diff --git a/src/gprs_pcu.c b/src/gprs_pcu.c
index 9a21cdb4..31ed8b71 100644
--- a/src/gprs_pcu.c
+++ b/src/gprs_pcu.c
@@ -33,6 +33,8 @@ static struct osmo_tdef T_defs_pcu[] = {
 	{ .T=1,     .default_val=30,  .unit=OSMO_TDEF_S,  .desc="BSSGP (un)blocking procedures timer (s)",  .val=0 },
 	{ .T=2,     .default_val=30,  .unit=OSMO_TDEF_S,  .desc="BSSGP reset procedure timer (s)",          .val=0 },
 	{ .T=3190,  .default_val=5,   .unit=OSMO_TDEF_S,  .desc="Return to packet idle mode after Packet DL Assignment on CCCH (s)", .val=0},
+	{ .T=PCU_TDEF_NEIGH_CACHE_ALIVE,   .default_val=5,  .unit=OSMO_TDEF_S,   .desc="[ARFCN+BSIC]->[RAC+CI] resolution cache entry storage timeout (s)", .val=0 },
+	{ .T=PCU_TDEF_SI_CACHE_ALIVE,      .default_val=5,  .unit=OSMO_TDEF_S,   .desc="[RAC+CI]->[SI] resolution cache entry storage timeout (s)", .val=0 },
 	{ .T=-2000, .default_val=2,   .unit=OSMO_TDEF_MS, .desc="Tbf reject for PRR timer (ms)",            .val=0 },
 	{ .T=-2001, .default_val=2,   .unit=OSMO_TDEF_S,  .desc="PACCH assignment timer (s)",               .val=0 },
 	{ .T=-2002, .default_val=200, .unit=OSMO_TDEF_MS, .desc="Waiting after IMM.ASS confirm timer (ms)", .val=0 },
@@ -114,8 +116,8 @@ struct gprs_pcu *gprs_pcu_alloc(void *ctx)
 
 	INIT_LLIST_HEAD(&pcu->bts_list);
 
-	pcu->neigh_cache = neigh_cache_alloc(pcu);
-	pcu->si_cache = si_cache_alloc(pcu);
+	pcu->neigh_cache = neigh_cache_alloc(pcu, osmo_tdef_get(pcu->T_defs, PCU_TDEF_NEIGH_CACHE_ALIVE, OSMO_TDEF_S, -1));
+	pcu->si_cache = si_cache_alloc(pcu, osmo_tdef_get(pcu->T_defs, PCU_TDEF_SI_CACHE_ALIVE, OSMO_TDEF_S, -1));
 
 	return pcu;
 }
diff --git a/src/gprs_pcu.h b/src/gprs_pcu.h
index 8e18f89e..4f22f68b 100644
--- a/src/gprs_pcu.h
+++ b/src/gprs_pcu.h
@@ -37,6 +37,9 @@
 #define MAX_EDGE_MCS 9
 #define MAX_GPRS_CS 4
 
+#define PCU_TDEF_NEIGH_CACHE_ALIVE (-10)
+#define PCU_TDEF_SI_CACHE_ALIVE    (-11)
+
 /* see bts->gsmtap_categ_mask */
 enum pcu_gsmtap_category {
 	PCU_GSMTAP_C_DL_UNKNOWN		= 0,	/* unknown or undecodable downlink blocks */
diff --git a/src/neigh_cache.c b/src/neigh_cache.c
index a4bdfbeb..ae619d3b 100644
--- a/src/neigh_cache.c
+++ b/src/neigh_cache.c
@@ -27,10 +27,6 @@
 #include <neigh_cache.h>
 #include <gprs_debug.h>
 
-#define KEEP_TIME_DEFAULT_SEC 5
-
-/*TODO: add a timer to the_pcu T_defs, pass value to struct neigh_cache instead of KEEP_TIME_DEFAULT_SEC */
-
 static inline bool neigh_cache_entry_key_eq(const struct neigh_cache_entry_key *a,
 					    const struct neigh_cache_entry_key *b)
 {
@@ -89,16 +85,23 @@ static void neigh_cache_schedule_cleanup(struct neigh_cache *cache)
 	osmo_timer_schedule(&cache->cleanup_timer, result.tv_sec, result.tv_nsec*1000);
 }
 
-struct neigh_cache *neigh_cache_alloc(void *ctx)
+struct neigh_cache *neigh_cache_alloc(void *ctx, unsigned int keep_time_sec)
 {
 	struct neigh_cache *cache = talloc_zero(ctx, struct neigh_cache);
 	OSMO_ASSERT(cache);
 	INIT_LLIST_HEAD(&cache->list);
 	osmo_timer_setup(&cache->cleanup_timer, neigh_cache_cleanup_cb, cache);
-	cache->keep_time_intval = (struct timespec){ .tv_sec = KEEP_TIME_DEFAULT_SEC, .tv_nsec = 0};
+	cache->keep_time_intval = (struct timespec){ .tv_sec = keep_time_sec, .tv_nsec = 0};
 	return cache;
 
 }
+
+void neigh_cache_set_keep_time_interval(struct neigh_cache *cache, unsigned int keep_time_sec)
+{
+	cache->keep_time_intval = (struct timespec){ .tv_sec = keep_time_sec, .tv_nsec = 0};
+	neigh_cache_schedule_cleanup(cache);
+}
+
 struct neigh_cache_entry *neigh_cache_add(struct neigh_cache *cache,
 					  const struct neigh_cache_entry_key *key,
 					  const struct osmo_cell_global_id_ps *value)
@@ -168,8 +171,6 @@ void neigh_cache_free(struct neigh_cache *cache)
 // SI CACHE
 ///////////////////
 
-/*TODO: add a timer to the_pcu T_defs, pass value to struct neigh_cache instead of KEEP_TIME_DEFAULT_SEC */
-
 static void si_cache_schedule_cleanup(struct si_cache *cache);
 static void si_cache_cleanup_cb(void *data)
 {
@@ -218,15 +219,22 @@ static void si_cache_schedule_cleanup(struct si_cache *cache)
 	osmo_timer_schedule(&cache->cleanup_timer, result.tv_sec, result.tv_nsec*1000);
 }
 
-struct si_cache *si_cache_alloc(void *ctx)
+struct si_cache *si_cache_alloc(void *ctx, unsigned int keep_time_sec)
 {
 	struct si_cache *cache = talloc_zero(ctx, struct si_cache);
 	OSMO_ASSERT(cache);
 	INIT_LLIST_HEAD(&cache->list);
 	osmo_timer_setup(&cache->cleanup_timer, si_cache_cleanup_cb, cache);
-	cache->keep_time_intval = (struct timespec){ .tv_sec = KEEP_TIME_DEFAULT_SEC, .tv_nsec = 0};
+	cache->keep_time_intval = (struct timespec){ .tv_sec = keep_time_sec, .tv_nsec = 0};
 	return cache;
 }
+
+void si_cache_set_keep_time_interval(struct si_cache *cache, unsigned int keep_time_sec)
+{
+	cache->keep_time_intval = (struct timespec){ .tv_sec = keep_time_sec, .tv_nsec = 0};
+	si_cache_schedule_cleanup(cache);
+}
+
 struct si_cache_entry *si_cache_add(struct si_cache *cache,
 				    const struct osmo_cell_global_id_ps *key,
 				    const struct si_cache_value *value)
diff --git a/src/neigh_cache.h b/src/neigh_cache.h
index 3fd56b7a..4fed0faf 100644
--- a/src/neigh_cache.h
+++ b/src/neigh_cache.h
@@ -55,7 +55,8 @@ struct neigh_cache_entry {
 	struct osmo_cell_global_id_ps value;
 };
 
-struct neigh_cache *neigh_cache_alloc(void *ctx);
+struct neigh_cache *neigh_cache_alloc(void *ctx, unsigned int keep_time_sec);
+void neigh_cache_set_keep_time_interval(struct neigh_cache *cache, unsigned int keep_time_sec);
 struct neigh_cache_entry *neigh_cache_add(struct neigh_cache *cache,
 					  const struct neigh_cache_entry_key *key,
 					  const struct osmo_cell_global_id_ps *value);
@@ -90,7 +91,8 @@ struct si_cache_entry {
 	struct si_cache_value value;
 };
 
-struct si_cache *si_cache_alloc(void *ctx);
+struct si_cache *si_cache_alloc(void *ctx, unsigned int keep_time_sec);
+void si_cache_set_keep_time_interval(struct si_cache *cache, unsigned int keep_time_sec);
 struct si_cache_entry *si_cache_add(struct si_cache *cache,
 				    const struct osmo_cell_global_id_ps *key,
 				    const struct si_cache_value *value);
diff --git a/src/pcu_vty.c b/src/pcu_vty.c
index 8f97f306..b0d1ac60 100644
--- a/src/pcu_vty.c
+++ b/src/pcu_vty.c
@@ -1064,10 +1064,25 @@ DEFUN_ATTR(cfg_pcu_timer, cfg_pcu_timer_cmd,
 	   OSMO_TDEF_VTY_DOC_SET,
 	   CMD_ATTR_IMMEDIATE)
 {
+	int rc;
+	struct osmo_tdef *t;
 	/* If any arguments are missing, redirect to 'show' */
 	if (argc < 2)
 		return show_timer(self, vty, argc, argv);
-	return osmo_tdef_vty_set_cmd(vty, the_pcu->T_defs, argv);
+	if ((rc = osmo_tdef_vty_set_cmd(vty, the_pcu->T_defs, argv)) != CMD_SUCCESS)
+		return rc;
+	t = osmo_tdef_vty_parse_T_arg(vty, the_pcu->T_defs, argv[0]);
+	switch (t->T) {
+	case PCU_TDEF_NEIGH_CACHE_ALIVE:
+		neigh_cache_set_keep_time_interval(the_pcu->neigh_cache, t->val);
+		break;
+	case PCU_TDEF_SI_CACHE_ALIVE:
+		si_cache_set_keep_time_interval(the_pcu->si_cache, t->val);
+		break;
+	default:
+		break;
+	}
+	return CMD_SUCCESS;
 }
 
 DEFUN(show_tbf,