diff --git a/openair2/ENB_APP/CONTROL_MODULES/S1AP/flexran_agent_s1ap.c b/openair2/ENB_APP/CONTROL_MODULES/S1AP/flexran_agent_s1ap.c
index 04a47406e1..d5fc5627a0 100644
--- a/openair2/ENB_APP/CONTROL_MODULES/S1AP/flexran_agent_s1ap.c
+++ b/openair2/ENB_APP/CONTROL_MODULES/S1AP/flexran_agent_s1ap.c
@@ -125,6 +125,39 @@ void flexran_agent_s1ap_destroy_stats_reply(Protocol__FlexStatsReply *reply) {
   }
 }
 
+void flexran_agent_handle_mme_update(mid_t mod_id,
+                                     size_t n_mme,
+                                     Protocol__FlexS1apMme **mme) {
+  if (n_mme == 0 || n_mme > 1) {
+    LOG_E(FLEXRAN_AGENT, "cannot handle %lu MMEs yet\n", n_mme);
+    return;
+  }
+
+  if (!mme[0]->s1_ip) {
+    LOG_E(FLEXRAN_AGENT, "no S1 IP present, cannot handle request\n");
+    return;
+  }
+
+  if (mme[0]->has_state
+      && mme[0]->state == PROTOCOL__FLEX_MME_STATE__FLMMES_DISCONNECTED) {
+    int rc = flexran_remove_s1ap_mme(mod_id, 1, &mme[0]->s1_ip);
+    if (rc == 0)
+      LOG_I(FLEXRAN_AGENT, "remove MME at IP %s\n", mme[0]->s1_ip);
+    else
+      LOG_W(FLEXRAN_AGENT,
+            "could not remove MME: flexran_remove_s1ap_mme() returned %d\n",
+            rc);
+  } else {
+    int rc = flexran_add_s1ap_mme(mod_id, 1, &mme[0]->s1_ip);
+    if (rc == 0)
+      LOG_I(FLEXRAN_AGENT, "add MME at IP %s\n", mme[0]->s1_ip);
+    else
+      LOG_W(FLEXRAN_AGENT,
+            "could not add MME: flexran_add_s1ap_mme() returned %d\n",
+            rc);
+  }
+}
+
 int flexran_agent_register_s1ap_xface(mid_t mod_id) {
   if (agent_s1ap_xface[mod_id]) {
     LOG_E(FLEXRAN_AGENT, "S1AP agent CM for eNB %d is already registered\n", mod_id);
diff --git a/openair2/ENB_APP/CONTROL_MODULES/S1AP/flexran_agent_s1ap.h b/openair2/ENB_APP/CONTROL_MODULES/S1AP/flexran_agent_s1ap.h
index 1cca6ac9c1..54ea2926a8 100644
--- a/openair2/ENB_APP/CONTROL_MODULES/S1AP/flexran_agent_s1ap.h
+++ b/openair2/ENB_APP/CONTROL_MODULES/S1AP/flexran_agent_s1ap.h
@@ -60,6 +60,11 @@ int flexran_agent_s1ap_stats_reply(mid_t mod_id,
 /* Free allocated S1AP stats message */
 void flexran_agent_s1ap_destroy_stats_reply(Protocol__FlexStatsReply *reply);
 
+/* Add or remove MME updates */
+void flexran_agent_handle_mme_update(mid_t mod_id,
+                                     size_t n_mme,
+                                     Protocol__FlexS1apMme **mme);
+
 /* Register technology specific interface callbacks */
 int flexran_agent_register_s1ap_xface(mid_t mod_id);
 
diff --git a/openair2/ENB_APP/flexran_agent_common.c b/openair2/ENB_APP/flexran_agent_common.c
index dc320ef974..ec0b780a3a 100644
--- a/openair2/ENB_APP/flexran_agent_common.c
+++ b/openair2/ENB_APP/flexran_agent_common.c
@@ -893,31 +893,34 @@ int flexran_agent_handle_enb_config_reply(mid_t mod_id, const void *params, Prot
   Protocol__FlexranMessage *input = (Protocol__FlexranMessage *)params;
   Protocol__FlexEnbConfigReply *enb_config = input->enb_config_reply_msg;
 
-  if (enb_config->n_cell_config == 0) {
-    LOG_W(FLEXRAN_AGENT,
-          "received enb_config_reply message does not contain a cell_config\n");
-    *msg = NULL;
-    return 0;
-  }
-
   if (enb_config->n_cell_config > 1)
     LOG_W(FLEXRAN_AGENT, "ignoring slice configs for other cell except cell 0\n");
 
-  if (flexran_agent_get_mac_xface(mod_id) && enb_config->cell_config[0]->slice_config) {
-    prepare_update_slice_config(mod_id, enb_config->cell_config[0]->slice_config);
-  } else if (enb_config->cell_config[0]->has_eutra_band
-          && enb_config->cell_config[0]->has_dl_freq
-          && enb_config->cell_config[0]->has_ul_freq
-          && enb_config->cell_config[0]->has_dl_bandwidth) {
-    initiate_soft_restart(mod_id, enb_config->cell_config[0]);
-  } else if (flexran_agent_get_rrc_xface(mod_id)
-          && enb_config->cell_config[0]->has_x2_ho_net_control) {
-    LOG_I(FLEXRAN_AGENT,
-          "setting X2 HO NetControl to %d\n",
-          enb_config->cell_config[0]->x2_ho_net_control);
-    const int rc = flexran_set_x2_ho_net_control(mod_id, enb_config->cell_config[0]->x2_ho_net_control);
-    if (rc < 0)
-      LOG_E(FLEXRAN_AGENT, "Error in configuring X2 handover controlled by network");
+  if (enb_config->n_cell_config > 0) {
+    if (flexran_agent_get_mac_xface(mod_id) && enb_config->cell_config[0]->slice_config) {
+      prepare_update_slice_config(mod_id, enb_config->cell_config[0]->slice_config);
+    }
+    if (enb_config->cell_config[0]->has_eutra_band
+        && enb_config->cell_config[0]->has_dl_freq
+        && enb_config->cell_config[0]->has_ul_freq
+        && enb_config->cell_config[0]->has_dl_bandwidth) {
+      initiate_soft_restart(mod_id, enb_config->cell_config[0]);
+    }
+    if (flexran_agent_get_rrc_xface(mod_id)
+        && enb_config->cell_config[0]->has_x2_ho_net_control) {
+      LOG_I(FLEXRAN_AGENT,
+            "setting X2 HO NetControl to %d\n",
+            enb_config->cell_config[0]->x2_ho_net_control);
+      const int rc = flexran_set_x2_ho_net_control(mod_id, enb_config->cell_config[0]->x2_ho_net_control);
+      if (rc < 0)
+        LOG_E(FLEXRAN_AGENT, "Error in configuring X2 handover controlled by network");
+    }
+  }
+
+  if (flexran_agent_get_s1ap_xface(mod_id) && enb_config->s1ap) {
+    flexran_agent_handle_mme_update(mod_id,
+                                    enb_config->s1ap->n_mme,
+                                    enb_config->s1ap->mme);
   }
 
   *msg = NULL;
diff --git a/openair2/ENB_APP/flexran_agent_ran_api.c b/openair2/ENB_APP/flexran_agent_ran_api.c
index abade20846..3306dfe61b 100644
--- a/openair2/ENB_APP/flexran_agent_ran_api.c
+++ b/openair2/ENB_APP/flexran_agent_ran_api.c
@@ -3634,6 +3634,97 @@ int flexran_get_s1ap_mme_conf(mid_t mod_id, mid_t mme_index, Protocol__FlexS1apM
   return 0;
 }
 
+int flexran_add_s1ap_mme(mid_t mod_id, size_t n_mme, char **mme_ipv4) {
+  s1ap_eNB_instance_t *s1ap = s1ap_eNB_get_instance(mod_id);
+  if (!s1ap) return -1;
+  if (!rrc_is_present(mod_id)) return -2;
+
+  /* Reconstruct S1AP_REGISTER_ENB_REQ */
+  MessageDef *m = itti_alloc_new_message(TASK_FLEXRAN_AGENT, S1AP_REGISTER_ENB_REQ);
+  RCconfig_S1(m, mod_id);
+
+  const int CC_id = 0;
+  eNB_RRC_INST *rrc = RC.rrc[CC_id];
+  RrcConfigurationReq *conf = &rrc->configuration;
+  S1AP_REGISTER_ENB_REQ(m).num_plmn = conf->num_plmn;
+  for (int i = 0; i < conf->num_plmn; ++i) {
+    S1AP_REGISTER_ENB_REQ(m).mcc[i] = conf->mcc[i];
+    S1AP_REGISTER_ENB_REQ(m).mnc[i] = conf->mnc[i];
+    S1AP_REGISTER_ENB_REQ(m).mnc_digit_length[i] = conf->mnc_digit_length[i];
+  }
+
+  /* reconstruct MME list, it might have been updated since initial
+   * configuration */
+  S1AP_REGISTER_ENB_REQ(m).nb_mme = 0;
+  struct s1ap_eNB_mme_data_s *mme = NULL;
+  RB_FOREACH(mme, s1ap_mme_map, &s1ap->s1ap_mme_head) {
+    const int n = S1AP_REGISTER_ENB_REQ(m).nb_mme;
+    S1AP_REGISTER_ENB_REQ(m).mme_ip_address[n].ipv4 = mme->mme_s1_ip.ipv4;
+    strcpy(S1AP_REGISTER_ENB_REQ(m).mme_ip_address[n].ipv4_address, mme->mme_s1_ip.ipv4_address);
+    S1AP_REGISTER_ENB_REQ(m).mme_ip_address[n].ipv6 = mme->mme_s1_ip.ipv6;
+    strcpy(S1AP_REGISTER_ENB_REQ(m).mme_ip_address[n].ipv6_address, mme->mme_s1_ip.ipv6_address);
+    S1AP_REGISTER_ENB_REQ(m).broadcast_plmn_num[n] = mme->broadcast_plmn_num;
+    for (int i = 0; i < mme->broadcast_plmn_num; ++i)
+      S1AP_REGISTER_ENB_REQ(m).broadcast_plmn_index[n][i] = mme->broadcast_plmn_index[i];
+    S1AP_REGISTER_ENB_REQ(m).nb_mme += 1;
+  }
+
+  if (S1AP_REGISTER_ENB_REQ(m).nb_mme + n_mme > S1AP_MAX_NB_MME_IP_ADDRESS)
+    return -1;
+
+  for (int i = 0; i < n_mme; ++i) {
+    const int n = S1AP_REGISTER_ENB_REQ(m).nb_mme;
+    strcpy(S1AP_REGISTER_ENB_REQ(m).mme_ip_address[n].ipv4_address, mme_ipv4[0]);
+    S1AP_REGISTER_ENB_REQ(m).mme_ip_address[n].ipv4 = 1;
+    S1AP_REGISTER_ENB_REQ(m).mme_ip_address[n].ipv6 = 0;
+    S1AP_REGISTER_ENB_REQ(m).broadcast_plmn_num[n] = S1AP_REGISTER_ENB_REQ(m).num_plmn;
+    for (int i = 0; i < S1AP_REGISTER_ENB_REQ(m).num_plmn; ++i)
+      S1AP_REGISTER_ENB_REQ(m).broadcast_plmn_index[n][i] = i;
+    S1AP_REGISTER_ENB_REQ(m).nb_mme += 1;
+  }
+
+  itti_send_msg_to_task (TASK_S1AP, ENB_MODULE_ID_TO_INSTANCE(mod_id), m);
+
+  return 0;
+}
+
+int flexran_remove_s1ap_mme(mid_t mod_id, size_t n_mme, char **mme_ipv4) {
+  s1ap_eNB_instance_t *s1ap = s1ap_eNB_get_instance(mod_id);
+  if (!s1ap) return -1;
+  struct s1ap_eNB_mme_data_s *mme = NULL;
+  RB_FOREACH(mme, s1ap_mme_map, &s1ap->s1ap_mme_head) {
+    if (mme->mme_s1_ip.ipv4
+        && strncmp(mme->mme_s1_ip.ipv4_address, mme_ipv4[0], 16) == 0)
+        break;
+  }
+  if (!mme)
+    return -2;
+
+  MessageDef *m = itti_alloc_new_message(TASK_FLEXRAN_AGENT, SCTP_CLOSE_ASSOCIATION);
+  SCTP_CLOSE_ASSOCIATION(m).assoc_id = mme->assoc_id;
+  itti_send_msg_to_task (TASK_SCTP, ENB_MODULE_ID_TO_INSTANCE(mod_id), m);
+
+  switch (mme->state) {
+    case S1AP_ENB_STATE_WAITING:
+      s1ap->s1ap_mme_nb -= 1;
+      if (s1ap->s1ap_mme_pending_nb > 0)
+        s1ap->s1ap_mme_pending_nb -= 1;
+      break;
+    case S1AP_ENB_STATE_CONNECTED:
+    case S1AP_ENB_OVERLOAD: /* I am not sure the decrements are right here */
+      s1ap->s1ap_mme_nb -= 1;
+      s1ap->s1ap_mme_associated_nb -= 1;
+      break;
+    case S1AP_ENB_STATE_DISCONNECTED:
+    default:
+      break;
+  }
+  RB_REMOVE(s1ap_mme_map, &s1ap->s1ap_mme_head, mme);
+
+  return 0;
+}
+
+
 int flexran_get_s1ap_ue(mid_t mod_id, rnti_t rnti, Protocol__FlexS1apUe * ue_conf){
   if (!rrc_is_present(mod_id)) return -1;
   s1ap_eNB_instance_t *s1ap = s1ap_eNB_get_instance(mod_id);
diff --git a/openair2/ENB_APP/flexran_agent_ran_api.h b/openair2/ENB_APP/flexran_agent_ran_api.h
index ce32883852..3c2803d663 100644
--- a/openair2/ENB_APP/flexran_agent_ran_api.h
+++ b/openair2/ENB_APP/flexran_agent_ran_api.h
@@ -832,6 +832,12 @@ int flexran_get_s1ap_mme_conf(mid_t mod_id, mid_t mme_index, Protocol__FlexS1apM
 /* Get the S1AP UE conf */
 int flexran_get_s1ap_ue(mid_t mod_id, rnti_t rnti, Protocol__FlexS1apUe * ue_conf);
 
+/* Add MMEs and re-issue S1AP Registration Request */
+int flexran_add_s1ap_mme(mid_t mod_id, size_t n_mme, char **mme_ipv4);
+
+/* Remove MMEs and and cut SCTP to MME */
+int flexran_remove_s1ap_mme(mid_t mod_id, size_t n_mme, char **mme_ipv4);
+
 /********************* general information *****************/
 /* get an ID for this BS (or part of a BS) */
 uint64_t flexran_get_bs_id(mid_t mod_id);