diff --git a/lib/include/srslte/interfaces/epc_interfaces.h b/lib/include/srslte/interfaces/epc_interfaces.h
index 703a59912..e4fc189c8 100644
--- a/lib/include/srslte/interfaces/epc_interfaces.h
+++ b/lib/include/srslte/interfaces/epc_interfaces.h
@@ -2,11 +2,28 @@
 #define SRSLTE_EPC_INTERFACES_H
 
 #include "srslte/srslte.h"
-
 #include "srslte/common/common.h"
 
 namespace srsepc {
 
+/*
+ * S1AP Interfaces
+ */
+//GTP-C -> S1AP
+class s1ap_interface_gtpc
+{
+public:
+  virtual bool send_initial_context_setup_request(uint64_t imsi) = 0;
+};
+
+//NAS -> S1AP
+class s1ap_interface_nas
+{
+public:
+  virtual bool send_initial_context_setup_request(uint64_t imsi) = 0;
+};
+
+//S1AP -> HSS
 class hss_interface_s1ap
 {
 public:
diff --git a/srsepc/hdr/mme/s1ap.h b/srsepc/hdr/mme/s1ap.h
index 503e87d74..c47c804e1 100644
--- a/srsepc/hdr/mme/s1ap.h
+++ b/srsepc/hdr/mme/s1ap.h
@@ -32,6 +32,7 @@
 #include "srslte/common/common.h"
 #include "srslte/common/log.h"
 #include "srslte/common/s1ap_pcap.h"
+#include "srslte/interfaces/epc_interfaces.h"
 
 #include <strings.h>
 #include <arpa/inet.h>
@@ -52,7 +53,8 @@ namespace srsepc{
 
 const uint16_t S1MME_PORT = 36412;
 
-class s1ap
+class s1ap:
+    public s1ap_interface_nas
 {
 public:
 
diff --git a/srsepc/hdr/mme/s1ap_ctx_mngmt_proc.h b/srsepc/hdr/mme/s1ap_ctx_mngmt_proc.h
index 2a82581fc..a61a9de02 100644
--- a/srsepc/hdr/mme/s1ap_ctx_mngmt_proc.h
+++ b/srsepc/hdr/mme/s1ap_ctx_mngmt_proc.h
@@ -47,7 +47,7 @@ public:
 
   void init(void);
 
-  bool send_initial_context_setup_request(emm_ctx_t *emm_ctx, ecm_ctx_t *ecm_ctx, esm_ctx_t *esm_ctx, sec_ctx_t *sec_ctx);
+  bool send_initial_context_setup_request(nas *nas_ctx);
   bool handle_initial_context_setup_response(LIBLTE_S1AP_MESSAGE_INITIALCONTEXTSETUPRESPONSE_STRUCT *in_ctxt_resp);
   bool handle_ue_context_release_request(LIBLTE_S1AP_MESSAGE_UECONTEXTRELEASEREQUEST_STRUCT *ue_rel, struct sctp_sndrcvinfo *enb_sri, srslte::byte_buffer_t *reply_buffer, bool *reply_flag);
   bool send_ue_context_release_command(ecm_ctx_t *ecm_ctx, srslte::byte_buffer_t *reply_buffer);
diff --git a/srsepc/src/mme/s1ap_ctx_mngmt_proc.cc b/srsepc/src/mme/s1ap_ctx_mngmt_proc.cc
index 4e20d8d33..2b79b5e1a 100644
--- a/srsepc/src/mme/s1ap_ctx_mngmt_proc.cc
+++ b/srsepc/src/mme/s1ap_ctx_mngmt_proc.cc
@@ -79,10 +79,7 @@ s1ap_ctx_mngmt_proc::init(void)
 }
 
 bool
-s1ap_ctx_mngmt_proc::send_initial_context_setup_request(emm_ctx_t *emm_ctx,
-                                                        ecm_ctx_t *ecm_ctx,
-                                                        esm_ctx_t *esm_ctx,
-                                                        sec_ctx_t *sec_ctx)
+s1ap_ctx_mngmt_proc::send_initial_context_setup_request(nas *nas_ctx)
 {
   //Prepare reply PDU
   LIBLTE_S1AP_S1AP_PDU_STRUCT pdu;
@@ -151,7 +148,7 @@ s1ap_ctx_mngmt_proc::send_initial_context_setup_request(emm_ctx_t *emm_ctx,
     //Attach procedure initiated from an attach request
     m_s1ap_log->console("Adding attach accept to Initial Context Setup Request\n");
     m_s1ap_log->info("Adding attach accept to Initial Context Setup Request\n");
-    m_s1ap_nas_transport->pack_attach_accept(emm_ctx, ecm_ctx, erab_ctx_req, &erab_ctx->pdn_addr_alloc, nas_buffer); 
+    nas_ctx->pack_attach_accept(emm_ctx, ecm_ctx, erab_ctx_req, &erab_ctx->pdn_addr_alloc, nas_buffer); 
   }
 
   srslte::byte_buffer_t *reply_buffer = m_pool->allocate();
diff --git a/srsepc/src/mme/s1ap_nas_transport.cc b/srsepc/src/mme/s1ap_nas_transport.cc
index 1bb871fb1..c3757783c 100644
--- a/srsepc/src/mme/s1ap_nas_transport.cc
+++ b/srsepc/src/mme/s1ap_nas_transport.cc
@@ -81,16 +81,13 @@ s1ap_nas_transport::init(hss_interface_s1ap * hss_)
 }
 
 
-bool 
+bool
 s1ap_nas_transport::handle_initial_ue_message(LIBLTE_S1AP_MESSAGE_INITIALUEMESSAGE_STRUCT *init_ue, struct sctp_sndrcvinfo *enb_sri, srslte::byte_buffer_t *reply_buffer, bool *reply_flag)
 {
 
   //Get info from initial UE message
   uint32_t enb_ue_s1ap_id = init_ue->eNB_UE_S1AP_ID.ENB_UE_S1AP_ID;
 
-  //Log unhandled Initial UE message IEs
-  log_unhandled_initial_ue_message_ies(init_ue);
-
   /*Check whether NAS Attach Request or Service Request*/
   bool mac_valid = false;
   uint8_t pd, msg_type, sec_hdr_type;
@@ -332,7 +329,6 @@ s1ap_nas_transport::handle_uplink_nas_transport(LIBLTE_S1AP_MESSAGE_UPLINKNASTRA
     return false;
   }
 
-
   if(*reply_flag == true)
   {
     m_s1ap_log->console("DL NAS: Sent Downlink NAS Message. DL NAS Count=%d, UL NAS count=%d\n",emm_ctx->security_ctxt.dl_nas_count,emm_ctx->security_ctxt.ul_nas_count );