diff --git a/src/session/session.cpp b/src/session/session.cpp
index b54bda2..2bfec93 100644
--- a/src/session/session.cpp
+++ b/src/session/session.cpp
@@ -472,40 +472,6 @@ void session_free_all_ex_data(struct session *sess)
     }
 }
 
-/******************************************************************************
- * session expire
- ******************************************************************************/
-
-// session expire
-void session_set_expirecb(struct session *sess, session_expire_cb expire_cb, void *expire_arg, uint64_t expire_abs_ts)
-{
-    struct timeout *timeout = &sess->timeout;
-
-    timeout_init(timeout, TIMEOUT_ABS);
-    timeout_setcb(timeout, NULL, sess);
-    sess->expire_cb = expire_cb;
-    sess->expire_arg = expire_arg;
-    sess->expire_abs_ts = expire_abs_ts;
-}
-
-void session_del_expirecb(struct session *sess)
-{
-    struct timeout *timeout = &sess->timeout;
-
-    timeout_init(timeout, 0);
-    sess->expire_cb = NULL;
-    sess->expire_arg = NULL;
-    sess->expire_abs_ts = 0;
-}
-
-void session_run_expirecb(struct session *sess)
-{
-    if (sess->expire_cb)
-    {
-        sess->expire_cb(sess, sess->expire_arg);
-    }
-}
-
 /******************************************************************************
  * session dump
  ******************************************************************************/
diff --git a/src/session/session.h b/src/session/session.h
index 0f1f5fd..2222a83 100644
--- a/src/session/session.h
+++ b/src/session/session.h
@@ -165,17 +165,6 @@ void *session_get0_ex_data(const struct session *sess, uint8_t idx);
 void session_free_ex_data(struct session *sess, uint8_t idx);
 void session_free_all_ex_data(struct session *sess);
 
-/******************************************************************************
- * session expire
- ******************************************************************************/
-
-typedef void (*session_expire_cb)(struct session *sess, void *arg);
-
-// session timer
-void session_set_expirecb(struct session *sess, session_expire_cb expire_cb, void *expire_arg, uint64_t expire_abs_ts);
-void session_del_expirecb(struct session *sess);
-void session_run_expirecb(struct session *sess);
-
 /******************************************************************************
  * session dump
  ******************************************************************************/
diff --git a/src/session/session_manager.cpp b/src/session/session_manager.cpp
index 5a7f13f..664ddc8 100644
--- a/src/session/session_manager.cpp
+++ b/src/session/session_manager.cpp
@@ -406,13 +406,6 @@ static int session_filter_run(struct session_manager *mgr, enum filter_stage sta
  * Session Manager
  ******************************************************************************/
 
-static void timer_update(struct session_timer *timer, struct session *sess, uint64_t abs_timeout)
-{
-     session_timer_del(timer, sess);
-     session_set_expirecb(sess, NULL, NULL, abs_timeout);
-     session_timer_add(timer, sess);
-}
-
 static void session_update(struct session *sess, enum session_state next_state, const struct packet *pkt, const struct tuple6 *key, enum session_dir dir, uint64_t now)
 {
      if (session_get_state(sess) == SESSION_STATE_INIT)
@@ -532,7 +525,7 @@ static struct session *session_manager_new_tcp_session(struct session_manager *m
      session_insert_tcp_payload(sess, tcp_hdr_get_seq(hdr), tcp_layer->pld_ptr, tcp_layer->pld_len, now);
 
      uint64_t timeout = (flags & TH_ACK) ? mgr->tcp_handshake_timeout : mgr->tcp_init_timeout;
-     timer_update(mgr->sess_timer, sess, now + timeout);
+     session_timer_update(mgr->sess_timer, sess, now + timeout);
      session_table_add(mgr->tcp_sess_table, key, sess);
 
      duplicated_packet_filter_add(mgr->dup_pkt_filter, pkt, now);
@@ -565,7 +558,7 @@ static struct session *session_manager_new_udp_session(struct session_manager *m
      session_transition_log(sess, SESSION_STATE_INIT, next_state, UDP_DATA);
      session_stat_inc(&mgr->stat.udp_sess, next_state);
 
-     timer_update(mgr->sess_timer, sess, now + mgr->udp_data_timeout);
+     session_timer_update(mgr->sess_timer, sess, now + mgr->udp_data_timeout);
      session_table_add(mgr->udp_sess_table, key, sess);
 
      return sess;
@@ -630,7 +623,7 @@ static int session_manager_update_tcp_session(struct session_manager *mgr, struc
      case SESSION_STATE_CLOSING:
           if (flags & TH_FIN)
           {
-               timeout = (history & C2S_FIN_RECV && history & S2C_FIN_RECV) ? mgr->tcp_half_closed_timeout : mgr->tcp_time_wait_timeout;
+               timeout = (history & C2S_FIN_RECV && history & S2C_FIN_RECV) ? mgr->tcp_time_wait_timeout : mgr->tcp_half_closed_timeout;
           }
           else if (flags & TH_RST)
           {
@@ -648,7 +641,7 @@ static int session_manager_update_tcp_session(struct session_manager *mgr, struc
           assert(0);
           break;
      }
-     timer_update(mgr->sess_timer, sess, now + timeout);
+     session_timer_update(mgr->sess_timer, sess, now + timeout);
 
      return 0;
 }
@@ -661,7 +654,7 @@ static int session_manager_update_udp_session(struct session_manager *mgr, struc
      session_update(sess, next_state, pkt, key, dir, now);
      session_transition_log(sess, curr_state, next_state, UDP_DATA);
      session_stat_update(mgr, sess, curr_state, next_state);
-     timer_update(mgr->sess_timer, sess, now + mgr->udp_data_timeout);
+     session_timer_update(mgr->sess_timer, sess, now + mgr->udp_data_timeout);
 
      return 0;
 }
@@ -723,7 +716,7 @@ struct session_manager *session_manager_new(struct session_manager_options *opts
      mgr->sess_pool = session_pool_new(mgr->max_tcp_session_num + mgr->max_udp_session_num);
      mgr->tcp_sess_table = session_table_new();
      mgr->udp_sess_table = session_table_new();
-     mgr->sess_timer = session_timer_new();
+     mgr->sess_timer = session_timer_new(now);
      mgr->dup_pkt_filter = duplicated_packet_filter_new(&duplicated_packet_filter_opts, now);
      mgr->evicte_sess_filter = evicted_session_filter_new(&evicted_session_filter_opts, now);
      if (mgr->sess_pool == NULL || mgr->tcp_sess_table == NULL || mgr->udp_sess_table == NULL || mgr->sess_timer == NULL || mgr->dup_pkt_filter == NULL || mgr->evicte_sess_filter == NULL)
@@ -909,7 +902,7 @@ struct session *session_manager_get_expired_session(struct session_manager *mgr,
                     assert(0);
                     break;
                }
-               timer_update(mgr->sess_timer, sess, now + timeout);
+               session_timer_update(mgr->sess_timer, sess, now + timeout);
                return NULL;
           }
      }
diff --git a/src/session/session_private.h b/src/session/session_private.h
index 5e3261a..cdf0e2f 100644
--- a/src/session/session_private.h
+++ b/src/session/session_private.h
@@ -82,11 +82,7 @@ struct session
      * Session Timer Zone
      ******************************/
 
-    // session timer
     struct timeout timeout;
-    session_expire_cb expire_cb;
-    void *expire_arg;
-    uint64_t expire_abs_ts;
 
     /******************************
      * Session Table Zone
@@ -103,9 +99,9 @@ struct session
      * Session Queue Node
      ******************************/
 
-    struct list_head evicte; // used for evicte queue
     struct list_head lru;    // used for lru queue
     struct list_head free;   // used for free queue
+    struct list_head evicte; // used for evicte queue
 };
 
 #ifdef __cpluscplus
diff --git a/src/session/session_timer.cpp b/src/session/session_timer.cpp
index db3dd36..56bdc32 100644
--- a/src/session/session_timer.cpp
+++ b/src/session/session_timer.cpp
@@ -6,7 +6,7 @@ struct session_timer
     struct timeouts *timeouts;
 };
 
-struct session_timer *session_timer_new()
+struct session_timer *session_timer_new(uint64_t now)
 {
     timeout_error_t err;
     struct session_timer *timer = (struct session_timer *)calloc(1, sizeof(struct session_timer));
@@ -20,6 +20,7 @@ struct session_timer *session_timer_new()
     {
         goto error;
     }
+    timeouts_update(timer->timeouts, now);
 
     return timer;
 
@@ -42,21 +43,26 @@ void session_timer_free(struct session_timer *timer)
     }
 }
 
-void session_timer_add(struct session_timer *timer, struct session *sess)
+void session_timer_add(struct session_timer *timer, struct session *sess, uint64_t expires)
 {
-    struct timeout *timeout = &sess->timeout;
-    timeouts_add(timer->timeouts, timeout, sess->expire_abs_ts);
+    timeout_init(&sess->timeout, TIMEOUT_ABS);
+    timeouts_add(timer->timeouts, &sess->timeout, expires);
 }
 
 void session_timer_del(struct session_timer *timer, struct session *sess)
 {
-    struct timeout *timeout = &sess->timeout;
-    timeouts_del(timer->timeouts, timeout);
+    timeouts_del(timer->timeouts, &sess->timeout);
 }
 
-struct session *session_timer_expire(struct session_timer *timer, uint64_t abs_current_ts)
+void session_timer_update(struct session_timer *timer, struct session *sess, uint64_t expires)
 {
-    timeouts_update(timer->timeouts, abs_current_ts);
+    session_timer_del(timer, sess);
+    session_timer_add(timer, sess, expires);
+}
+
+struct session *session_timer_expire(struct session_timer *timer, uint64_t now)
+{
+    timeouts_update(timer->timeouts, now);
 
     struct timeout *timeout = timeouts_get(timer->timeouts);
     if (timeout == NULL)
@@ -64,8 +70,7 @@ struct session *session_timer_expire(struct session_timer *timer, uint64_t abs_c
         return NULL;
     }
 
-    struct session *sess = (struct session *)timeout->callback.arg;
-    return sess;
+    return container_of(timeout, struct session, timeout);
 }
 
 uint64_t session_timer_next_expire_interval(struct session_timer *timer)
diff --git a/src/session/session_timer.h b/src/session/session_timer.h
index 0bef69f..5788f4d 100644
--- a/src/session/session_timer.h
+++ b/src/session/session_timer.h
@@ -9,9 +9,10 @@ extern "C"
 #include "session.h"
 
 struct session_timer;
-struct session_timer *session_timer_new();
+struct session_timer *session_timer_new(uint64_t now);
 void session_timer_free(struct session_timer *timer);
-void session_timer_add(struct session_timer *timer, struct session *sess);
+void session_timer_update(struct session_timer *timer, struct session *sess, uint64_t expires);
+void session_timer_add(struct session_timer *timer, struct session *sess, uint64_t expires);
 void session_timer_del(struct session_timer *timer, struct session *sess);
 /*
  * return one session which timeout, or NULL if no session timeout.
diff --git a/src/session/test/gtest_sess_mgr_tcp_reassembly.cpp b/src/session/test/gtest_sess_mgr_tcp_reassembly.cpp
index ac2c9ad..62eedfc 100644
--- a/src/session/test/gtest_sess_mgr_tcp_reassembly.cpp
+++ b/src/session/test/gtest_sess_mgr_tcp_reassembly.cpp
@@ -238,8 +238,8 @@ TEST(SESS_MGR_TCP_REASSEMBLY, OUT_OF_ORDER)
     session_consume_tcp_payload(sess, len);
 
     // expire session
-    EXPECT_TRUE(session_manager_get_expired_session(mgr, 7 + opts.tcp_data_timeout) == NULL);                // active -> closing
-    sess = session_manager_get_expired_session(mgr, 7 + opts.tcp_data_timeout + opts.tcp_time_wait_timeout); // closing -> closed
+    EXPECT_TRUE(session_manager_get_expired_session(mgr, 7 + opts.tcp_data_timeout) == NULL);           // active -> closing
+    sess = session_manager_get_expired_session(mgr, 7 + opts.tcp_data_timeout + opts.tcp_data_timeout); // closing -> closed
     EXPECT_TRUE(sess);
     EXPECT_TRUE(session_get_state(sess) == SESSION_STATE_CLOSED);
     EXPECT_TRUE(session_get_closing_reason(sess) == CLOSING_BY_TIMEOUT);
@@ -330,8 +330,8 @@ TEST(SESS_MGR_TCP_REASSEMBLY, SEQ_WRAPAROUND)
     session_consume_tcp_payload(sess, len);
 
     // expire session
-    EXPECT_TRUE(session_manager_get_expired_session(mgr, 4 + opts.tcp_data_timeout) == NULL);                // active -> closing
-    sess = session_manager_get_expired_session(mgr, 4 + opts.tcp_data_timeout + opts.tcp_time_wait_timeout); // closing -> closed
+    EXPECT_TRUE(session_manager_get_expired_session(mgr, 4 + opts.tcp_data_timeout) == NULL);           // active -> closing
+    sess = session_manager_get_expired_session(mgr, 4 + opts.tcp_data_timeout + opts.tcp_data_timeout); // closing -> closed
     EXPECT_TRUE(sess);
     EXPECT_TRUE(session_get_state(sess) == SESSION_STATE_CLOSED);
     EXPECT_TRUE(session_get_closing_reason(sess) == CLOSING_BY_TIMEOUT);
diff --git a/src/session/test/gtest_session_timer.cpp b/src/session/test/gtest_session_timer.cpp
index 4e4bb5f..40b1b99 100644
--- a/src/session/test/gtest_session_timer.cpp
+++ b/src/session/test/gtest_session_timer.cpp
@@ -3,62 +3,42 @@
 #include "session_timer.h"
 #include "session_private.h"
 
-static void session_expire(struct session *sess, void *arg)
-{
-    printf("=== session %lu expired ===\n", session_get_id(sess));
-}
-
-TEST(SESSION_TIMER, ADD_DEL)
-{
-    struct session sess;
-    struct session_timer *timer = session_timer_new();
-    EXPECT_TRUE(timer != NULL);
-
-    session_init(&sess);
-    session_set_id(&sess, 1);
-    session_set_expirecb(&sess, session_expire, NULL, 1000);
-
-    session_timer_add(timer, &sess);
-    session_timer_del(timer, &sess);
-
-    session_timer_free(timer);
-}
-
 TEST(SESSION_TIMER, EXPIRE)
 {
     struct session *sess = NULL;
     struct session sess1;
     struct session sess2;
     struct session sess3;
-    struct session_timer *timer = session_timer_new();
+    struct session_timer *timer = session_timer_new(100);
     EXPECT_TRUE(timer != NULL);
 
     session_init(&sess1);
     session_init(&sess2);
     session_init(&sess3);
-    session_set_id(&sess1, 1);
-    session_set_id(&sess2, 2);
-    session_set_id(&sess3, 3);
-    session_set_expirecb(&sess1, session_expire, NULL, 5);
-    session_set_expirecb(&sess2, session_expire, NULL, 5);
-    session_set_expirecb(&sess3, session_expire, NULL, 10);
 
-    session_timer_add(timer, &sess1);
-    session_timer_add(timer, &sess2);
-    session_timer_add(timer, &sess3);
+    session_timer_add(timer, &sess1, 100 + 5);
+    session_timer_add(timer, &sess2, 100 + 5);
+    session_timer_add(timer, &sess3, 100 + 10);
 
-    for (uint64_t abs_current_ts = 0; abs_current_ts < 15; abs_current_ts++)
-    {
-        printf("current timestamp %lu\n", abs_current_ts);
-        do
-        {
-            sess = session_timer_expire(timer, abs_current_ts);
-            if (sess != NULL)
-            {
-                session_run_expirecb(sess);
-            }
-        } while (sess);
-    }
+    // not expire
+    sess = session_timer_expire(timer, 100 + 4);
+    EXPECT_TRUE(sess == NULL);
+    // expire
+    sess = session_timer_expire(timer, 100 + 5);
+    EXPECT_TRUE(sess == &sess1);
+    sess = session_timer_expire(timer, 100 + 5);
+    EXPECT_TRUE(sess == &sess2);
+    // not expire
+    sess = session_timer_expire(timer, 100 + 5);
+    EXPECT_TRUE(sess == NULL);
+    sess = session_timer_expire(timer, 100 + 9);
+    EXPECT_TRUE(sess == NULL);
+    // expire
+    sess = session_timer_expire(timer, 100 + 10);
+    EXPECT_TRUE(sess == &sess3);
+    // not expire
+    sess = session_timer_expire(timer, 100 + 10);
+    EXPECT_TRUE(sess == NULL);
 
     session_timer_free(timer);
 }
@@ -69,40 +49,65 @@ TEST(SESSION_TIMER, BEFORE_EXPIRE_DEL)
     struct session sess1;
     struct session sess2;
     struct session sess3;
-    struct session_timer *timer = session_timer_new();
+    struct session_timer *timer = session_timer_new(1);
     EXPECT_TRUE(timer != NULL);
 
     session_init(&sess1);
     session_init(&sess2);
     session_init(&sess3);
-    session_set_id(&sess1, 1);
-    session_set_id(&sess2, 2);
-    session_set_id(&sess3, 3);
-    session_set_expirecb(&sess1, session_expire, NULL, 5);
-    session_set_expirecb(&sess2, session_expire, NULL, 5);
-    session_set_expirecb(&sess3, session_expire, NULL, 10);
 
-    session_timer_add(timer, &sess1);
-    session_timer_add(timer, &sess2);
-    session_timer_add(timer, &sess3);
+    session_timer_add(timer, &sess1, 100 + 5);
+    session_timer_add(timer, &sess2, 100 + 5);
+    session_timer_add(timer, &sess3, 100 + 10);
 
-    for (uint64_t abs_current_ts = 0; abs_current_ts < 15; abs_current_ts++)
-    {
-        printf("current timestamp %lu\n", abs_current_ts);
-        if (abs_current_ts == 2)
-        {
-            printf("delete timer 2\n");
-            session_timer_del(timer, &sess2);
-        }
-        do
-        {
-            sess = session_timer_expire(timer, abs_current_ts);
-            if (sess != NULL)
-            {
-                session_run_expirecb(sess);
-            }
-        } while (sess);
-    }
+    // not expire
+    sess = session_timer_expire(timer, 100 + 4);
+    EXPECT_TRUE(sess == NULL);
+    // del sess1
+    session_timer_del(timer, &sess1);
+    // expire
+    sess = session_timer_expire(timer, 100 + 5);
+    EXPECT_TRUE(sess == &sess2);
+    sess = session_timer_expire(timer, 100 + 5);
+    EXPECT_TRUE(sess == NULL);
+    // expire
+    sess = session_timer_expire(timer, 100 + 10);
+    EXPECT_TRUE(sess == &sess3);
+    // not expire
+    sess = session_timer_expire(timer, 100 + 10);
+    EXPECT_TRUE(sess == NULL);
+
+    session_timer_free(timer);
+}
+
+TEST(SESSION_TIMER, AFTER_EXPIRE_DEL)
+{
+    struct session *sess = NULL;
+    struct session sess1;
+    struct session sess2;
+    struct session sess3;
+    struct session_timer *timer = session_timer_new(1);
+    EXPECT_TRUE(timer != NULL);
+
+    session_init(&sess1);
+    session_init(&sess2);
+    session_init(&sess3);
+
+    session_timer_add(timer, &sess1, 100 + 5);
+    session_timer_add(timer, &sess2, 100 + 5);
+    session_timer_add(timer, &sess3, 100 + 10);
+
+    // expire
+    sess = session_timer_expire(timer, 100 + 5);
+    EXPECT_TRUE(sess == &sess1);
+    // del sess2
+    session_timer_del(timer, &sess2);
+    // not expire
+    sess = session_timer_expire(timer, 100 + 5);
+    EXPECT_TRUE(sess == NULL);
+    // expire
+    sess = session_timer_expire(timer, 100 + 10);
+    EXPECT_TRUE(sess == &sess3);
 
     session_timer_free(timer);
 }
@@ -112,43 +117,32 @@ TEST(SESSION_TIMER, BEFORE_EXPIRE_UPDATE)
     struct session *sess = NULL;
     struct session sess1;
     struct session sess2;
-    struct session sess3;
-    struct session_timer *timer = session_timer_new();
+    struct session_timer *timer = session_timer_new(100);
     EXPECT_TRUE(timer != NULL);
 
     session_init(&sess1);
     session_init(&sess2);
-    session_init(&sess3);
-    session_set_id(&sess1, 1);
-    session_set_id(&sess2, 2);
-    session_set_id(&sess3, 3);
-    session_set_expirecb(&sess1, session_expire, NULL, 5);
-    session_set_expirecb(&sess2, session_expire, NULL, 5);
-    session_set_expirecb(&sess3, session_expire, NULL, 10);
 
-    session_timer_add(timer, &sess1);
-    session_timer_add(timer, &sess2);
-    session_timer_add(timer, &sess3);
+    session_timer_add(timer, &sess1, 100 + 5);
+    session_timer_add(timer, &sess2, 100 + 10);
 
-    for (uint64_t abs_current_ts = 0; abs_current_ts < 15; abs_current_ts++)
-    {
-        printf("current timestamp %lu\n", abs_current_ts);
-        if (abs_current_ts == 2)
-        {
-            printf("update timer 2\n");
-            session_timer_del(timer, &sess2);
-            session_set_expirecb(&sess2, session_expire, NULL, 8);
-            session_timer_add(timer, &sess2);
-        }
-        do
-        {
-            sess = session_timer_expire(timer, abs_current_ts);
-            if (sess != NULL)
-            {
-                session_run_expirecb(sess);
-            }
-        } while (sess);
-    }
+    // not expire
+    sess = session_timer_expire(timer, 100 + 4);
+    EXPECT_TRUE(sess == NULL);
+    // expire
+    sess = session_timer_expire(timer, 100 + 5);
+    EXPECT_TRUE(sess == &sess1);
+    // not expire
+    sess = session_timer_expire(timer, 100 + 5);
+    EXPECT_TRUE(sess == NULL);
+    // update sess2
+    session_timer_update(timer, &sess2, 100 + 20);
+    // not expire
+    sess = session_timer_expire(timer, 100 + 19);
+    EXPECT_TRUE(sess == NULL);
+    // expire
+    sess = session_timer_expire(timer, 100 + 20);
+    EXPECT_TRUE(sess == &sess2);
 
     session_timer_free(timer);
 }
@@ -157,20 +151,16 @@ TEST(SESSION_TIMER, NEXT_EXPIRE_INTERVAL)
 {
     struct session sess1;
     struct session sess2;
-    struct session_timer *timer = session_timer_new();
+    struct session_timer *timer = session_timer_new(100);
     EXPECT_TRUE(timer != NULL);
 
     session_init(&sess1);
     session_init(&sess2);
-    session_set_id(&sess1, 1);
-    session_set_id(&sess2, 2);
-    session_set_expirecb(&sess1, session_expire, NULL, 1000);
-    session_set_expirecb(&sess2, session_expire, NULL, 1000);
 
     EXPECT_TRUE(session_timer_next_expire_interval(timer) == UINT64_MAX);
 
-    session_timer_add(timer, &sess1);
-    session_timer_add(timer, &sess2);
+    session_timer_add(timer, &sess1, 1000);
+    session_timer_add(timer, &sess2, 1000);
     EXPECT_TRUE(session_timer_next_expire_interval(timer) < UINT64_MAX);
 
     EXPECT_TRUE(session_timer_expire(timer, 900) == NULL);
diff --git a/src/session/test/gtest_state_tcp_active_to_closing.cpp b/src/session/test/gtest_state_tcp_active_to_closing.cpp
index a6f1913..ad2c888 100644
--- a/src/session/test/gtest_state_tcp_active_to_closing.cpp
+++ b/src/session/test/gtest_state_tcp_active_to_closing.cpp
@@ -370,7 +370,7 @@ TEST(TCP_ACTIVE_TO_CLOSING, BY_DATA_TIMEOUT)
 
     // expire session
     EXPECT_TRUE(session_manager_get_expired_session(mgr, 2 + opts.tcp_data_timeout) == NULL);
-    sess = session_manager_get_expired_session(mgr, 2 + opts.tcp_data_timeout + opts.tcp_time_wait_timeout);
+    sess = session_manager_get_expired_session(mgr, 2 + opts.tcp_data_timeout + opts.tcp_data_timeout);
     EXPECT_TRUE(sess);
     EXPECT_TRUE(session_get_state(sess) == SESSION_STATE_CLOSED);
     EXPECT_TRUE(session_get_closing_reason(sess) == CLOSING_BY_TIMEOUT);
@@ -451,7 +451,7 @@ TEST(TCP_ACTIVE_TO_CLOSING, BY_C2S_HALF_CLOSED_TIMEOUT)
     EXPECT_TRUE(stat->tcp_sess.nr_sess_closing == 1);
 
     // expire session
-    sess = session_manager_get_expired_session(mgr, 3 + opts.tcp_time_wait_timeout);
+    sess = session_manager_get_expired_session(mgr, 3 + opts.tcp_half_closed_timeout);
     EXPECT_TRUE(sess);
     EXPECT_TRUE(session_get_state(sess) == SESSION_STATE_CLOSED);
     EXPECT_TRUE(session_get_closing_reason(sess) == CLOSING_BY_CLIENT_FIN);
@@ -532,7 +532,7 @@ TEST(TCP_ACTIVE_TO_CLOSING, BY_S2C_HALF_CLOSED_TIMEOUT)
     EXPECT_TRUE(stat->tcp_sess.nr_sess_closing == 1);
 
     // expire session
-    sess = session_manager_get_expired_session(mgr, 3 + opts.tcp_time_wait_timeout);
+    sess = session_manager_get_expired_session(mgr, 3 + opts.tcp_half_closed_timeout);
     EXPECT_TRUE(sess);
     EXPECT_TRUE(session_get_state(sess) == SESSION_STATE_CLOSED);
     EXPECT_TRUE(session_get_closing_reason(sess) == CLOSING_BY_SERVER_FIN);
diff --git a/src/session/test/gtest_state_tcp_init_to_opening.cpp b/src/session/test/gtest_state_tcp_init_to_opening.cpp
index 3023a3c..abf0076 100644
--- a/src/session/test/gtest_state_tcp_init_to_opening.cpp
+++ b/src/session/test/gtest_state_tcp_init_to_opening.cpp
@@ -105,8 +105,8 @@ TEST(TCP_INIT_TO_OPENING, BY_SYN)
     EXPECT_TRUE(stat->tcp_sess.nr_sess_closing == 0);
 
     // expire session
-    EXPECT_TRUE(session_manager_get_expired_session(mgr, 1 + opts.tcp_init_timeout) == NULL);                // opening -> closing
-    sess = session_manager_get_expired_session(mgr, 1 + opts.tcp_init_timeout + opts.tcp_time_wait_timeout); // closing -> closed
+    EXPECT_TRUE(session_manager_get_expired_session(mgr, 1 + opts.tcp_init_timeout) == NULL);           // opening -> closing
+    sess = session_manager_get_expired_session(mgr, 1 + opts.tcp_init_timeout + opts.tcp_data_timeout); // closing -> closed
     EXPECT_TRUE(sess);
     EXPECT_TRUE(session_get_state(sess) == SESSION_STATE_CLOSED);
     EXPECT_TRUE(session_get_closing_reason(sess) == CLOSING_BY_TIMEOUT);
@@ -186,7 +186,7 @@ TEST(TCP_INIT_TO_OPENING, BY_SYNACK)
 
     // expire session
     EXPECT_TRUE(session_manager_get_expired_session(mgr, 1 + opts.tcp_handshake_timeout) == NULL);
-    sess = session_manager_get_expired_session(mgr, 1 + opts.tcp_handshake_timeout + opts.tcp_time_wait_timeout);
+    sess = session_manager_get_expired_session(mgr, 1 + opts.tcp_handshake_timeout + opts.tcp_data_timeout);
     EXPECT_TRUE(sess);
     EXPECT_TRUE(session_get_state(sess) == SESSION_STATE_CLOSED);
     EXPECT_TRUE(session_get_closing_reason(sess) == CLOSING_BY_TIMEOUT);
@@ -277,7 +277,7 @@ TEST(TCP_INIT_TO_OPENING, BY_SYN_SYNACK)
 
     // expire session
     EXPECT_TRUE(session_manager_get_expired_session(mgr, 2 + opts.tcp_handshake_timeout) == NULL);
-    sess = session_manager_get_expired_session(mgr, 2 + opts.tcp_handshake_timeout + opts.tcp_time_wait_timeout);
+    sess = session_manager_get_expired_session(mgr, 2 + opts.tcp_handshake_timeout + opts.tcp_data_timeout);
     EXPECT_TRUE(sess);
     EXPECT_TRUE(session_get_state(sess) == SESSION_STATE_CLOSED);
     EXPECT_TRUE(session_get_closing_reason(sess) == CLOSING_BY_TIMEOUT);
@@ -378,7 +378,7 @@ TEST(TCP_INIT_TO_OPENING, BY_SYN_SYNACK_ACK)
 
     // expire session
     EXPECT_TRUE(session_manager_get_expired_session(mgr, 3 + opts.tcp_data_timeout) == NULL);
-    sess = session_manager_get_expired_session(mgr, 3 + opts.tcp_data_timeout + opts.tcp_time_wait_timeout);
+    sess = session_manager_get_expired_session(mgr, 3 + opts.tcp_data_timeout + opts.tcp_data_timeout);
     EXPECT_TRUE(sess);
     EXPECT_TRUE(session_get_state(sess) == SESSION_STATE_CLOSED);
     EXPECT_TRUE(session_get_closing_reason(sess) == CLOSING_BY_TIMEOUT);
@@ -476,7 +476,7 @@ TEST(TCP_INIT_TO_OPENING, BY_SYN_RETRANSMISSION)
 
     // expire session
     EXPECT_TRUE(session_manager_get_expired_session(mgr, 2 + opts.tcp_init_timeout) == NULL);
-    sess = session_manager_get_expired_session(mgr, 2 + opts.tcp_init_timeout + opts.tcp_time_wait_timeout);
+    sess = session_manager_get_expired_session(mgr, 2 + opts.tcp_init_timeout + opts.tcp_data_timeout);
     EXPECT_TRUE(sess);
     EXPECT_TRUE(session_get_state(sess) == SESSION_STATE_CLOSED);
     EXPECT_TRUE(session_get_closing_reason(sess) == CLOSING_BY_TIMEOUT);
@@ -575,7 +575,7 @@ TEST(TCP_INIT_TO_OPENING, BY_SYNACK_RETRANSMISSION)
 
     // expire session
     EXPECT_TRUE(session_manager_get_expired_session(mgr, 2 + opts.tcp_handshake_timeout) == NULL);
-    sess = session_manager_get_expired_session(mgr, 2 + opts.tcp_handshake_timeout + opts.tcp_time_wait_timeout);
+    sess = session_manager_get_expired_session(mgr, 2 + opts.tcp_handshake_timeout + opts.tcp_data_timeout);
     EXPECT_TRUE(sess);
     EXPECT_TRUE(session_get_state(sess) == SESSION_STATE_CLOSED);
     EXPECT_TRUE(session_get_closing_reason(sess) == CLOSING_BY_TIMEOUT);
@@ -666,7 +666,7 @@ TEST(TCP_INIT_TO_OPENING, BY_C2S_ASMMETRIC)
 
     // expire session
     EXPECT_TRUE(session_manager_get_expired_session(mgr, 2 + opts.tcp_data_timeout) == NULL);
-    sess = session_manager_get_expired_session(mgr, 2 + opts.tcp_data_timeout + opts.tcp_time_wait_timeout);
+    sess = session_manager_get_expired_session(mgr, 2 + opts.tcp_data_timeout + opts.tcp_data_timeout);
     EXPECT_TRUE(sess);
     EXPECT_TRUE(session_get_state(sess) == SESSION_STATE_CLOSED);
     EXPECT_TRUE(session_get_closing_reason(sess) == CLOSING_BY_TIMEOUT);
@@ -757,7 +757,7 @@ TEST(TCP_INIT_TO_OPENING, BY_S2C_ASMMETRIC)
 
     // expire session
     EXPECT_TRUE(session_manager_get_expired_session(mgr, 2 + opts.tcp_data_timeout) == NULL);
-    sess = session_manager_get_expired_session(mgr, 2 + opts.tcp_data_timeout + opts.tcp_time_wait_timeout);
+    sess = session_manager_get_expired_session(mgr, 2 + opts.tcp_data_timeout + opts.tcp_data_timeout);
     EXPECT_TRUE(sess);
     EXPECT_TRUE(session_get_state(sess) == SESSION_STATE_CLOSED);
     EXPECT_TRUE(session_get_closing_reason(sess) == CLOSING_BY_TIMEOUT);
diff --git a/src/session/test/gtest_state_tcp_opening_to_active.cpp b/src/session/test/gtest_state_tcp_opening_to_active.cpp
index 4cee83c..e2637bd 100644
--- a/src/session/test/gtest_state_tcp_opening_to_active.cpp
+++ b/src/session/test/gtest_state_tcp_opening_to_active.cpp
@@ -115,7 +115,7 @@ TEST(TCP_OPENING_TO_ACTIVE, BY_SYN_C2S_DATA)
 
     // expire session
     EXPECT_TRUE(session_manager_get_expired_session(mgr, 2 + opts.tcp_data_timeout) == NULL);
-    sess = session_manager_get_expired_session(mgr, 2 + opts.tcp_data_timeout + opts.tcp_time_wait_timeout);
+    sess = session_manager_get_expired_session(mgr, 2 + opts.tcp_data_timeout + opts.tcp_data_timeout);
     EXPECT_TRUE(sess);
     EXPECT_TRUE(session_get_state(sess) == SESSION_STATE_CLOSED);
     EXPECT_TRUE(session_get_closing_reason(sess) == CLOSING_BY_TIMEOUT);
@@ -205,7 +205,7 @@ TEST(TCP_OPENING_TO_ACTIVE, BY_SYNACK_S2C_DATA)
 
     // expire session
     EXPECT_TRUE(session_manager_get_expired_session(mgr, 2 + opts.tcp_data_timeout) == NULL);
-    sess = session_manager_get_expired_session(mgr, 2 + opts.tcp_data_timeout + opts.tcp_time_wait_timeout);
+    sess = session_manager_get_expired_session(mgr, 2 + opts.tcp_data_timeout + opts.tcp_data_timeout);
     EXPECT_TRUE(sess);
     EXPECT_TRUE(session_get_state(sess) == SESSION_STATE_CLOSED);
     EXPECT_TRUE(session_get_closing_reason(sess) == CLOSING_BY_TIMEOUT);
diff --git a/src/session/test/gtest_state_tcp_opening_to_closing.cpp b/src/session/test/gtest_state_tcp_opening_to_closing.cpp
index 6c7b73b..9f82aa2 100644
--- a/src/session/test/gtest_state_tcp_opening_to_closing.cpp
+++ b/src/session/test/gtest_state_tcp_opening_to_closing.cpp
@@ -376,7 +376,7 @@ TEST(TCP_OPENING_TO_CLOSING, BY_INIT_TIMEOUT)
 
     // expire session
     EXPECT_TRUE(session_manager_get_expired_session(mgr, 1 + opts.tcp_init_timeout) == NULL);
-    sess = session_manager_get_expired_session(mgr, 1 + opts.tcp_init_timeout + opts.tcp_time_wait_timeout);
+    sess = session_manager_get_expired_session(mgr, 1 + opts.tcp_init_timeout + opts.tcp_data_timeout);
     EXPECT_TRUE(sess);
     EXPECT_TRUE(session_get_state(sess) == SESSION_STATE_CLOSED);
     EXPECT_TRUE(session_get_closing_reason(sess) == CLOSING_BY_TIMEOUT);
@@ -466,7 +466,7 @@ TEST(TCP_OPENING_TO_CLOSING, BY_HANDSHAKE_TIMEOUT)
 
     // expire session
     EXPECT_TRUE(session_manager_get_expired_session(mgr, 2 + opts.tcp_handshake_timeout) == NULL);
-    sess = session_manager_get_expired_session(mgr, 2 + opts.tcp_handshake_timeout + opts.tcp_time_wait_timeout);
+    sess = session_manager_get_expired_session(mgr, 2 + opts.tcp_handshake_timeout + opts.tcp_data_timeout);
     EXPECT_TRUE(sess);
     EXPECT_TRUE(session_get_state(sess) == SESSION_STATE_CLOSED);
     EXPECT_TRUE(session_get_closing_reason(sess) == CLOSING_BY_TIMEOUT);
@@ -567,7 +567,7 @@ TEST(TCP_OPENING_TO_CLOSING, BY_DATA_TIMEOUT)
 
     // expire session
     EXPECT_TRUE(session_manager_get_expired_session(mgr, 3 + opts.tcp_data_timeout) == NULL);
-    sess = session_manager_get_expired_session(mgr, 3 + opts.tcp_data_timeout + opts.tcp_time_wait_timeout);
+    sess = session_manager_get_expired_session(mgr, 3 + opts.tcp_data_timeout + opts.tcp_data_timeout);
     EXPECT_TRUE(sess);
     EXPECT_TRUE(session_get_state(sess) == SESSION_STATE_CLOSED);
     EXPECT_TRUE(session_get_closing_reason(sess) == CLOSING_BY_TIMEOUT);
@@ -656,7 +656,7 @@ TEST(TCP_OPENING_TO_CLOSING, BY_C2S_HALF_FIN)
     EXPECT_TRUE(stat->tcp_sess.nr_sess_closing == 1);
 
     // expire session
-    sess = session_manager_get_expired_session(mgr, 2 + opts.tcp_time_wait_timeout);
+    sess = session_manager_get_expired_session(mgr, 2 + opts.tcp_half_closed_timeout);
     EXPECT_TRUE(sess);
     EXPECT_TRUE(session_get_state(sess) == SESSION_STATE_CLOSED);
     EXPECT_TRUE(session_get_closing_reason(sess) == CLOSING_BY_CLIENT_FIN);
@@ -745,7 +745,7 @@ TEST(TCP_OPENING_TO_CLOSING, BY_S2C_HALF_FIN)
     EXPECT_TRUE(stat->tcp_sess.nr_sess_closing == 1);
 
     // expire session
-    sess = session_manager_get_expired_session(mgr, 2 + opts.tcp_time_wait_timeout);
+    sess = session_manager_get_expired_session(mgr, 2 + opts.tcp_half_closed_timeout);
     EXPECT_TRUE(sess);
     EXPECT_TRUE(session_get_state(sess) == SESSION_STATE_CLOSED);
     EXPECT_TRUE(session_get_closing_reason(sess) == CLOSING_BY_SERVER_FIN);
diff --git a/src/session/test/gtest_timeout_tcp_data.cpp b/src/session/test/gtest_timeout_tcp_data.cpp
index 9c946e7..82d6816 100644
--- a/src/session/test/gtest_timeout_tcp_data.cpp
+++ b/src/session/test/gtest_timeout_tcp_data.cpp
@@ -79,7 +79,7 @@ TEST(TIMEOUT, TCP_TIMEOUT_DATA)
 
     // expire session
     EXPECT_TRUE(session_manager_get_expired_session(mgr, 2 + opts.tcp_data_timeout) == NULL);
-    sess = session_manager_get_expired_session(mgr, 2 + opts.tcp_data_timeout + opts.tcp_time_wait_timeout);
+    sess = session_manager_get_expired_session(mgr, 2 + opts.tcp_data_timeout + opts.tcp_data_timeout);
     EXPECT_TRUE(sess);
     EXPECT_TRUE(session_get_state(sess) == SESSION_STATE_CLOSED);
     EXPECT_TRUE(session_get_closing_reason(sess) == CLOSING_BY_TIMEOUT);
diff --git a/src/session/test/gtest_timeout_tcp_handshake.cpp b/src/session/test/gtest_timeout_tcp_handshake.cpp
index 96182d1..414a03e 100644
--- a/src/session/test/gtest_timeout_tcp_handshake.cpp
+++ b/src/session/test/gtest_timeout_tcp_handshake.cpp
@@ -69,7 +69,7 @@ TEST(TIMEOUT, TCP_TIMEOUT_HANDSHAKE)
 
     // expire session
     EXPECT_TRUE(session_manager_get_expired_session(mgr, 1 + opts.tcp_handshake_timeout) == NULL);
-    sess = session_manager_get_expired_session(mgr, 1 + opts.tcp_handshake_timeout + opts.tcp_time_wait_timeout);
+    sess = session_manager_get_expired_session(mgr, 1 + opts.tcp_handshake_timeout + opts.tcp_data_timeout);
     EXPECT_TRUE(sess);
     EXPECT_TRUE(session_get_state(sess) == SESSION_STATE_CLOSED);
     EXPECT_TRUE(session_get_closing_reason(sess) == CLOSING_BY_TIMEOUT);
diff --git a/src/session/test/gtest_timeout_tcp_init.cpp b/src/session/test/gtest_timeout_tcp_init.cpp
index 28f621d..f34b664 100644
--- a/src/session/test/gtest_timeout_tcp_init.cpp
+++ b/src/session/test/gtest_timeout_tcp_init.cpp
@@ -68,8 +68,8 @@ TEST(TIMEOUT, TCP_TIMEOUT_INIT)
     EXPECT_TRUE(sess);
 
     // expire session
-    EXPECT_TRUE(session_manager_get_expired_session(mgr, 1 + opts.tcp_init_timeout) == NULL);                // opening -> closing
-    sess = session_manager_get_expired_session(mgr, 1 + opts.tcp_init_timeout + opts.tcp_time_wait_timeout); // closing -> closed
+    EXPECT_TRUE(session_manager_get_expired_session(mgr, 1 + opts.tcp_init_timeout) == NULL);           // opening -> closing
+    sess = session_manager_get_expired_session(mgr, 1 + opts.tcp_init_timeout + opts.tcp_data_timeout); // closing -> closed
     EXPECT_TRUE(sess);
     EXPECT_TRUE(session_get_state(sess) == SESSION_STATE_CLOSED);
     EXPECT_TRUE(session_get_closing_reason(sess) == CLOSING_BY_TIMEOUT);