diff --git a/srsepc/hdr/mme/s1ap_common.h b/srsepc/hdr/mme/s1ap_common.h
index f5462ad65..2d693eba9 100644
--- a/srsepc/hdr/mme/s1ap_common.h
+++ b/srsepc/hdr/mme/s1ap_common.h
@@ -33,6 +33,47 @@ static const uint8_t MAX_TA=255;  //Maximum TA supported
 static const uint8_t MAX_BPLMN=6; //Maximum broadcasted PLMNs per TAC
 static const uint8_t MAX_ERABS_PER_UE = 16;
 
+// MME EMM states (3GPP 24.301 v10.0.0, section 5.1.3.4)
+typedef enum {
+  EMM_STATE_DEREGISTERED = 0,
+  EMM_STATE_COMMON_PROCEDURE_INITIATED,
+  EMM_STATE_REGISTERED,
+  EMM_STATE_DEREGISTERED_INITIATED,
+  EMM_STATE_N_ITEMS,
+} emm_state_t;
+static const char emm_state_text[EMM_STATE_N_ITEMS][100] = {"DEREGISTERED",
+                                                            "COMMON PROCEDURE INITIATED",
+                                                            "REGISTERED",
+                                                            "DEREGISTERED INITIATED"};
+
+// MME ECM states (3GPP 23.401 v10.0.0, section 4.6.3)
+typedef enum {
+  ECM_STATE_IDLE = 0,
+  ECM_STATE_CONNECTED,
+  ECM_STATE_N_ITEMS,
+} ecm_state_t;
+static const char ecm_state_text[ECM_STATE_N_ITEMS][100] = {"IDLE",
+                                                            "CONNECTED"};
+
+// MME ESM states (3GPP 23.401 v10.0.0, section 4.6.3)
+typedef enum {
+  ESM_BEARER_CONTEXT_INACTIVE = 0,
+  ESM_BEARER_CONTEXT_ACTIVE_PENDING,
+  ESM_BEARER_CONTEXT_ACTIVE,
+  ESM_BEARER_CONTEXT_INACTIVE_PENDING,
+  ESM_BEARER_CONTEXT_MODIFY_PENDING,
+  ESM_BEARER_PROCEDURE_TRANSACTION_INACTIVE,
+  ESM_BEARER_PROCEDURE_TRANSACTION_PENDING,
+  ESM_STATE_N_ITEMS,
+} esm_state_t;
+static const char esm_state_text[ESM_STATE_N_ITEMS][100] = {"CONTEXT INACTIVE",
+                                                            "CONTEXT ACTIVE PENDING",
+                                                            "CONTEXT ACTIVE",
+                                                            "CONTEXT_INACTIVE_PENDING",
+                                                            "CONTEXT_MODIFY_PENDING",
+                                                            "PROCEDURE_TRANSACTION_INACTIVE"
+                                                            "PROCEDURE_TRANSACTION_PENDING"};
+
 enum erab_state
 {
   ERAB_DEACTIVATED,
@@ -74,6 +115,9 @@ typedef struct{
   srslte::INTEGRITY_ALGORITHM_ID_ENUM integ_algo;
   uint8_t k_nas_enc[32];
   uint8_t k_nas_int[32];
+  LIBLTE_MME_UE_NETWORK_CAPABILITY_STRUCT ue_network_cap;
+  bool ms_network_cap_present;
+  LIBLTE_MME_MS_NETWORK_CAPABILITY_STRUCT ms_network_cap;
 } eps_security_ctx_t;
 
 typedef struct{
@@ -89,11 +133,9 @@ typedef struct{
   uint32_t mme_ue_s1ap_id;
   uint16_t enb_id;
   struct   sctp_sndrcvinfo enb_sri;
+  emm_state_t emm_state;
   eps_security_ctx_t security_ctxt;
   erab_ctx_t erabs_ctx[MAX_ERABS_PER_UE];
-  LIBLTE_MME_UE_NETWORK_CAPABILITY_STRUCT ue_network_cap;
-  bool ms_network_cap_present;
-  LIBLTE_MME_MS_NETWORK_CAPABILITY_STRUCT ms_network_cap;
   bool eit;
   uint8_t procedure_transaction_id;
 } ue_ctx_t;
diff --git a/srsepc/src/mme/s1ap_ctx_mngmt_proc.cc b/srsepc/src/mme/s1ap_ctx_mngmt_proc.cc
index 7dffe3c35..1d6df8cf3 100644
--- a/srsepc/src/mme/s1ap_ctx_mngmt_proc.cc
+++ b/srsepc/src/mme/s1ap_ctx_mngmt_proc.cc
@@ -143,7 +143,7 @@ s1ap_ctx_mngmt_proc::send_initial_context_setup_request(uint32_t mme_ue_s1ap_id,
   bzero(in_ctxt_req->UESecurityCapabilities.integrityProtectionAlgorithms.buffer,sizeof(uint8_t)*16); 
   for(int i = 0; i<3; i++)
   {
-    if(ue_ctx->ue_network_cap.eea[i+1] == true)
+    if(ue_ctx->security_ctxt.ue_network_cap.eea[i+1] == true)
     {
       in_ctxt_req->UESecurityCapabilities.encryptionAlgorithms.buffer[i] = 1;          //EEA supported
     }
@@ -151,7 +151,7 @@ s1ap_ctx_mngmt_proc::send_initial_context_setup_request(uint32_t mme_ue_s1ap_id,
     {
       in_ctxt_req->UESecurityCapabilities.encryptionAlgorithms.buffer[i] = 0;          //EEA not supported
     }
-    if(ue_ctx->ue_network_cap.eia[i+1] == true)
+    if(ue_ctx->security_ctxt.ue_network_cap.eia[i+1] == true)
     {
       in_ctxt_req->UESecurityCapabilities.integrityProtectionAlgorithms.buffer[i] = 1;          //EEA supported
     }
diff --git a/srsepc/src/mme/s1ap_nas_transport.cc b/srsepc/src/mme/s1ap_nas_transport.cc
index 7ba6fbe25..a200369a7 100644
--- a/srsepc/src/mme/s1ap_nas_transport.cc
+++ b/srsepc/src/mme/s1ap_nas_transport.cc
@@ -250,11 +250,11 @@ s1ap_nas_transport::handle_nas_imsi_attach_request(uint32_t enb_ue_s1ap_id,
   ue_ctx.mme_ue_s1ap_id = m_s1ap->get_next_mme_ue_s1ap_id();
 
   //Save UE network capabilities
-  memcpy(&ue_ctx.ue_network_cap, &attach_req.ue_network_cap, sizeof(LIBLTE_MME_UE_NETWORK_CAPABILITY_STRUCT));
-  ue_ctx.ms_network_cap_present =  attach_req.ms_network_cap_present;
+  memcpy(&ue_ctx.security_ctxt.ue_network_cap, &attach_req.ue_network_cap, sizeof(LIBLTE_MME_UE_NETWORK_CAPABILITY_STRUCT));
+  ue_ctx.security_ctxt.ms_network_cap_present =  attach_req.ms_network_cap_present;
   if(attach_req.ms_network_cap_present)
   {
-    memcpy(&ue_ctx.ms_network_cap, &attach_req.ms_network_cap, sizeof(LIBLTE_MME_MS_NETWORK_CAPABILITY_STRUCT));
+    memcpy(&ue_ctx.security_ctxt.ms_network_cap, &attach_req.ms_network_cap, sizeof(LIBLTE_MME_MS_NETWORK_CAPABILITY_STRUCT));
   }
   uint8_t eps_bearer_id = pdn_con_req.eps_bearer_id;             //TODO: Unused
   ue_ctx.procedure_transaction_id = pdn_con_req.proc_transaction_id; 
@@ -345,11 +345,11 @@ s1ap_nas_transport::handle_nas_guti_attach_request(uint32_t enb_ue_s1ap_id,
     ue_ctx.mme_ue_s1ap_id = m_s1ap->get_next_mme_ue_s1ap_id();
 
     //Save UE network capabilities
-    memcpy(&ue_ctx.ue_network_cap, &attach_req.ue_network_cap, sizeof(LIBLTE_MME_UE_NETWORK_CAPABILITY_STRUCT));
-    ue_ctx.ms_network_cap_present =  attach_req.ms_network_cap_present;
+    memcpy(&ue_ctx.security_ctxt.ue_network_cap, &attach_req.ue_network_cap, sizeof(LIBLTE_MME_UE_NETWORK_CAPABILITY_STRUCT));
+    ue_ctx.security_ctxt.ms_network_cap_present =  attach_req.ms_network_cap_present;
     if(attach_req.ms_network_cap_present)
     {
-      memcpy(&ue_ctx.ms_network_cap, &attach_req.ms_network_cap, sizeof(LIBLTE_MME_MS_NETWORK_CAPABILITY_STRUCT));
+      memcpy(&ue_ctx.security_ctxt.ms_network_cap, &attach_req.ms_network_cap, sizeof(LIBLTE_MME_MS_NETWORK_CAPABILITY_STRUCT));
     }
     uint8_t eps_bearer_id = pdn_con_req.eps_bearer_id;             //TODO: Unused
     ue_ctx.procedure_transaction_id = pdn_con_req.proc_transaction_id; 
@@ -863,14 +863,14 @@ s1ap_nas_transport::pack_security_mode_command(srslte::byte_buffer_t *reply_msg,
   sm_cmd.nas_ksi.nas_ksi=0; 
 
   //Replay UE security cap
-  memcpy(sm_cmd.ue_security_cap.eea,ue_ctx->ue_network_cap.eea,8*sizeof(bool));
-  memcpy(sm_cmd.ue_security_cap.eia,ue_ctx->ue_network_cap.eia,8*sizeof(bool));
-  sm_cmd.ue_security_cap.uea_present = ue_ctx->ue_network_cap.uea_present;
-  memcpy(sm_cmd.ue_security_cap.uea,ue_ctx->ue_network_cap.uea,8*sizeof(bool));
-  sm_cmd.ue_security_cap.uia_present = ue_ctx->ue_network_cap.uia_present;
-  memcpy(sm_cmd.ue_security_cap.uia,ue_ctx->ue_network_cap.uia,8*sizeof(bool));
-  sm_cmd.ue_security_cap.gea_present = ue_ctx->ms_network_cap_present;
-  memcpy(sm_cmd.ue_security_cap.gea,ue_ctx->ms_network_cap.gea,8*sizeof(bool));
+  memcpy(sm_cmd.ue_security_cap.eea,ue_ctx->security_ctxt.ue_network_cap.eea,8*sizeof(bool));
+  memcpy(sm_cmd.ue_security_cap.eia,ue_ctx->security_ctxt.ue_network_cap.eia,8*sizeof(bool));
+  sm_cmd.ue_security_cap.uea_present = ue_ctx->security_ctxt.ue_network_cap.uea_present;
+  memcpy(sm_cmd.ue_security_cap.uea,ue_ctx->security_ctxt.ue_network_cap.uea,8*sizeof(bool));
+  sm_cmd.ue_security_cap.uia_present = ue_ctx->security_ctxt.ue_network_cap.uia_present;
+  memcpy(sm_cmd.ue_security_cap.uia,ue_ctx->security_ctxt.ue_network_cap.uia,8*sizeof(bool));
+  sm_cmd.ue_security_cap.gea_present = ue_ctx->security_ctxt.ms_network_cap_present;
+  memcpy(sm_cmd.ue_security_cap.gea,ue_ctx->security_ctxt.ms_network_cap.gea,8*sizeof(bool));
 
   sm_cmd.imeisv_req_present=false;
   sm_cmd.nonce_ue_present=false;