diff --git a/openbsc/include/openbsc/gprs_gmm.h b/openbsc/include/openbsc/gprs_gmm.h
index 5b3321f..702b9b9 100644
--- a/openbsc/include/openbsc/gprs_gmm.h
+++ b/openbsc/include/openbsc/gprs_gmm.h
@@ -22,4 +22,6 @@
 int gprs_gmm_rx_resume(struct gprs_ra_id *raid, uint32_t tlli,
 		       uint8_t suspend_ref);
 
+time_t gprs_max_time_to_idle(void);
+
 #endif /* _GPRS_GMM_H */
diff --git a/openbsc/include/openbsc/gprs_llc.h b/openbsc/include/openbsc/gprs_llc.h
index fc6216c..d54b72e 100644
--- a/openbsc/include/openbsc/gprs_llc.h
+++ b/openbsc/include/openbsc/gprs_llc.h
@@ -161,8 +161,13 @@
 	uint16_t bvci;
 	uint16_t nsei;
 	struct gprs_llc_lle lle[NUM_SAPIS];
+
+	/* Internal management */
+	uint32_t age_timestamp;
 };
 
+#define GPRS_LLME_RESET_AGE (0)
+
 extern struct llist_head gprs_llc_llmes;
 
 /* LLC low level types */
diff --git a/openbsc/include/openbsc/gprs_sgsn.h b/openbsc/include/openbsc/gprs_sgsn.h
index 00cf5cc..7940e1d 100644
--- a/openbsc/include/openbsc/gprs_sgsn.h
+++ b/openbsc/include/openbsc/gprs_sgsn.h
@@ -246,6 +246,7 @@
 extern struct llist_head sgsn_pdp_ctxts;
 
 uint32_t sgsn_alloc_ptmsi(void);
+void sgsn_inst_init(void);
 
 /* High-level function to be called in case a GGSN has disappeared or
  * ottherwise lost state (recovery procedure) */
diff --git a/openbsc/include/openbsc/sgsn.h b/openbsc/include/openbsc/sgsn.h
index 8a45146..4bd4127 100644
--- a/openbsc/include/openbsc/sgsn.h
+++ b/openbsc/include/openbsc/sgsn.h
@@ -52,6 +52,8 @@
 	struct gsn_t *gsn;
 	/* Subscriber */
 	struct gprs_gsup_client *gsup_client;
+	/* LLME inactivity timer */
+	struct osmo_timer_list llme_timer;
 };
 
 extern struct sgsn_instance *sgsn;
diff --git a/openbsc/src/gprs/Makefile.am b/openbsc/src/gprs/Makefile.am
index bdbad19..bc3e21e 100644
--- a/openbsc/src/gprs/Makefile.am
+++ b/openbsc/src/gprs/Makefile.am
@@ -27,4 +27,4 @@
 			gsm_04_08_gprs.c
 osmo_sgsn_LDADD = 	\
 			$(top_builddir)/src/libcommon/libcommon.a \
-			-lgtp $(OSMO_LIBS) $(LIBOSMOABIS_LIBS)
+			-lgtp $(OSMO_LIBS) $(LIBOSMOABIS_LIBS) -lrt
diff --git a/openbsc/src/gprs/gprs_gmm.c b/openbsc/src/gprs/gprs_gmm.c
index 3977c66..1e1372c 100644
--- a/openbsc/src/gprs/gprs_gmm.c
+++ b/openbsc/src/gprs/gprs_gmm.c
@@ -70,6 +70,7 @@
 #define GSM0408_T3313_SECS	30	/* waiting for paging response */
 #define GSM0408_T3314_SECS	44	/* force to STBY on expiry, Ready timer */
 #define GSM0408_T3316_SECS	44
+#define GSM0408_MOBILE_REACHABLE_SECS (GSM0408_T3312_SECS + 4 * 60)
 
 /* Section 11.3 / Table 11.2d Timers of Session Management - network side */
 #define GSM0408_T3385_SECS	8	/* wait for ACT PDP CTX REQ */
@@ -140,6 +141,11 @@
 	osmo_timer_del(&mm->timer);
 }
 
+time_t gprs_max_time_to_idle(void)
+{
+	return GSM0408_T3314_SECS + GSM0408_MOBILE_REACHABLE_SECS;
+}
+
 /* Send a message through the underlying layer */
 static int gsm48_gmm_sendmsg(struct msgb *msg, int command,
 			     struct sgsn_mm_ctx *mm)
diff --git a/openbsc/src/gprs/gprs_llc.c b/openbsc/src/gprs/gprs_llc.c
index 0b4613e..9b5bf4b 100644
--- a/openbsc/src/gprs/gprs_llc.c
+++ b/openbsc/src/gprs/gprs_llc.c
@@ -256,6 +256,7 @@
 	llme->tlli = tlli;
 	llme->old_tlli = 0xffffffff;
 	llme->state = GPRS_LLMS_UNASSIGNED;
+	llme->age_timestamp = GPRS_LLME_RESET_AGE;
 
 	for (i = 0; i < ARRAY_SIZE(llme->lle); i++)
 		lle_init(llme, i);
@@ -622,6 +623,9 @@
 		return 0;
 	}
 
+	/* reset age computation */
+	lle->llme->age_timestamp = GPRS_LLME_RESET_AGE;
+
 	/* decrypt information field + FCS, if needed! */
 	if (llhp.is_encrypted) {
 		uint32_t iov_ui = 0; /* FIXME: randomly select for TLLI */
diff --git a/openbsc/src/gprs/gprs_llc_vty.c b/openbsc/src/gprs/gprs_llc_vty.c
index ab52699..f399b27 100644
--- a/openbsc/src/gprs/gprs_llc_vty.c
+++ b/openbsc/src/gprs/gprs_llc_vty.c
@@ -23,6 +23,7 @@
 #include <unistd.h>
 #include <errno.h>
 #include <stdint.h>
+#include <time.h>
 
 #include <arpa/inet.h>
 
@@ -69,9 +70,13 @@
 static void vty_dump_llme(struct vty *vty, struct gprs_llc_llme *llme)
 {
 	unsigned int i;
+	struct timespec now_tp = {0};
+	clock_gettime(CLOCK_MONOTONIC, &now_tp);
 
-	vty_out(vty, "TLLI %08x (Old TLLI %08x) BVCI=%u NSEI=%u: State %s%s",
+	vty_out(vty, "TLLI %08x (Old TLLI %08x) BVCI=%u NSEI=%u Age=%d: State %s%s",
 		llme->tlli, llme->old_tlli, llme->bvci, llme->nsei,
+		llme->age_timestamp == GPRS_LLME_RESET_AGE ? 0 :
+		(int)(now_tp.tv_sec - (time_t)llme->age_timestamp),
 		get_value_string(gprs_llc_state_strs, llme->state), VTY_NEWLINE);
 
 	for (i = 0; i < ARRAY_SIZE(valid_sapis); i++) {
diff --git a/openbsc/src/gprs/gprs_sgsn.c b/openbsc/src/gprs/gprs_sgsn.c
index 6f70664..2b78d31 100644
--- a/openbsc/src/gprs/gprs_sgsn.c
+++ b/openbsc/src/gprs/gprs_sgsn.c
@@ -37,6 +37,10 @@
 #include <openbsc/gprs_gmm.h>
 #include "openbsc/gprs_llc.h"
 
+#include <time.h>
+
+#define GPRS_LLME_CHECK_TICK 30
+
 extern struct sgsn_instance *sgsn;
 
 LLIST_HEAD(sgsn_mm_ctxts);
@@ -508,3 +512,62 @@
 
 	sgsn_auth_update(mmctx);
 }
+
+static void sgsn_llme_cleanup_free(struct gprs_llc_llme *llme)
+{
+	struct sgsn_mm_ctx *mmctx = NULL;
+
+	llist_for_each_entry(mmctx, &sgsn_mm_ctxts, list) {
+		if (llme == mmctx->llme) {
+			gsm0408_gprs_access_cancelled(mmctx, SGSN_ERROR_CAUSE_NONE);
+			return;
+		}
+	}
+
+	/* No MM context found */
+	LOGP(DGPRS, LOGL_INFO, "Deleting orphaned LLME, TLLI 0x%08x\n",
+	     llme->tlli);
+	gprs_llgmm_assign(llme, llme->tlli, 0xffffffff, GPRS_ALGO_GEA0, NULL);
+}
+
+static void sgsn_llme_check_cb(void *data_)
+{
+	struct gprs_llc_llme *llme, *llme_tmp;
+	struct timespec now_tp;
+	time_t now, age;
+	time_t max_age = gprs_max_time_to_idle();
+
+	int rc;
+
+	rc = clock_gettime(CLOCK_MONOTONIC, &now_tp);
+	OSMO_ASSERT(rc >= 0);
+	now = now_tp.tv_sec;
+
+	LOGP(DGPRS, LOGL_DEBUG,
+	     "Checking for inactive LLMEs, time = %u\n", (unsigned)now);
+
+	llist_for_each_entry_safe(llme, llme_tmp, &gprs_llc_llmes, list) {
+		if (llme->age_timestamp == GPRS_LLME_RESET_AGE)
+			llme->age_timestamp = now;
+
+		age = now - llme->age_timestamp;
+
+		if (age > max_age || age < 0) {
+			LOGP(DGPRS, LOGL_INFO,
+			     "Inactivity timeout for TLLI 0x%08x, age %d\n",
+			     llme->tlli, (int)age);
+			sgsn_llme_cleanup_free(llme);
+		}
+	}
+
+	osmo_timer_schedule(&sgsn->llme_timer, GPRS_LLME_CHECK_TICK, 0);
+}
+
+void sgsn_inst_init()
+{
+	sgsn->llme_timer.cb = sgsn_llme_check_cb;
+	sgsn->llme_timer.data = NULL;
+
+	osmo_timer_schedule(&sgsn->llme_timer, GPRS_LLME_CHECK_TICK, 0);
+}
+
diff --git a/openbsc/src/gprs/sgsn_main.c b/openbsc/src/gprs/sgsn_main.c
index f26b812..0db90d5 100644
--- a/openbsc/src/gprs/sgsn_main.c
+++ b/openbsc/src/gprs/sgsn_main.c
@@ -337,6 +337,7 @@
 	bssgp_nsi = sgsn_inst.cfg.nsi = sgsn_nsi;
 
 	gprs_llc_init("/usr/local/lib/osmocom/crypt/");
+	sgsn_inst_init();
 
 	gprs_ns_vty_init(bssgp_nsi);
 	bssgp_vty_init();
diff --git a/openbsc/tests/sgsn/Makefile.am b/openbsc/tests/sgsn/Makefile.am
index c1b5fbd..693cf79 100644
--- a/openbsc/tests/sgsn/Makefile.am
+++ b/openbsc/tests/sgsn/Makefile.am
@@ -32,5 +32,5 @@
 	$(LIBOSMOCORE_LIBS) \
 	$(LIBOSMOGSM_LIBS) \
 	$(LIBOSMOGB_LIBS) \
-	-lgtp
+	-lgtp -lrt