_PCU.receive(PCUIF_Message:?) -> value msg_rx {
 		setverdict(fail, "Unexpected message received: ", msg_rx, " vs exp: ",
-			   tr_PCUIF_CONTAINER(0, tr_PCUIF_CONT_OTHER(100, payloadRep)));
+			   tr_PCUIF_CONTAINER(0, tr_PCUIF_CONT_OTHER(PCU_IF_MSG_NEIGH_ADDR_REQ, payloadRep)));
 	}
 	[] T.timeout { setverdict(fail, "Timeout waiting for ANR request on BSC inteface"); }
 	}
diff --git a/library/Osmocom_CTRL_Adapter.ttcn b/library/Osmocom_CTRL_Adapter.ttcn
index 34ea300..6a9706e 100644
--- a/library/Osmocom_CTRL_Adapter.ttcn
+++ b/library/Osmocom_CTRL_Adapter.ttcn
@@ -22,6 +22,7 @@
 
 type component CTRL_Adapter_CT {
 	var IPA_Emulation_CT vc_CTRL_IPA;
+	var boolean ipa_is_up := false;
 	/* test port for the CTRL interface of the BSC */
 	port IPA_CTRL_PT IPA_CTRL;
 }
@@ -29,10 +30,13 @@
 /* wait for IPA CTRL link to connect and send UP */
 function f_ipa_ctrl_wait_link_up()
 runs on CTRL_Adapter_CT {
+	if (ipa_is_up == true) {
+		return;
+	}
 	timer T := 10.0;
 	T.start;
 	alt {
-	[] IPA_CTRL.receive(tr_ASP_IPA_EV(ASP_IPA_EVENT_UP)) { }
+	[] IPA_CTRL.receive(tr_ASP_IPA_EV(ASP_IPA_EVENT_UP)) { ipa_is_up := true; }
 	[] T.timeout {
 		setverdict(fail, "Timeout CTRL waiting for ASP_IPA_EVENT_UP");
 		mtc.stop;
@@ -40,13 +44,16 @@
 	}
 }
 
-/* wait for IPA CTRL link to connect and send UP */
+/* wait for IPA CTRL link to connect and send DOWN */
 function f_ipa_ctrl_wait_link_down()
 runs on CTRL_Adapter_CT {
+	if (ipa_is_up == false) {
+		return;
+	}
 	timer T := 10.0;
 	T.start;
 	alt {
-	[] IPA_CTRL.receive(tr_ASP_IPA_EV(ASP_IPA_EVENT_DOWN)) { }
+	[] IPA_CTRL.receive(tr_ASP_IPA_EV(ASP_IPA_EVENT_DOWN)) { ipa_is_up := false; }
 	[] T.timeout {
 		setverdict(fail, "Timeout CTRL waiting for ASP_IPA_EVENT_DOWN");
 		mtc.stop;
diff --git a/library/PCUIF_Types.ttcn b/library/PCUIF_Types.ttcn
index 1e57fb2..dcae4e6 100644
--- a/library/PCUIF_Types.ttcn
+++ b/library/PCUIF_Types.ttcn
@@ -38,7 +38,10 @@
 	PCU_IF_MSG_INTERF_IND		('53'O),
 	PCU_IF_MSG_PAG_REQ		('60'O),
 	PCU_IF_MSG_TXT_IND		('70'O),
-	PCU_IF_MSG_CONTAINER		('80'O)
+	PCU_IF_MSG_CONTAINER		('80'O),
+	/* Container payload message types: */
+	PCU_IF_MSG_NEIGH_ADDR_REQ	('81'O),
+	PCU_IF_MSG_NEIGH_ADDR_CNF	('82'O)
 } with { variant "FIELDLENGTH(8)" };
 
 type enumerated PCUIF_Sapi {
@@ -254,15 +257,37 @@
 	variant (tlli) "BYTEORDER(last)"
 };
 
+type record PCUIF_neigh_addr_req {
+	uint16_t	local_lac,
+	uint16_t	local_ci,
+	uint16_t	tgt_arfcn,
+	uint8_t		tgt_bsic
+} with { variant (local_lac) "BYTEORDER(last)"
+	 variant (local_ci) "BYTEORDER(last)"
+	 variant (tgt_arfcn) "BYTEORDER(last)" };
+
+type record PCUIF_neigh_addr_cnf {
+	PCUIF_neigh_addr_req orig_req,
+	uint8_t 	error_code,
+	uint16_t	mcc,
+	uint16_t	mnc,
+	uint8_t		mnc_3_digits,
+	uint16_t	lac,
+	uint8_t		rac,
+	uint16_t	cell_identity
+} with { variant (mcc) "BYTEORDER(last)"
+	 variant (mnc) "BYTEORDER(last)"
+	 variant (lac) "BYTEORDER(last)"
+	 variant (cell_identity) "BYTEORDER(last)" };
+
 type union PCUIF_ContainerMsgUnion {
-	 /* This field can be removed once first container message is added, see
-	  * https://bugs.eclipse.org/bugs/show_bug.cgi?id=574469 */
-	octetstring tmp_fixme,
+	PCUIF_neigh_addr_req	neigh_addr_req,
+	PCUIF_neigh_addr_cnf	neigh_addr_cnf,
 	octetstring	other
 } with { variant "" };
 
 type record PCUIF_container {
-	uint8_t		msg_type,
+	PCUIF_MsgType	msg_type,
 	OCT1		spare,
 	uint16_t	len, /* network byte order */
 	PCUIF_ContainerMsgUnion	u
@@ -270,7 +295,8 @@
 	variant (len) "BYTEORDER(last)"
 	variant (len) "LENGTHTO(u)"
 	variant (u) "CROSSTAG(
-			tmp_fixme, 	msg_type = 255;
+			neigh_addr_req,	msg_type = PCU_IF_MSG_NEIGH_ADDR_REQ;
+			neigh_addr_cnf,	msg_type = PCU_IF_MSG_NEIGH_ADDR_CNF;
 			other,		OTHERWISE)"
 };
 
@@ -1026,7 +1052,7 @@
 	}
 }
 
-template (value) PCUIF_container ts_PCUIF_CONT_OTHER(uint8_t msg_type, template (value) octetstring payload) := {
+template (value) PCUIF_container ts_PCUIF_CONT_OTHER(PCUIF_MsgType msg_type, template (value) octetstring payload) := {
 	msg_type := msg_type,
 	spare := '00'O,
 	len := lengthof(payload),
@@ -1034,7 +1060,7 @@
 		other := payload
 	}
 }
-template (present) PCUIF_container tr_PCUIF_CONT_OTHER(template (present) uint8_t msg_type,
+template (present) PCUIF_container tr_PCUIF_CONT_OTHER(template (present) PCUIF_MsgType msg_type,
 						       template (present) octetstring payload) := {
 	msg_type := msg_type,
 	spare := '00'O,
@@ -1044,6 +1070,77 @@
 	}
 }
 
+template (present) PCUIF_container tr_PCUIF_CONT_NEIGH_ADDR_REQ(template (present) uint16_t local_lac := ?,
+								template (present) uint16_t local_ci := ?,
+								template (present) uint16_t tgt_arfcn := ?,
+								template (present) uint8_t tgt_bsic := ?) := {
+	msg_type := PCU_IF_MSG_NEIGH_ADDR_REQ,
+	spare := '00'O,
+	len := ?,
+	u := {
+		neigh_addr_req := {
+			local_lac := local_lac,
+			local_ci := local_ci,
+			tgt_arfcn := tgt_arfcn,
+			tgt_bsic := tgt_bsic
+		}
+	}
+}
+template (present) PCUIF_Message tr_PCUIF_NEIGH_ADDR_REQ(template (present) uint8_t bts_nr,
+								template (present) uint16_t local_lac := ?,
+								template (present) uint16_t local_ci := ?,
+								template (present) uint16_t tgt_arfcn := ?,
+								template (present) uint8_t tgt_bsic := ?) := {
+	msg_type := PCU_IF_MSG_CONTAINER,
+	bts_nr := bts_nr,
+	spare := '0000'O,
+	u := {
+		container := tr_PCUIF_CONT_NEIGH_ADDR_REQ(local_lac, local_ci, tgt_arfcn, tgt_bsic)
+	}
+}
+
+template (value) PCUIF_container ts_PCUIF_CONT_NEIGH_ADDR_CNF(template (value) PCUIF_neigh_addr_req orig_req,
+							template (value) uint8_t error_code := 0,
+							template (value) uint16_t mcc := 0,
+							template (value) uint16_t mnc := 0,
+							template (value) uint8_t mnc_3_digits := 0,
+							template (value) uint16_t lac := 0,
+							template (value) uint8_t rac := 0,
+							template (value) uint16_t cell_identity := 0) := {
+	msg_type := PCU_IF_MSG_NEIGH_ADDR_CNF,
+	spare := '00'O,
+	len := 0, /* overwritten */
+	u := {
+		neigh_addr_cnf := {
+			orig_req := orig_req,
+			error_code := error_code,
+			mcc := mcc,
+			mnc := mnc,
+			mnc_3_digits := mnc_3_digits,
+			lac := lac,
+			rac := rac,
+			cell_identity := cell_identity
+		}
+	}
+}
+template (value) PCUIF_Message ts_PCUIF_NEIGH_ADDR_CNF(template (value) uint8_t bts_nr,
+							template (value) PCUIF_neigh_addr_req orig_req,
+							template (value) uint8_t error_code := 0,
+							template (value) uint16_t mcc := 0,
+							template (value) uint16_t mnc := 0,
+							template (value) uint8_t mnc_3_digits := 0,
+							template (value) uint16_t lac := 0,
+							template (value) uint8_t rac := 0,
+							template (value) uint16_t cell_identity := 0) := {
+	msg_type := PCU_IF_MSG_CONTAINER,
+	bts_nr := bts_nr,
+	spare := '0000'O,
+	u := {
+		container := ts_PCUIF_CONT_NEIGH_ADDR_CNF(orig_req, error_code, mcc, mnc, mnc_3_digits,
+							  lac, rac, cell_identity)
+	}
+}
+
 function f_PCUIF_PDCHMask_set(inout PCUIF_info_ind info, BIT8 pdch_mask,
 			      template (present) uint8_t trx_nr := ?)
 {
diff --git a/pcu/PCU_Tests.ttcn b/pcu/PCU_Tests.ttcn
index c23e58c..15c451b 100644
--- a/pcu/PCU_Tests.ttcn
+++ b/pcu/PCU_Tests.ttcn
@@ -69,7 +69,7 @@
 	charstring mp_pcu_statsd_ip := "127.0.0.1";
 	integer mp_pcu_statsd_port := 8125;
 
-	charstring mp_ctrl_neigh_ip := "127.0.0.1";
+	charstring mp_ctrl_neigh_ip := ""; /* Use new PCUIF over IPA multiplex for Neigh Addr Resolution */
 	integer mp_ctrl_neigh_port := 4248;
 
 	boolean mp_osmo_pcu_newer_than_0_9_0 := true; /* Drop after OsmoPCU > 0.9.0 was released */
@@ -4391,10 +4391,35 @@
 	}
 }
 
+private function f_handle_nacc_rac_ci_query(PCUIF_info_ind info_ind, GsmArfcn req_arfcn, uint6_t req_bsic,
+					   boolean answer := true, boolean use_old_ctrl_iface := false)
+runs on RAW_PCU_Test_CT {
+	if (use_old_ctrl_iface == true) {
+		f_ipa_ctrl_wait_link_up();
+		var charstring ctrl_var := "neighbor_resolve_cgi_ps_from_lac_ci." &
+					    int2str(info_ind.lac) & "." &
+					    int2str(info_ind.cell_id) & "." &
+					    int2str(req_arfcn) & "." &
+					    int2str(req_bsic);
+		if (answer) {
+			f_ctrl_exp_get(IPA_CTRL, ctrl_var, "023-43-423-2-5");
+		} else {
+			f_ctrl_exp_get(IPA_CTRL, ctrl_var, omit);
+		}
+	} else {
+		var PCUIF_Message pcu_msg;
+		BTS.receive(tr_PCUIF_NEIGH_ADDR_REQ(0, info_ind.lac, info_ind.cell_id, req_arfcn, req_bsic)) -> value pcu_msg;
+		if (answer) {
+			BTS.send(ts_PCUIF_NEIGH_ADDR_CNF(0, pcu_msg.u.container.u.neigh_addr_req, 0, 23, 43, 0, 423, 2, 5));
+		}
+	}
+}
+
 /* Start NACC from MS side */
 private function f_outbound_nacc_success(inout GprsMS ms, PCUIF_info_ind info_ind,
 					 boolean exp_rac_ci_query := true, boolean exp_si_query := true,
-					 boolean skip_final_ctrl_ack := false)
+					 boolean skip_final_ctrl_ack := false,
+					 boolean use_old_ctrl_iface := false)
 runs on RAW_PCU_Test_CT {
 	var template (value) RlcmacUlCtrlMsg cell_chf_notif;
 	var RlcmacDlBlock dl_block;
@@ -4408,13 +4433,7 @@
 
 	if (exp_rac_ci_query == true) {
 		/* osmo-pcu should now ask for resolution: */
-		f_ipa_ctrl_wait_link_up();
-		var charstring ctrl_var := "neighbor_resolve_cgi_ps_from_lac_ci." &
-					    int2str(info_ind.lac) & "." &
-					    int2str(info_ind.cell_id) & "." &
-					    int2str(req_arfcn) & "." &
-					    int2str(req_bsic);
-		f_ctrl_exp_get(IPA_CTRL, ctrl_var, "023-43-423-2-5");
+		f_handle_nacc_rac_ci_query(info_ind, req_arfcn, req_bsic, true, use_old_ctrl_iface);
 	}
 
 	if (exp_si_query == true) {
@@ -4443,9 +4462,12 @@
 	var PollFnCtx pollctx;
 	var GprsMS ms;
 	var PCUIF_info_ind info_ind := valueof(ts_PCUIF_INFO_default);
+	var boolean use_old_ctrl_iface := mp_ctrl_neigh_ip != "";
 
-	/* Initialize osmo-bsc emulation neighbor resolution CTRL port */
-	f_ipa_ctrl_start_server(mp_ctrl_neigh_ip, mp_ctrl_neigh_port);
+	if (use_old_ctrl_iface) {
+		/* Initialize osmo-bsc emulation neighbor resolution CTRL port */
+		f_ipa_ctrl_start_server(mp_ctrl_neigh_ip, mp_ctrl_neigh_port);
+	}
 
 	/* Initialize NS/BSSGP side */
 	f_init_bssgp();
@@ -4469,7 +4491,7 @@
 	f_ms_tx_ul_block(ms, ts_RLCMAC_CTRL_ACK(ms.tlli), pollctx.fn, nr := pollctx.tstrxbts);
 
 	/* Start NACC from MS side */
-	f_outbound_nacc_success(ms, info_ind);
+	f_outbound_nacc_success(ms, info_ind, use_old_ctrl_iface := use_old_ctrl_iface);
 
 	f_shutdown(__BFILE__, __LINE__, final := true);
 }
@@ -4481,9 +4503,12 @@
 	var RlcmacDlBlock dl_block;
 	var uint32_t sched_fn;
 	var PCUIF_info_ind info_ind := valueof(ts_PCUIF_INFO_default);
+	var boolean use_old_ctrl_iface := mp_ctrl_neigh_ip != "";
 
-	/* Initialize osmo-bsc emulation neighbor resolution CTRL port */
-	f_ipa_ctrl_start_server(mp_ctrl_neigh_ip, mp_ctrl_neigh_port);
+	if (use_old_ctrl_iface) {
+		/* Initialize osmo-bsc emulation neighbor resolution CTRL port */
+		f_ipa_ctrl_start_server(mp_ctrl_neigh_ip, mp_ctrl_neigh_port);
+	}
 
 	/* Initialize NS/BSSGP side */
 	f_init_bssgp();
@@ -4507,7 +4532,7 @@
 	f_ms_tx_ul_block(ms, ts_RLCMAC_CTRL_ACK(ms.tlli), pollctx.fn, nr := pollctx.tstrxbts);
 
 	/* Start NACC from MS side, avoid sending final CTRL ACK */
-	f_outbound_nacc_success(ms, info_ind, skip_final_ctrl_ack := true);
+	f_outbound_nacc_success(ms, info_ind, skip_final_ctrl_ack := true, use_old_ctrl_iface := use_old_ctrl_iface);
 
 	/* Wait until we receive something non-dummy */
 	dl_block := f_skip_dummy(0, sched_fn);
@@ -4530,9 +4555,12 @@
 	var GprsMS ms;
 	var PCUIF_info_ind info_ind := valueof(ts_PCUIF_INFO_default);
 	var template (value) RlcmacUlCtrlMsg cell_chf_notif;
+	var boolean use_old_ctrl_iface := mp_ctrl_neigh_ip != "";
 
-	/* Initialize osmo-bsc emulation neighbor resolution CTRL port */
-	f_ipa_ctrl_start_server(mp_ctrl_neigh_ip, mp_ctrl_neigh_port);
+	if (use_old_ctrl_iface) {
+		/* Initialize osmo-bsc emulation neighbor resolution CTRL port */
+		f_ipa_ctrl_start_server(mp_ctrl_neigh_ip, mp_ctrl_neigh_port);
+	}
 
 	/* Initialize NS/BSSGP side */
 	f_init_bssgp();
@@ -4558,10 +4586,10 @@
 	f_ms_tx_ul_block(ms, ts_RLCMAC_CTRL_ACK(ms.tlli), pollctx.fn, nr := pollctx.tstrxbts);
 
 	/* Start NACC from MS side */
-	f_outbound_nacc_success(ms, info_ind);
+	f_outbound_nacc_success(ms, info_ind, use_old_ctrl_iface := use_old_ctrl_iface);
 
 	/* First NACC procedure is done, let's try to start a new one now that previous queries are cached: */
-	f_outbound_nacc_success(ms, info_ind, false, false);
+	f_outbound_nacc_success(ms, info_ind, false, false, use_old_ctrl_iface := use_old_ctrl_iface);
 
 	f_shutdown(__BFILE__, __LINE__, final := true);
 }
@@ -4574,9 +4602,12 @@
 	var GprsMS ms;
 	var PCUIF_info_ind info_ind := valueof(ts_PCUIF_INFO_default);
 	var template (value) RlcmacUlCtrlMsg cell_chf_notif;
+	var boolean use_old_ctrl_iface := mp_ctrl_neigh_ip != "";
 
-	/* Initialize osmo-bsc emulation neighbor resolution CTRL port */
-	f_ipa_ctrl_start_server(mp_ctrl_neigh_ip, mp_ctrl_neigh_port);
+	if (use_old_ctrl_iface) {
+		/* Initialize osmo-bsc emulation neighbor resolution CTRL port */
+		f_ipa_ctrl_start_server(mp_ctrl_neigh_ip, mp_ctrl_neigh_port);
+	}
 
 	/* Initialize NS/BSSGP side */
 	f_init_bssgp();
@@ -4602,14 +4633,14 @@
 	f_ms_tx_ul_block(ms, ts_RLCMAC_CTRL_ACK(ms.tlli), pollctx.fn, nr := pollctx.tstrxbts);
 
 	/* Start NACC from MS side */
-	f_outbound_nacc_success(ms, info_ind);
+	f_outbound_nacc_success(ms, info_ind, use_old_ctrl_iface := use_old_ctrl_iface);
 
 	/* CTRL client should have disconnected from us */
 	f_ipa_ctrl_wait_link_down();
 	/* wait for cache entries to time out */
 	f_sleep(2.0);
 	/* First NACC procedure is done, let's try to start a new one now that previous queries have timed out: */
-	f_outbound_nacc_success(ms, info_ind);
+	f_outbound_nacc_success(ms, info_ind, use_old_ctrl_iface := use_old_ctrl_iface);
 
 	f_shutdown(__BFILE__, __LINE__, final := true);
 }
@@ -4680,9 +4711,12 @@
 	var PCUIF_info_ind info_ind := valueof(ts_PCUIF_INFO_default);
 	var GsmArfcn req_arfcn := 862;
 	var uint6_t req_bsic := 43;
+	var boolean use_old_ctrl_iface := mp_ctrl_neigh_ip != "";
 
-	/* Initialize osmo-bsc emulation neighbor resolution CTRL port */
-	f_ipa_ctrl_start_server(mp_ctrl_neigh_ip, mp_ctrl_neigh_port);
+	if (use_old_ctrl_iface) {
+		/* Initialize osmo-bsc emulation neighbor resolution CTRL port */
+		f_ipa_ctrl_start_server(mp_ctrl_neigh_ip, mp_ctrl_neigh_port);
+	}
 
 	/* Initialize NS/BSSGP side */
 	f_init_bssgp();
@@ -4710,14 +4744,8 @@
 	f_ms_tx_ul_block(ms, ts_RLC_UL_CTRL_ACK(cell_chf_notif), 0, nr := f_ms_tx_TsTrxBtsNum(ms));
 
 	/* osmo-pcu should now ask for resolution: */
-	f_ipa_ctrl_wait_link_up();
-	var charstring ctrl_var := "neighbor_resolve_cgi_ps_from_lac_ci." &
-				    int2str(info_ind.lac) & "." &
-				    int2str(info_ind.cell_id) & "." &
-				    int2str(req_arfcn) & "." &
-				    int2str(req_bsic);
 	/* we receive RAC+CI resolution request, but we never answer to it, timeout should occur */
-	f_ctrl_exp_get(IPA_CTRL, ctrl_var, omit);
+	f_handle_nacc_rac_ci_query(info_ind, req_arfcn, req_bsic, false, use_old_ctrl_iface);
 
 	/* Wait until we receive something non-dummy */
 	dl_block := f_skip_dummy(0, sched_fn);
@@ -4780,7 +4808,7 @@
 				    int2str(info_ind.cell_id) & "." &
 				    int2str(req_arfcn) & "." &
 				    int2str(req_bsic);
-	/* we receive RAC+CI resolution request and we send incorrectlt formated response */
+	/* we receive RAC+CI resolution request and we send incorrectly formated response */
 	f_ctrl_exp_get(IPA_CTRL, ctrl_var, "foobar-error");
 
 	/* Wait until we receive something non-dummy */
@@ -4808,6 +4836,7 @@
 	var PCUIF_info_ind info_ind := valueof(ts_PCUIF_INFO_default);
 	var GsmArfcn req_arfcn := 862;
 	var uint6_t req_bsic := 43;
+	var boolean use_old_ctrl_iface := mp_ctrl_neigh_ip != "";
 	var BssgpCellId src := valueof(ts_BssgpCellId(ts_RAI(ts_LAI(f_enc_BcdMccMnc(info_ind.mcc, info_ind.mnc, info_ind.mnc_3_digits == 1), /* '262F42'H */
 								    info_ind.lac),
 							     info_ind.rac),
@@ -4819,8 +4848,10 @@
 	var template RIM_Routing_Address src_addr := t_RIM_Routing_Address_cid(src);
 	var template RIM_Routing_Address dst_addr := t_RIM_Routing_Address_cid(dst);
 
-	/* Initialize osmo-bsc emulation neighbor resolution CTRL port */
-	f_ipa_ctrl_start_server(mp_ctrl_neigh_ip, mp_ctrl_neigh_port);
+	if (use_old_ctrl_iface) {
+		/* Initialize osmo-bsc emulation neighbor resolution CTRL port */
+		f_ipa_ctrl_start_server(mp_ctrl_neigh_ip, mp_ctrl_neigh_port);
+	}
 
 	/* Initialize NS/BSSGP side */
 	f_init_bssgp();
@@ -4848,13 +4879,7 @@
 	f_ms_tx_ul_block(ms, ts_RLC_UL_CTRL_ACK(cell_chf_notif), 0, nr := f_ms_tx_TsTrxBtsNum(ms));
 
 	/* osmo-pcu should now ask for resolution: */
-	f_ipa_ctrl_wait_link_up();
-	var charstring ctrl_var := "neighbor_resolve_cgi_ps_from_lac_ci." &
-				    int2str(info_ind.lac) & "." &
-				    int2str(info_ind.cell_id) & "." &
-				    int2str(req_arfcn) & "." &
-				    int2str(req_bsic);
-	f_ctrl_exp_get(IPA_CTRL, ctrl_var, "023-43-423-2-5");
+	f_handle_nacc_rac_ci_query(info_ind, req_arfcn, req_bsic, true, use_old_ctrl_iface);
 
 	/* RIM procedure: */
 	RIM.receive(tr_RAN_INFORMATION_REQUEST(tr_RIM_Routing_Information(RIM_ADDR_GERAN_CELL_ID, dst_addr),
@@ -4886,11 +4911,16 @@
 	var RlcmacDlBlock dl_block;
 	var uint32_t sched_fn;
 	var CtrlMessage rx_ctrl;
+	var charstring ctrl_var;
+	var PCUIF_Message pcu_msg;
 	var GsmArfcn req_arfcn := 862;
 	var uint6_t req_bsic := 43;
+	var boolean use_old_ctrl_iface := mp_ctrl_neigh_ip != "";
 
-	/* Initialize osmo-bsc emulation neighbor resolution CTRL port */
-	f_ipa_ctrl_start_server(mp_ctrl_neigh_ip, mp_ctrl_neigh_port);
+	if (use_old_ctrl_iface) {
+		/* Initialize osmo-bsc emulation neighbor resolution CTRL port */
+		f_ipa_ctrl_start_server(mp_ctrl_neigh_ip, mp_ctrl_neigh_port);
+	}
 
 	/* Initialize NS/BSSGP side */
 	f_init_bssgp();
@@ -4918,25 +4948,40 @@
 	f_ms_tx_ul_block(ms, ts_RLC_UL_CTRL_ACK(cell_chf_notif), 0, nr := f_ms_tx_TsTrxBtsNum(ms));
 
 	/* osmo-pcu should now ask for resolution: */
-	f_ipa_ctrl_wait_link_up();
-	var charstring ctrl_var := "neighbor_resolve_cgi_ps_from_lac_ci." &
-				    int2str(info_ind.lac) & "." &
-				    int2str(info_ind.cell_id) & "." &
-				    int2str(req_arfcn) & "." &
-				    int2str(req_bsic);
-	IPA_CTRL.receive(tr_CtrlMsgGet(?, ctrl_var)) -> value rx_ctrl;
+	if (use_old_ctrl_iface) {
+		f_ipa_ctrl_wait_link_up();
+		ctrl_var := "neighbor_resolve_cgi_ps_from_lac_ci." &
+			    int2str(info_ind.lac) & "." &
+			    int2str(info_ind.cell_id) & "." &
+			    int2str(req_arfcn) & "." &
+			    int2str(req_bsic);
+		IPA_CTRL.receive(tr_CtrlMsgGet(?, ctrl_var)) -> value rx_ctrl;
+	} else {
+		BTS.receive(tr_PCUIF_NEIGH_ADDR_REQ(0, info_ind.lac, info_ind.cell_id, req_arfcn, req_bsic)) -> value pcu_msg;
+	}
+
 	/* Before receiving CTRL response, MS retransmits Pkt cell Chg Notif */
 	f_ms_tx_ul_block(ms, ts_RLC_UL_CTRL_ACK(cell_chf_notif), 0, nr := f_ms_tx_TsTrxBtsNum(ms));
 	f_sleep(0.2); /* let some time to avoid race conditons between CTRL and RLCMAC */
-	IPA_CTRL.send(ts_CtrlMsgGetRepl(rx_ctrl.cmd.id, valueof(ctrl_var), valueof("023-43-423-2-5")));
+
+	if (use_old_ctrl_iface) {
+		IPA_CTRL.send(ts_CtrlMsgGetRepl(rx_ctrl.cmd.id, valueof(ctrl_var), valueof("023-43-423-2-5")));
+	} else {
+		BTS.send(ts_PCUIF_NEIGH_ADDR_CNF(0, pcu_msg.u.container.u.neigh_addr_req, 0, 23, 43, 0, 423, 2, 5));
+	}
+
 	timer T := 2.0;
 	T.start;
 	alt {
 	[] as_outbound_nacc_rim_resolve(info_ind, do_repeat := true);
-	[] IPA_CTRL.receive(tr_CtrlMsgGet(?, ctrl_var)) -> value rx_ctrl {
+	[use_old_ctrl_iface] IPA_CTRL.receive(tr_CtrlMsgGet(?, ctrl_var)) -> value rx_ctrl {
 		setverdict(fail, "Received unexpected CTRL resolution after duplicate Pkt Cell Change Notification:", rx_ctrl);
 		f_shutdown(__BFILE__, __LINE__);
 		}
+	[not use_old_ctrl_iface] BTS.receive(tr_PCUIF_NEIGH_ADDR_REQ(0, info_ind.lac, info_ind.cell_id, req_arfcn, req_bsic)) -> value pcu_msg {
+		setverdict(fail, "Received unexpected PCUIF resolution after duplicate Pkt Cell Change Notification:", pcu_msg);
+		f_shutdown(__BFILE__, __LINE__);
+		}
 	[] T.timeout {
 		setverdict(pass);
 		}
@@ -4971,9 +5016,12 @@
 	var CtrlMessage rx_ctrl;
 	var GsmArfcn req_arfcn := 862;
 	var uint6_t req_bsic := 43;
+	var boolean use_old_ctrl_iface := mp_ctrl_neigh_ip != "";
 
-	/* Initialize osmo-bsc emulation neighbor resolution CTRL port */
-	f_ipa_ctrl_start_server(mp_ctrl_neigh_ip, mp_ctrl_neigh_port);
+	if (use_old_ctrl_iface) {
+		/* Initialize osmo-bsc emulation neighbor resolution CTRL port */
+		f_ipa_ctrl_start_server(mp_ctrl_neigh_ip, mp_ctrl_neigh_port);
+	}
 
 	/* Initialize NS/BSSGP side */
 	f_init_bssgp();
@@ -5001,13 +5049,7 @@
 	f_ms_tx_ul_block(ms, ts_RLC_UL_CTRL_ACK(cell_chf_notif), 0, nr := f_ms_tx_TsTrxBtsNum(ms));
 
 	/* osmo-pcu should now ask for resolution: */
-	f_ipa_ctrl_wait_link_up();
-	var charstring ctrl_var := "neighbor_resolve_cgi_ps_from_lac_ci." &
-				    int2str(info_ind.lac) & "." &
-				    int2str(info_ind.cell_id) & "." &
-				    int2str(req_arfcn) & "." &
-				    int2str(req_bsic);
-	f_ctrl_exp_get(IPA_CTRL, ctrl_var, "023-43-423-2-5");
+	f_handle_nacc_rac_ci_query(info_ind, req_arfcn, req_bsic, true, use_old_ctrl_iface);
 	as_outbound_nacc_rim_resolve(info_ind, do_answer := false);
 	/* Before receiving RIM response, MS retransmits Pkt cell Chg Notif */
 	f_ms_tx_ul_block(ms, ts_RLC_UL_CTRL_ACK(cell_chf_notif), 0, nr := f_ms_tx_TsTrxBtsNum(ms));
@@ -5054,9 +5096,12 @@
 	var CtrlMessage rx_ctrl;
 	var GsmArfcn req_arfcn := 862;
 	var uint6_t req_bsic := 43;
+	var boolean use_old_ctrl_iface := mp_ctrl_neigh_ip != "";
 
-	/* Initialize osmo-bsc emulation neighbor resolution CTRL port */
-	f_ipa_ctrl_start_server(mp_ctrl_neigh_ip, mp_ctrl_neigh_port);
+	if (use_old_ctrl_iface) {
+		/* Initialize osmo-bsc emulation neighbor resolution CTRL port */
+		f_ipa_ctrl_start_server(mp_ctrl_neigh_ip, mp_ctrl_neigh_port);
+	}
 
 	/* Initialize NS/BSSGP side */
 	f_init_bssgp();
@@ -5084,13 +5129,7 @@
 	f_ms_tx_ul_block(ms, ts_RLC_UL_CTRL_ACK(cell_chf_notif), 0, nr := f_ms_tx_TsTrxBtsNum(ms));
 
 	/* osmo-pcu should now ask for resolution: */
-	f_ipa_ctrl_wait_link_up();
-	var charstring ctrl_var := "neighbor_resolve_cgi_ps_from_lac_ci." &
-				    int2str(info_ind.lac) & "." &
-				    int2str(info_ind.cell_id) & "." &
-				    int2str(req_arfcn) & "." &
-				    int2str(req_bsic);
-	f_ctrl_exp_get(IPA_CTRL, ctrl_var, "023-43-423-2-5");
+	f_handle_nacc_rac_ci_query(info_ind, req_arfcn, req_bsic, true, use_old_ctrl_iface);
 	/* RIM procedure: */
 	as_outbound_nacc_rim_resolve(info_ind);
 
@@ -5125,9 +5164,12 @@
 	var CtrlMessage rx_ctrl;
 	var GsmArfcn req_arfcn := 862;
 	var uint6_t req_bsic := 43;
+	var boolean use_old_ctrl_iface := mp_ctrl_neigh_ip != "";
 
-	/* Initialize osmo-bsc emulation neighbor resolution CTRL port */
-	f_ipa_ctrl_start_server(mp_ctrl_neigh_ip, mp_ctrl_neigh_port);
+	if (use_old_ctrl_iface) {
+		/* Initialize osmo-bsc emulation neighbor resolution CTRL port */
+		f_ipa_ctrl_start_server(mp_ctrl_neigh_ip, mp_ctrl_neigh_port);
+	}
 
 	/* Initialize NS/BSSGP side */
 	f_init_bssgp();
@@ -5155,13 +5197,7 @@
 	f_ms_tx_ul_block(ms, ts_RLC_UL_CTRL_ACK(cell_chf_notif), 0, nr := f_ms_tx_TsTrxBtsNum(ms));
 
 	/* osmo-pcu should now ask for resolution: */
-	f_ipa_ctrl_wait_link_up();
-	var charstring ctrl_var := "neighbor_resolve_cgi_ps_from_lac_ci." &
-				    int2str(info_ind.lac) & "." &
-				    int2str(info_ind.cell_id) & "." &
-				    int2str(req_arfcn) & "." &
-				    int2str(req_bsic);
-	f_ctrl_exp_get(IPA_CTRL, ctrl_var, "023-43-423-2-5");
+	f_handle_nacc_rac_ci_query(info_ind, req_arfcn, req_bsic, true, use_old_ctrl_iface);
 	/* RIM procedure: */
 	as_outbound_nacc_rim_resolve(info_ind);
 
@@ -5195,9 +5231,12 @@
 	var CtrlMessage rx_ctrl;
 	var GsmArfcn req_arfcn := 862;
 	var uint6_t req_bsic := 43;
+	var boolean use_old_ctrl_iface := mp_ctrl_neigh_ip != "";
 
-	/* Initialize osmo-bsc emulation neighbor resolution CTRL port */
-	f_ipa_ctrl_start_server(mp_ctrl_neigh_ip, mp_ctrl_neigh_port);
+	if (use_old_ctrl_iface) {
+		/* Initialize osmo-bsc emulation neighbor resolution CTRL port */
+		f_ipa_ctrl_start_server(mp_ctrl_neigh_ip, mp_ctrl_neigh_port);
+	}
 
 	/* Initialize NS/BSSGP side */
 	f_init_bssgp();
@@ -5225,13 +5264,7 @@
 	f_ms_tx_ul_block(ms, ts_RLC_UL_CTRL_ACK(cell_chf_notif), 0, nr := f_ms_tx_TsTrxBtsNum(ms));
 
 	/* osmo-pcu should now ask for resolution: */
-	f_ipa_ctrl_wait_link_up();
-	var charstring ctrl_var := "neighbor_resolve_cgi_ps_from_lac_ci." &
-				    int2str(info_ind.lac) & "." &
-				    int2str(info_ind.cell_id) & "." &
-				    int2str(req_arfcn) & "." &
-				    int2str(req_bsic);
-	f_ctrl_exp_get(IPA_CTRL, ctrl_var, "023-43-423-2-5");
+	f_handle_nacc_rac_ci_query(info_ind, req_arfcn, req_bsic, true, use_old_ctrl_iface);
 	/* RIM procedure: */
 	as_outbound_nacc_rim_resolve(info_ind);
 
@@ -5264,11 +5297,16 @@
 	var RlcmacDlBlock dl_block;
 	var uint32_t sched_fn;
 	var CtrlMessage rx_ctrl;
+	var charstring ctrl_var;
+	var PCUIF_Message pcu_msg;
 	var GsmArfcn req_arfcn := 862;
 	var uint6_t req_bsic := 43;
+	var boolean use_old_ctrl_iface := mp_ctrl_neigh_ip != "";
 
-	/* Initialize osmo-bsc emulation neighbor resolution CTRL port */
-	f_ipa_ctrl_start_server(mp_ctrl_neigh_ip, mp_ctrl_neigh_port);
+	if (use_old_ctrl_iface) {
+		/* Initialize osmo-bsc emulation neighbor resolution CTRL port */
+		f_ipa_ctrl_start_server(mp_ctrl_neigh_ip, mp_ctrl_neigh_port);
+	}
 
 	/* Initialize NS/BSSGP side */
 	f_init_bssgp();
@@ -5296,25 +5334,28 @@
 	f_ms_tx_ul_block(ms, ts_RLC_UL_CTRL_ACK(cell_chf_notif), 0, nr := f_ms_tx_TsTrxBtsNum(ms));
 
 	/* osmo-pcu should now ask for resolution: */
-	f_ipa_ctrl_wait_link_up();
-	var charstring ctrl_var := "neighbor_resolve_cgi_ps_from_lac_ci." &
-				    int2str(info_ind.lac) & "." &
-				    int2str(info_ind.cell_id) & "." &
-				    int2str(req_arfcn) & "." &
-				    int2str(req_bsic);
-	IPA_CTRL.receive(tr_CtrlMsgGet(?, ctrl_var)) -> value rx_ctrl;
+	if (use_old_ctrl_iface) {
+		f_ipa_ctrl_wait_link_up();
+		ctrl_var := "neighbor_resolve_cgi_ps_from_lac_ci." &
+			    int2str(info_ind.lac) & "." &
+			    int2str(info_ind.cell_id) & "." &
+			    int2str(req_arfcn) & "." &
+			    int2str(req_bsic);
+		IPA_CTRL.receive(tr_CtrlMsgGet(?, ctrl_var)) -> value rx_ctrl;
+	} else {
+		BTS.receive(tr_PCUIF_NEIGH_ADDR_REQ(0, info_ind.lac, info_ind.cell_id, req_arfcn, req_bsic)) -> value pcu_msg;
+	}
 	/* Before receiving CTRL response, MS retransmits Pkt cell Chg Notif with different tgt arfcn */
 	cell_chf_notif := ts_RlcMacUlCtrl_PKT_CELL_CHG_NOTIF(ms.ul_tbf.tfi, req_arfcn + 1, req_bsic + 1);
 	f_ms_tx_ul_block(ms, ts_RLC_UL_CTRL_ACK(cell_chf_notif), 0, nr := f_ms_tx_TsTrxBtsNum(ms));
 	f_sleep(0.2); /* let some time to avoid race conditons between CTRL and RLCMAC */
-	IPA_CTRL.send(ts_CtrlMsgGetRepl(rx_ctrl.cmd.id, valueof(ctrl_var), valueof("023-43-423-2-5")));
+	if (use_old_ctrl_iface) {
+		IPA_CTRL.send(ts_CtrlMsgGetRepl(rx_ctrl.cmd.id, valueof(ctrl_var), valueof("023-43-423-2-5")));
+	} else {
+		BTS.send(ts_PCUIF_NEIGH_ADDR_CNF(0, pcu_msg.u.container.u.neigh_addr_req, 0, 23, 43, 0, 423, 2, 5));
+	}
 	/* We should now receive a 2nd CTRL request with the new ARFCN+BSIC */
-	ctrl_var := "neighbor_resolve_cgi_ps_from_lac_ci." &
-		    int2str(info_ind.lac) & "." &
-		    int2str(info_ind.cell_id) & "." &
-		    int2str(req_arfcn + 1) & "." &
-		    int2str(req_bsic + 1);
-	f_ctrl_exp_get(IPA_CTRL, ctrl_var, "023-43-423-2-5");
+	f_handle_nacc_rac_ci_query(info_ind, req_arfcn + 1, req_bsic + 1, true, use_old_ctrl_iface);
 
 	/* And finally everything continues as usual with RIN procedure */
 	as_outbound_nacc_rim_resolve(info_ind);
@@ -5349,9 +5390,12 @@
 	var CtrlMessage rx_ctrl;
 	var GsmArfcn req_arfcn := 862;
 	var uint6_t req_bsic := 43;
+	var boolean use_old_ctrl_iface := mp_ctrl_neigh_ip != "";
 
-	/* Initialize osmo-bsc emulation neighbor resolution CTRL port */
-	f_ipa_ctrl_start_server(mp_ctrl_neigh_ip, mp_ctrl_neigh_port);
+	if (use_old_ctrl_iface) {
+		/* Initialize osmo-bsc emulation neighbor resolution CTRL port */
+		f_ipa_ctrl_start_server(mp_ctrl_neigh_ip, mp_ctrl_neigh_port);
+	}
 
 	/* Initialize NS/BSSGP side */
 	f_init_bssgp();
@@ -5379,13 +5423,7 @@
 	f_ms_tx_ul_block(ms, ts_RLC_UL_CTRL_ACK(cell_chf_notif), 0, nr := f_ms_tx_TsTrxBtsNum(ms));
 
 	/* osmo-pcu should now ask for resolution: */
-	f_ipa_ctrl_wait_link_up();
-	var charstring ctrl_var := "neighbor_resolve_cgi_ps_from_lac_ci." &
-				    int2str(info_ind.lac) & "." &
-				    int2str(info_ind.cell_id) & "." &
-				    int2str(req_arfcn) & "." &
-				    int2str(req_bsic);
-	f_ctrl_exp_get(IPA_CTRL, ctrl_var, "023-43-423-2-5");
+	f_handle_nacc_rac_ci_query(info_ind, req_arfcn, req_bsic, true, use_old_ctrl_iface);
 	as_outbound_nacc_rim_resolve(info_ind, do_answer := false);
 	/* Before receiving RIM response, MS retransmits Pkt cell Chg Notif with different tgt cell: */
 	cell_chf_notif := ts_RlcMacUlCtrl_PKT_CELL_CHG_NOTIF(ms.ul_tbf.tfi, req_arfcn + 1, req_bsic + 1);
@@ -5394,12 +5432,7 @@
 	f_outbound_nacc_rim_tx_resp(info_ind);
 
 	/* As a result, CTRL + RIM resolution for new tgt cell should now be done: */
-	ctrl_var := "neighbor_resolve_cgi_ps_from_lac_ci." &
-		    int2str(info_ind.lac) & "." &
-		    int2str(info_ind.cell_id) & "." &
-		    int2str(req_arfcn + 1) & "." &
-		    int2str(req_bsic + 1);
-	f_ctrl_exp_get(IPA_CTRL, ctrl_var, "023-43-423-2-5");
+	f_handle_nacc_rac_ci_query(info_ind, req_arfcn + 1, req_bsic + 1, true, use_old_ctrl_iface);
 
 	/* And finally everything continues as usual with RIN procedure */
 	as_outbound_nacc_rim_resolve(info_ind);
@@ -5434,9 +5467,12 @@
 	var CtrlMessage rx_ctrl;
 	var GsmArfcn req_arfcn := 862;
 	var uint6_t req_bsic := 43;
+	var boolean use_old_ctrl_iface := mp_ctrl_neigh_ip != "";
 
-	/* Initialize osmo-bsc emulation neighbor resolution CTRL port */
-	f_ipa_ctrl_start_server(mp_ctrl_neigh_ip, mp_ctrl_neigh_port);
+	if (use_old_ctrl_iface) {
+		/* Initialize osmo-bsc emulation neighbor resolution CTRL port */
+		f_ipa_ctrl_start_server(mp_ctrl_neigh_ip, mp_ctrl_neigh_port);
+	}
 
 	/* Initialize NS/BSSGP side */
 	f_init_bssgp();
@@ -5464,13 +5500,7 @@
 	f_ms_tx_ul_block(ms, ts_RLC_UL_CTRL_ACK(cell_chf_notif), 0, nr := f_ms_tx_TsTrxBtsNum(ms));
 
 	/* osmo-pcu should now ask for resolution: */
-	f_ipa_ctrl_wait_link_up();
-	var charstring ctrl_var := "neighbor_resolve_cgi_ps_from_lac_ci." &
-				    int2str(info_ind.lac) & "." &
-				    int2str(info_ind.cell_id) & "." &
-				    int2str(req_arfcn) & "." &
-				    int2str(req_bsic);
-	f_ctrl_exp_get(IPA_CTRL, ctrl_var, "023-43-423-2-5");
+	f_handle_nacc_rac_ci_query(info_ind, req_arfcn, req_bsic, true, use_old_ctrl_iface);
 	/* RIM procedure: */
 	as_outbound_nacc_rim_resolve(info_ind);
 
@@ -5480,12 +5510,7 @@
 	f_ms_tx_ul_block(ms, ts_RLC_UL_CTRL_ACK(cell_chf_notif), 0, nr := f_ms_tx_TsTrxBtsNum(ms));
 
 	/* It should trigger RAC_CI resolution to start again: */
-	ctrl_var := "neighbor_resolve_cgi_ps_from_lac_ci." &
-			int2str(info_ind.lac) & "." &
-			int2str(info_ind.cell_id) & "." &
-			int2str(req_arfcn + 1) & "." &
-			int2str(req_bsic + 1);
-	f_ctrl_exp_get(IPA_CTRL, ctrl_var, "023-43-423-2-5");
+	f_handle_nacc_rac_ci_query(info_ind, req_arfcn + 1, req_bsic + 1, true, use_old_ctrl_iface);
 	/* RIM procedure: */
 	as_outbound_nacc_rim_resolve(info_ind);
 	/* Transmit SI back to MS */
@@ -5515,9 +5540,12 @@
 	var CtrlMessage rx_ctrl;
 	var GsmArfcn req_arfcn := 862;
 	var uint6_t req_bsic := 43;
+	var boolean use_old_ctrl_iface := mp_ctrl_neigh_ip != "";
 
-	/* Initialize osmo-bsc emulation neighbor resolution CTRL port */
-	f_ipa_ctrl_start_server(mp_ctrl_neigh_ip, mp_ctrl_neigh_port);
+	if (use_old_ctrl_iface) {
+		/* Initialize osmo-bsc emulation neighbor resolution CTRL port */
+		f_ipa_ctrl_start_server(mp_ctrl_neigh_ip, mp_ctrl_neigh_port);
+	}
 
 	/* Initialize NS/BSSGP side */
 	f_init_bssgp();
@@ -5545,13 +5573,7 @@
 	f_ms_tx_ul_block(ms, ts_RLC_UL_CTRL_ACK(cell_chf_notif), 0, nr := f_ms_tx_TsTrxBtsNum(ms));
 
 	/* osmo-pcu should now ask for resolution: */
-	f_ipa_ctrl_wait_link_up();
-	var charstring ctrl_var := "neighbor_resolve_cgi_ps_from_lac_ci." &
-				    int2str(info_ind.lac) & "." &
-				    int2str(info_ind.cell_id) & "." &
-				    int2str(req_arfcn) & "." &
-				    int2str(req_bsic);
-	f_ctrl_exp_get(IPA_CTRL, ctrl_var, "023-43-423-2-5");
+	f_handle_nacc_rac_ci_query(info_ind, req_arfcn, req_bsic, true, use_old_ctrl_iface);
 	/* RIM procedure: */
 	as_outbound_nacc_rim_resolve(info_ind);
 
@@ -5562,16 +5584,12 @@
 	cell_chf_notif := ts_RlcMacUlCtrl_PKT_CELL_CHG_NOTIF(ms.ul_tbf.tfi, req_arfcn + 1, req_bsic + 1);
 	f_ms_tx_ul_block(ms, ts_RLC_UL_CTRL_ACK(cell_chf_notif), 0, nr := f_ms_tx_TsTrxBtsNum(ms));
 
+	/* It should trigger RAC_CI resolution to start again: */
+	f_handle_nacc_rac_ci_query(info_ind, req_arfcn + 1, req_bsic + 1, true, use_old_ctrl_iface);
+
 	/* PCU TBF NACC state changed, so we should next receive a dummy block: */
 	f_rx_rlcmac_dl_block_exp_dummy(dl_block, nr := f_ms_tx_TsTrxBtsNum(ms));
 
-	/* It should trigger RAC_CI resolution to start again: */
-	ctrl_var := "neighbor_resolve_cgi_ps_from_lac_ci." &
-			int2str(info_ind.lac) & "." &
-			int2str(info_ind.cell_id) & "." &
-			int2str(req_arfcn + 1) & "." &
-			int2str(req_bsic + 1);
-	f_ctrl_exp_get(IPA_CTRL, ctrl_var, "023-43-423-2-5");
 	/* RIM procedure: */
 	as_outbound_nacc_rim_resolve(info_ind);
 	/* Transmit SI back to MS */
@@ -5601,9 +5619,12 @@
 	var CtrlMessage rx_ctrl;
 	var GsmArfcn req_arfcn := 862;
 	var uint6_t req_bsic := 43;
+	var boolean use_old_ctrl_iface := mp_ctrl_neigh_ip != "";
 
-	/* Initialize osmo-bsc emulation neighbor resolution CTRL port */
-	f_ipa_ctrl_start_server(mp_ctrl_neigh_ip, mp_ctrl_neigh_port);
+	if (use_old_ctrl_iface) {
+		/* Initialize osmo-bsc emulation neighbor resolution CTRL port */
+		f_ipa_ctrl_start_server(mp_ctrl_neigh_ip, mp_ctrl_neigh_port);
+	}
 
 	/* Initialize NS/BSSGP side */
 	f_init_bssgp();
@@ -5631,13 +5652,7 @@
 	f_ms_tx_ul_block(ms, ts_RLC_UL_CTRL_ACK(cell_chf_notif), 0, nr := f_ms_tx_TsTrxBtsNum(ms));
 
 	/* osmo-pcu should now ask for resolution: */
-	f_ipa_ctrl_wait_link_up();
-	var charstring ctrl_var := "neighbor_resolve_cgi_ps_from_lac_ci." &
-				    int2str(info_ind.lac) & "." &
-				    int2str(info_ind.cell_id) & "." &
-				    int2str(req_arfcn) & "." &
-				    int2str(req_bsic);
-	f_ctrl_exp_get(IPA_CTRL, ctrl_var, "023-43-423-2-5");
+	f_handle_nacc_rac_ci_query(info_ind, req_arfcn, req_bsic, true, use_old_ctrl_iface);
 	/* RIM procedure: */
 	as_outbound_nacc_rim_resolve(info_ind);
 
@@ -5655,21 +5670,32 @@
 	cell_chf_notif := ts_RlcMacUlCtrl_PKT_CELL_CHG_NOTIF(ms.ul_tbf.tfi, req_arfcn + 1, req_bsic + 1);
 	f_ms_tx_ul_block(ms, ts_RLC_UL_CTRL_ACK(cell_chf_notif), 0, nr := f_ms_tx_TsTrxBtsNum(ms));
 
+	/* It should trigger RAC_CI resolution to start again: */
+	/* When using new PCUIF interface for resolution, we must
+	 * PCUIF.receive() here since that's the first message in the PCUIF
+	 * queue that PCU will have sent. Calling other functions doing
+	 * PCUIF.receive() (like f_ms_tx_ul_block() below) will make them fail
+	 * due to unexpected message receive. */
+	if (not use_old_ctrl_iface) {
+		f_handle_nacc_rac_ci_query(info_ind, req_arfcn + 1, req_bsic + 1, true, use_old_ctrl_iface);
+	}
+
 	/* PKT CELL CHG CONTINUE ACK/NACK sets poll+rrbp requesting PACKET CONTROL ACK */
 	if (dl_block.ctrl.mac_hdr.rrbp_valid) {
 		sched_fn := f_rrbp_ack_fn(sched_fn, dl_block.ctrl.mac_hdr.rrbp);
 		f_ms_tx_ul_block(ms, ts_RLCMAC_CTRL_ACK(ms.tlli), sched_fn);
 	}
+
+	/* When using CTRL interface, we must schedule the ACK before (see
+	 * above) blocking here waiting for the resoltion, otherwise we'll be
+	 * too late scheduling by the time the resolution is done. */
+	if (use_old_ctrl_iface) {
+		f_handle_nacc_rac_ci_query(info_ind, req_arfcn + 1, req_bsic + 1, true, use_old_ctrl_iface);
+	}
+
 	/* PCU TBF NACC state changed, so we should next receive a dummy block: */
 	f_rx_rlcmac_dl_block_exp_dummy(dl_block);
 
-	/* It should trigger RAC_CI resolution to start again: */
-	ctrl_var := "neighbor_resolve_cgi_ps_from_lac_ci." &
-			int2str(info_ind.lac) & "." &
-			int2str(info_ind.cell_id) & "." &
-			int2str(req_arfcn + 1) & "." &
-			int2str(req_bsic + 1);
-	f_ctrl_exp_get(IPA_CTRL, ctrl_var, "023-43-423-2-5");
 	/* RIM procedure: */
 	as_outbound_nacc_rim_resolve(info_ind);
 	/* Transmit SI back to MS */
@@ -5700,9 +5726,12 @@
 	var GsmArfcn req_arfcn := 862;
 	var uint6_t req_bsic := 43;
 	var octetstring data := f_rnd_octstring(10);
+	var boolean use_old_ctrl_iface := mp_ctrl_neigh_ip != "";
 
-	/* Initialize osmo-bsc emulation neighbor resolution CTRL port */
-	f_ipa_ctrl_start_server(mp_ctrl_neigh_ip, mp_ctrl_neigh_port);
+	if (use_old_ctrl_iface) {
+		/* Initialize osmo-bsc emulation neighbor resolution CTRL port */
+		f_ipa_ctrl_start_server(mp_ctrl_neigh_ip, mp_ctrl_neigh_port);
+	}
 
 	/* Initialize NS/BSSGP side */
 	f_init_bssgp();
@@ -5730,13 +5759,7 @@
 	f_ms_tx_ul_block(ms, ts_RLC_UL_CTRL_ACK(cell_chf_notif), 0, nr := f_ms_tx_TsTrxBtsNum(ms));
 
 	/* osmo-pcu should now ask for resolution: */
-	f_ipa_ctrl_wait_link_up();
-	var charstring ctrl_var := "neighbor_resolve_cgi_ps_from_lac_ci." &
-				    int2str(info_ind.lac) & "." &
-				    int2str(info_ind.cell_id) & "." &
-				    int2str(req_arfcn) & "." &
-				    int2str(req_bsic);
-	f_ctrl_exp_get(IPA_CTRL, ctrl_var, "023-43-423-2-5");
+	f_handle_nacc_rac_ci_query(info_ind, req_arfcn, req_bsic, true, use_old_ctrl_iface);
 	/* RIM procedure: */
 	as_outbound_nacc_rim_resolve(info_ind);
 
@@ -6122,9 +6145,7 @@
 	execute( TC_nacc_outbound_success_no_ctrl_ack() );
 	execute( TC_nacc_outbound_success_twice() );
 	execute( TC_nacc_outbound_success_twice_nocache() );
-	execute( TC_nacc_outbound_rac_ci_resolve_conn_refused() );
 	execute( TC_nacc_outbound_rac_ci_resolve_timeout() );
-	execute( TC_nacc_outbound_rac_ci_resolve_fail_parse_response() );
 	execute( TC_nacc_outbound_si_resolve_timeout() );
 	execute( TC_nacc_outbound_pkt_cell_chg_notif_dup() );
 	execute( TC_nacc_outbound_pkt_cell_chg_notif_dup2() );
@@ -6137,6 +6158,10 @@
 	execute( TC_nacc_outbound_pkt_cell_chg_notif_twice4() );
 	execute( TC_nacc_outbound_pkt_cell_chg_notif_twice5() );
 	execute( TC_nacc_outbound_pkt_cell_chg_notif_unassigned_dl_tbf() );
+	if (mp_ctrl_neigh_ip != "") { /* PCU using old CTRL neigh addr resolution iface */
+		execute( TC_nacc_outbound_rac_ci_resolve_conn_refused() );
+		execute( TC_nacc_outbound_rac_ci_resolve_fail_parse_response() );
+	}
 
 	execute( TC_rim_ran_info_req_single_rep() );
 	execute( TC_rim_ran_info_req_single_rep_eutran() );