diff --git a/openbsc/include/openbsc/gprs_sgsn.h b/openbsc/include/openbsc/gprs_sgsn.h
index 7a429cd..c88a2bb 100644
--- a/openbsc/include/openbsc/gprs_sgsn.h
+++ b/openbsc/include/openbsc/gprs_sgsn.h
@@ -152,7 +152,6 @@
 /* Allocate a new SGSN MM context */
 struct sgsn_mm_ctx *sgsn_mm_ctx_alloc(uint32_t tlli,
 					const struct gprs_ra_id *raid);
-void sgsn_mm_ctx_free(struct sgsn_mm_ctx *mm);
 void sgsn_mm_ctx_cleanup_free(struct sgsn_mm_ctx *ctx);
 
 struct sgsn_ggsn_ctx *sgsn_mm_ctx_find_ggsn_ctx(struct sgsn_mm_ctx *mmctx,
@@ -208,6 +207,11 @@
 	struct osmo_timer_list	timer;
 	unsigned int		T;		/* Txxxx number */
 	unsigned int		num_T_exp;	/* number of consecutive T expirations */
+
+	struct osmo_timer_list	cdr_timer;	/* CDR record wird timer */
+	struct timespec		cdr_start;	/* The start of the CDR */
+	uint64_t		cdr_bytes_in;
+	uint64_t		cdr_bytes_out;
 };
 
 #define LOGPDPCTXP(level, pdp, fmt, args...) \
diff --git a/openbsc/include/openbsc/sgsn.h b/openbsc/include/openbsc/sgsn.h
index 7d3a68c..0f9a59f 100644
--- a/openbsc/include/openbsc/sgsn.h
+++ b/openbsc/include/openbsc/sgsn.h
@@ -16,6 +16,11 @@
 	SGSN_AUTH_POLICY_REMOTE
 };
 
+struct sgsn_cdr {
+	char *filename;
+	int interval;
+};
+
 struct sgsn_config {
 	/* parsed from config file */
 
@@ -33,6 +38,9 @@
 
 	int require_authentication;
 	int require_update_location;
+
+	/* CDR configuration */
+	struct sgsn_cdr cdr;
 };
 
 struct sgsn_instance {
@@ -85,4 +93,10 @@
 int sndcp_llunitdata_ind(struct msgb *msg, struct gprs_llc_lle *lle,
 			 uint8_t *hdr, uint16_t len);
 
+
+/*
+ * CDR related functionality
+ */
+int sgsn_cdr_init(struct sgsn_instance *sgsn);
+
 #endif
diff --git a/openbsc/include/openbsc/signal.h b/openbsc/include/openbsc/signal.h
index 39319f1..8f27b38 100644
--- a/openbsc/include/openbsc/signal.h
+++ b/openbsc/include/openbsc/signal.h
@@ -1,5 +1,5 @@
 /* Generic signalling/notification infrastructure */
-/* (C) 2009-2010 by Holger Hans Peter Freyther <zecke@selfish.org>
+/* (C) 2009-2010, 2015 by Holger Hans Peter Freyther <zecke@selfish.org>
  * (C) 2009 by Harald Welte <laforge@gnumonks.org>
  * (C) 2010 by On-Waves
  * All Rights Reserved
@@ -46,6 +46,7 @@
 	SS_MSC,
 	SS_HO,
 	SS_CCCH,
+	SS_SGSN,
 };
 
 /* SS_PAGING signals */
@@ -241,4 +242,22 @@
 	uint16_t rach_access_count;
 };
 
+/* GPRS SGSN signals SS_SGSN */
+enum signal_sgsn {
+	S_SGSN_ATTACH,
+	S_SGSN_DETACH,
+	S_SGSN_UPDATE,
+	S_SGSN_PDP_ACT,
+	S_SGSN_PDP_DEACT,
+	S_SGSN_PDP_TERMINATE,
+	S_SGSN_PDP_FREE,
+	S_SGSN_MM_FREE,
+};
+
+struct sgsn_mm_ctx;
+struct sgsn_signal_data {
+	struct sgsn_mm_ctx *mm;
+	struct sgsn_pdp_ctx *pdp;	/* non-NULL for PDP_ACT, PDP_DEACT, PDP_FREE */
+};
+
 #endif
diff --git a/openbsc/src/gprs/Makefile.am b/openbsc/src/gprs/Makefile.am
index bc3e21e..3d02822 100644
--- a/openbsc/src/gprs/Makefile.am
+++ b/openbsc/src/gprs/Makefile.am
@@ -24,7 +24,7 @@
 			gprs_llc.c gprs_llc_parse.c gprs_llc_vty.c crc24.c \
 			sgsn_ctrl.c sgsn_auth.c gprs_subscriber.c \
 			gprs_gsup_messages.c gprs_utils.c gprs_gsup_client.c \
-			gsm_04_08_gprs.c
+			gsm_04_08_gprs.c sgsn_cdr.c
 osmo_sgsn_LDADD = 	\
 			$(top_builddir)/src/libcommon/libcommon.a \
 			-lgtp $(OSMO_LIBS) $(LIBOSMOABIS_LIBS) -lrt
diff --git a/openbsc/src/gprs/gprs_gmm.c b/openbsc/src/gprs/gprs_gmm.c
index ace0c2e..8ada3d4 100644
--- a/openbsc/src/gprs/gprs_gmm.c
+++ b/openbsc/src/gprs/gprs_gmm.c
@@ -52,6 +52,7 @@
 #include <openbsc/gprs_gmm.h>
 #include <openbsc/gprs_utils.h>
 #include <openbsc/sgsn.h>
+#include <openbsc/signal.h>
 
 #include <pdp.h>
 
@@ -545,9 +546,45 @@
 	return gsm48_gmm_authorize(ctx);
 }
 
+static void extract_subscr_msisdn(struct sgsn_mm_ctx *ctx)
+{
+	struct gsm_mncc_number called;
+	uint8_t msisdn[sizeof(ctx->subscr->sgsn_data->msisdn) + 1];
+
+	/* Convert MSISDN from encoded to string.. */
+	if (!ctx->subscr)
+		return;
+
+	if (ctx->subscr->sgsn_data->msisdn_len < 1)
+		return;
+
+	/* prepare the data for the decoder */
+	memset(&called, 0, sizeof(called));
+	msisdn[0] = ctx->subscr->sgsn_data->msisdn_len;
+	memcpy(&msisdn[1], ctx->subscr->sgsn_data->msisdn,
+		ctx->subscr->sgsn_data->msisdn_len);
+
+	/* decode the string now */
+	gsm48_decode_called(&called, msisdn);
+
+	/* Prepend a '+' for international numbers */
+	if (called.plan == 1 && called.type == 1) {
+		ctx->msisdn[0] = '+';
+		strncpy(&ctx->msisdn[1], called.number,
+			sizeof(ctx->msisdn) - 1);
+	} else {
+		strncpy(&ctx->msisdn[0], called.number,
+			sizeof(ctx->msisdn) - 1);
+	}
+}
+
 /* Check if we can already authorize a subscriber */
 static int gsm48_gmm_authorize(struct sgsn_mm_ctx *ctx)
 {
+#ifndef PTMSI_ALLOC
+	struct sgsn_signal_data sig_data;
+#endif
+
 	/* Request IMSI and IMEI from the MS if they are unknown */
 	if (!strlen(ctx->imei)) {
 		ctx->t3370_id_type = GSM_MI_TYPE_IMEI;
@@ -604,11 +641,16 @@
 			  "no pending request, authorization completed\n");
 		break;
 	case GSM48_MT_GMM_ATTACH_REQ:
+
+		extract_subscr_msisdn(ctx);
 #ifdef PTMSI_ALLOC
 		/* Start T3350 and re-transmit up to 5 times until ATTACH COMPLETE */
 		mmctx_timer_start(ctx, 3350, GSM0408_T3350_SECS);
 		ctx->t3350_mode = GMM_T3350_MODE_ATT;
 #else
+		memset(&sig_data, 0, sizeof(sig_data));
+		sig_data.mm = mmctx;
+		osmo_signal_dispatch(SS_SGSN, S_SGSN_ATTACH, &sig_data);
 		ctx->mm_state = GMM_REGISTERED_NORMAL;
 #endif
 
@@ -942,8 +984,13 @@
 			rc = gsm48_tx_gmm_det_ack_oldmsg(msg, 0);
 	}
 
-	if (ctx)
+	if (ctx) {
+		struct sgsn_signal_data sig_data;
+		memset(&sig_data, 0, sizeof(sig_data));
+		sig_data.mm = ctx;
+		osmo_signal_dispatch(SS_SGSN, S_SGSN_DETACH, &sig_data);
 		mm_ctx_cleanup_free(ctx, "GPRS DETACH REQUEST");
+	}
 
 	return rc;
 }
@@ -1049,6 +1096,9 @@
 static int gsm48_rx_gmm_ra_upd_req(struct sgsn_mm_ctx *mmctx, struct msgb *msg,
 				   struct gprs_llc_llme *llme)
 {
+#ifndef PTMSI_ALLOC
+	struct sgsn_signal_data sig_data;
+#endif
 	struct gsm48_hdr *gh = (struct gsm48_hdr *) msgb_gmmh(msg);
 	uint8_t *cur = gh->data;
 	uint8_t ms_ra_acc_cap_len;
@@ -1134,6 +1184,10 @@
 #else
 	/* Make sure we are NORMAL (i.e. not SUSPENDED anymore) */
 	mmctx->mm_state = GMM_REGISTERED_NORMAL;
+
+	memset(&sig_data, 0, sizeof(sig_data));
+	sig_data.mm = mmctx;
+	osmo_signal_dispatch(SS_SGSN, S_SGSN_UPDATE, &sig_data);
 #endif
 	/* Even if there is no P-TMSI allocated, the MS will switch from
 	 * foreign TLLI to local TLLI */
@@ -1183,6 +1237,7 @@
 static int gsm0408_rcv_gmm(struct sgsn_mm_ctx *mmctx, struct msgb *msg,
 			   struct gprs_llc_llme *llme)
 {
+	struct sgsn_signal_data sig_data;
 	struct gsm48_hdr *gh = (struct gsm48_hdr *) msgb_gmmh(msg);
 	int rc;
 
@@ -1264,6 +1319,10 @@
 				  GPRS_ALGO_GEA0, NULL);
 		mmctx->mm_state = GMM_REGISTERED_NORMAL;
 		rc = 0;
+
+		memset(&sig_data, 0, sizeof(sig_data));
+		sig_data.mm = mmctx;
+		osmo_signal_dispatch(SS_SGSN, S_SGSN_ATTACH, &sig_data);
 		break;
 	case GSM48_MT_GMM_RA_UPD_COMPL:
 		/* only in case SGSN offered new P-TMSI */
@@ -1278,6 +1337,10 @@
 				  GPRS_ALGO_GEA0, NULL);
 		mmctx->mm_state = GMM_REGISTERED_NORMAL;
 		rc = 0;
+
+		memset(&sig_data, 0, sizeof(sig_data));
+		sig_data.mm = mmctx;
+		osmo_signal_dispatch(SS_SGSN, S_SGSN_UPDATE, &sig_data);
 		break;
 	case GSM48_MT_GMM_PTMSI_REALL_COMPL:
 		LOGMMCTXP(LOGL_INFO, mmctx, "-> PTMSI REALLLICATION COMPLETE\n");
diff --git a/openbsc/src/gprs/gprs_sgsn.c b/openbsc/src/gprs/gprs_sgsn.c
index 711540e..5fe4e61 100644
--- a/openbsc/src/gprs/gprs_sgsn.c
+++ b/openbsc/src/gprs/gprs_sgsn.c
@@ -36,6 +36,7 @@
 #include <openbsc/gsm_04_08_gprs.h>
 #include <openbsc/gprs_gmm.h>
 #include <openbsc/gprs_utils.h>
+#include <openbsc/signal.h>
 #include "openbsc/gprs_llc.h"
 
 #include <time.h>
@@ -183,7 +184,7 @@
 
 /* this is a hard _free_ function, it doesn't clean up the PDP contexts
  * in libgtp! */
-void sgsn_mm_ctx_free(struct sgsn_mm_ctx *mm)
+static void sgsn_mm_ctx_free(struct sgsn_mm_ctx *mm)
 {
 	struct sgsn_pdp_ctx *pdp, *pdp2;
 
@@ -204,6 +205,7 @@
 	struct gprs_llc_llme *llme = mm->llme;
 	uint32_t tlli = mm->tlli;
 	struct sgsn_pdp_ctx *pdp, *pdp2;
+	struct sgsn_signal_data sig_data;
 
 	/* delete all existing PDP contexts for this MS */
 	llist_for_each_entry_safe(pdp, pdp2, &mm->pdp_list, list) {
@@ -217,6 +219,11 @@
 		osmo_timer_del(&mm->timer);
 	}
 
+	memset(&sig_data, 0, sizeof(sig_data));
+	sig_data.mm = mm;
+	osmo_signal_dispatch(SS_SGSN, S_SGSN_MM_FREE, &sig_data);
+
+
 	/* Detach from subscriber which is possibly freed then */
 	if (mm->subscr) {
 		struct gsm_subscriber *subscr = subscr_get(mm->subscr);
@@ -289,6 +296,8 @@
  */
 void sgsn_pdp_ctx_terminate(struct sgsn_pdp_ctx *pdp)
 {
+	struct sgsn_signal_data sig_data;
+
 	OSMO_ASSERT(pdp->mm != NULL);
 
 	/* There might still be pending callbacks in libgtp. So the parts of
@@ -299,6 +308,10 @@
 	/* Force the deactivation of the SNDCP layer */
 	sndcp_sm_deactivate_ind(&pdp->mm->llme->lle[pdp->sapi], pdp->nsapi);
 
+	memset(&sig_data, 0, sizeof(sig_data));
+	sig_data.pdp = pdp;
+	osmo_signal_dispatch(SS_SGSN, S_SGSN_PDP_TERMINATE, &sig_data);
+
 	/* Detach from MM context */
 	llist_del(&pdp->list);
 	pdp->mm = NULL;
@@ -313,6 +326,12 @@
  */
 void sgsn_pdp_ctx_free(struct sgsn_pdp_ctx *pdp)
 {
+	struct sgsn_signal_data sig_data;
+
+	memset(&sig_data, 0, sizeof(sig_data));
+	sig_data.pdp = pdp;
+	osmo_signal_dispatch(SS_SGSN, S_SGSN_PDP_FREE, &sig_data);
+
 	rate_ctr_group_free(pdp->ctrg);
 	if (pdp->mm)
 		llist_del(&pdp->list);
diff --git a/openbsc/src/gprs/sgsn_cdr.c b/openbsc/src/gprs/sgsn_cdr.c
new file mode 100644
index 0000000..0fcdd3b
--- /dev/null
+++ b/openbsc/src/gprs/sgsn_cdr.c
@@ -0,0 +1,254 @@
+/* GPRS SGSN CDR dumper */
+
+/* (C) 2015 by Holger Hans Peter Freyther
+ * 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 <openbsc/sgsn.h>
+#include <openbsc/signal.h>
+#include <openbsc/gprs_utils.h>
+#include <openbsc/debug.h>
+
+#include <openbsc/vty.h>
+
+#include <gtp.h>
+#include <pdp.h>
+
+#include <arpa/inet.h>
+
+#include <time.h>
+
+#include <stdio.h>
+#include <inttypes.h>
+
+/* TODO...avoid going through a global */
+extern struct sgsn_instance *sgsn;
+
+/**
+ * The CDR module will generate an entry like:
+ *
+ * IMSI, # Subscriber IMSI
+ * IMEI, # Subscriber IMEI
+ * MSISDN, # Subscriber MISDN
+ * Charging_Timestamp, # Event start Time
+ * Charging_UTC, # Time zone of event start time
+ * Duration, # Session DURATION
+ * Cell_Id, # CELL_ID
+ * Location_Area, # LAC
+ * GGSN_ADDR, # GGSN_ADDR
+ * SGSN_ADDR, # SGSN_ADDR
+ * APNI, # APNI
+ * PDP_ADDR, # PDP_ADDR
+ * VOL_IN, # VOL_IN in Bytes
+ * VOL_OUT, # VOL_OUT in Bytes
+ * CAUSE_FOR_TERM, # CAUSE_FOR_TERM
+ */
+
+
+static void maybe_print_header(FILE *cdr_file)
+{
+	if (ftell(cdr_file) != 0)
+		return;
+
+	fprintf(cdr_file, "timestamp,imsi,imei,msisdn,cell_id,lac,event,pdp_duration,ggsn_addr,sgsn_addr,apni,eua_addr,vol_in,vol_out\n");
+}
+
+static void cdr_log_mm(struct sgsn_instance *inst, const char *ev,
+			struct sgsn_mm_ctx *mmctx)
+{
+	FILE *cdr_file;
+	struct tm tm;
+	struct timeval tv;
+
+	if (!inst->cfg.cdr.filename)
+		return;
+
+	cdr_file = fopen(inst->cfg.cdr.filename, "a");
+	if (!cdr_file) {
+		LOGP(DGPRS, LOGL_ERROR, "Failed to open %s\n",
+			inst->cfg.cdr.filename);
+		return;
+	}
+
+	maybe_print_header(cdr_file);
+	gettimeofday(&tv, NULL);
+	gmtime_r(&tv.tv_sec, &tm);
+	fprintf(cdr_file, "%04d%02d%02d%02d%02d%02d%03d,%s,%s,%s,%d,%d,%s\n",
+		tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
+		tm.tm_hour, tm.tm_min, tm.tm_sec,
+		(int)(tv.tv_usec / 1000),
+		mmctx->imsi,
+		mmctx->imei,
+		mmctx->msisdn,
+		mmctx->cell_id,
+		mmctx->ra.lac,
+		ev);
+
+	fclose(cdr_file);
+}
+
+static void extract_eua(struct ul66_t *eua, char *eua_addr)
+{
+	if (eua->l < 2)
+		return;
+
+	/* there is no addr for ETSI/PPP */
+	if ((eua->v[0] & 0x0F) != 1) {
+		strcpy(eua_addr, "ETSI");
+		return;
+	}
+
+	if (eua->v[1] == 0x21 && eua->l == 6)
+		inet_ntop(AF_INET, &eua->v[2], eua_addr, INET_ADDRSTRLEN);
+	else if (eua->v[1] == 0x57 && eua->l == 18)
+		inet_ntop(AF_INET6, &eua->v[2], eua_addr, INET6_ADDRSTRLEN);
+	else {
+		/* e.g. both IPv4 and IPv6 */
+		strcpy(eua_addr, "Unknown address");
+	}
+}
+
+static void cdr_log_pdp(struct sgsn_instance *inst, const char *ev,
+			struct sgsn_pdp_ctx *pdp)
+{
+	FILE *cdr_file;
+	char apni[(pdp->lib ? pdp->lib->apn_use.l : 0) + 1];
+	char ggsn_addr[INET_ADDRSTRLEN + 1];
+	char sgsn_addr[INET_ADDRSTRLEN + 1];
+	char eua_addr[INET6_ADDRSTRLEN + 1];
+	struct tm tm;
+	struct timeval tv;
+	time_t duration;
+	struct timespec tp;
+
+	if (!inst->cfg.cdr.filename)
+		return;
+
+	memset(apni, 0, sizeof(apni));
+	memset(ggsn_addr, 0, sizeof(ggsn_addr));
+	memset(eua_addr, 0, sizeof(eua_addr));
+
+
+	if (pdp->lib) {
+		gprs_apn_to_str(apni, pdp->lib->apn_use.v, pdp->lib->apn_use.l);
+		inet_ntop(AF_INET, &pdp->lib->hisaddr0.s_addr, ggsn_addr, sizeof(ggsn_addr));
+		extract_eua(&pdp->lib->eua, eua_addr);
+	}
+
+	if (pdp->ggsn)
+		inet_ntop(AF_INET, &pdp->ggsn->gsn->gsnc.s_addr, sgsn_addr, sizeof(sgsn_addr));
+
+	cdr_file = fopen(inst->cfg.cdr.filename, "a");
+	if (!cdr_file) {
+		LOGP(DGPRS, LOGL_ERROR, "Failed to open %s\n",
+			inst->cfg.cdr.filename);
+		return;
+	}
+
+	maybe_print_header(cdr_file);
+
+	clock_gettime(CLOCK_MONOTONIC, &tp);
+	gettimeofday(&tv, NULL);
+
+	/* convert the timestamp to UTC */
+	gmtime_r(&tv.tv_sec, &tm);
+
+	/* Check the duration of the PDP context */
+	duration = tp.tv_sec - pdp->cdr_start.tv_sec;
+
+	fprintf(cdr_file,
+		"%04d%02d%02d%02d%02d%02d%03d,%s,%s,%s,%d,%d,%s,%ld,%s,%s,%s,%s,%" PRIu64 ",%" PRIu64 "\n",
+		tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
+		tm.tm_hour, tm.tm_min, tm.tm_sec,
+		(int)(tv.tv_usec / 1000),
+		pdp->mm ? pdp->mm->imsi : "N/A",
+		pdp->mm ? pdp->mm->imei : "N/A",
+		pdp->mm ? pdp->mm->msisdn : "N/A",
+		pdp->mm ? pdp->mm->cell_id : -1,
+		pdp->mm ? pdp->mm->ra.lac : -1,
+		ev,
+		(unsigned long ) duration,
+		ggsn_addr,
+		sgsn_addr,
+		apni,
+		eua_addr,
+		pdp->cdr_bytes_in,
+		pdp->cdr_bytes_out);
+	fclose(cdr_file);
+}
+
+static void cdr_pdp_timeout(void *_data)
+{
+	struct sgsn_pdp_ctx *pdp = _data;
+	cdr_log_pdp(sgsn, "pdp-periodic", pdp);
+	osmo_timer_schedule(&pdp->cdr_timer, sgsn->cfg.cdr.interval, 0);
+}
+
+static int handle_sgsn_sig(unsigned int subsys, unsigned int signal,
+			void *handler_data, void *_signal_data)
+{
+	struct sgsn_signal_data *signal_data = _signal_data;
+	struct sgsn_instance *inst = handler_data;
+
+	if (subsys != SS_SGSN)
+		return 0;
+
+	switch (signal) {
+	case S_SGSN_ATTACH:
+		cdr_log_mm(inst, "attach", signal_data->mm);
+		break;
+	case S_SGSN_UPDATE:
+		cdr_log_mm(inst, "update", signal_data->mm);
+		break;
+	case S_SGSN_DETACH:
+		cdr_log_mm(inst, "detach", signal_data->mm);
+		break;
+	case S_SGSN_MM_FREE:
+		cdr_log_mm(inst, "free", signal_data->mm);
+		break;
+	case S_SGSN_PDP_ACT:
+		clock_gettime(CLOCK_MONOTONIC, &signal_data->pdp->cdr_start);
+		cdr_log_pdp(inst, "pdp-act", signal_data->pdp);
+		signal_data->pdp->cdr_timer.cb = cdr_pdp_timeout;
+		signal_data->pdp->cdr_timer.data = signal_data->pdp;
+		osmo_timer_schedule(&signal_data->pdp->cdr_timer, inst->cfg.cdr.interval, 0);
+		break;
+	case S_SGSN_PDP_DEACT:
+		cdr_log_pdp(inst, "pdp-deact", signal_data->pdp);
+		osmo_timer_del(&signal_data->pdp->cdr_timer);
+		break;
+	case S_SGSN_PDP_TERMINATE:
+		cdr_log_pdp(inst, "pdp-terminate", signal_data->pdp);
+		osmo_timer_del(&signal_data->pdp->cdr_timer);
+		break;
+	case S_SGSN_PDP_FREE:
+		cdr_log_pdp(inst, "pdp-free", signal_data->pdp);
+		osmo_timer_del(&signal_data->pdp->cdr_timer);
+		break;
+	}
+
+	return 0;
+}
+
+int sgsn_cdr_init(struct sgsn_instance *sgsn)
+{
+	/* register for CDR related events */
+	sgsn->cfg.cdr.interval = 10 * 60;
+	osmo_signal_register_handler(SS_SGSN, handle_sgsn_sig, sgsn);
+
+	return 0;
+}
diff --git a/openbsc/src/gprs/sgsn_libgtp.c b/openbsc/src/gprs/sgsn_libgtp.c
index eee3ef2..9972cdd 100644
--- a/openbsc/src/gprs/sgsn_libgtp.c
+++ b/openbsc/src/gprs/sgsn_libgtp.c
@@ -287,6 +287,7 @@
 /* The GGSN has confirmed the creation of a PDP Context */
 static int create_pdp_conf(struct pdp_t *pdp, void *cbp, int cause)
 {
+	struct sgsn_signal_data sig_data;
 	struct sgsn_pdp_ctx *pctx = cbp;
 	uint8_t reject_cause;
 
@@ -322,6 +323,11 @@
 	/* Activate the SNDCP layer */
 	sndcp_sm_activate_ind(&pctx->mm->llme->lle[pctx->sapi], pctx->nsapi);
 
+	/* Inform others about it */
+	memset(&sig_data, 0, sizeof(sig_data));
+	sig_data.pdp = pctx;
+	osmo_signal_dispatch(SS_SGSN, S_SGSN_PDP_ACT, &sig_data);
+
 	/* Send PDP CTX ACT to MS */
 	return gsm48_tx_gsm_act_pdp_acc(pctx);
 
@@ -349,12 +355,17 @@
 /* Confirmation of a PDP Context Delete */
 static int delete_pdp_conf(struct pdp_t *pdp, void *cbp, int cause)
 {
+	struct sgsn_signal_data sig_data;
 	struct sgsn_pdp_ctx *pctx = cbp;
 	int rc = 0;
 
 	LOGPDPCTXP(LOGL_INFO, pctx, "Received DELETE PDP CTX CONF, cause=%d(%s)\n",
 		cause, get_value_string(gtp_cause_strs, cause));
 
+	memset(&sig_data, 0, sizeof(sig_data));
+	sig_data.pdp = pctx;
+	osmo_signal_dispatch(SS_SGSN, S_SGSN_PDP_DEACT, &sig_data);
+
 	if (pctx->mm) {
 		/* Deactivate the SNDCP layer */
 		sndcp_sm_deactivate_ind(&pctx->mm->llme->lle[pctx->sapi], pctx->nsapi);
@@ -523,6 +534,9 @@
 	rate_ctr_inc(&mm->ctrg->ctr[GMM_CTR_PKTS_UDATA_OUT]);
 	rate_ctr_add(&mm->ctrg->ctr[GMM_CTR_BYTES_UDATA_OUT], len);
 
+	/* It is easier to have a global count */
+	pdp->cdr_bytes_out += len;
+
 	return sndcp_unitdata_req(msg, &mm->llme->lle[pdp->sapi],
 				  pdp->nsapi, mm);
 }
@@ -558,6 +572,9 @@
 	rate_ctr_inc(&mmctx->ctrg->ctr[GMM_CTR_PKTS_UDATA_IN]);
 	rate_ctr_add(&mmctx->ctrg->ctr[GMM_CTR_BYTES_UDATA_IN], npdu_len);
 
+	/* It is easier to have a global count */
+	pdp->cdr_bytes_in += npdu_len;
+
 	return gtp_data_req(pdp->ggsn->gsn, pdp->lib, npdu, npdu_len);
 }
 
diff --git a/openbsc/src/gprs/sgsn_main.c b/openbsc/src/gprs/sgsn_main.c
index 0db90d5..d5f7f65 100644
--- a/openbsc/src/gprs/sgsn_main.c
+++ b/openbsc/src/gprs/sgsn_main.c
@@ -344,6 +344,7 @@
 	gprs_llc_vty_init();
 	gprs_sndcp_vty_init();
 	sgsn_auth_init();
+	sgsn_cdr_init(&sgsn_inst);
 	/* FIXME: register signal handler for SS_L_NS */
 
 	rc = sgsn_parse_config(sgsn_inst.config_file, &sgsn_inst.cfg);
diff --git a/openbsc/src/gprs/sgsn_vty.c b/openbsc/src/gprs/sgsn_vty.c
index be575d3..8b6e3ec 100644
--- a/openbsc/src/gprs/sgsn_vty.c
+++ b/openbsc/src/gprs/sgsn_vty.c
@@ -1,6 +1,7 @@
 /*
  * (C) 2010-2013 by Harald Welte <laforge@gnumonks.org>
  * (C) 2010 by On-Waves
+ * (C) 2015 by Holger Hans Peter Freyther
  * All Rights Reserved
  *
  * This program is free software; you can redistribute it and/or modify
@@ -164,6 +165,12 @@
 				actx->ggsn->id, VTY_NEWLINE);
 	}
 
+	if (g_cfg->cdr.filename)
+		vty_out(vty, " cdr filename %s%s", g_cfg->cdr.filename, VTY_NEWLINE);
+	else
+		vty_out(vty, " no cdr filename%s", VTY_NEWLINE);
+	vty_out(vty, " cdr interval %d%s", g_cfg->cdr.interval, VTY_NEWLINE);
+
 	return CMD_SUCCESS;
 }
 
@@ -811,6 +818,32 @@
 	return CMD_SUCCESS;
 }
 
+DEFUN(cfg_cdr_filename, cfg_cdr_filename_cmd,
+	"cdr filename NAME",
+	"CDR\nSet filename\nname\n")
+{
+	talloc_free(g_cfg->cdr.filename);
+	g_cfg->cdr.filename = talloc_strdup(tall_vty_ctx, argv[0]);
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_no_cdr_filename, cfg_no_cdr_filename_cmd,
+	"no cdr filename",
+	NO_STR "CDR\nDisable CDR generation\n")
+{
+	talloc_free(g_cfg->cdr.filename);
+	g_cfg->cdr.filename = NULL;
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_cdr_interval, cfg_cdr_interval_cmd,
+	"cdr interval <1-2147483647>",
+	"CDR\nPDP periodic log interval\nSeconds\n")
+{
+	g_cfg->cdr.interval = atoi(argv[0]);
+	return CMD_SUCCESS;
+}
+
 int sgsn_vty_init(void)
 {
 	install_element_ve(&show_sgsn_cmd);
@@ -842,6 +875,9 @@
 	install_element(SGSN_NODE, &cfg_apn_imsi_ggsn_cmd);
 	install_element(SGSN_NODE, &cfg_apn_name_cmd);
 	install_element(SGSN_NODE, &cfg_no_apn_name_cmd);
+	install_element(SGSN_NODE, &cfg_cdr_filename_cmd);
+	install_element(SGSN_NODE, &cfg_no_cdr_filename_cmd);
+	install_element(SGSN_NODE, &cfg_cdr_interval_cmd);
 
 	return 0;
 }
diff --git a/openbsc/tests/sgsn/sgsn_test.c b/openbsc/tests/sgsn/sgsn_test.c
index d9b162d..879dfe3 100644
--- a/openbsc/tests/sgsn/sgsn_test.c
+++ b/openbsc/tests/sgsn/sgsn_test.c
@@ -953,6 +953,8 @@
 		/* check that the MM context has not been removed due to a
 		 * failed authorization */
 		OSMO_ASSERT(ctx == sgsn_mm_ctx_by_tlli(foreign_tlli, &raid));
+		if (ctx->subscr && ctx->subscr->sgsn_data->msisdn_len > 0)
+			OSMO_ASSERT(strcmp(ctx->msisdn, "+49166213323") == 0);
 	}
 
 	if (retry && sgsn_tx_counter == 0)
@@ -1151,6 +1153,8 @@
 			0x10, 0x01, 0x01,
 			0x11, 0x02, 0xf1, 0x21, /* IPv4 */
 			0x12, 0x09, 0x04, 't', 'e', 's', 't', 0x03, 'a', 'p', 'n',
+		0x08, 0x07, /* MSISDN 49166213323 encoded */
+			0x91, 0x94, 0x61, 0x26, 0x31, 0x23, 0xF3,
 	};
 
 	OSMO_ASSERT(!mmctx || mmctx->subscr);
diff --git a/openbsc/tests/vty_test_runner.py b/openbsc/tests/vty_test_runner.py
index 3581b67..4cd4665 100644
--- a/openbsc/tests/vty_test_runner.py
+++ b/openbsc/tests/vty_test_runner.py
@@ -891,6 +891,34 @@
         res = self.vty.command("show running-config")
         self.assertEquals(res.find("apn internet"), -1)
 
+    def testVtyCDR(self):
+        self.vty.enable()
+        self.assertTrue(self.vty.verify('configure terminal', ['']))
+        self.assertEquals(self.vty.node(), 'config')
+        self.assertTrue(self.vty.verify('sgsn', ['']))
+        self.assertEquals(self.vty.node(), 'config-sgsn')
+
+        res = self.vty.command("show running-config")
+        self.assert_(res.find("no cdr filename") > 0)
+
+        self.vty.command("cdr filename bla.cdr")
+        res = self.vty.command("show running-config")
+        self.assertEquals(res.find("no cdr filename"), -1)
+        self.assert_(res.find(" cdr filename bla.cdr") > 0)
+
+        self.vty.command("no cdr filename")
+        res = self.vty.command("show running-config")
+        self.assert_(res.find("no cdr filename") > 0)
+        self.assertEquals(res.find(" cdr filename bla.cdr"), -1)
+
+        res = self.vty.command("show running-config")
+        self.assert_(res.find(" cdr interval 600") > 0)
+
+        self.vty.command("cdr interval 900")
+        res = self.vty.command("show running-config")
+        self.assert_(res.find(" cdr interval 900") > 0)
+        self.assertEquals(res.find(" cdr interval 600"), -1)
+
 def add_nat_test(suite, workdir):
     if not os.path.isfile(os.path.join(workdir, "src/osmo-bsc_nat/osmo-bsc_nat")):
         print("Skipping the NAT test")