diff --git a/lib/diameter/s6a/message.h b/lib/diameter/s6a/message.h
index 943d20e8b..ae314dd10 100644
--- a/lib/diameter/s6a/message.h
+++ b/lib/diameter/s6a/message.h
@@ -59,9 +59,6 @@ extern "C" {
 #define OGS_DIAM_S6A_ULR_INITIAL_ATTACH_IND             (1 << 5)
 #define OGS_DIAM_S6A_ULR_PS_LCS_SUPPORTED_BY_UE         (1 << 6)
 
-#define OGS_DIAM_S6A_CLR_S6A_S6D_INDICATOR              (1)
-#define OGS_DIAM_S6A_CLR_REATTACH_REQUIRED              (1 << 1)
-
 #define OGS_DIAM_S6A_UE_SRVCC_NOT_SUPPORTED             (0)
 #define OGS_DIAM_S6A_UE_SRVCC_SUPPORTED                 (1)
 
@@ -148,8 +145,8 @@ typedef struct ogs_diam_s6a_ula_message_s {
 } ogs_diam_s6a_ula_message_t;
 
 typedef struct ogs_diam_s6a_clr_message_s {
-#define OGS_DIAM_S6A_CLR_FLAGS_S6A_S6D_INDICATOR            (0)
-#define OGS_DIAM_S6A_CLR_FLAGS_REATTACH_REQUIRED            (1)
+#define OGS_DIAM_S6A_CLR_FLAGS_S6A_S6D_INDICATOR            (1)
+#define OGS_DIAM_S6A_CLR_FLAGS_REATTACH_REQUIRED            (1 << 1)
     uint32_t clr_flags;
 } ogs_diam_s6a_clr_message_t;
 
diff --git a/lib/gtp/xact.h b/lib/gtp/xact.h
index efcc36135..51f7a4b81 100644
--- a/lib/gtp/xact.h
+++ b/lib/gtp/xact.h
@@ -100,10 +100,10 @@ typedef struct ogs_gtp_xact_s {
 #define OGS_GTP_DELETE_SEND_DETACH_ACCEPT 2
 #define OGS_GTP_DELETE_SEND_DEACTIVATE_BEARER_CONTEXT_REQUEST 3
 #define OGS_GTP_DELETE_SEND_UE_CONTEXT_RELEASE_COMMAND 4
-#define OGS_GTP_DELETE_HANDLE_PDN_CONNECTIVITY_REQUEST 5
-#define OGS_GTP_DELETE_UE_CONTEXT_REMOVE 6
-#define OGS_GTP_DELETE_IN_PATH_SWITCH_REQUEST 7
-#define OGS_GTP_DELETE_NO_ACTION 8
+#define OGS_GTP_DELETE_SEND_S1_REMOVE_AND_UNLINK 5
+#define OGS_GTP_DELETE_HANDLE_PDN_CONNECTIVITY_REQUEST 6
+#define OGS_GTP_DELETE_UE_CONTEXT_REMOVE 7
+#define OGS_GTP_DELETE_IN_PATH_SWITCH_REQUEST 8
     int             delete_action;
 
 #define OGS_GTP_RELEASE_SEND_UE_CONTEXT_RELEASE_COMMAND     1
diff --git a/src/mme/emm-build.c b/src/mme/emm-build.c
index 36f981d80..67a15a315 100644
--- a/src/mme/emm-build.c
+++ b/src/mme/emm-build.c
@@ -437,11 +437,12 @@ ogs_pkbuf_t *emm_build_security_mode_command(mme_ue_t *mme_ue)
     return nas_eps_security_encode(mme_ue, &message);
 }
 
-ogs_pkbuf_t *emm_build_detach_request(mme_ue_t *mme_ue)
+ogs_pkbuf_t *emm_build_detach_request(mme_ue_t *mme_ue, uint8_t detach_type)
 {
     ogs_nas_eps_message_t message;
 
     ogs_assert(mme_ue);
+    ogs_assert(detach_type);
 
     memset(&message, 0, sizeof(message));
     message.h.security_header_type = 
@@ -451,7 +452,7 @@ ogs_pkbuf_t *emm_build_detach_request(mme_ue_t *mme_ue)
     message.emm.h.protocol_discriminator = OGS_NAS_PROTOCOL_DISCRIMINATOR_EMM;
     message.emm.h.message_type = OGS_NAS_EPS_DETACH_REQUEST;
 
-    message.emm.detach_request_to_ue.detach_type.value = mme_ue->mme_to_ue_detach_type;
+    message.emm.detach_request_to_ue.detach_type.value = detach_type;
 
     return nas_eps_security_encode(mme_ue, &message);
 }
diff --git a/src/mme/emm-build.h b/src/mme/emm-build.h
index 14f01e888..ba2dc793d 100644
--- a/src/mme/emm-build.h
+++ b/src/mme/emm-build.h
@@ -37,7 +37,7 @@ ogs_pkbuf_t *emm_build_security_mode_command(mme_ue_t *mme_ue);
 ogs_pkbuf_t *emm_build_authentication_request(mme_ue_t *mme_ue);
 ogs_pkbuf_t *emm_build_authentication_reject(void);
 
-ogs_pkbuf_t *emm_build_detach_request(mme_ue_t *mme_ue);
+ogs_pkbuf_t *emm_build_detach_request(mme_ue_t *mme_ue, uint8_t detach_type);
 ogs_pkbuf_t *emm_build_detach_accept(mme_ue_t *mme_ue);
 
 ogs_pkbuf_t *emm_build_tau_accept(mme_ue_t *mme_ue);
diff --git a/src/mme/emm-handler.c b/src/mme/emm-handler.c
index a6d72bdbe..34c89f733 100644
--- a/src/mme/emm-handler.c
+++ b/src/mme/emm-handler.c
@@ -403,8 +403,6 @@ int emm_handle_detach_request(
     if (detach_request->detach_type.switch_off)
         ogs_debug("    Switch-Off");
 
-    ogs_info("    IMSI[%s]", mme_ue->imsi_bcd);
-
     return OGS_OK;
 }
 
diff --git a/src/mme/emm-sm.c b/src/mme/emm-sm.c
index 611d72a8a..24ed763a3 100644
--- a/src/mme/emm-sm.c
+++ b/src/mme/emm-sm.c
@@ -129,16 +129,6 @@ static void common_register_state(ogs_fsm_t *s, mme_event_t *e)
                 break;
             }
 
-            if (mme_ue->mme_to_ue_detach_pending) {
-                ogs_assert(OGS_OK == nas_eps_send_detach_request(mme_ue));
-                mme_gtp_send_delete_all_sessions(mme_ue, OGS_GTP_DELETE_NO_ACTION);
-                if (MME_P_TMSI_IS_AVAILABLE(mme_ue)) {
-                    ogs_assert(OGS_OK ==
-                        sgsap_send_detach_indication(mme_ue));
-                }
-                break;
-            }
-
             if (!MME_UE_HAVE_IMSI(mme_ue)) {
                 ogs_info("Service request : Unknown UE");
                 ogs_assert(OGS_OK ==
@@ -540,8 +530,7 @@ static void common_register_state(ogs_fsm_t *s, mme_event_t *e)
             }
 
             if (MME_P_TMSI_IS_AVAILABLE(mme_ue)) {
-                ogs_assert(OGS_OK ==
-                    sgsap_send_detach_indication(mme_ue));
+                ogs_assert(OGS_OK == sgsap_send_detach_indication(mme_ue));
             } else {
                 mme_send_delete_session_or_detach(mme_ue);
             }
@@ -550,17 +539,16 @@ static void common_register_state(ogs_fsm_t *s, mme_event_t *e)
             break;
 
         case OGS_NAS_EPS_DETACH_ACCEPT:
-            ogs_debug("Detach accept");
+            ogs_info("[%s] Detach accept", mme_ue->imsi_bcd);
 
             CLEAR_MME_UE_TIMER(mme_ue->t3422);
 
-            if (enb_ue) {
-                s1ap_send_ue_context_release_command(enb_ue,
-                        S1AP_Cause_PR_nas, S1AP_CauseNas_detach,
-                        S1AP_UE_CTX_REL_UE_CONTEXT_REMOVE, 0);
+            if (MME_P_TMSI_IS_AVAILABLE(mme_ue)) {
+                ogs_assert(OGS_OK == sgsap_send_detach_indication(mme_ue));
             } else {
-                ogs_warn("[%s] No S1 Context", mme_ue->imsi_bcd);
+                mme_send_delete_session_or_detach(mme_ue);
             }
+
             OGS_FSM_TRAN(s, &emm_state_de_registered);
             break;
 
@@ -612,18 +600,8 @@ static void common_register_state(ogs_fsm_t *s, mme_event_t *e)
                         mme_ue->imsi_bcd);
                 CLEAR_MME_UE_TIMER(mme_ue->t3413);
 
-                mme_send_after_paging(mme_ue, OGS_GTP2_CAUSE_UNABLE_TO_PAGE_UE);
-
-                if (CS_CALL_SERVICE_INDICATOR(mme_ue) ||
-                    SMS_SERVICE_INDICATOR(mme_ue)) {
-                    ogs_assert(OGS_OK ==
-                        sgsap_send_ue_unreachable(mme_ue,
-                            SGSAP_SGS_CAUSE_UE_UNREACHABLE));
-
-                }
-    
-                CLEAR_SERVICE_INDICATOR(mme_ue);
-
+                ogs_assert(MME_PAGING_ONGOING(mme_ue));
+                mme_send_after_paging(mme_ue, true);
             } else {
                 mme_ue->t3413.retry_count++;
                 /*
@@ -642,6 +620,7 @@ static void common_register_state(ogs_fsm_t *s, mme_event_t *e)
                         "Stop retransmission");
                 OGS_FSM_TRAN(&mme_ue->sm, &emm_state_exception);
             } else {
+                ogs_assert(mme_ue->t3470.pkbuf);
                 rv = nas_eps_send_identity_request(mme_ue);
                 if (rv == OGS_OK) {
                     mme_ue->t3470.retry_count++;
@@ -659,7 +638,8 @@ static void common_register_state(ogs_fsm_t *s, mme_event_t *e)
                         "Stop retransmission");
                 OGS_FSM_TRAN(&mme_ue->sm, &emm_state_exception);
             } else {
-                rv = nas_eps_send_detach_request(mme_ue);
+                ogs_assert(mme_ue->t3422.pkbuf);
+                rv = nas_eps_send_detach_request(mme_ue, 0);
                 if (rv == OGS_OK) {
                     mme_ue->t3422.retry_count++;
                 } else {
diff --git a/src/mme/mme-context.h b/src/mme/mme-context.h
index 484378fb6..048f9f06c 100644
--- a/src/mme/mme-context.h
+++ b/src/mme/mme-context.h
@@ -321,9 +321,6 @@ struct mme_ue_s {
         };
     } nas_eps;
 
-    bool            mme_to_ue_detach_pending;
-    uint8_t         mme_to_ue_detach_type;
-
     /* UE identity */
 #define MME_UE_HAVE_IMSI(__mME) \
     ((__mME) && ((__mME)->imsi_len))
@@ -454,6 +451,34 @@ struct mme_ue_s {
      (((__mME)->enb_ue == NULL) || (enb_ue_cycle((__mME)->enb_ue) == NULL)))
     enb_ue_t        *enb_ue;    /* S1 UE context */
 
+    struct {
+#define MME_CLEAR_PAGING_INFO(__mME) \
+    do { \
+        ogs_assert(__mME); \
+        (__mME)->paging.type = 0; \
+    } while(0)
+
+#define MME_STORE_PAGING_INFO(__mME, __tYPE, __dATA) \
+    do { \
+        ogs_assert(__mME); \
+        ogs_assert(__tYPE); \
+        (__mME)->paging.type = __tYPE; \
+        (__mME)->paging.data = __dATA; \
+    } while(0)
+
+#define MME_PAGING_ONGOING(__mME) ((__mME) && ((__mME)->paging.type))
+
+#define MME_PAGING_TYPE_DOWNLINK_DATA_NOTIFICATION 1
+#define MME_PAGING_TYPE_CREATE_BEARER 2
+#define MME_PAGING_TYPE_UPDATE_BEARER 3
+#define MME_PAGING_TYPE_DELETE_BEARER 4
+#define MME_PAGING_TYPE_CS_CALL_SERVICE 5
+#define MME_PAGING_TYPE_SMS_SERVICE 6
+#define MME_PAGING_TYPE_DETACH_TO_UE 7
+        int type;
+        void *data;
+    } paging;
+
     /* SGW UE context */
     sgw_ue_t        *sgw_ue;
 
@@ -687,9 +712,10 @@ typedef struct mme_bearer_s {
     /* Related Context */
     mme_ue_t        *mme_ue;
     mme_sess_t      *sess;
+
     struct {
         ogs_gtp_xact_t  *xact;
-    } create, update, delete, notify, current;
+    } create, update, delete, notify;
 } mme_bearer_t;
 
 void mme_context_init(void);
diff --git a/src/mme/mme-path.c b/src/mme/mme-path.c
index b5eeff8f0..7a1bfa9c8 100644
--- a/src/mme/mme-path.c
+++ b/src/mme/mme-path.c
@@ -19,19 +19,43 @@
 
 #include "s1ap-path.h"
 #include "nas-path.h"
+#include "sgsap-path.h"
 #include "mme-gtp-path.h"
 #include "mme-path.h"
+#include "mme-sm.h"
 
 void mme_send_delete_session_or_detach(mme_ue_t *mme_ue)
 {
     ogs_assert(mme_ue);
 
-    if (SESSION_CONTEXT_IS_AVAILABLE(mme_ue)) {
-        mme_gtp_send_delete_all_sessions(mme_ue,
-                OGS_GTP_DELETE_SEND_DETACH_ACCEPT);
-    } else {
-        ogs_assert(OGS_OK ==
-            nas_eps_send_detach_accept(mme_ue));
+    switch (mme_ue->nas_eps.type) {
+    case MME_EPS_TYPE_DETACH_REQUEST_FROM_UE:
+        if (SESSION_CONTEXT_IS_AVAILABLE(mme_ue)) {
+            mme_gtp_send_delete_all_sessions(
+                    mme_ue, OGS_GTP_DELETE_SEND_DETACH_ACCEPT);
+        } else {
+            ogs_assert(OGS_OK == nas_eps_send_detach_accept(mme_ue));
+        }
+        break;
+    case MME_EPS_TYPE_DETACH_REQUEST_TO_UE:
+        if (SESSION_CONTEXT_IS_AVAILABLE(mme_ue)) {
+            mme_gtp_send_delete_all_sessions(
+                    mme_ue, OGS_GTP_DELETE_SEND_S1_REMOVE_AND_UNLINK);
+        } else {
+            enb_ue_t *enb_ue = enb_ue_cycle(mme_ue->enb_ue);
+            if (enb_ue) {
+                ogs_assert(OGS_OK ==
+                    s1ap_send_ue_context_release_command(enb_ue,
+                        S1AP_Cause_PR_nas, S1AP_CauseNas_normal_release,
+                        S1AP_UE_CTX_REL_S1_REMOVE_AND_UNLINK, 0));
+            } else {
+                ogs_warn("[%s] No S1 Context", mme_ue->imsi_bcd);
+            }
+        }
+        break;
+    default:
+        ogs_fatal("    Invalid OGS_NAS_EPS TYPE[%d]", mme_ue->nas_eps.type);
+        ogs_assert_if_reached();
     }
 }
 
@@ -75,72 +99,131 @@ void mme_send_release_access_bearer_or_ue_context_release(enb_ue_t *enb_ue)
     }
 }
 
-void mme_send_after_paging(mme_ue_t *mme_ue, uint8_t cause_value)
+void mme_send_after_paging(mme_ue_t *mme_ue, bool failed)
 {
-    mme_sess_t *sess = NULL;
     mme_bearer_t *bearer = NULL;
 
     ogs_assert(mme_ue);
 
-    ogs_list_for_each(&mme_ue->sess_list, sess) {
-        ogs_list_for_each(&sess->bearer_list, bearer) {
-            ogs_gtp_xact_t *xact = NULL;
-            uint8_t type;
-
-            xact = ogs_gtp_xact_cycle(bearer->current.xact);
-            if (xact) {
-                /*
-                 * It may conflict with GTP transaction already used.
-                 * To avoid this, check `xact->step` to see if
-                 * the transaction has already been committed.
-                 */
-                type = xact->seq[xact->step-1].type;
-
-                switch (type) {
-                case OGS_GTP2_DOWNLINK_DATA_NOTIFICATION_TYPE:
-                    ogs_assert(OGS_OK ==
-                        mme_gtp_send_downlink_data_notification_ack(
-                            bearer, cause_value));
-                    break;
-                case OGS_GTP2_CREATE_BEARER_REQUEST_TYPE:
-                    if (cause_value == OGS_GTP2_CAUSE_REQUEST_ACCEPTED) {
-                        ogs_assert(OGS_OK ==
-                        nas_eps_send_activate_dedicated_bearer_context_request(
-                                bearer));
-                    } else {
-                        ogs_assert(OGS_OK ==
-                            mme_gtp_send_create_bearer_response(
-                                bearer, cause_value));
-                    }
-                    break;
-                case OGS_GTP2_UPDATE_BEARER_REQUEST_TYPE:
-                    if (cause_value == OGS_GTP2_CAUSE_REQUEST_ACCEPTED) {
-                        ogs_assert(OGS_OK ==
-                            nas_eps_send_modify_bearer_context_request(bearer,
-                                (xact->update_flags &
-                                    OGS_GTP_MODIFY_QOS_UPDATE) ? 1 : 0,
-                                (xact->update_flags &
-                                    OGS_GTP_MODIFY_TFT_UPDATE) ? 1 : 0));
-                    } else {
-                        ogs_assert(OGS_OK ==
-                            mme_gtp_send_update_bearer_response(
-                                bearer, cause_value));
-                    }
-                    break;
-                case OGS_GTP2_DELETE_BEARER_REQUEST_TYPE:
-                    if (cause_value == OGS_GTP2_CAUSE_REQUEST_ACCEPTED) {
-                        ogs_assert(OGS_OK ==
-                        nas_eps_send_deactivate_bearer_context_request(bearer));
-                    } else {
-                        ogs_assert(OGS_OK ==
-                            mme_gtp_send_delete_bearer_response(
-                                bearer, cause_value));
-                    }
-                    break;
-                default:
-                    break;
-                }
-            }
+    switch (mme_ue->paging.type) {
+    case MME_PAGING_TYPE_DOWNLINK_DATA_NOTIFICATION:
+        bearer = mme_bearer_cycle(mme_ue->paging.data);
+        if (!bearer) {
+            ogs_error("No Bearer [%d]", mme_ue->paging.type);
+            goto cleanup;
         }
+
+        if (failed == true) {
+            ogs_assert(OGS_OK ==
+                mme_gtp_send_downlink_data_notification_ack(
+                    bearer, OGS_GTP2_CAUSE_UNABLE_TO_PAGE_UE));
+        } else {
+            ogs_assert(OGS_OK ==
+                mme_gtp_send_downlink_data_notification_ack(
+                    bearer, OGS_GTP2_CAUSE_REQUEST_ACCEPTED));
+        }
+        break;
+    case MME_PAGING_TYPE_CREATE_BEARER:
+        bearer = mme_bearer_cycle(mme_ue->paging.data);
+        if (!bearer) {
+            ogs_error("No Bearer [%d]", mme_ue->paging.type);
+            goto cleanup;
+        }
+
+        if (failed == true) {
+            ogs_assert(OGS_OK ==
+                mme_gtp_send_create_bearer_response(
+                    bearer, OGS_GTP2_CAUSE_UNABLE_TO_PAGE_UE));
+        } else {
+            ogs_assert(OGS_OK ==
+                nas_eps_send_activate_dedicated_bearer_context_request(bearer));
+        }
+        break;
+    case MME_PAGING_TYPE_UPDATE_BEARER:
+        bearer = mme_bearer_cycle(mme_ue->paging.data);
+        if (!bearer) {
+            ogs_error("No Bearer [%d]", mme_ue->paging.type);
+            goto cleanup;
+        }
+
+        if (failed == true) {
+            ogs_assert(OGS_OK ==
+                mme_gtp_send_update_bearer_response(
+                    bearer, OGS_GTP2_CAUSE_UNABLE_TO_PAGE_UE));
+        } else {
+            ogs_gtp_xact_t *xact = ogs_gtp_xact_cycle(bearer->update.xact);
+            if (!xact) {
+                ogs_error("No GTP xact");
+                goto cleanup;
+            }
+
+            ogs_assert(OGS_OK ==
+                nas_eps_send_modify_bearer_context_request(bearer,
+                    (xact->update_flags &
+                        OGS_GTP_MODIFY_QOS_UPDATE) ? 1 : 0,
+                    (xact->update_flags &
+                        OGS_GTP_MODIFY_TFT_UPDATE) ? 1 : 0));
+        }
+        break;
+    case MME_PAGING_TYPE_DELETE_BEARER:
+        bearer = mme_bearer_cycle(mme_ue->paging.data);
+        if (!bearer) {
+            ogs_error("No Bearer [%d]", mme_ue->paging.type);
+            goto cleanup;
+        }
+
+        if (failed == true) {
+            ogs_assert(OGS_OK ==
+                mme_gtp_send_delete_bearer_response(
+                    bearer, OGS_GTP2_CAUSE_UNABLE_TO_PAGE_UE));
+        } else {
+            ogs_assert(OGS_OK ==
+                nas_eps_send_deactivate_bearer_context_request(bearer));
+        }
+        break;
+    case MME_PAGING_TYPE_CS_CALL_SERVICE:
+        if (failed == true) {
+            ogs_assert(OGS_OK ==
+                sgsap_send_service_request(
+                    mme_ue, SGSAP_SGS_CAUSE_UE_UNREACHABLE));
+        } else {
+            /* Nothing */
+        }
+        break;
+    case MME_PAGING_TYPE_SMS_SERVICE:
+        if (failed == true) {
+            ogs_assert(OGS_OK ==
+                sgsap_send_service_request(
+                    mme_ue, SGSAP_SGS_CAUSE_UE_UNREACHABLE));
+        } else {
+            ogs_assert(OGS_OK ==
+                sgsap_send_service_request(
+                    mme_ue, SGSAP_EMM_CONNECTED_MODE));
+        }
+        break;
+    case MME_PAGING_TYPE_DETACH_TO_UE:
+        if (failed == true) {
+            if (MME_P_TMSI_IS_AVAILABLE(mme_ue)) {
+                ogs_assert(OGS_OK == sgsap_send_detach_indication(mme_ue));
+            } else {
+                mme_send_delete_session_or_detach(mme_ue);
+            }
+
+            OGS_FSM_TRAN(&mme_ue->sm, &emm_state_de_registered);
+        } else {
+            uint8_t detach_type = (uintptr_t)mme_ue->paging.data;
+            ogs_assert(detach_type);
+
+            ogs_assert(OGS_OK ==
+                    nas_eps_send_detach_request(mme_ue, detach_type));
+        }
+        break;
+    default:
+        ogs_fatal("Invalid Paging Type[%d]", mme_ue->paging.type);
+        ogs_assert_if_reached();
     }
+
+cleanup:
+    CLEAR_SERVICE_INDICATOR(mme_ue);
+    MME_CLEAR_PAGING_INFO(mme_ue);
 }
diff --git a/src/mme/mme-path.h b/src/mme/mme-path.h
index 8d9b27391..afc6f13e8 100644
--- a/src/mme/mme-path.h
+++ b/src/mme/mme-path.h
@@ -30,7 +30,7 @@ void mme_send_delete_session_or_detach(mme_ue_t *mme_ue);
 void mme_send_delete_session_or_mme_ue_context_release(mme_ue_t *mme_ue);
 void mme_send_release_access_bearer_or_ue_context_release(enb_ue_t *enb_ue);
 
-void mme_send_after_paging(mme_ue_t *mme_ue, uint8_t cause_value);
+void mme_send_after_paging(mme_ue_t *mme_ue, bool failed);
 
 #ifdef __cplusplus
 }
diff --git a/src/mme/mme-s11-handler.c b/src/mme/mme-s11-handler.c
index df248e31b..6a0de237b 100644
--- a/src/mme/mme-s11-handler.c
+++ b/src/mme/mme-s11-handler.c
@@ -603,6 +603,20 @@ void mme_s11_handle_delete_session_response(
                 ogs_error("ENB-S1 Context has already been removed");
         }
 
+    } else if (action == OGS_GTP_DELETE_SEND_S1_REMOVE_AND_UNLINK) {
+        if (mme_sess_count(mme_ue) == 1) /* Last Session */ {
+            enb_ue_t *enb_ue = NULL;
+
+            enb_ue = enb_ue_cycle(mme_ue->enb_ue);
+            if (enb_ue) {
+                ogs_assert(OGS_OK ==
+                    s1ap_send_ue_context_release_command(enb_ue,
+                        S1AP_Cause_PR_nas, S1AP_CauseNas_normal_release,
+                        S1AP_UE_CTX_REL_S1_REMOVE_AND_UNLINK, 0));
+            } else
+                ogs_error("ENB-S1 Context has already been removed");
+        }
+
     } else if (action == OGS_GTP_DELETE_HANDLE_PDN_CONNECTIVITY_REQUEST) {
         if (mme_sess_count(mme_ue) == 1) /* Last Session */ {
             rv = nas_eps_send_emm_to_esm(mme_ue,
@@ -636,8 +650,6 @@ void mme_s11_handle_delete_session_response(
 
         return;
 
-    } else if (action == OGS_GTP_DELETE_NO_ACTION) {
-        
     } else {
         ogs_fatal("Invalid action = %d", action);
         ogs_assert_if_reached();
@@ -805,7 +817,6 @@ void mme_s11_handle_create_bearer_request(
      * If GTP-xact Holding timer is expired,
      * OLD bearer->xact memory will be automatically removed.
      */
-    bearer->current.xact = xact;
     bearer->create.xact = xact;
 
     /* Before Activate DEDICATED bearer, check DEFAULT bearer status */
@@ -814,6 +825,8 @@ void mme_s11_handle_create_bearer_request(
 
     if (OGS_FSM_CHECK(&default_bearer->sm, esm_state_active)) {
         if (ECM_IDLE(mme_ue)) {
+            MME_STORE_PAGING_INFO(mme_ue,
+                    MME_PAGING_TYPE_CREATE_BEARER, bearer);
             ogs_assert(OGS_OK == s1ap_send_paging(mme_ue, S1AP_CNDomain_ps));
         } else {
             ogs_assert(OGS_OK ==
@@ -906,7 +919,6 @@ void mme_s11_handle_update_bearer_request(
      * If GTP-xact Holding timer is expired,
      * OLD bearer->xact memory will be automatically removed.
      */
-    bearer->current.xact = xact;
     bearer->update.xact = xact;
 
     if (req->bearer_contexts.bearer_level_qos.presence == 1) {
@@ -938,6 +950,8 @@ void mme_s11_handle_update_bearer_request(
     if (req->bearer_contexts.bearer_level_qos.presence == 1 ||
         req->bearer_contexts.tft.presence == 1) {
         if (ECM_IDLE(mme_ue)) {
+            MME_STORE_PAGING_INFO(mme_ue,
+                    MME_PAGING_TYPE_UPDATE_BEARER, bearer);
             ogs_assert(OGS_OK == s1ap_send_paging(mme_ue, S1AP_CNDomain_ps));
         } else {
             ogs_assert(OGS_OK ==
@@ -1067,10 +1081,10 @@ void mme_s11_handle_delete_bearer_request(
      * If GTP-xact Holding timer is expired,
      * OLD bearer->xact memory will be automatically removed.
      */
-    bearer->current.xact = xact;
     bearer->delete.xact = xact;
 
     if (ECM_IDLE(mme_ue)) {
+        MME_STORE_PAGING_INFO(mme_ue, MME_PAGING_TYPE_DELETE_BEARER, bearer);
         ogs_assert(OGS_OK == s1ap_send_paging(mme_ue, S1AP_CNDomain_ps));
     } else {
         ogs_assert(OGS_OK ==
@@ -1295,7 +1309,6 @@ void mme_s11_handle_downlink_data_notification(
      * If GTP-xact Holding timer is expired,
      * OLD bearer->xact memory will be automatically removed.
      */
-    bearer->current.xact = xact;
     bearer->notify.xact = xact;
 
     if (noti->cause.presence) {
@@ -1319,6 +1332,8 @@ void mme_s11_handle_downlink_data_notification(
  * before step 9, the MME shall not send S1 interface paging messages
  */
     if (ECM_IDLE(mme_ue)) {
+        MME_STORE_PAGING_INFO(mme_ue,
+                MME_PAGING_TYPE_DOWNLINK_DATA_NOTIFICATION, bearer);
         ogs_assert(OGS_OK == s1ap_send_paging(mme_ue, S1AP_CNDomain_ps));
 
     } else if (ECM_CONNECTED(mme_ue)) {
diff --git a/src/mme/mme-s6a-handler.c b/src/mme/mme-s6a-handler.c
index 14cf36490..4054045fd 100644
--- a/src/mme/mme-s6a-handler.c
+++ b/src/mme/mme-s6a-handler.c
@@ -105,23 +105,29 @@ void mme_s6a_handle_ula(mme_ue_t *mme_ue,
 void mme_s6a_handle_clr(mme_ue_t *mme_ue,
         ogs_diam_s6a_clr_message_t *clr_message)
 {
+    uint8_t detach_type = 0;
+
     ogs_assert(mme_ue);
     ogs_assert(clr_message);    
 
-    if (clr_message->clr_flags & OGS_DIAM_S6A_CLR_REATTACH_REQUIRED) {
-        mme_ue->mme_to_ue_detach_type = OGS_NAS_DETACH_TYPE_TO_UE_RE_ATTACH_REQUIRED;
-    } else {
-        mme_ue->mme_to_ue_detach_type = OGS_NAS_DETACH_TYPE_TO_UE_RE_ATTACH_NOT_REQUIRED;
-    }
+    /* Set NAS EPS Type */
+    mme_ue->nas_eps.type = MME_EPS_TYPE_DETACH_REQUEST_TO_UE;
+    ogs_debug("    OGS_NAS_EPS TYPE[%d]", mme_ue->nas_eps.type);
+
+    if (clr_message->clr_flags & OGS_DIAM_S6A_CLR_FLAGS_REATTACH_REQUIRED)
+        detach_type = OGS_NAS_DETACH_TYPE_TO_UE_RE_ATTACH_REQUIRED;
+    else
+        detach_type = OGS_NAS_DETACH_TYPE_TO_UE_RE_ATTACH_NOT_REQUIRED;
     
     if (OGS_FSM_CHECK(&mme_ue->sm, emm_state_de_registered)) {
-        // Remove all trace of subscriber even when detached.
+        /* Remove all trace of subscriber even when detached. */
         mme_ue_hash_remove(mme_ue);
         mme_ue_remove(mme_ue);
     } else if (ECM_IDLE(mme_ue)) {
+        MME_STORE_PAGING_INFO(mme_ue,
+                MME_PAGING_TYPE_DETACH_TO_UE, (void *)(uintptr_t)detach_type);
         ogs_assert(OGS_OK == s1ap_send_paging(mme_ue, S1AP_CNDomain_ps));
-        mme_ue->mme_to_ue_detach_pending = true;
     } else {
-        ogs_assert(OGS_OK == nas_eps_send_detach_request(mme_ue));
+        ogs_assert(OGS_OK == nas_eps_send_detach_request(mme_ue, detach_type));
     }
 }
diff --git a/src/mme/mme-sm.c b/src/mme/mme-sm.c
index 131397e3f..b76093bf2 100644
--- a/src/mme/mme-sm.c
+++ b/src/mme/mme-sm.c
@@ -460,8 +460,8 @@ void mme_state_operational(ogs_fsm_t *s, mme_event_t *e)
                 ogs_info("[%s] Attach reject [OGS_NAS_EMM_CAUSE:%d]",
                         mme_ue->imsi_bcd, emm_cause);
                 ogs_assert(OGS_OK ==
-                    nas_eps_send_attach_reject(mme_ue,
-                        emm_cause, OGS_NAS_ESM_CAUSE_PROTOCOL_ERROR_UNSPECIFIED));
+                    nas_eps_send_attach_reject(mme_ue, emm_cause,
+                        OGS_NAS_ESM_CAUSE_PROTOCOL_ERROR_UNSPECIFIED));
 
                 ogs_assert(OGS_OK ==
                     s1ap_send_ue_context_release_command(enb_ue,
@@ -508,14 +508,6 @@ void mme_state_operational(ogs_fsm_t *s, mme_event_t *e)
             break;
         case OGS_DIAM_S6A_CMD_CODE_CANCEL_LOCATION:
             mme_s6a_handle_clr(mme_ue, &s6a_message->clr_message);
-
-            if (SESSION_CONTEXT_IS_AVAILABLE(mme_ue) && !mme_ue->mme_to_ue_detach_pending) {
-                mme_gtp_send_delete_all_sessions(mme_ue, OGS_GTP_DELETE_NO_ACTION);
-            }
-            if (MME_P_TMSI_IS_AVAILABLE(mme_ue)) {
-                ogs_assert(OGS_OK ==
-                    sgsap_send_detach_indication(mme_ue));
-            }
             break;
         default:
             ogs_error("Invalid Type[%d]", s6a_message->cmd_code);
diff --git a/src/mme/nas-path.c b/src/mme/nas-path.c
index 7cd25cae3..d822174ef 100644
--- a/src/mme/nas-path.c
+++ b/src/mme/nas-path.c
@@ -256,24 +256,19 @@ int nas_eps_send_authentication_reject(mme_ue_t *mme_ue)
     return rv;
 }
 
-int nas_eps_send_detach_request(mme_ue_t *mme_ue)
+int nas_eps_send_detach_request(mme_ue_t *mme_ue, uint8_t detach_type)
 {
     int rv;
- 
-    enb_ue_t *enb_ue = NULL;
     ogs_pkbuf_t *emmbuf = NULL;
 
-    ogs_assert(mme_ue);
-    enb_ue = enb_ue_cycle(mme_ue->enb_ue);
-    ogs_expect_or_return_val(enb_ue, OGS_ERROR);
-
     ogs_debug("[%s] Detach request to UE", mme_ue->imsi_bcd);
 
     if (mme_ue->t3422.pkbuf) {
         emmbuf = mme_ue->t3422.pkbuf;
         ogs_expect_or_return_val(emmbuf, OGS_ERROR);
     } else {
-        emmbuf = emm_build_identity_request(mme_ue);
+        ogs_assert(detach_type);
+        emmbuf = emm_build_detach_request(mme_ue, detach_type);
         ogs_expect_or_return_val(emmbuf, OGS_ERROR);
     }
 
@@ -282,10 +277,6 @@ int nas_eps_send_detach_request(mme_ue_t *mme_ue)
     ogs_timer_start(mme_ue->t3422.timer, 
             mme_timer_cfg(MME_TIMER_T3422)->duration);    
 
-    /* send detach request */
-    emmbuf = emm_build_detach_request(mme_ue);
-    ogs_expect_or_return_val(emmbuf, OGS_ERROR);
-
     rv = nas_eps_send_to_downlink_nas_transport(mme_ue, emmbuf);
     ogs_expect_or_return_val(rv == OGS_OK, rv);
 
diff --git a/src/mme/nas-path.h b/src/mme/nas-path.h
index 3e3183485..56138d12d 100644
--- a/src/mme/nas-path.h
+++ b/src/mme/nas-path.h
@@ -43,7 +43,7 @@ int nas_eps_send_authentication_reject(mme_ue_t *mme_ue);
 
 int nas_eps_send_security_mode_command(mme_ue_t *mme_ue);
 
-int nas_eps_send_detach_request(mme_ue_t *mme_ue);
+int nas_eps_send_detach_request(mme_ue_t *mme_ue, uint8_t detach_type);
 int nas_eps_send_detach_accept(mme_ue_t *mme_ue);
 
 int nas_eps_send_pdn_connectivity_reject(
diff --git a/src/mme/s1ap-handler.c b/src/mme/s1ap-handler.c
index 539df1a4d..0ebdc57c1 100644
--- a/src/mme/s1ap-handler.c
+++ b/src/mme/s1ap-handler.c
@@ -764,15 +764,8 @@ void s1ap_handle_initial_context_setup_response(
         }
     }
 
-    if (mme_ue->nas_eps.type != MME_EPS_TYPE_ATTACH_REQUEST)
-        mme_send_after_paging(mme_ue, OGS_GTP2_CAUSE_REQUEST_ACCEPTED);
-
-    if (SMS_SERVICE_INDICATOR(mme_ue)) {
-        ogs_assert(OGS_OK ==
-            sgsap_send_service_request(mme_ue, SGSAP_EMM_CONNECTED_MODE));
-    }
-
-    CLEAR_SERVICE_INDICATOR(mme_ue);
+    if (MME_PAGING_ONGOING(mme_ue))
+        mme_send_after_paging(mme_ue, false);
 }
 
 void s1ap_handle_initial_context_setup_failure(
diff --git a/src/mme/sgsap-build.c b/src/mme/sgsap-build.c
index 65c5cf315..c14967759 100644
--- a/src/mme/sgsap-build.c
+++ b/src/mme/sgsap-build.c
@@ -19,7 +19,6 @@
 
 #include "mme-context.h"
 
-#include "sgsap-types.h"
 #include "sgsap-build.h"
 #include "sgsap-conv.h"
 
diff --git a/src/mme/sgsap-build.h b/src/mme/sgsap-build.h
index 76287e346..12810e9c8 100644
--- a/src/mme/sgsap-build.h
+++ b/src/mme/sgsap-build.h
@@ -22,6 +22,8 @@
 
 #include "mme-context.h"
 
+#include "sgsap-types.h"
+
 #ifdef __cplusplus
 extern "C" {
 #endif
diff --git a/src/mme/sgsap-handler.c b/src/mme/sgsap-handler.c
index 458bc73b3..7d2a1b8ca 100644
--- a/src/mme/sgsap-handler.c
+++ b/src/mme/sgsap-handler.c
@@ -272,9 +272,7 @@ void sgsap_handle_detach_ack(mme_vlr_t *vlr, ogs_pkbuf_t *pkbuf)
 
     ogs_debug("    IMSI[%s]", mme_ue->imsi_bcd);
 
-    if (!mme_ue->mme_to_ue_detach_pending) {
-        mme_send_delete_session_or_detach(mme_ue);
-    }
+    mme_send_delete_session_or_detach(mme_ue);
 }
 
 void sgsap_handle_paging_request(mme_vlr_t *vlr, ogs_pkbuf_t *pkbuf)
@@ -354,11 +352,15 @@ void sgsap_handle_paging_request(mme_vlr_t *vlr, ogs_pkbuf_t *pkbuf)
         if (ECM_IDLE(mme_ue)) {
             if (CS_CALL_SERVICE_INDICATOR(mme_ue)) {
                 /* UE will respond Extended Service Request in PS CNDomain*/
+                MME_STORE_PAGING_INFO(mme_ue,
+                        MME_PAGING_TYPE_CS_CALL_SERVICE, NULL);
                 ogs_assert(OGS_OK ==
                     s1ap_send_paging(mme_ue, S1AP_CNDomain_cs));
 
             } else if (SMS_SERVICE_INDICATOR(mme_ue)) {
                 /* UE will respond Service Request in PS CNDomain*/
+                MME_STORE_PAGING_INFO(mme_ue,
+                        MME_PAGING_TYPE_SMS_SERVICE, NULL);
                 ogs_assert(OGS_OK ==
                     s1ap_send_paging(mme_ue, S1AP_CNDomain_ps));
             } else
diff --git a/src/mme/sgsap-path.c b/src/mme/sgsap-path.c
index c61a718e3..073655905 100644
--- a/src/mme/sgsap-path.c
+++ b/src/mme/sgsap-path.c
@@ -22,8 +22,6 @@
 #include "mme-event.h"
 #include "mme-sm.h"
 
-#include "sgsap-types.h"
-#include "sgsap-build.h"
 #include "sgsap-path.h"
 
 int sgsap_open()
@@ -251,4 +249,4 @@ int sgsap_send_ue_unreachable(mme_ue_t *mme_ue, uint8_t sgs_cause)
     ogs_expect(rv == OGS_OK);
 
     return rv;
-}
\ No newline at end of file
+}
diff --git a/src/mme/sgsap-path.h b/src/mme/sgsap-path.h
index 1ecfb71a6..a1a9b35be 100644
--- a/src/mme/sgsap-path.h
+++ b/src/mme/sgsap-path.h
@@ -23,6 +23,8 @@
 #include "mme-context.h"
 #include "mme-event.h"
 
+#include "sgsap-build.h"
+
 #ifdef __cplusplus
 extern "C" {
 #endif