diff --git a/Makefile b/Makefile
index 9f210d0..e47a07b 100644
--- a/Makefile
+++ b/Makefile
@@ -4,7 +4,7 @@ CFLAGS=-Wall -g -DPACKAGE_VERSION=\"0.0\"
 %.o: %.c
 	$(CC) $(CFLAGS) -o $@ -c $^ -I/usr/local/include/
 
-v5le: main.o logging.o v5x_data.o lapv5.o v5x_protocol.o v51_le_ctrl.o v51_le_provisioning.o v52_le_user_port_fsm.o ph_socket.o
+v5le: main.o logging.o v5x_data.o lapv5.o v5x_protocol.o v51_le_ctrl.o v51_le_provisioning.o v52_le_user_port_fsm.o ph_socket.o v5x_l2_mgmt.o
 	$(CC) -o $@ $^ $(LIBS)
 
 clean:
diff --git a/v5x_l2_mgmt.c b/v5x_l2_mgmt.c
new file mode 100644
index 0000000..7c61303
--- /dev/null
+++ b/v5x_l2_mgmt.c
@@ -0,0 +1,184 @@
+/* Management information forwarding between AN <-> LE */
+
+/* (C) 2022 by Andreas Eversberg <jolly@eversberg.eu>
+ *
+ * All Rights Reserved
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ *
+ * 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 <stdint.h>
+#include <osmocom/gsm/tlv.h>
+
+#include "v5x_internal.h"
+#include "v5x_l2_mgmt.h"
+#include "v52_le_user_port_fsm.h"
+#include "v5x_le_pstn_fsm.h"
+#include "logging.h"
+
+void v51_mgmt_init(void)
+{
+	LOGP(DV5MGMT, LOGL_NOTICE, "Using V5x management\n");
+}
+
+/* received management primitives from LE (NAT protocol via PH-socket) */
+void v5x_mph_rcv_le(struct v5x_user_port *v5up, uint8_t prim, uint8_t *data, int length)
+{
+	ph_socket_t *s = &v5up->ph_socket;
+
+	switch (prim) {
+	case PH_PRIM_CTRL_REQ:
+		if (length && *data == PH_CTRL_UNBLOCK) {
+			LOGP(DV5MGMT, LOGL_INFO, "Received unblocking from LE of port %d.\n", v5up->nr);
+			v5up->le_unblocked = true;
+			v51_mph_snd(v5up, MPH_UBR);
+			if (v5up->pstn.proto && v5up->an_unblocked)
+				v5x_pstn_mdu_snd(v5up, MDU_CTRL_port_unblocked);
+			if (!v5up->an_unblocked) {
+				LOGP(DV5MGMT, LOGL_INFO, "Reply with blocking, because AN is blocked.\n");
+				uint8_t ctrl = PH_CTRL_BLOCK;
+				ph_socket_tx_msg(&v5up->ph_socket, v5up->type == V5X_USER_TYPE_ISDN ? 3 : 0, PH_PRIM_CTRL_IND, &ctrl, 1);
+			}
+		}
+		if (length && *data == PH_CTRL_BLOCK) {
+			LOGP(DV5MGMT, LOGL_INFO, "Received blocking from LE of port %d.\n", v5up->nr);
+			v5up->le_unblocked = false;
+			v51_mph_snd(v5up, MPH_BI);
+			if (v5up->pstn.proto)
+				v5x_pstn_mdu_snd(v5up, MDU_CTRL_port_blocked);
+		}
+		break;
+	case PH_PRIM_ACT_REQ:
+		LOGP(DV5MGMT, LOGL_INFO, "Received activation from LE of port %d.\n", v5up->nr);
+		if (!v5up->an_unblocked) {
+			ph_socket_tx_msg(s, 3, PH_PRIM_DACT_IND, NULL, 0);
+			break;
+		}
+		v51_mph_snd(v5up, MPH_AR);
+		break;
+	case PH_PRIM_DACT_REQ:
+		LOGP(DV5MGMT, LOGL_INFO, "Received deactivation from LE of port %d.\n", v5up->nr);
+		v51_mph_snd(v5up, MPH_DR);
+		break;
+	default:
+		LOGP(DV5MGMT, LOGL_INFO, "Received unknown prim %d from LE for port %d.\n", prim, v5up->nr);
+	}
+}
+
+static void _block_unblock_socket(struct v5x_user_port *v5up, bool block)
+{
+	uint8_t ctrl;
+
+	if (block && v5up->an_unblocked) {
+		v5up->an_unblocked = 0;
+		ctrl = PH_CTRL_BLOCK;
+		ph_socket_tx_msg(&v5up->ph_socket, v5up->type == V5X_USER_TYPE_ISDN ? 3 : 0, PH_PRIM_CTRL_IND, &ctrl, 1);
+		return;
+	}
+	if (!block && !v5up->an_unblocked) {
+		v5up->an_unblocked = 1;
+		ctrl = PH_CTRL_UNBLOCK;
+		ph_socket_tx_msg(&v5up->ph_socket, v5up->type == V5X_USER_TYPE_ISDN ? 3 : 0, PH_PRIM_CTRL_IND, &ctrl, 1);
+		return;
+	}
+}
+
+/* received management primitives from AN (via port control protocol) */
+void v5x_mph_rcv_an(struct v5x_user_port *v5up, enum v5x_mph_prim prim, uint8_t perf_grading)
+{
+	switch (prim) {
+	case MPH_UBR:
+		LOGP(DV5MGMT, LOGL_INFO, "Received unblocking request from AN of port %d.\n", v5up->nr);
+		if (v5up->le_unblocked) {
+			LOGP(DV5MGMT, LOGL_INFO, "Reply with unblocking request.\n");
+			v51_mph_snd(v5up, MPH_UBR);
+			_block_unblock_socket(v5up, false);
+			if (v5up->pstn.proto)
+				v5x_pstn_mdu_snd(v5up, MDU_CTRL_port_unblocked);
+		} else
+			LOGP(DV5MGMT, LOGL_INFO, "Ignore unblocking request from AN, because LE is blocked.\n");
+		break;
+	case MPH_UBI:
+		LOGP(DV5MGMT, LOGL_INFO, "Received unblocking indication from AN of port %d.\n", v5up->nr);
+		_block_unblock_socket(v5up, false);
+		if (v5up->pstn.proto)
+			v5x_pstn_mdu_snd(v5up, MDU_CTRL_port_unblocked);
+		break;
+	case MPH_BR:
+		LOGP(DV5MGMT, LOGL_INFO, "Received blocking request from AN of port %d.\n", v5up->nr);
+		v51_mph_snd(v5up, MPH_BI);
+		_block_unblock_socket(v5up, true);
+		if (v5up->pstn.proto)
+			v5x_pstn_mdu_snd(v5up, MDU_CTRL_port_blocked);
+		break;
+	case MPH_BI:
+		LOGP(DV5MGMT, LOGL_INFO, "Received blocking indication from AN of port %d.\n", v5up->nr);
+		_block_unblock_socket(v5up, true);
+		if (v5up->pstn.proto)
+			v5x_pstn_mdu_snd(v5up, MDU_CTRL_port_blocked);
+		break;
+	case MPH_AI:
+		LOGP(DV5MGMT, LOGL_INFO, "Received activation indication from AN of port %d.\n", v5up->nr);
+		ph_socket_tx_msg(&v5up->ph_socket, 3, PH_PRIM_ACT_IND, NULL, 0);
+		break;
+	case MPH_DI:
+		LOGP(DV5MGMT, LOGL_INFO, "Received deactivation indication from AN of port %d.\n", v5up->nr);
+		ph_socket_tx_msg(&v5up->ph_socket, 3, PH_PRIM_DACT_IND, NULL, 0);
+		break;
+	default:
+		LOGP(DV5MGMT, LOGL_INFO, "Received unknown prim %d from AN for port %d.\n", prim, v5up->nr);
+	}
+}
+
+/* receive FE-message from NAT (PH-socket) and forward it to the PSTN protocol */
+void v5x_fe_rcv_le(struct v5x_user_port *v5up, struct msgb *msg)
+{
+	enum v5x_fe_prim prim;
+
+	prim = *msg->data;
+	msgb_pull(msg, 1);
+
+	LOGP(DV5MGMT, LOGL_INFO, "MSG: NAT -> PSTN_LE\n");
+	v5x_pstn_fe_snd(v5up, prim, msg);
+}
+
+/* receive FE-message from PSTN protocol and forward it to NAT (PH-socket) */
+void v5x_pstn_rcv_fe(struct v5x_user_port *v5up, enum v5x_fe_prim prim, struct msgb *msg)
+{
+	*msgb_push(msg, 1) = prim;
+
+	LOGP(DV5MGMT, LOGL_INFO, "MSG: PSTN_LE -> NAT\n");
+	ph_socket_tx_msg(&v5up->ph_socket, 0, PH_PRIM_DATA_IND, msg->data, msg->len);
+
+	msgb_free(msg);
+}
+
+/* receive MDU primitives from PSTN protocol */
+void v5x_pstn_rcv_mdu(struct v5x_user_port *v5up, enum v5x_mgmt_prim prim)
+{
+	switch (prim) {
+	case MDU_error_ind:
+		LOGP(DV5MGMT, LOGL_NOTICE, "Received MDU-error_indication from PSTN protocol of port %d.\n", v5up->nr);
+		break;
+	case MDU_CTRL_port_restart_ack:
+		//FIXME: handle restart procedure
+		break;
+	default:
+		LOGP(DV5MGMT, LOGL_INFO, "Received unknown prim %d from PSTN protocol for port %d.\n", prim, v5up->nr);
+	}
+}
diff --git a/v5x_l2_mgmt.h b/v5x_l2_mgmt.h
new file mode 100644
index 0000000..686287c
--- /dev/null
+++ b/v5x_l2_mgmt.h
@@ -0,0 +1,7 @@
+
+void v51_mgmt_init(void);
+void v5x_mph_rcv_le(struct v5x_user_port *v5up, uint8_t prim, uint8_t *data, int length);
+void v5x_mph_rcv_an(struct v5x_user_port *v5up, enum v5x_mph_prim prim, uint8_t perf_grading);
+void v5x_fe_rcv_le(struct v5x_user_port *v5up, struct msgb *msg);
+void v5x_pstn_rcv_fe(struct v5x_user_port *v5up, enum v5x_fe_prim prim, struct msgb *msg);
+void v5x_pstn_rcv_mdu(struct v5x_user_port *v5up, enum v5x_mgmt_prim prim);