diff --git a/src/amf/amf-sm.c b/src/amf/amf-sm.c
index 1ef0fdc0b..cabeb0404 100644
--- a/src/amf/amf-sm.c
+++ b/src/amf/amf-sm.c
@@ -64,7 +64,7 @@ void amf_state_operational(ogs_fsm_t *s, amf_event_t *e)
 
     ogs_sbi_object_t *sbi_object = NULL;
     ogs_sbi_xact_t *sbi_xact = NULL;
-    int state = AMF_SESS_SM_CONTEXT_NO_STATE;
+    int state = AMF_CREATE_SM_CONTEXT_NO_STATE;
     ogs_sbi_stream_t *stream = NULL;
     ogs_sbi_request_t *sbi_request = NULL;
 
@@ -436,8 +436,32 @@ void amf_state_operational(ogs_fsm_t *s, amf_event_t *e)
                 break;
 
             DEFAULT
-                amf_nsmf_pdusession_handle_create_sm_context(
+                rv = amf_nsmf_pdusession_handle_create_sm_context(
                         sess, &sbi_message);
+                if (rv != OGS_OK) {
+                    /*
+                     * 1. First PDU session establishment request
+                     *    (PSI:5, internet)
+                     * 2. First session created
+                     * 3. Seconds PDU session establishment request
+                     *    (PSI:5, ims)
+                     * 4. AMF sends DUPLICATED_PDU_SESSION_ID to the SMF
+                     * 5. AMF try to create second PDU session.
+                     * 6. But, Second session rejected due to Subscription Info.
+                     *
+                     * In above situation, AMF need to clear SM_CONTEXT_REF.
+                     * Otherwise, AMF have redundant PDU session.
+                     *
+                     * Moreover, AMF could send UEContextReleaseRequest
+                     * with deactivating this redundant session.
+                     *
+                     * So, if CreateSMContext is failed,
+                     * we'll clear SM_CONTEXT_REF.
+                     */
+                    if (SESSION_CONTEXT_IN_SMF(sess)) {
+                        CLEAR_SM_CONTEXT_REF(sess);
+                    }
+                }
             END
             break;
 
diff --git a/src/amf/context.c b/src/amf/context.c
index f5dbe61ee..9ee19fadc 100644
--- a/src/amf/context.c
+++ b/src/amf/context.c
@@ -1143,6 +1143,9 @@ void amf_ue_remove(amf_ue_t *amf_ue)
 
     amf_ue_fsm_fini(amf_ue);
 
+    /* Remove all session context */
+    amf_sess_remove_all(amf_ue);
+
     /* Clear hash table */
     if (amf_ue->m_tmsi) {
         ogs_hash_set(self.guti_ue_hash,
@@ -1203,8 +1206,6 @@ void amf_ue_remove(amf_ue_t *amf_ue)
 
     amf_ue_deassociate(amf_ue);
 
-    amf_sess_remove_all(amf_ue);
-
     ogs_pool_free(&amf_ue_pool, amf_ue);
 
     ogs_info("[Removed] Number of AMF-UEs is now %d",
diff --git a/src/amf/gmm-handler.c b/src/amf/gmm-handler.c
index 0276f9123..953919780 100644
--- a/src/amf/gmm-handler.c
+++ b/src/amf/gmm-handler.c
@@ -512,7 +512,7 @@ int gmm_handle_deregistration_request(amf_ue_t *amf_ue,
 
     ogs_info("[%s]    SUCI", amf_ue->suci);
 
-    amf_sbi_send_release_all_sessions(amf_ue, AMF_SESS_SM_CONTEXT_NO_STATE);
+    amf_sbi_send_release_all_sessions(amf_ue, AMF_RELEASE_SM_CONTEXT_NO_STATE);
 
     if (ogs_list_count(&amf_ue->sess_list) == 0)
         nas_5gs_send_de_registration_accept(amf_ue);
@@ -679,8 +679,6 @@ int gmm_handle_ul_nas_transport(amf_ue_t *amf_ue,
     ogs_nas_dnn_t *dnn = NULL;
     ogs_nas_5gsm_header_t *gsm_header = NULL;
 
-    bool duplicated_pdu_session_id = false;
-
     ogs_assert(amf_ue);
     ogs_assert(ul_nas_transport);
 
@@ -743,8 +741,6 @@ int gmm_handle_ul_nas_transport(amf_ue_t *amf_ue,
             if (!sess) {
                 sess = amf_sess_add(amf_ue, *pdu_session_id);
                 ogs_assert(sess);
-            } else {
-                duplicated_pdu_session_id = true;
             }
         } else {
             sess = amf_sess_find_by_psi(amf_ue, *pdu_session_id);
@@ -786,7 +782,7 @@ int gmm_handle_ul_nas_transport(amf_ue_t *amf_ue,
             }
 
             if (!selected_s_nssai) {
-                ogs_error("No S_NSSAI : Set default S_NSSAI using AMF config");
+                ogs_warn("No S_NSSAI : Set default S_NSSAI using AMF config");
                 selected_s_nssai = &amf_self()->plmn_support[0].s_nssai[0];
                 ogs_assert(selected_s_nssai);
             }
@@ -814,9 +810,9 @@ int gmm_handle_ul_nas_transport(amf_ue_t *amf_ue,
             ogs_info("UE SUPI[%s] DNN[%s] S_NSSAI[SST:%d SD:0x%x]",
                 amf_ue->supi, sess->dnn, sess->s_nssai.sst, sess->s_nssai.sd.v);
 
-            if (duplicated_pdu_session_id == false) {
+            if (!SESSION_CONTEXT_IN_SMF(sess)) {
                 amf_sess_sbi_discover_and_send(OpenAPI_nf_type_SMF,
-                        sess, AMF_SESS_SM_CONTEXT_NO_STATE, NULL,
+                        sess, AMF_CREATE_SM_CONTEXT_NO_STATE, NULL,
                         amf_nsmf_pdusession_build_create_sm_context);
             } else {
                 memset(&param, 0, sizeof(param));
diff --git a/src/amf/gmm-sm.c b/src/amf/gmm-sm.c
index 688838bd1..405718498 100644
--- a/src/amf/gmm-sm.c
+++ b/src/amf/gmm-sm.c
@@ -161,7 +161,7 @@ static void common_register_state(ogs_fsm_t *s, amf_event_t *e)
             } else {
 
                 amf_sbi_send_release_all_sessions(
-                        amf_ue, AMF_SESS_SM_CONTEXT_NO_STATE);
+                        amf_ue, AMF_RELEASE_SM_CONTEXT_NO_STATE);
                 if (amf_sess_xact_count(amf_ue) == xact_count) {
                     amf_ue_sbi_discover_and_send(
                             OpenAPI_nf_type_AUSF, amf_ue, NULL,
@@ -228,7 +228,7 @@ static void common_register_state(ogs_fsm_t *s, amf_event_t *e)
             }
 
             amf_sbi_send_release_all_sessions(
-                        amf_ue, AMF_SESS_SM_CONTEXT_NO_STATE);
+                        amf_ue, AMF_RELEASE_SM_CONTEXT_NO_STATE);
             if (amf_sess_xact_count(amf_ue) == xact_count) {
                 amf_ue_sbi_discover_and_send(OpenAPI_nf_type_AUSF, amf_ue, NULL,
                         amf_nausf_auth_build_authenticate);
@@ -1002,7 +1002,7 @@ void gmm_state_initial_context_setup(ogs_fsm_t *s, amf_event_t *e)
             }
 
             amf_sbi_send_release_all_sessions(
-                        amf_ue, AMF_SESS_SM_CONTEXT_NO_STATE);
+                        amf_ue, AMF_RELEASE_SM_CONTEXT_NO_STATE);
             if (amf_sess_xact_count(amf_ue) == xact_count) {
                 amf_ue_sbi_discover_and_send(OpenAPI_nf_type_AUSF, amf_ue, NULL,
                         amf_nausf_auth_build_authenticate);
@@ -1071,7 +1071,8 @@ void gmm_state_exception(ogs_fsm_t *s, amf_event_t *e)
         AMF_UE_CLEAR_N2_TRANSFER(amf_ue, pdu_session_resource_setup_request);
         CLEAR_AMF_UE_ALL_TIMERS(amf_ue);
 
-        amf_sbi_send_release_all_sessions(amf_ue, AMF_SESS_SM_CONTEXT_NO_STATE);
+        amf_sbi_send_release_all_sessions(
+                amf_ue, AMF_RELEASE_SM_CONTEXT_NO_STATE);
 
         if (ogs_list_count(&amf_ue->sess_list) == 0)
             ngap_send_amf_ue_context_release_command(amf_ue,
@@ -1128,7 +1129,7 @@ void gmm_state_exception(ogs_fsm_t *s, amf_event_t *e)
             } else {
 
                 amf_sbi_send_release_all_sessions(
-                        amf_ue, AMF_SESS_SM_CONTEXT_NO_STATE);
+                        amf_ue, AMF_RELEASE_SM_CONTEXT_NO_STATE);
                 if (amf_sess_xact_count(amf_ue) == xact_count) {
                     amf_ue_sbi_discover_and_send(
                             OpenAPI_nf_type_AUSF, amf_ue, NULL,
diff --git a/src/amf/namf-handler.c b/src/amf/namf-handler.c
index 819177b62..afacdd9cf 100644
--- a/src/amf/namf-handler.c
+++ b/src/amf/namf-handler.c
@@ -465,7 +465,7 @@ int amf_namf_callback_handle_sm_context_status(
 
         ogs_debug("[%s:%d] SM context remove", amf_ue->supi, sess->psi);
         amf_nsmf_pdusession_handle_release_sm_context(
-                sess, AMF_SESS_SM_CONTEXT_NO_STATE);
+                sess, AMF_RELEASE_SM_CONTEXT_NO_STATE);
     }
 
 cleanup:
diff --git a/src/amf/ngap-path.c b/src/amf/ngap-path.c
index 612a2b554..56414b66e 100644
--- a/src/amf/ngap-path.c
+++ b/src/amf/ngap-path.c
@@ -53,7 +53,12 @@ int ngap_send_to_gnb(amf_gnb_t *gnb, ogs_pkbuf_t *pkbuf, uint16_t stream_no)
     ogs_assert(gnb);
     ogs_assert(pkbuf);
     ogs_assert(gnb->sctp.sock);
-    ogs_assert(gnb->sctp.sock->fd != INVALID_SOCKET);
+    if (gnb->sctp.sock->fd == INVALID_SOCKET) {
+        ogs_fatal("gNB SCTP socket has already been destroyed");
+        ogs_log_hexdump(OGS_LOG_FATAL, pkbuf->data, pkbuf->len);
+        ogs_assert_if_reached();
+        return OGS_ERROR;
+    }
 
     ogs_debug("    IP[%s] RAN_ID[%d]",
             OGS_ADDR(gnb->sctp.addr, buf), gnb->gnb_id);
diff --git a/src/amf/nsmf-handler.c b/src/amf/nsmf-handler.c
index 66063242e..50784adc3 100644
--- a/src/amf/nsmf-handler.c
+++ b/src/amf/nsmf-handler.c
@@ -135,7 +135,6 @@ int amf_nsmf_pdusession_handle_create_sm_context(
         }
 
         nas_5gs_send_back_5gsm_message_from_sbi(sess, recvmsg->res_status);
-
         return OGS_ERROR;
     }
 
@@ -398,7 +397,7 @@ int amf_nsmf_pdusession_handle_update_sm_context(
                         "(DUPLICATED_PDU_SESSION_ID)", amf_ue->supi, sess->psi);
 
                 amf_sess_sbi_discover_and_send(OpenAPI_nf_type_SMF,
-                        sess, AMF_SESS_SM_CONTEXT_NO_STATE, NULL,
+                        sess, AMF_CREATE_SM_CONTEXT_NO_STATE, NULL,
                         amf_nsmf_pdusession_build_create_sm_context);
 
             } else if (state == AMF_UPDATE_SM_CONTEXT_PATH_SWITCH_REQUEST) {
@@ -527,7 +526,7 @@ int amf_nsmf_pdusession_handle_update_sm_context(
 
                 ogs_debug("[%s:%d] SM context remove", amf_ue->supi, sess->psi);
                 amf_nsmf_pdusession_handle_release_sm_context(
-                        sess, AMF_SESS_SM_CONTEXT_NO_STATE);
+                        sess, AMF_RELEASE_SM_CONTEXT_NO_STATE);
             }
         }
     } else {
@@ -547,13 +546,15 @@ int amf_nsmf_pdusession_handle_update_sm_context(
 
         SmContextUpdateError = recvmsg->SmContextUpdateError;
         if (!SmContextUpdateError) {
-            ogs_error("[%d:%d] No SmContextUpdateError", sess->psi, sess->pti);
+            ogs_error("[%d:%d] No SmContextUpdateError [%d]",
+                    sess->psi, sess->pti, recvmsg->res_status);
             ngap_send_error_indication2(amf_ue,
                     NGAP_Cause_PR_protocol, NGAP_CauseProtocol_semantic_error);
             return OGS_ERROR;
         }
         if (!SmContextUpdateError->error) {
-            ogs_error("[%d:%d] No Error", sess->psi, sess->pti);
+            ogs_error("[%d:%d] No Error [%d]",
+                    sess->psi, sess->pti, recvmsg->res_status);
             ngap_send_error_indication2(amf_ue,
                     NGAP_Cause_PR_protocol, NGAP_CauseProtocol_semantic_error);
             return OGS_ERROR;
@@ -597,8 +598,12 @@ int amf_nsmf_pdusession_handle_update_sm_context(
         }
 #endif
 
+        ogs_error("[%d:%d] HTTP response error [%d]",
+                sess->psi, sess->pti, recvmsg->res_status);
+#if 0 /* Is it needed */
         ngap_send_error_indication2(amf_ue,
                 NGAP_Cause_PR_protocol, NGAP_CauseProtocol_semantic_error);
+#endif
 
         return OGS_ERROR;
     }
@@ -640,8 +645,7 @@ int amf_nsmf_pdusession_handle_release_sm_context(amf_sess_t *sess, int state)
 
     } else {
 
-        /* Check last session */
-        if (ogs_list_count(&amf_ue->sess_list) == 0) {
+        if (SESSION_SYNC_DONE(amf_ue, state)) {
 
             if (state == AMF_RELEASE_SM_CONTEXT_NG_CONTEXT_REMOVE) {
                 /*
@@ -664,7 +668,7 @@ int amf_nsmf_pdusession_handle_release_sm_context(amf_sess_t *sess, int state)
                 /* Not reached here */
                 ogs_assert_if_reached();
 
-            } else {
+            } else if (state == AMF_RELEASE_SM_CONTEXT_NO_STATE) {
                 /* NO_STATE */
 
                 if (OGS_FSM_CHECK(&amf_ue->sm, gmm_state_authentication)) {
@@ -723,6 +727,9 @@ int amf_nsmf_pdusession_handle_release_sm_context(amf_sess_t *sess, int state)
                     ogs_fatal("Release SM Context : INVALID STATE");
                     ogs_assert_if_reached();
                 }
+            } else {
+                ogs_fatal("Release SM STATE undefined");
+                ogs_assert_if_reached();
             }
         }
     }
diff --git a/src/amf/sbi-path.h b/src/amf/sbi-path.h
index b7bdc7eaf..8f0cc7d56 100644
--- a/src/amf/sbi-path.h
+++ b/src/amf/sbi-path.h
@@ -37,7 +37,7 @@ void amf_ue_sbi_discover_and_send(OpenAPI_nf_type_e target_nf_type,
         amf_ue_t *amf_ue, void *data,
         ogs_sbi_request_t *(*build)(amf_ue_t *amf_ue, void *data));
 
-#define AMF_SESS_SM_CONTEXT_NO_STATE                0
+#define AMF_CREATE_SM_CONTEXT_NO_STATE              0
 #define AMF_UPDATE_SM_CONTEXT_ACTIVATED             11
 #define AMF_UPDATE_SM_CONTEXT_DEACTIVATED           12
 #define AMF_UPDATE_SM_CONTEXT_REGISTRATION_REQUEST  13
@@ -51,9 +51,10 @@ void amf_ue_sbi_discover_and_send(OpenAPI_nf_type_e target_nf_type,
 #define AMF_UPDATE_SM_CONTEXT_HANDOVER_REQ_ACK      21
 #define AMF_UPDATE_SM_CONTEXT_HANDOVER_NOTIFY       22
 #define AMF_UPDATE_SM_CONTEXT_HANDOVER_CANCEL       23
-#define AMF_RELEASE_SM_CONTEXT_NG_CONTEXT_REMOVE    31
-#define AMF_RELEASE_SM_CONTEXT_REGISTRATION_ACCEPT  32
-#define AMF_RELEASE_SM_CONTEXT_SERVICE_ACCEPT       33
+#define AMF_RELEASE_SM_CONTEXT_NO_STATE             31
+#define AMF_RELEASE_SM_CONTEXT_NG_CONTEXT_REMOVE    32
+#define AMF_RELEASE_SM_CONTEXT_REGISTRATION_ACCEPT  33
+#define AMF_RELEASE_SM_CONTEXT_SERVICE_ACCEPT       34
 #define AMF_REMOVE_S1_CONTEXT_BY_LO_CONNREFUSED     51
 #define AMF_REMOVE_S1_CONTEXT_BY_RESET_ALL          52
 #define AMF_REMOVE_S1_CONTEXT_BY_RESET_PARTIAL      53
diff --git a/src/mme/s1ap-path.c b/src/mme/s1ap-path.c
index 35965b0ed..aaa469f30 100644
--- a/src/mme/s1ap-path.c
+++ b/src/mme/s1ap-path.c
@@ -54,7 +54,12 @@ int s1ap_send_to_enb(mme_enb_t *enb, ogs_pkbuf_t *pkbuf, uint16_t stream_no)
     ogs_assert(enb);
     ogs_assert(pkbuf);
     ogs_assert(enb->sctp.sock);
-    ogs_assert(enb->sctp.sock->fd != INVALID_SOCKET);
+    if (enb->sctp.sock->fd == INVALID_SOCKET) {
+        ogs_fatal("eNB SCTP socket has already been destroyed");
+        ogs_log_hexdump(OGS_LOG_FATAL, pkbuf->data, pkbuf->len);
+        ogs_assert_if_reached();
+        return OGS_ERROR;
+    }
 
     ogs_debug("    IP[%s] ENB_ID[%d]",
             OGS_ADDR(enb->sctp.addr, buf), enb->enb_id);
diff --git a/src/smf/context.c b/src/smf/context.c
index b09e72baf..e7b7325d3 100644
--- a/src/smf/context.c
+++ b/src/smf/context.c
@@ -570,6 +570,8 @@ void smf_ue_remove(smf_ue_t *smf_ue)
 
     ogs_list_remove(&self.smf_ue_list, smf_ue);
 
+    smf_sess_remove_all(smf_ue);
+
     if (smf_ue->supi) {
         ogs_hash_set(self.supi_hash, smf_ue->supi, strlen(smf_ue->supi), NULL);
         ogs_free(smf_ue->supi);
@@ -579,8 +581,6 @@ void smf_ue_remove(smf_ue_t *smf_ue)
         ogs_hash_set(self.imsi_hash, smf_ue->imsi, smf_ue->imsi_len, NULL);
     }
 
-    smf_sess_remove_all(smf_ue);
-
     ogs_pool_free(&smf_ue_pool, smf_ue);
 
     ogs_info("[Removed] Number of SMF-UEs is now %d",
@@ -1112,11 +1112,11 @@ void smf_sess_remove(smf_sess_t *sess)
     smf_ue = sess->smf_ue;
     ogs_assert(smf_ue);
    
-    ogs_info("Removed Session: UE IMSI:[%s] DNN:[%s] IPv4:[%s] IPv6:[%s]",
-           smf_ue->imsi_bcd,
-           sess->pdn.dnn,
-       sess->ipv4 ? OGS_INET_NTOP(&sess->ipv4->addr, buf1) : "",
-       sess->ipv6 ? OGS_INET6_NTOP(&sess->ipv6->addr, buf2) : "");
+    ogs_info("Removed Session: UE IMSI:[%s] DNN:[%s:%d] IPv4:[%s] IPv6:[%s]",
+            smf_ue->supi ? smf_ue->supi : smf_ue->imsi_bcd,
+            sess->pdn.dnn, sess->psi,
+            sess->ipv4 ? OGS_INET_NTOP(&sess->ipv4->addr, buf1) : "",
+            sess->ipv6 ? OGS_INET6_NTOP(&sess->ipv6->addr, buf2) : "");
 
     ogs_list_remove(&smf_ue->sess_list, sess);
 
diff --git a/src/smf/gsm-sm.c b/src/smf/gsm-sm.c
index 2a8119b61..bcbd5904b 100644
--- a/src/smf/gsm-sm.c
+++ b/src/smf/gsm-sm.c
@@ -121,14 +121,14 @@ void smf_gsm_state_operational(ogs_fsm_t *s, smf_event_t *e)
                     ogs_sbi_server_send_error(stream, sbi_message->res_status,
                         sbi_message, strerror, NULL);
                     ogs_free(strerror);
+
+                    OGS_FSM_TRAN(s, smf_gsm_state_exception);
                     break;
                 }
 
                 if (smf_nudm_sdm_handle_get(
                             sess, stream, sbi_message) != true) {
-                    ogs_sbi_server_send_error(stream,
-                            OGS_SBI_HTTP_STATUS_INTERNAL_SERVER_ERROR,
-                            sbi_message, "HTTP response error", smf_ue->supi);
+                    OGS_FSM_TRAN(s, smf_gsm_state_session_will_release);
                 }
                 break;
 
@@ -143,6 +143,7 @@ void smf_gsm_state_operational(ogs_fsm_t *s, smf_event_t *e)
                         OGS_SBI_HTTP_STATUS_BAD_REQUEST,
                         sbi_message, strerror, NULL);
                 ogs_free(strerror);
+                OGS_FSM_TRAN(s, smf_gsm_state_exception);
             END
             break;
 
@@ -365,6 +366,30 @@ void smf_gsm_state_operational(ogs_fsm_t *s, smf_event_t *e)
     }
 }
 
+void smf_gsm_state_session_will_release(ogs_fsm_t *s, smf_event_t *e)
+{
+    smf_sess_t *sess = NULL;
+    ogs_assert(s);
+    ogs_assert(e);
+
+    smf_sm_debug(e);
+
+    sess = e->sess;
+    ogs_assert(sess);
+
+    switch (e->id) {
+    case OGS_FSM_ENTRY_SIG:
+        break;
+
+    case OGS_FSM_EXIT_SIG:
+        break;
+
+    default:
+        ogs_error("Unknown event %s", smf_event_get_name(e));
+        break;
+    }
+}
+
 void smf_gsm_state_exception(ogs_fsm_t *s, smf_event_t *e)
 {
     smf_sess_t *sess = NULL;
diff --git a/src/smf/nudm-handler.c b/src/smf/nudm-handler.c
index ee997f385..e0051585d 100644
--- a/src/smf/nudm-handler.c
+++ b/src/smf/nudm-handler.c
@@ -25,6 +25,7 @@ bool smf_nudm_sdm_handle_get(smf_sess_t *sess, ogs_sbi_stream_t *stream,
 {
     char *strerror = NULL;
     smf_ue_t *smf_ue = NULL;
+    ogs_pkbuf_t *n1smbuf = NULL;
 
     OpenAPI_sm_context_created_data_t SmContextCreatedData;
 
@@ -68,7 +69,18 @@ bool smf_nudm_sdm_handle_get(smf_sess_t *sess, ogs_sbi_stream_t *stream,
     if (!dnnConfigurationList) {
         strerror = ogs_msprintf("[%s:%d] No dnnConfigurations",
                 smf_ue->supi, sess->psi);
-        goto cleanup;
+        ogs_assert(strerror);
+
+        n1smbuf = gsm_build_pdu_session_establishment_reject(sess,
+            OGS_5GSM_CAUSE_MISSING_OR_UNKNOWN_DNN);
+        ogs_assert(n1smbuf);
+
+        ogs_warn("%s", strerror);
+        smf_sbi_send_sm_context_create_error(stream,
+                OGS_SBI_HTTP_STATUS_NOT_FOUND, strerror, NULL, n1smbuf);
+        ogs_free(strerror);
+
+        return false;
     }
 
     OpenAPI_list_for_each(dnnConfigurationList, node) {
diff --git a/src/smf/smf-sm.c b/src/smf/smf-sm.c
index 2148a383c..fc43a453a 100644
--- a/src/smf/smf-sm.c
+++ b/src/smf/smf-sm.c
@@ -554,6 +554,9 @@ void smf_state_operational(ogs_fsm_t *s, smf_event_t *e)
             if (OGS_FSM_CHECK(&sess->sm, smf_gsm_state_exception)) {
                 ogs_error("[%s] State machine exception", smf_ue->supi);
                 SMF_SESS_CLEAR(sess);
+            } else if (OGS_FSM_CHECK(
+                        &sess->sm, smf_gsm_state_session_will_release)) {
+                SMF_SESS_CLEAR(sess);
             }
             break;
 
diff --git a/src/smf/smf-sm.h b/src/smf/smf-sm.h
index 3369ac935..2a7914b5b 100644
--- a/src/smf/smf-sm.h
+++ b/src/smf/smf-sm.h
@@ -44,6 +44,7 @@ void smf_nf_state_exception(ogs_fsm_t *s, smf_event_t *e);
 void smf_gsm_state_initial(ogs_fsm_t *s, smf_event_t *e);
 void smf_gsm_state_final(ogs_fsm_t *s, smf_event_t *e);
 void smf_gsm_state_operational(ogs_fsm_t *s, smf_event_t *e);
+void smf_gsm_state_session_will_release(ogs_fsm_t *s, smf_event_t *e);
 void smf_gsm_state_exception(ogs_fsm_t *s, smf_event_t *e);
 
 void smf_pfcp_state_initial(ogs_fsm_t *s, smf_event_t *e);
diff --git a/tests/common/nas-path.c b/tests/common/nas-path.c
index fedaac266..7e4bd1a1a 100644
--- a/tests/common/nas-path.c
+++ b/tests/common/nas-path.c
@@ -90,6 +90,8 @@ void testgsm_recv(test_sess_t *sess, ogs_pkbuf_t *pkbuf)
         testgsm_handle_pdu_session_establishment_accept(sess,
                 &message.gsm.pdu_session_establishment_accept);
         break;
+    case OGS_NAS_5GS_PDU_SESSION_ESTABLISHMENT_REJECT:
+        break;
     case OGS_NAS_5GS_PDU_SESSION_MODIFICATION_COMMAND:
         testgsm_handle_pdu_session_modification_command(sess,
                 &message.gsm.pdu_session_modification_command);
diff --git a/tests/vonr/session-test.c b/tests/vonr/session-test.c
index 6f24f9e07..b267aae99 100644
--- a/tests/vonr/session-test.c
+++ b/tests/vonr/session-test.c
@@ -2144,6 +2144,831 @@ static void test4_func(abts_case *tc, void *data)
     test_ue_remove(test_ue);
 }
 
+static void test5_func(abts_case *tc, void *data)
+{
+    int rv;
+    ogs_socknode_t *ngap;
+    ogs_socknode_t *gtpu;
+    ogs_pkbuf_t *gmmbuf;
+    ogs_pkbuf_t *gsmbuf;
+    ogs_pkbuf_t *nasbuf;
+    ogs_pkbuf_t *sendbuf;
+    ogs_pkbuf_t *recvbuf;
+    ogs_ngap_message_t message;
+    int i;
+
+    uint8_t tmp[OGS_MAX_SDU_LEN];
+    char *_gtp_payload = "34ff0024"
+        "0000000100000085 010002004500001c 0c0b000040015a7a 0a2d00010a2d0002"
+        "00000964cd7c291f";
+
+    ogs_nas_5gs_mobile_identity_suci_t mobile_identity_suci;
+    test_ue_t *test_ue = NULL;
+    test_sess_t *sess5 = NULL, *sess6 = NULL;
+    test_bearer_t *qos_flow1 = NULL, *qos_flow2 = NULL;
+
+    const char *_k_string = "70d49a71dd1a2b806a25abe0ef749f1e";
+    uint8_t k[OGS_KEY_LEN];
+    const char *_opc_string = "6f1bf53d624b3a43af6592854e2444c7";
+    uint8_t opc[OGS_KEY_LEN];
+
+    mongoc_collection_t *collection = NULL;
+    bson_t *doc = NULL;
+    int64_t count = 0;
+    bson_error_t error;
+    const char *json =
+      "{"
+        "\"_id\" : { \"$oid\" : \"597223158b8861d7605378c6\" }, "
+        "\"imsi\" : \"901700000021309\","
+        "\"ambr\" : { "
+          "\"uplink\" : { \"$numberLong\" : \"1024000\" }, "
+          "\"downlink\" : { \"$numberLong\" : \"1024000\" } "
+        "},"
+        "\"pdn\" : ["
+          "{"
+            "\"apn\" : \"internet\", "
+            "\"_id\" : { \"$oid\" : \"597223158b8861d7605378c7\" }, "
+            "\"ambr\" : {"
+              "\"uplink\" : { \"$numberLong\" : \"1024000\" }, "
+              "\"downlink\" : { \"$numberLong\" : \"1024000\" } "
+            "},"
+            "\"qos\" : { "
+              "\"qci\" : 9, "
+              "\"arp\" : { "
+                "\"priority_level\" : 8,"
+                "\"pre_emption_vulnerability\" : 1, "
+                "\"pre_emption_capability\" : 1"
+              "} "
+            "}, "
+            "\"type\" : 2"
+          "}"
+        "],"
+        "\"security\" : { "
+          "\"k\" : \"70d49a71dd1a2b806a25abe0ef749f1e\", "
+          "\"opc\" : \"6f1bf53d624b3a43af6592854e2444c7\", "
+          "\"amf\" : \"8000\", "
+          "\"sqn\" : { \"$numberLong\" : \"25235952177090\" } "
+        "}, "
+        "\"subscribed_rau_tau_timer\" : 12,"
+        "\"network_access_mode\" : 2, "
+        "\"subscriber_status\" : 0, "
+        "\"access_restriction_data\" : 32, "
+        "\"__v\" : 0 "
+      "}";
+
+    /* Setup Test UE & Session Context */
+    memset(&mobile_identity_suci, 0, sizeof(mobile_identity_suci));
+
+    mobile_identity_suci.h.supi_format = OGS_NAS_5GS_SUPI_FORMAT_IMSI;
+    mobile_identity_suci.h.type = OGS_NAS_5GS_MOBILE_IDENTITY_SUCI;
+    mobile_identity_suci.routing_indicator1 = 0;
+    mobile_identity_suci.routing_indicator2 = 0xf;
+    mobile_identity_suci.routing_indicator3 = 0xf;
+    mobile_identity_suci.routing_indicator4 = 0xf;
+    mobile_identity_suci.protection_scheme_id = OGS_NAS_5GS_NULL_SCHEME;
+    mobile_identity_suci.home_network_pki_value = 0;
+    mobile_identity_suci.scheme_output[0] = 0;
+    mobile_identity_suci.scheme_output[1] = 0;
+    mobile_identity_suci.scheme_output[2] = 0x20;
+    mobile_identity_suci.scheme_output[3] = 0x31;
+    mobile_identity_suci.scheme_output[4] = 0x90;
+
+    test_ue = test_ue_add_by_suci(&mobile_identity_suci, 13);
+    ogs_assert(test_ue);
+
+    test_ue->nr_cgi.cell_id = 0x40001;
+
+    test_ue->nas.registration.type = OGS_NAS_KSI_NO_KEY_IS_AVAILABLE;
+    test_ue->nas.registration.follow_on_request = 1;
+    test_ue->nas.registration.value = OGS_NAS_5GS_REGISTRATION_TYPE_INITIAL;
+
+    OGS_HEX(_k_string, strlen(_k_string), test_ue->k);
+    OGS_HEX(_opc_string, strlen(_opc_string), test_ue->opc);
+
+    /* gNB connects to AMF */
+    ngap = testngap_client(AF_INET);
+    ABTS_PTR_NOTNULL(tc, ngap);
+
+    /* gNB connects to UPF */
+    gtpu = test_gtpu_server(1, AF_INET);
+    ABTS_PTR_NOTNULL(tc, gtpu);
+
+    /* Send NG-Setup Reqeust */
+    sendbuf = testngap_build_ng_setup_request(0x4000, 22);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
+    /* Receive NG-Setup Response */
+    recvbuf = testgnb_ngap_read(ngap);
+    ABTS_PTR_NOTNULL(tc, recvbuf);
+    testngap_recv(test_ue, recvbuf);
+
+    /********** Insert Subscriber in Database */
+    collection = mongoc_client_get_collection(
+        ogs_mongoc()->client, ogs_mongoc()->name, "subscribers");
+    ABTS_PTR_NOTNULL(tc, collection);
+    doc = BCON_NEW("imsi", BCON_UTF8(test_ue->imsi));
+    ABTS_PTR_NOTNULL(tc, doc);
+
+    count = mongoc_collection_count (
+        collection, MONGOC_QUERY_NONE, doc, 0, 0, NULL, &error);
+    if (count) {
+        ABTS_TRUE(tc, mongoc_collection_remove(collection,
+                MONGOC_REMOVE_SINGLE_REMOVE, doc, NULL, &error))
+    }
+    bson_destroy(doc);
+
+    doc = bson_new_from_json((const uint8_t *)json, -1, &error);;
+    ABTS_PTR_NOTNULL(tc, doc);
+    ABTS_TRUE(tc, mongoc_collection_insert(collection,
+                MONGOC_INSERT_NONE, doc, NULL, &error));
+    bson_destroy(doc);
+
+    doc = BCON_NEW("imsi", BCON_UTF8(test_ue->imsi));
+    ABTS_PTR_NOTNULL(tc, doc);
+    do {
+        count = mongoc_collection_count (
+            collection, MONGOC_QUERY_NONE, doc, 0, 0, NULL, &error);
+    } while (count == 0);
+    bson_destroy(doc);
+
+    /* Send Registration request */
+    test_ue->registration_request_param.guti = 1;
+    gmmbuf = testgmm_build_registration_request(test_ue, NULL);
+    ABTS_PTR_NOTNULL(tc, gmmbuf);
+
+    test_ue->registration_request_param.gmm_capability = 1;
+    test_ue->registration_request_param.requested_nssai = 1;
+    test_ue->registration_request_param.last_visited_registered_tai = 1;
+    test_ue->registration_request_param.ue_usage_setting = 1;
+    nasbuf = testgmm_build_registration_request(test_ue, NULL);
+    ABTS_PTR_NOTNULL(tc, nasbuf);
+
+    sendbuf = testngap_build_initial_ue_message(test_ue, gmmbuf, false, true);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
+    /* Receive Identity request */
+    recvbuf = testgnb_ngap_read(ngap);
+    ABTS_PTR_NOTNULL(tc, recvbuf);
+    testngap_recv(test_ue, recvbuf);
+
+    /* Send Identity response */
+    gmmbuf = testgmm_build_identity_response(test_ue);
+    ABTS_PTR_NOTNULL(tc, gmmbuf);
+    sendbuf = testngap_build_uplink_nas_transport(test_ue, gmmbuf);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
+    /* Receive Authentication request */
+    recvbuf = testgnb_ngap_read(ngap);
+    ABTS_PTR_NOTNULL(tc, recvbuf);
+    testngap_recv(test_ue, recvbuf);
+
+    /* Send Authentication response */
+    gmmbuf = testgmm_build_authentication_response(test_ue);
+    ABTS_PTR_NOTNULL(tc, gmmbuf);
+    sendbuf = testngap_build_uplink_nas_transport(test_ue, gmmbuf);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
+    /* Receive Security mode command */
+    recvbuf = testgnb_ngap_read(ngap);
+    ABTS_PTR_NOTNULL(tc, recvbuf);
+    testngap_recv(test_ue, recvbuf);
+
+    /* Send Security mode complete */
+    gmmbuf = testgmm_build_security_mode_complete(test_ue, nasbuf);
+    ABTS_PTR_NOTNULL(tc, gmmbuf);
+    sendbuf = testngap_build_uplink_nas_transport(test_ue, gmmbuf);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
+    /* Receive Initial context setup request +
+     * Registration accept */
+    recvbuf = testgnb_ngap_read(ngap);
+    ABTS_PTR_NOTNULL(tc, recvbuf);
+    testngap_recv(test_ue, recvbuf);
+    ABTS_INT_EQUAL(tc,
+            NGAP_ProcedureCode_id_InitialContextSetup,
+            test_ue->ngap_procedure_code);
+
+    /* Send UE radio capability info indication */
+    sendbuf = testngap_build_ue_radio_capability_info_indication(test_ue);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
+    /* Send Initial context setup response */
+    sendbuf = testngap_build_initial_context_setup_response(test_ue, false);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
+    /* Send Registration complete */
+    gmmbuf = testgmm_build_registration_complete(test_ue);
+    ABTS_PTR_NOTNULL(tc, gmmbuf);
+    sendbuf = testngap_build_uplink_nas_transport(test_ue, gmmbuf);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
+    /* Receive Configuration update command */
+    recvbuf = testgnb_ngap_read(ngap);
+    ABTS_PTR_NOTNULL(tc, recvbuf);
+    testngap_recv(test_ue, recvbuf);
+
+    /* Send PDU session establishment request */
+    sess5 = test_sess_add_by_dnn_and_psi(test_ue, "internet", 5);
+    ogs_assert(sess5);
+
+    sess5->ul_nas_transport_param.request_type =
+        OGS_NAS_5GS_REQUEST_TYPE_INITIAL;
+    sess5->ul_nas_transport_param.dnn = 1;
+    sess5->ul_nas_transport_param.s_nssai = 1;
+
+    gsmbuf = testgsm_build_pdu_session_establishment_request(sess5);
+    ABTS_PTR_NOTNULL(tc, gsmbuf);
+    gmmbuf = testgmm_build_ul_nas_transport(sess5,
+            OGS_NAS_PAYLOAD_CONTAINER_N1_SM_INFORMATION, gsmbuf);
+    ABTS_PTR_NOTNULL(tc, gmmbuf);
+    sendbuf = testngap_build_uplink_nas_transport(test_ue, gmmbuf);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
+    /* Receive PDUSessionResourceSetupRequest +
+     * DL NAS transport +
+     * PDU session establishment accept */
+    recvbuf = testgnb_ngap_read(ngap);
+    ABTS_PTR_NOTNULL(tc, recvbuf);
+    testngap_recv(test_ue, recvbuf);
+    ABTS_INT_EQUAL(tc,
+            NGAP_ProcedureCode_id_PDUSessionResourceSetup,
+            test_ue->ngap_procedure_code);
+
+    /* Send PDUSessionResourceSetupResponse */
+    sendbuf = testngap_sess_build_pdu_session_resource_setup_response(sess5);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
+    /* Send PDU session establishment request */
+    sess6 = test_sess_add_by_dnn_and_psi(test_ue, "ims", 6);
+    ogs_assert(sess6);
+
+    sess6->ul_nas_transport_param.request_type =
+        OGS_NAS_5GS_REQUEST_TYPE_INITIAL;
+    sess6->ul_nas_transport_param.dnn = 1;
+    sess6->ul_nas_transport_param.s_nssai = 1;
+
+    gsmbuf = testgsm_build_pdu_session_establishment_request(sess6);
+    ABTS_PTR_NOTNULL(tc, gsmbuf);
+    gmmbuf = testgmm_build_ul_nas_transport(sess6,
+            OGS_NAS_PAYLOAD_CONTAINER_N1_SM_INFORMATION, gsmbuf);
+    ABTS_PTR_NOTNULL(tc, gmmbuf);
+    sendbuf = testngap_build_uplink_nas_transport(test_ue, gmmbuf);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
+    /* Receive PDU session establishment reject */
+    recvbuf = testgnb_ngap_read(ngap);
+    ABTS_PTR_NOTNULL(tc, recvbuf);
+    testngap_recv(test_ue, recvbuf);
+
+    /* Send De-registration request */
+    gmmbuf = testgmm_build_de_registration_request(test_ue, 1);
+    ABTS_PTR_NOTNULL(tc, gmmbuf);
+    sendbuf = testngap_build_uplink_nas_transport(test_ue, gmmbuf);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
+    /* Receive UEContextReleaseCommand */
+    recvbuf = testgnb_ngap_read(ngap);
+    ABTS_PTR_NOTNULL(tc, recvbuf);
+    testngap_recv(test_ue, recvbuf);
+    ABTS_INT_EQUAL(tc,
+            NGAP_ProcedureCode_id_UEContextRelease,
+            test_ue->ngap_procedure_code);
+
+    /* Send UEContextReleaseComplete */
+    sendbuf = testngap_build_ue_context_release_complete(test_ue);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
+#if 0
+    /* Send PDU session establishment request */
+    sess5 = test_sess_add_by_dnn_and_psi(test_ue, "ims", 5);
+    ogs_assert(sess5);
+
+    sess5->ul_nas_transport_param.request_type =
+        OGS_NAS_5GS_REQUEST_TYPE_INITIAL;
+    sess5->ul_nas_transport_param.dnn = 1;
+    sess5->ul_nas_transport_param.s_nssai = 1;
+
+    gsmbuf = testgsm_build_pdu_session_establishment_request(sess5);
+    ABTS_PTR_NOTNULL(tc, gsmbuf);
+    gmmbuf = testgmm_build_ul_nas_transport(sess5,
+            OGS_NAS_PAYLOAD_CONTAINER_N1_SM_INFORMATION, gsmbuf);
+    ABTS_PTR_NOTNULL(tc, gmmbuf);
+    sendbuf = testngap_build_uplink_nas_transport(test_ue, gmmbuf);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
+    /* Receive PDU session establishment reject */
+    recvbuf = testgnb_ngap_read(ngap);
+    ABTS_PTR_NOTNULL(tc, recvbuf);
+    testngap_recv(test_ue, recvbuf);
+
+    /* Test Session Remove */
+    test_sess_remove(sess5);
+
+    /* Send PDU session establishment request */
+    sess6 = test_sess_add_by_dnn_and_psi(test_ue, "internet", 6);
+    ogs_assert(sess6);
+
+    sess6->ul_nas_transport_param.request_type =
+        OGS_NAS_5GS_REQUEST_TYPE_INITIAL;
+    sess6->ul_nas_transport_param.dnn = 1;
+    sess6->ul_nas_transport_param.s_nssai = 1;
+
+    gsmbuf = testgsm_build_pdu_session_establishment_request(sess6);
+    ABTS_PTR_NOTNULL(tc, gsmbuf);
+    gmmbuf = testgmm_build_ul_nas_transport(sess6,
+            OGS_NAS_PAYLOAD_CONTAINER_N1_SM_INFORMATION, gsmbuf);
+    ABTS_PTR_NOTNULL(tc, gmmbuf);
+    sendbuf = testngap_build_uplink_nas_transport(test_ue, gmmbuf);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+#endif
+
+#if 0
+    /* Receive PDUSessionResourceSetupRequest +
+     * DL NAS transport +
+     * PDU session establishment accept */
+    recvbuf = testgnb_ngap_read(ngap);
+    ABTS_PTR_NOTNULL(tc, recvbuf);
+    testngap_recv(test_ue, recvbuf);
+    ABTS_INT_EQUAL(tc,
+            NGAP_ProcedureCode_id_PDUSessionResourceSetup,
+            test_ue->ngap_procedure_code);
+#endif
+
+#if 0
+    /* Send UEContextReleaseRequest */
+    sendbuf = testngap_build_ue_context_release_request(test_ue,
+            NGAP_Cause_PR_radioNetwork, NGAP_CauseRadioNetwork_user_inactivity,
+            true);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
+    /* Receive UEContextReleaseCommand */
+    recvbuf = testgnb_ngap_read(ngap);
+    ABTS_PTR_NOTNULL(tc, recvbuf);
+    testngap_recv(test_ue, recvbuf);
+    ABTS_INT_EQUAL(tc,
+            NGAP_ProcedureCode_id_UEContextRelease,
+            test_ue->ngap_procedure_code);
+
+    /* Send UEContextReleaseComplete */
+    sendbuf = testngap_build_ue_context_release_complete(test_ue);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+#endif
+
+    ogs_msleep(300);
+
+    /********** Remove Subscriber in Database */
+    doc = BCON_NEW("imsi", BCON_UTF8(test_ue->imsi));
+    ABTS_PTR_NOTNULL(tc, doc);
+    ABTS_TRUE(tc, mongoc_collection_remove(collection,
+            MONGOC_REMOVE_SINGLE_REMOVE, doc, NULL, &error))
+    bson_destroy(doc);
+
+    mongoc_collection_destroy(collection);
+
+    /* gNB disonncect from UPF */
+    testgnb_gtpu_close(gtpu);
+
+    /* gNB disonncect from AMF */
+    testgnb_ngap_close(ngap);
+
+    /* Clear Test UE Context */
+    test_ue_remove(test_ue);
+}
+
+static void test6_func(abts_case *tc, void *data)
+{
+    int rv;
+    ogs_socknode_t *ngap;
+    ogs_socknode_t *gtpu;
+    ogs_pkbuf_t *gmmbuf;
+    ogs_pkbuf_t *gsmbuf;
+    ogs_pkbuf_t *nasbuf;
+    ogs_pkbuf_t *sendbuf;
+    ogs_pkbuf_t *recvbuf;
+    ogs_ngap_message_t message;
+    int i;
+
+    uint8_t tmp[OGS_MAX_SDU_LEN];
+    char *_gtp_payload = "34ff0024"
+        "0000000100000085 010002004500001c 0c0b000040015a7a 0a2d00010a2d0002"
+        "00000964cd7c291f";
+
+    ogs_nas_5gs_mobile_identity_suci_t mobile_identity_suci;
+    test_ue_t *test_ue = NULL;
+    test_sess_t *sess5 = NULL, *sess6 = NULL;
+    test_bearer_t *qos_flow1 = NULL, *qos_flow2 = NULL;
+
+    const char *_k_string = "70d49a71dd1a2b806a25abe0ef749f1e";
+    uint8_t k[OGS_KEY_LEN];
+    const char *_opc_string = "6f1bf53d624b3a43af6592854e2444c7";
+    uint8_t opc[OGS_KEY_LEN];
+
+    mongoc_collection_t *collection = NULL;
+    bson_t *doc = NULL;
+    int64_t count = 0;
+    bson_error_t error;
+    const char *json =
+      "{"
+        "\"_id\" : { \"$oid\" : \"597223158b8861d7605378c6\" }, "
+        "\"imsi\" : \"901700000021309\","
+        "\"ambr\" : { "
+          "\"uplink\" : { \"$numberLong\" : \"1024000\" }, "
+          "\"downlink\" : { \"$numberLong\" : \"1024000\" } "
+        "},"
+        "\"pdn\" : ["
+          "{"
+            "\"apn\" : \"internet\", "
+            "\"_id\" : { \"$oid\" : \"597223158b8861d7605378c7\" }, "
+            "\"ambr\" : {"
+              "\"uplink\" : { \"$numberLong\" : \"1024000\" }, "
+              "\"downlink\" : { \"$numberLong\" : \"1024000\" } "
+            "},"
+            "\"qos\" : { "
+              "\"qci\" : 9, "
+              "\"arp\" : { "
+                "\"priority_level\" : 8,"
+                "\"pre_emption_vulnerability\" : 1, "
+                "\"pre_emption_capability\" : 1"
+              "} "
+            "}, "
+            "\"type\" : 2"
+          "}"
+        "],"
+        "\"security\" : { "
+          "\"k\" : \"70d49a71dd1a2b806a25abe0ef749f1e\", "
+          "\"opc\" : \"6f1bf53d624b3a43af6592854e2444c7\", "
+          "\"amf\" : \"8000\", "
+          "\"sqn\" : { \"$numberLong\" : \"25235952177090\" } "
+        "}, "
+        "\"subscribed_rau_tau_timer\" : 12,"
+        "\"network_access_mode\" : 2, "
+        "\"subscriber_status\" : 0, "
+        "\"access_restriction_data\" : 32, "
+        "\"__v\" : 0 "
+      "}";
+
+    /* Setup Test UE & Session Context */
+    memset(&mobile_identity_suci, 0, sizeof(mobile_identity_suci));
+
+    mobile_identity_suci.h.supi_format = OGS_NAS_5GS_SUPI_FORMAT_IMSI;
+    mobile_identity_suci.h.type = OGS_NAS_5GS_MOBILE_IDENTITY_SUCI;
+    mobile_identity_suci.routing_indicator1 = 0;
+    mobile_identity_suci.routing_indicator2 = 0xf;
+    mobile_identity_suci.routing_indicator3 = 0xf;
+    mobile_identity_suci.routing_indicator4 = 0xf;
+    mobile_identity_suci.protection_scheme_id = OGS_NAS_5GS_NULL_SCHEME;
+    mobile_identity_suci.home_network_pki_value = 0;
+    mobile_identity_suci.scheme_output[0] = 0;
+    mobile_identity_suci.scheme_output[1] = 0;
+    mobile_identity_suci.scheme_output[2] = 0x20;
+    mobile_identity_suci.scheme_output[3] = 0x31;
+    mobile_identity_suci.scheme_output[4] = 0x90;
+
+    test_ue = test_ue_add_by_suci(&mobile_identity_suci, 13);
+    ogs_assert(test_ue);
+
+    test_ue->nr_cgi.cell_id = 0x40001;
+
+    test_ue->nas.registration.type = OGS_NAS_KSI_NO_KEY_IS_AVAILABLE;
+    test_ue->nas.registration.follow_on_request = 1;
+    test_ue->nas.registration.value = OGS_NAS_5GS_REGISTRATION_TYPE_INITIAL;
+
+    OGS_HEX(_k_string, strlen(_k_string), test_ue->k);
+    OGS_HEX(_opc_string, strlen(_opc_string), test_ue->opc);
+
+    /* gNB connects to AMF */
+    ngap = testngap_client(AF_INET);
+    ABTS_PTR_NOTNULL(tc, ngap);
+
+    /* gNB connects to UPF */
+    gtpu = test_gtpu_server(1, AF_INET);
+    ABTS_PTR_NOTNULL(tc, gtpu);
+
+    /* Send NG-Setup Reqeust */
+    sendbuf = testngap_build_ng_setup_request(0x4000, 22);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
+    /* Receive NG-Setup Response */
+    recvbuf = testgnb_ngap_read(ngap);
+    ABTS_PTR_NOTNULL(tc, recvbuf);
+    testngap_recv(test_ue, recvbuf);
+
+    /********** Insert Subscriber in Database */
+    collection = mongoc_client_get_collection(
+        ogs_mongoc()->client, ogs_mongoc()->name, "subscribers");
+    ABTS_PTR_NOTNULL(tc, collection);
+    doc = BCON_NEW("imsi", BCON_UTF8(test_ue->imsi));
+    ABTS_PTR_NOTNULL(tc, doc);
+
+    count = mongoc_collection_count (
+        collection, MONGOC_QUERY_NONE, doc, 0, 0, NULL, &error);
+    if (count) {
+        ABTS_TRUE(tc, mongoc_collection_remove(collection,
+                MONGOC_REMOVE_SINGLE_REMOVE, doc, NULL, &error))
+    }
+    bson_destroy(doc);
+
+    doc = bson_new_from_json((const uint8_t *)json, -1, &error);;
+    ABTS_PTR_NOTNULL(tc, doc);
+    ABTS_TRUE(tc, mongoc_collection_insert(collection,
+                MONGOC_INSERT_NONE, doc, NULL, &error));
+    bson_destroy(doc);
+
+    doc = BCON_NEW("imsi", BCON_UTF8(test_ue->imsi));
+    ABTS_PTR_NOTNULL(tc, doc);
+    do {
+        count = mongoc_collection_count (
+            collection, MONGOC_QUERY_NONE, doc, 0, 0, NULL, &error);
+    } while (count == 0);
+    bson_destroy(doc);
+
+    /* Send Registration request */
+    test_ue->registration_request_param.guti = 1;
+    gmmbuf = testgmm_build_registration_request(test_ue, NULL);
+    ABTS_PTR_NOTNULL(tc, gmmbuf);
+
+    test_ue->registration_request_param.gmm_capability = 1;
+    test_ue->registration_request_param.requested_nssai = 1;
+    test_ue->registration_request_param.last_visited_registered_tai = 1;
+    test_ue->registration_request_param.ue_usage_setting = 1;
+    nasbuf = testgmm_build_registration_request(test_ue, NULL);
+    ABTS_PTR_NOTNULL(tc, nasbuf);
+
+    sendbuf = testngap_build_initial_ue_message(test_ue, gmmbuf, false, true);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
+    /* Receive Identity request */
+    recvbuf = testgnb_ngap_read(ngap);
+    ABTS_PTR_NOTNULL(tc, recvbuf);
+    testngap_recv(test_ue, recvbuf);
+
+    /* Send Identity response */
+    gmmbuf = testgmm_build_identity_response(test_ue);
+    ABTS_PTR_NOTNULL(tc, gmmbuf);
+    sendbuf = testngap_build_uplink_nas_transport(test_ue, gmmbuf);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
+    /* Receive Authentication request */
+    recvbuf = testgnb_ngap_read(ngap);
+    ABTS_PTR_NOTNULL(tc, recvbuf);
+    testngap_recv(test_ue, recvbuf);
+
+    /* Send Authentication response */
+    gmmbuf = testgmm_build_authentication_response(test_ue);
+    ABTS_PTR_NOTNULL(tc, gmmbuf);
+    sendbuf = testngap_build_uplink_nas_transport(test_ue, gmmbuf);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
+    /* Receive Security mode command */
+    recvbuf = testgnb_ngap_read(ngap);
+    ABTS_PTR_NOTNULL(tc, recvbuf);
+    testngap_recv(test_ue, recvbuf);
+
+    /* Send Security mode complete */
+    gmmbuf = testgmm_build_security_mode_complete(test_ue, nasbuf);
+    ABTS_PTR_NOTNULL(tc, gmmbuf);
+    sendbuf = testngap_build_uplink_nas_transport(test_ue, gmmbuf);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
+    /* Receive Initial context setup request +
+     * Registration accept */
+    recvbuf = testgnb_ngap_read(ngap);
+    ABTS_PTR_NOTNULL(tc, recvbuf);
+    testngap_recv(test_ue, recvbuf);
+    ABTS_INT_EQUAL(tc,
+            NGAP_ProcedureCode_id_InitialContextSetup,
+            test_ue->ngap_procedure_code);
+
+    /* Send UE radio capability info indication */
+    sendbuf = testngap_build_ue_radio_capability_info_indication(test_ue);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
+    /* Send Initial context setup response */
+    sendbuf = testngap_build_initial_context_setup_response(test_ue, false);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
+    /* Send Registration complete */
+    gmmbuf = testgmm_build_registration_complete(test_ue);
+    ABTS_PTR_NOTNULL(tc, gmmbuf);
+    sendbuf = testngap_build_uplink_nas_transport(test_ue, gmmbuf);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
+    /* Receive Configuration update command */
+    recvbuf = testgnb_ngap_read(ngap);
+    ABTS_PTR_NOTNULL(tc, recvbuf);
+    testngap_recv(test_ue, recvbuf);
+
+    /* Send PDU session establishment request */
+    sess5 = test_sess_add_by_dnn_and_psi(test_ue, "internet", 5);
+    ogs_assert(sess5);
+
+    sess5->ul_nas_transport_param.request_type =
+        OGS_NAS_5GS_REQUEST_TYPE_INITIAL;
+    sess5->ul_nas_transport_param.dnn = 1;
+    sess5->ul_nas_transport_param.s_nssai = 1;
+
+    gsmbuf = testgsm_build_pdu_session_establishment_request(sess5);
+    ABTS_PTR_NOTNULL(tc, gsmbuf);
+    gmmbuf = testgmm_build_ul_nas_transport(sess5,
+            OGS_NAS_PAYLOAD_CONTAINER_N1_SM_INFORMATION, gsmbuf);
+    ABTS_PTR_NOTNULL(tc, gmmbuf);
+    sendbuf = testngap_build_uplink_nas_transport(test_ue, gmmbuf);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
+    /* Receive PDUSessionResourceSetupRequest +
+     * DL NAS transport +
+     * PDU session establishment accept */
+    recvbuf = testgnb_ngap_read(ngap);
+    ABTS_PTR_NOTNULL(tc, recvbuf);
+    testngap_recv(test_ue, recvbuf);
+    ABTS_INT_EQUAL(tc,
+            NGAP_ProcedureCode_id_PDUSessionResourceSetup,
+            test_ue->ngap_procedure_code);
+
+    /* Send PDUSessionResourceSetupResponse */
+    sendbuf = testngap_sess_build_pdu_session_resource_setup_response(sess5);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
+    /* Send PDU session establishment request */
+    sess6 = test_sess_add_by_dnn_and_psi(test_ue, "ims", 6);
+    ogs_assert(sess6);
+
+    sess6->ul_nas_transport_param.request_type =
+        OGS_NAS_5GS_REQUEST_TYPE_INITIAL;
+    sess6->ul_nas_transport_param.dnn = 1;
+    sess6->ul_nas_transport_param.s_nssai = 1;
+
+    gsmbuf = testgsm_build_pdu_session_establishment_request(sess6);
+    ABTS_PTR_NOTNULL(tc, gsmbuf);
+    gmmbuf = testgmm_build_ul_nas_transport(sess6,
+            OGS_NAS_PAYLOAD_CONTAINER_N1_SM_INFORMATION, gsmbuf);
+    ABTS_PTR_NOTNULL(tc, gmmbuf);
+    sendbuf = testngap_build_uplink_nas_transport(test_ue, gmmbuf);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
+    /* Receive PDU session establishment reject */
+    recvbuf = testgnb_ngap_read(ngap);
+    ABTS_PTR_NOTNULL(tc, recvbuf);
+    testngap_recv(test_ue, recvbuf);
+
+    /* Remove All Test Session */
+    test_sess_remove(sess6);
+
+    /* Send PDU session establishment request */
+    sess5 = test_sess_add_by_dnn_and_psi(test_ue, "ims", 5);
+    ogs_assert(sess5);
+
+    sess5->ul_nas_transport_param.request_type =
+        OGS_NAS_5GS_REQUEST_TYPE_INITIAL;
+    sess5->ul_nas_transport_param.dnn = 1;
+    sess5->ul_nas_transport_param.s_nssai = 1;
+
+    gsmbuf = testgsm_build_pdu_session_establishment_request(sess5);
+    ABTS_PTR_NOTNULL(tc, gsmbuf);
+    gmmbuf = testgmm_build_ul_nas_transport(sess5,
+            OGS_NAS_PAYLOAD_CONTAINER_N1_SM_INFORMATION, gsmbuf);
+    ABTS_PTR_NOTNULL(tc, gmmbuf);
+    sendbuf = testngap_build_uplink_nas_transport(test_ue, gmmbuf);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
+    /* Receive PDU session establishment reject */
+    recvbuf = testgnb_ngap_read(ngap);
+    ABTS_PTR_NOTNULL(tc, recvbuf);
+    testngap_recv(test_ue, recvbuf);
+
+    /* Test Session Remove */
+    test_sess_remove(sess5);
+
+    /* Send PDU session establishment request */
+    sess6 = test_sess_add_by_dnn_and_psi(test_ue, "internet", 6);
+    ogs_assert(sess6);
+
+    sess6->ul_nas_transport_param.request_type =
+        OGS_NAS_5GS_REQUEST_TYPE_INITIAL;
+    sess6->ul_nas_transport_param.dnn = 1;
+    sess6->ul_nas_transport_param.s_nssai = 1;
+
+    gsmbuf = testgsm_build_pdu_session_establishment_request(sess6);
+    ABTS_PTR_NOTNULL(tc, gsmbuf);
+    gmmbuf = testgmm_build_ul_nas_transport(sess6,
+            OGS_NAS_PAYLOAD_CONTAINER_N1_SM_INFORMATION, gsmbuf);
+    ABTS_PTR_NOTNULL(tc, gmmbuf);
+    sendbuf = testngap_build_uplink_nas_transport(test_ue, gmmbuf);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
+    /* Receive PDUSessionResourceSetupRequest +
+     * DL NAS transport +
+     * PDU session establishment accept */
+    recvbuf = testgnb_ngap_read(ngap);
+    ABTS_PTR_NOTNULL(tc, recvbuf);
+    testngap_recv(test_ue, recvbuf);
+    ABTS_INT_EQUAL(tc,
+            NGAP_ProcedureCode_id_PDUSessionResourceSetup,
+            test_ue->ngap_procedure_code);
+
+    /* Send UEContextReleaseRequest */
+    sendbuf = testngap_build_ue_context_release_request(test_ue,
+            NGAP_Cause_PR_radioNetwork, NGAP_CauseRadioNetwork_user_inactivity,
+            true);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
+    /* Receive UEContextReleaseCommand */
+    recvbuf = testgnb_ngap_read(ngap);
+    ABTS_PTR_NOTNULL(tc, recvbuf);
+    testngap_recv(test_ue, recvbuf);
+    ABTS_INT_EQUAL(tc,
+            NGAP_ProcedureCode_id_UEContextRelease,
+            test_ue->ngap_procedure_code);
+
+    /* Send UEContextReleaseComplete */
+    sendbuf = testngap_build_ue_context_release_complete(test_ue);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
+    ogs_msleep(300);
+
+    /********** Remove Subscriber in Database */
+    doc = BCON_NEW("imsi", BCON_UTF8(test_ue->imsi));
+    ABTS_PTR_NOTNULL(tc, doc);
+    ABTS_TRUE(tc, mongoc_collection_remove(collection,
+            MONGOC_REMOVE_SINGLE_REMOVE, doc, NULL, &error))
+    bson_destroy(doc);
+
+    mongoc_collection_destroy(collection);
+
+    /* gNB disonncect from UPF */
+    testgnb_gtpu_close(gtpu);
+
+    /* gNB disonncect from AMF */
+    testgnb_ngap_close(ngap);
+
+    /* Clear Test UE Context */
+    test_ue_remove(test_ue);
+}
+
 abts_suite *test_session(abts_suite *suite)
 {
     suite = ADD_SUITE(suite)
@@ -2152,6 +2977,8 @@ abts_suite *test_session(abts_suite *suite)
     abts_run_test(suite, test2_func, NULL);
     abts_run_test(suite, test3_func, NULL);
     abts_run_test(suite, test4_func, NULL);
+    abts_run_test(suite, test5_func, NULL);
+    abts_run_test(suite, test6_func, NULL);
 
     return suite;
 }