diff --git a/include/osmocom/sgsn/Makefile.am b/include/osmocom/sgsn/Makefile.am
index 0ab00fe..9ddc2bc 100644
--- a/include/osmocom/sgsn/Makefile.am
+++ b/include/osmocom/sgsn/Makefile.am
@@ -6,6 +6,7 @@
 	gprs_gb.h \
 	gprs_gb_parse.h \
 	gprs_gmm.h \
+	gprs_gmm_fsm.h \
 	gprs_gmm_attach.h \
 	gprs_mm_state_gb_fsm.h \
 	gprs_mm_state_iu_fsm.h \
diff --git a/include/osmocom/sgsn/gprs_gmm_fsm.h b/include/osmocom/sgsn/gprs_gmm_fsm.h
new file mode 100644
index 0000000..fd5b4bf
--- /dev/null
+++ b/include/osmocom/sgsn/gprs_gmm_fsm.h
@@ -0,0 +1,34 @@
+#pragma once
+
+#include <osmocom/core/fsm.h>
+
+/* 3GPP TS 24.008 § 4.1.3.3 GMM mobility management states on the network side */
+enum gmm_fsm_states {
+	ST_GMM_DEREGISTERED,		/* 4.1.3.3.1.1 */
+	ST_GMM_COMMON_PROC_INIT,	/* 4.1.3.3.1.2 */
+	ST_GMM_REGISTERED_NORMAL,	/* 4.1.3.3.2.1 */
+	ST_GMM_REGISTERED_SUSPENDED,	/* 4.1.3.3.2.2 */
+	ST_GMM_DEREGISTERED_INIT,	/* 4.1.3.3.1.4 */
+};
+
+enum gmm_fsm_events {
+	E_GMM_COMMON_PROC_INIT_REQ,
+	/* E_GMM_COMMON_PROC_FAILED, NOT USED */
+	/* E_GMM_LOWER_LAYER_FAILED, NOT USED */
+	E_GMM_COMMON_PROC_SUCCESS,
+	E_GMM_ATTACH_SUCCESS,
+	/* E_GMM_NET_INIT_DETACH_REQ, NOT USED */
+	/* E_GMM_MS_INIT_DETACH_REQ, NOT USED */
+	/* E_GMM_DETACH_ACCEPTED, */
+	E_GMM_SUSPEND,
+	E_GMM_RESUME,
+	E_GMM_CLEANUP,
+};
+
+static inline bool gmm_fsm_is_registered(struct osmo_fsm_inst *fi)
+{
+	return fi->state == ST_GMM_REGISTERED_NORMAL ||
+	       fi->state == ST_GMM_REGISTERED_SUSPENDED;
+}
+
+extern struct osmo_fsm gmm_fsm;
diff --git a/include/osmocom/sgsn/gprs_sgsn.h b/include/osmocom/sgsn/gprs_sgsn.h
index 20e0e06..0a52a7d 100644
--- a/include/osmocom/sgsn/gprs_sgsn.h
+++ b/include/osmocom/sgsn/gprs_sgsn.h
@@ -23,15 +23,6 @@
 
 enum gsm48_gsm_cause;
 
-/* 3GPP TS 24.008 § 4.1.3.3 GMM mobility management states on the network side */
-enum gprs_gmm_state {
-	GMM_DEREGISTERED,		/* 4.1.3.3.1.1 */
-	GMM_COMMON_PROC_INIT,		/* 4.1.3.3.1.2 */
-	GMM_REGISTERED_NORMAL,		/* 4.1.3.3.2.1 */
-	GMM_REGISTERED_SUSPENDED,	/* 4.1.3.3.2.2 */
-	GMM_DEREGISTERED_INIT,		/* 4.1.3.3.1.4 */
-};
-
 enum gprs_mm_ctr {
 	GMM_CTR_PKTS_SIG_IN,
 	GMM_CTR_PKTS_SIG_OUT,
@@ -128,7 +119,7 @@
 	enum sgsn_ran_type	ran_type;
 
 	char 			imsi[GSM23003_IMSI_MAX_DIGITS+1];
-	enum gprs_gmm_state	gmm_state;
+	struct osmo_fsm_inst	*gmm_fsm;
 	uint32_t 		p_tmsi;
 	uint32_t 		p_tmsi_old;	/* old P-TMSI before new is confirmed */
 	uint32_t 		p_tmsi_sig;
diff --git a/src/sgsn/Makefile.am b/src/sgsn/Makefile.am
index a8da943..4402c9c 100644
--- a/src/sgsn/Makefile.am
+++ b/src/sgsn/Makefile.am
@@ -43,6 +43,7 @@
 	gprs_gb.c \
 	gprs_gmm_attach.c \
 	gprs_gmm.c \
+	gprs_gmm_fsm.c \
 	gprs_mm_state_gb_fsm.c \
 	gprs_mm_state_iu_fsm.c \
 	gprs_ranap.c \
diff --git a/src/sgsn/gprs_gmm.c b/src/sgsn/gprs_gmm.c
index 399f7bf..3317a09 100644
--- a/src/sgsn/gprs_gmm.c
+++ b/src/sgsn/gprs_gmm.c
@@ -57,6 +57,7 @@
 #include <osmocom/sgsn/gprs_gmm_attach.h>
 #include <osmocom/sgsn/gprs_mm_state_gb_fsm.h>
 #include <osmocom/sgsn/gprs_mm_state_iu_fsm.h>
+#include <osmocom/sgsn/gprs_gmm_fsm.h>
 #include <osmocom/sgsn/signal.h>
 #include <osmocom/sgsn/gprs_sndcp.h>
 #include <osmocom/sgsn/gprs_ranap.h>
@@ -211,7 +212,7 @@
 	LOGMMCTXP(LOGL_INFO, ctx, "Cleaning MM context due to %s\n", log_text);
 
 	/* Mark MM state as deregistered */
-	ctx->gmm_state = GMM_DEREGISTERED;
+	osmo_fsm_inst_dispatch(ctx->gmm_fsm, E_GMM_CLEANUP, NULL);
 
 	switch(ctx->ran_type) {
 	case MM_CTX_T_UTRAN_Iu:
@@ -967,7 +968,7 @@
 		memset(&sig_data, 0, sizeof(sig_data));
 		sig_data.mm = mmctx;
 		osmo_signal_dispatch(SS_SGSN, S_SGSN_ATTACH, &sig_data);
-		ctx->gmm_state = GMM_REGISTERED_NORMAL;
+		osmo_fsm_inst_dispatch(mm->gmm_fsm, E_GMM_ATTACH_SUCCESS, NULL);
 #endif
 
 		return gsm48_tx_gmm_att_ack(ctx);
@@ -1009,8 +1010,8 @@
 
 void gsm0408_gprs_access_granted(struct sgsn_mm_ctx *ctx)
 {
-	switch (ctx->gmm_state) {
-	case GMM_COMMON_PROC_INIT:
+	switch (ctx->gmm_fsm->state) {
+	case ST_GMM_COMMON_PROC_INIT:
 		LOGMMCTXP(LOGL_NOTICE, ctx,
 		     "Authorized, continuing procedure, IMSI=%s\n",
 		     ctx->imsi);
@@ -1030,8 +1031,8 @@
 	if (gmm_cause == SGSN_ERROR_CAUSE_NONE)
 		gmm_cause = GMM_CAUSE_GPRS_NOTALLOWED;
 
-	switch (ctx->gmm_state) {
-	case GMM_COMMON_PROC_INIT:
+	switch (ctx->gmm_fsm->state) {
+	case ST_GMM_COMMON_PROC_INIT:
 		LOGMMCTXP(LOGL_NOTICE, ctx,
 			  "Not authorized, rejecting ATTACH REQUEST "
 			  "with cause '%s' (%d)\n",
@@ -1040,8 +1041,8 @@
 		if (ctx->gmm_att_req.fsm->state != ST_INIT)
 			osmo_fsm_inst_dispatch(ctx->gmm_att_req.fsm, E_REJECT, (void *) (long) gmm_cause);
 		break;
-	case GMM_REGISTERED_NORMAL:
-	case GMM_REGISTERED_SUSPENDED:
+	case ST_GMM_REGISTERED_NORMAL:
+	case ST_GMM_REGISTERED_SUSPENDED:
 		LOGMMCTXP(LOGL_NOTICE, ctx,
 			  "Authorization lost, detaching "
 			  "with cause '%s' (%d)\n",
@@ -1142,7 +1143,7 @@
 {
 	uint32_t ptmsi;
 	/* Don't change the P-TMSI if a P-TMSI re-assignment is under way */
-	if (ctx->gmm_state != GMM_COMMON_PROC_INIT) {
+	if (ctx->gmm_fsm->state != ST_GMM_COMMON_PROC_INIT) {
 		ptmsi = sgsn_alloc_ptmsi();
 		if (ptmsi != GSM_RESERVED_TMSI) {
 			ctx->p_tmsi_old = ctx->p_tmsi;
@@ -1150,7 +1151,7 @@
 		} else
 			LOGMMCTXP(LOGL_ERROR, ctx, "P-TMSI allocation failure: using old one.\n");
 	}
-	ctx->gmm_state = GMM_COMMON_PROC_INIT;
+	osmo_fsm_inst_dispatch(ctx->gmm_fsm, E_GMM_COMMON_PROC_INIT_REQ, NULL);
 }
 
 /* 3GPP TS 24.008 § 9.4.1 Attach request */
@@ -1360,7 +1361,7 @@
 	mmctx->t3350_mode = GMM_T3350_MODE_NONE;
 	mmctx->p_tmsi_old = 0;
 	mmctx->pending_req = 0;
-	mmctx->gmm_state = GMM_REGISTERED_NORMAL;
+	osmo_fsm_inst_dispatch(mmctx->gmm_fsm, E_GMM_ATTACH_SUCCESS, NULL);
 	switch(mmctx->ran_type) {
 	case MM_CTX_T_UTRAN_Iu:
 		osmo_fsm_inst_dispatch(mmctx->iu.mm_state_fsm, E_PMM_PS_ATTACH, NULL);
@@ -1658,11 +1659,10 @@
 				mmctx->p_tmsi, mmctx->p_tmsi_old,
 				mmctx->gb.tlli, mmctx->gb.tlli_new,
 				osmo_rai_name(&mmctx->ra));
-
-			mmctx->gmm_state = GMM_COMMON_PROC_INIT;
+			osmo_fsm_inst_dispatch(mmctx->gmm_fsm, E_GMM_COMMON_PROC_INIT_REQ, NULL);
 		}
 	} else if (!gprs_ra_id_equals(&mmctx->ra, &old_ra_id) ||
-		mmctx->gmm_state == GMM_DEREGISTERED)
+		mmctx->gmm_fsm->state == ST_GMM_DEREGISTERED)
 	{
 		/* We cannot use the mmctx */
 		LOGMMCTXP(LOGL_INFO, mmctx,
@@ -1715,7 +1715,7 @@
 	mmctx_timer_start(mmctx, 3350);
 #else
 	/* Make sure we are NORMAL (i.e. not SUSPENDED anymore) */
-	mmctx->gmm_state = GMM_REGISTERED_NORMAL;
+	osmo_fsm_inst_dispatch(mm->gmm_fsm, E_GMM_ATTACH_SUCCESS, NULL);
 
 	memset(&sig_data, 0, sizeof(sig_data));
 	sig_data.mm = mmctx;
@@ -1768,7 +1768,7 @@
 	mmctx->t3350_mode = GMM_T3350_MODE_NONE;
 	mmctx->p_tmsi_old = 0;
 	mmctx->pending_req = 0;
-	mmctx->gmm_state = GMM_REGISTERED_NORMAL;
+	osmo_fsm_inst_dispatch(mmctx->gmm_fsm, E_GMM_COMMON_PROC_SUCCESS, NULL);
 	switch(mmctx->ran_type) {
 	case MM_CTX_T_UTRAN_Iu:
 		osmo_fsm_inst_dispatch(mmctx->iu.mm_state_fsm, E_PMM_RA_UPDATE, NULL);
@@ -1883,7 +1883,7 @@
 		goto rejected;
 	}
 
-	ctx->gmm_state = GMM_COMMON_PROC_INIT;
+	osmo_fsm_inst_dispatch(ctx->gmm_fsm, E_GMM_COMMON_PROC_INIT_REQ, NULL);
 
 	ctx->iu.service.type = service_type;
 
@@ -2832,15 +2832,14 @@
 		return -EINVAL;
 	}
 
-	if (mmctx->gmm_state != GMM_REGISTERED_NORMAL &&
-	    mmctx->gmm_state != GMM_REGISTERED_SUSPENDED) {
+	if (!gmm_fsm_is_registered(mmctx->gmm_fsm)) {
 		LOGMMCTXP(LOGL_NOTICE, mmctx, "SUSPEND request while state "
 			"!= REGISTERED (TLLI=%08x)\n", tlli);
 		return -EINVAL;
 	}
 
 	/* Transition from REGISTERED_NORMAL to REGISTERED_SUSPENDED */
-	mmctx->gmm_state = GMM_REGISTERED_SUSPENDED;
+	osmo_fsm_inst_dispatch(mmctx->gmm_fsm, E_GMM_SUSPEND, NULL);
 	return 0;
 }
 
@@ -2858,8 +2857,7 @@
 		return -EINVAL;
 	}
 
-	if (mmctx->gmm_state != GMM_REGISTERED_NORMAL &&
-	    mmctx->gmm_state != GMM_REGISTERED_SUSPENDED) {
+	if (!gmm_fsm_is_registered(mmctx->gmm_fsm)) {
 		LOGMMCTXP(LOGL_NOTICE, mmctx, "RESUME request while state "
 			"!= SUSPENDED (TLLI=%08x)\n", tlli);
 		/* FIXME: should we not simply ignore it? */
@@ -2867,6 +2865,6 @@
 	}
 
 	/* Transition from SUSPENDED to NORMAL */
-	mmctx->gmm_state = GMM_REGISTERED_NORMAL;
+	osmo_fsm_inst_dispatch(mmctx->gmm_fsm, E_GMM_RESUME, NULL);
 	return 0;
 }
diff --git a/src/sgsn/gprs_gmm_fsm.c b/src/sgsn/gprs_gmm_fsm.c
new file mode 100644
index 0000000..fac06f2
--- /dev/null
+++ b/src/sgsn/gprs_gmm_fsm.c
@@ -0,0 +1,187 @@
+#include <osmocom/core/tdef.h>
+
+#include <osmocom/sgsn/gprs_gmm_fsm.h>
+
+#include <osmocom/sgsn/debug.h>
+#include <osmocom/sgsn/sgsn.h>
+
+#define X(s) (1 << (s))
+
+static const struct osmo_tdef_state_timeout gmm_fsm_timeouts[32] = {
+	[ST_GMM_DEREGISTERED] = { },
+	[ST_GMM_COMMON_PROC_INIT] = { },
+	[ST_GMM_REGISTERED_NORMAL] = { },
+	[ST_GMM_REGISTERED_SUSPENDED] = { },
+	[ST_GMM_DEREGISTERED_INIT] = { },
+};
+
+#define gmm_fsm_state_chg(fi, NEXT_STATE) \
+	osmo_tdef_fsm_inst_state_chg(fi, NEXT_STATE, gmm_fsm_timeouts, sgsn->cfg.T_defs, -1)
+
+static void st_gmm_deregistered(struct osmo_fsm_inst *fi, uint32_t event, void *data)
+{
+	switch(event) {
+	case E_GMM_COMMON_PROC_INIT_REQ:
+		gmm_fsm_state_chg(fi, ST_GMM_COMMON_PROC_INIT);
+		break;
+	case E_GMM_ATTACH_SUCCESS:
+		gmm_fsm_state_chg(fi, ST_GMM_REGISTERED_NORMAL);
+		break;
+	}
+}
+
+static void st_gmm_common_proc_init(struct osmo_fsm_inst *fi, uint32_t event, void *data)
+{
+	switch(event) {
+	/* TODO: events not used
+	case E_GMM_LOWER_LAYER_FAILED:
+	case E_GMM_COMMON_PROC_FAILED:
+		gmm_fsm_state_chg(fi, ST_GMM_DEREGISTERED);
+		break;
+	*/
+	case E_GMM_COMMON_PROC_SUCCESS:
+	case E_GMM_ATTACH_SUCCESS:
+		gmm_fsm_state_chg(fi, ST_GMM_REGISTERED_NORMAL);
+		break;
+	}
+}
+
+static void st_gmm_registered_normal(struct osmo_fsm_inst *fi, uint32_t event, void *data)
+{
+	switch(event) {
+	case E_GMM_COMMON_PROC_INIT_REQ:
+		gmm_fsm_state_chg(fi, ST_GMM_COMMON_PROC_INIT);
+		break;
+	/* case E_GMM_NET_INIT_DETACH_REQ:
+		gmm_fsm_state_chg(fi, ST_GMM_DEREGISTERED_INIT);
+		break; */
+	/* case E_GMM_MS_INIT_DETACH_REQ:
+		gmm_fsm_state_chg(fi, ST_GMM_DEREGISTERED);
+		break; */
+	case E_GMM_SUSPEND:
+		gmm_fsm_state_chg(fi, ST_GMM_REGISTERED_SUSPENDED);
+		break;
+	}
+}
+
+static void st_gmm_registered_suspended(struct osmo_fsm_inst *fi, uint32_t event, void *data)
+{
+	switch(event) {
+	case E_GMM_RESUME:
+		gmm_fsm_state_chg(fi, ST_GMM_REGISTERED_NORMAL);
+		break;
+	}
+}
+
+static void st_gmm_deregistered_init(struct osmo_fsm_inst *fi, uint32_t event, void *data)
+{
+	switch(event) {
+	/* TODO: events not used in osmo-sgsn code
+	case E_GMM_DETACH_ACCEPTED:
+	case E_GMM_LOWER_LAYER_FAILED:
+		gmm_fsm_state_chg(fi, ST_GMM_DEREGISTERED);
+		break;
+	*/
+	}
+}
+
+static struct osmo_fsm_state gmm_fsm_states[] = {
+	[ST_GMM_DEREGISTERED] = {
+		.in_event_mask =
+			X(E_GMM_COMMON_PROC_INIT_REQ) |
+			X(E_GMM_ATTACH_SUCCESS),
+		.out_state_mask = X(ST_GMM_COMMON_PROC_INIT),
+		.name = "Deregistered",
+		.action = st_gmm_deregistered,
+	},
+	[ST_GMM_COMMON_PROC_INIT] = {
+		.in_event_mask =
+			/* X(E_GMM_LOWER_LAYER_FAILED) | */
+			/* X(E_GMM_COMMON_PROC_FAILED) | */
+			X(E_GMM_COMMON_PROC_SUCCESS) |
+			X(E_GMM_ATTACH_SUCCESS),
+		.out_state_mask =
+			X(ST_GMM_DEREGISTERED) |
+			X(ST_GMM_REGISTERED_NORMAL),
+		.name = "CommonProcedureInitiated",
+		.action = st_gmm_common_proc_init,
+	},
+	[ST_GMM_REGISTERED_NORMAL] = {
+		.in_event_mask =
+			X(E_GMM_COMMON_PROC_INIT_REQ) |
+			/* X(E_GMM_NET_INIT_DETACH_REQ) | */
+			/* X(E_GMM_MS_INIT_DETACH_REQ) | */
+			X(E_GMM_SUSPEND),
+		.out_state_mask =
+			X(ST_GMM_DEREGISTERED) |
+			X(ST_GMM_COMMON_PROC_INIT) |
+			X(ST_GMM_DEREGISTERED_INIT) |
+			X(ST_GMM_REGISTERED_SUSPENDED),
+		.name = "Registered.NORMAL",
+		.action = st_gmm_registered_normal,
+	},
+	[ST_GMM_REGISTERED_SUSPENDED] = {
+		.in_event_mask = X(E_GMM_RESUME),
+		.out_state_mask =
+			X(ST_GMM_DEREGISTERED) |
+			X(ST_GMM_REGISTERED_NORMAL),
+		.name = "Registered.SUSPENDED",
+		.action = st_gmm_registered_suspended,
+	},
+	[ST_GMM_DEREGISTERED_INIT] = {
+		.in_event_mask = 0
+			/* X(E_GMM_DETACH_ACCEPTED) | */
+			/* X(E_GMM_LOWER_LAYER_FAILED) */,
+		.out_state_mask = X(ST_GMM_DEREGISTERED),
+		.name = "DeregisteredInitiated",
+		.action = st_gmm_deregistered_init,
+	},
+};
+
+const struct value_string gmm_fsm_event_names[] = {
+	OSMO_VALUE_STRING(E_GMM_COMMON_PROC_INIT_REQ),
+	/* OSMO_VALUE_STRING(E_GMM_COMMON_PROC_FAILED), */
+	/*  OSMO_VALUE_STRING(E_GMM_LOWER_LAYER_FAILED),  */
+	OSMO_VALUE_STRING(E_GMM_COMMON_PROC_SUCCESS),
+	OSMO_VALUE_STRING(E_GMM_ATTACH_SUCCESS),
+	/*  OSMO_VALUE_STRING(E_GMM_NET_INIT_DETACH_REQ), */
+	/*  OSMO_VALUE_STRING(E_GMM_MS_INIT_DETACH_REQ), */
+	/* OSMO_VALUE_STRING(E_GMM_DETACH_ACCEPTED), */
+	OSMO_VALUE_STRING(E_GMM_SUSPEND),
+	OSMO_VALUE_STRING(E_GMM_CLEANUP),
+	{ 0, NULL }
+};
+
+void gmm_fsm_allstate_action(struct osmo_fsm_inst *fi, uint32_t event, void *data) {
+	switch (event) {
+	case E_GMM_CLEANUP:
+		switch (fi->state) {
+		case ST_GMM_DEREGISTERED:
+			break;
+		default:
+			gmm_fsm_state_chg(fi, ST_GMM_DEREGISTERED);
+			break;
+		}
+	}
+}
+
+int gmm_fsm_timer_cb(struct osmo_fsm_inst *fi)
+{
+	return 0;
+}
+
+struct osmo_fsm gmm_fsm = {
+	.name = "GMM",
+	.states = gmm_fsm_states,
+	.num_states = ARRAY_SIZE(gmm_fsm_states),
+	.event_names = gmm_fsm_event_names,
+	.allstate_event_mask = X(E_GMM_CLEANUP),
+	.allstate_action = gmm_fsm_allstate_action,
+	.log_subsys = DMM,
+	.timer_cb = gmm_fsm_timer_cb,
+};
+
+static __attribute__((constructor)) void gmm_fsm_init(void)
+{
+	osmo_fsm_register(&gmm_fsm);
+}
diff --git a/src/sgsn/gprs_sgsn.c b/src/sgsn/gprs_sgsn.c
index 387c0d5..1c23d06 100644
--- a/src/sgsn/gprs_sgsn.c
+++ b/src/sgsn/gprs_sgsn.c
@@ -44,6 +44,7 @@
 #include <osmocom/sgsn/gprs_gmm_attach.h>
 #include <osmocom/sgsn/gprs_mm_state_gb_fsm.h>
 #include <osmocom/sgsn/gprs_mm_state_iu_fsm.h>
+#include <osmocom/sgsn/gprs_gmm_fsm.h>
 #include <osmocom/sgsn/gprs_llc.h>
 
 #include <pdp.h>
@@ -234,7 +235,6 @@
 	if (!ctx)
 		return NULL;
 
-	ctx->gmm_state = GMM_DEREGISTERED;
 	ctx->auth_triplet.key_seq = GSM_KEY_SEQ_INVAL;
 	ctx->ctrg = rate_ctr_group_alloc(ctx, &mmctx_ctrg_desc, rate_ctr_id);
 	if (!ctx->ctrg) {
@@ -242,6 +242,7 @@
 		talloc_free(ctx);
 		return NULL;
 	}
+	ctx->gmm_fsm = osmo_fsm_inst_alloc(&gmm_fsm, ctx, ctx, LOGL_DEBUG, "gmm_fsm");
 	ctx->gmm_att_req.fsm = osmo_fsm_inst_alloc(&gmm_attach_req_fsm, ctx, ctx, LOGL_DEBUG, "gb_gmm_req");
 	INIT_LLIST_HEAD(&ctx->pdp_list);
 
@@ -368,6 +369,8 @@
 		osmo_fsm_inst_free(mm->gb.mm_state_fsm);
 	if (mm->iu.mm_state_fsm)
 		osmo_fsm_inst_free(mm->iu.mm_state_fsm);
+	if (mm->gmm_fsm)
+		osmo_fsm_inst_free(mm->gmm_fsm);
 
 	sgsn_mm_ctx_free(mm);
 	mm = NULL;
@@ -736,7 +739,7 @@
 {
 	/* the MM context can be deleted while the GGSN is not reachable or
 	 * if has been crashed. */
-	if (pctx->mm && pctx->mm->gmm_state == GMM_REGISTERED_NORMAL) {
+	if (pctx->mm && pctx->mm->gmm_fsm->state == ST_GMM_REGISTERED_NORMAL) {
 		gsm48_tx_gsm_deact_pdp_req(pctx, GSM_CAUSE_NET_FAIL, true);
 		sgsn_ggsn_ctx_remove_pdp(pctx->ggsn, pctx);
 	} else  {
diff --git a/src/sgsn/sgsn_libgtp.c b/src/sgsn/sgsn_libgtp.c
index 5e3f48f..f6d7a69 100644
--- a/src/sgsn/sgsn_libgtp.c
+++ b/src/sgsn/sgsn_libgtp.c
@@ -51,6 +51,7 @@
 #include <osmocom/sgsn/gprs_subscriber.h>
 #include <osmocom/sgsn/gprs_sndcp.h>
 #include <osmocom/sgsn/gprs_ranap.h>
+#include <osmocom/sgsn/gprs_gmm_fsm.h>
 
 #include <gtp.h>
 #include <pdp.h>
@@ -655,8 +656,8 @@
 	msgb_bvci(msg) = mm->gb.bvci;
 	msgb_nsei(msg) = mm->gb.nsei;
 
-	switch (mm->gmm_state) {
-	case GMM_REGISTERED_SUSPENDED:
+	switch (mm->gmm_fsm->state) {
+	case ST_GMM_REGISTERED_SUSPENDED:
 		/* initiate PS PAGING procedure */
 		memset(&pinfo, 0, sizeof(pinfo));
 		pinfo.mode = BSSGP_PAGING_PS;
@@ -670,11 +671,11 @@
 		rate_ctr_inc(&mm->ctrg->ctr[GMM_CTR_PAGING_PS]);
 		/* FIXME: queue the packet we received from GTP */
 		break;
-	case GMM_REGISTERED_NORMAL:
+	case ST_GMM_REGISTERED_NORMAL:
 		break;
 	default:
 		LOGP(DGPRS, LOGL_ERROR, "GTP DATA IND for TLLI %08X in state "
-			"%u\n", mm->gb.tlli, mm->gmm_state);
+			"%s\n", mm->gb.tlli, osmo_fsm_inst_state_name(mm->gmm_fsm));
 		msgb_free(msg);
 		return -1;
 	}
diff --git a/src/sgsn/sgsn_vty.c b/src/sgsn/sgsn_vty.c
index 184ece7..9200822 100644
--- a/src/sgsn/sgsn_vty.c
+++ b/src/sgsn/sgsn_vty.c
@@ -476,15 +476,6 @@
 	return add_apn_ggsn_mapping(vty, argv[0], argv[1], atoi(argv[2]));
 }
 
-const struct value_string gprs_mm_st_strs[] = {
-	{ GMM_DEREGISTERED, "DEREGISTERED" },
-	{ GMM_COMMON_PROC_INIT, "COMMON PROCEDURE (INIT)" },
-	{ GMM_REGISTERED_NORMAL, "REGISTERED (NORMAL)" },
-	{ GMM_REGISTERED_SUSPENDED, "REGISTERED (SUSPENDED)" },
-	{ GMM_DEREGISTERED_INIT, "DEREGISTERED (INIT)" },
-	{ 0, NULL }
-};
-
 char *sgsn_gtp_ntoa(struct ul16_t *ul)
 {
 	struct in_addr ia;
@@ -546,7 +537,7 @@
 	vty_out(vty, "%s  MSISDN: %s, TLLI: %08x%s HLR: %s",
 		pfx, mm->msisdn, id, mm->hlr, VTY_NEWLINE);
 	vty_out(vty, "%s  GMM State: %s, Routeing Area: %s, Cell ID: %u%s",
-		pfx, get_value_string(gprs_mm_st_strs, mm->gmm_state),
+		pfx, osmo_fsm_inst_state_name(mm->gmm_fsm),
 		osmo_rai_name(&mm->ra), mm->gb.cell_id, VTY_NEWLINE);
 	vty_out(vty, "%s  MM State: %s, RAN Type: %s%s", pfx, mm_state_name,
 		get_value_string(sgsn_ran_type_names, mm->ran_type), VTY_NEWLINE);
diff --git a/tests/sgsn/Makefile.am b/tests/sgsn/Makefile.am
index 7ba70eb..9afe0f7 100644
--- a/tests/sgsn/Makefile.am
+++ b/tests/sgsn/Makefile.am
@@ -48,6 +48,7 @@
 	$(top_builddir)/src/sgsn/gprs_sndcp.o \
 	$(top_builddir)/src/sgsn/gprs_gmm_attach.o \
 	$(top_builddir)/src/sgsn/gprs_gmm.o \
+	$(top_builddir)/src/sgsn/gprs_gmm_fsm.o \
 	$(top_builddir)/src/sgsn/gprs_mm_state_gb_fsm.o \
 	$(top_builddir)/src/sgsn/gprs_mm_state_iu_fsm.o \
 	$(top_builddir)/src/sgsn/gprs_sgsn.o \
diff --git a/tests/sgsn/sgsn_test.c b/tests/sgsn/sgsn_test.c
index cc25d47..7399573 100644
--- a/tests/sgsn/sgsn_test.c
+++ b/tests/sgsn/sgsn_test.c
@@ -28,6 +28,7 @@
 #include <osmocom/gsupclient/gsup_client.h>
 #include <osmocom/sgsn/gprs_utils.h>
 #include <osmocom/sgsn/gprs_gb_parse.h>
+#include <osmocom/sgsn/gprs_gmm_fsm.h>
 
 #include <osmocom/gprs/gprs_bssgp.h>
 
@@ -192,7 +193,6 @@
 
 	lle = gprs_lle_get_or_create(tlli, 3);
 	ctx = sgsn_mm_ctx_alloc_gb(tlli, raid);
-	ctx->gmm_state = GMM_REGISTERED_NORMAL;
 	ctx->gb.llme = lle->llme;
 
 	ictx = sgsn_mm_ctx_by_tlli(tlli, raid);
@@ -1286,7 +1286,7 @@
 
 	ctx = sgsn_mm_ctx_by_tlli(foreign_tlli, &raid);
 	OSMO_ASSERT(ctx != NULL);
-	OSMO_ASSERT(ctx->gmm_state == GMM_COMMON_PROC_INIT);
+	OSMO_ASSERT(ctx->gmm_fsm->state == ST_GMM_COMMON_PROC_INIT);
 
 	/* we expect an identity request (IMEI) */
 	OSMO_ASSERT(sgsn_tx_counter == 1);
@@ -1306,7 +1306,7 @@
 	 * authorization */
 	OSMO_ASSERT(ctx == sgsn_mm_ctx_by_tlli(foreign_tlli, &raid));
 
-	OSMO_ASSERT(ctx->gmm_state == GMM_COMMON_PROC_INIT);
+	OSMO_ASSERT(ctx->gmm_fsm->state == ST_GMM_COMMON_PROC_INIT);
 
 	/* we expect an attach accept/reject */
 	OSMO_ASSERT(sgsn_tx_counter == 1);
@@ -1320,7 +1320,7 @@
 	send_0408_message(ctx->gb.llme, foreign_tlli, &raid,
 			  attach_compl, ARRAY_SIZE(attach_compl));
 
-	OSMO_ASSERT(ctx->gmm_state == GMM_REGISTERED_NORMAL);
+	OSMO_ASSERT(ctx->gmm_fsm->state == ST_GMM_REGISTERED_NORMAL);
 
 	/* we don't expect a response */
 	OSMO_ASSERT(sgsn_tx_counter == 0);