diff --git a/src/mme/mme_ctx.c b/src/mme/mme_ctx.c
index 43c38dc7f7..614155de24 100644
--- a/src/mme/mme_ctx.c
+++ b/src/mme/mme_ctx.c
@@ -274,10 +274,7 @@ ue_ctx_t* mme_ctx_ue_add(enb_ctx_t *enb)
     list_init(&ue->erab_list);
     list_init(&ue->s11_list);
 
-    if (self.mme_ue_s1ap_id == 0) self.mme_ue_s1ap_id = 1;
-    ue->mme_ue_s1ap_id = self.mme_ue_s1ap_id;
-
-    self.mme_ue_s1ap_id = self.mme_ue_s1ap_id + 1;
+    ue->mme_ue_s1ap_id = NEXT_ID(self.mme_ue_s1ap_id, 0xffffffff);
 
     list_append(&enb->ue_list, ue);
     
diff --git a/test/nas_sm_test.c b/test/nas_sm_test.c
index 46cbbc867b..01625e86f9 100644
--- a/test/nas_sm_test.c
+++ b/test/nas_sm_test.c
@@ -47,7 +47,7 @@ static void nas_sm_test1(abts_case *tc, void *data)
     pkbuf_free(recvbuf);
 
     /* Send Initial-UE Message */
-    mme_self()->mme_ue_s1ap_id = 16777373;
+    mme_self()->mme_ue_s1ap_id = 16777372;
     rv = tests1ap_build_initial_ue_msg(&sendbuf);
     ABTS_INT_EQUAL(tc, CORE_OK, rv);
     rv = tests1ap_enb_send(sock, sendbuf);