diff --git a/trunk/src/app/srs_app_conn.hpp b/trunk/src/app/srs_app_conn.hpp
index 148e36edc..b4b7037cc 100644
--- a/trunk/src/app/srs_app_conn.hpp
+++ b/trunk/src/app/srs_app_conn.hpp
@@ -92,6 +92,7 @@ public:
     virtual void on_thread_stop();
 public:
     /**
+    * reset and start sample of bytes.
     * when server to get the kbps of connection,
     * it cannot wait the connection terminated then get the kbps,
     * it must sample the kbps every some interval, for instance, 9s to sample all connections kbps,
diff --git a/trunk/src/app/srs_app_kbps.hpp b/trunk/src/app/srs_app_kbps.hpp
index bb6faee91..b6295d294 100644
--- a/trunk/src/app/srs_app_kbps.hpp
+++ b/trunk/src/app/srs_app_kbps.hpp
@@ -122,12 +122,12 @@ public:
 * to statistic the kbps of io.
 * itself can be a statistic source, for example, used for SRS bytes stat.
 * there are two usage scenarios:
-* 1. connections to calc kbps:
+* 1. connections to calc kbps by sample():
 *       set_io(in, out)
 *       sample()
 *       get_xxx_kbps().
 *   the connections know how many bytes already send/recv.
-* 2. server to calc kbps:
+* 2. server to calc kbps by add_delta():
 *       set_io(NULL, NULL)
 *       for each connection in connections:
 *           add_delta(connections) // where connection is a IKbpsDelta*
diff --git a/trunk/src/app/srs_app_server.cpp b/trunk/src/app/srs_app_server.cpp
index 84cbfca75..066e0f1c9 100644
--- a/trunk/src/app/srs_app_server.cpp
+++ b/trunk/src/app/srs_app_server.cpp
@@ -745,8 +745,12 @@ void SrsServer::remove(SrsConnection* conn)
     
     srs_info("conn removed. conns=%d", (int)conns.size());
     
-    // resample the resource of specified connection.
-    resample_kbps(conn);
+    // resample the kbps to collect the delta.
+    conn->kbps_resample();
+    
+    // add delta of connection to server kbps.,
+    // for next sample() of server kbps can get the stat.
+    kbps->add_delta(conn);
     
     // all connections are created by server,
     // so we free it here.
@@ -862,8 +866,8 @@ int SrsServer::do_cycle()
                 srs_update_network_devices();
             }
             if ((i % SRS_SYS_NETWORK_RTMP_SERVER_RESOLUTION_TIMES) == 0) {
-                srs_info("update network rtmp server info.");
-                resample_kbps(NULL);
+                srs_info("update network server kbps info.");
+                resample_kbps();
                 srs_update_rtmp_server((int)conns.size(), kbps);
             }
     #ifdef SRS_AUTO_HTTP_PARSER
@@ -1013,31 +1017,24 @@ void SrsServer::close_listeners(SrsListenerType type)
     }
 }
 
-void SrsServer::resample_kbps(SrsConnection* conn, bool do_resample)
+void SrsServer::resample_kbps()
 {
-    // resample all when conn is NULL.
-    if (!conn) {
-        for (std::vector<SrsConnection*>::iterator it = conns.begin(); it != conns.end(); ++it) {
-            SrsConnection* client = *it;
-            srs_assert(client);
-            
-            // only resample, do resample when all finished.
-            resample_kbps(client, false);
-        }
+    // collect delta from all clients.
+    for (std::vector<SrsConnection*>::iterator it = conns.begin(); it != conns.end(); ++it) {
+        SrsConnection* conn = *it;
+    
+        // resample the kbps to collect the delta.
+        conn->kbps_resample();
         
-        kbps->sample();
-        return;
+        // add delta of connection to server kbps.,
+        // for next sample() of server kbps can get the stat.
+        kbps->add_delta(conn);
     }
     
-    // resample for connection.
-    conn->kbps_resample();
-    
-    kbps->add_delta(conn);
-    
-    // resample for server.
-    if (do_resample) {
-        kbps->sample();
-    }
+    // TODO: FXME: support all other connections.
+
+    // sample the kbps, get the stat.
+    kbps->sample();
 }
 
 int SrsServer::accept_client(SrsListenerType type, st_netfd_t client_stfd)
diff --git a/trunk/src/app/srs_app_server.hpp b/trunk/src/app/srs_app_server.hpp
index cf8e3dea6..02c218858 100644
--- a/trunk/src/app/srs_app_server.hpp
+++ b/trunk/src/app/srs_app_server.hpp
@@ -278,12 +278,9 @@ private:
     */
     virtual void close_listeners(SrsListenerType type);
     /**
-    * resample the server kbps. 
-    * if conn is NULL, resample all connections delta, then calc the total kbps.
-    * @param conn, the connection to do resample the kbps. NULL to resample all connections.
-    * @param do_resample, whether resample the server kbps. always false when sample a connection.
+    * resample the server kbs.
     */
-    virtual void resample_kbps(SrsConnection* conn, bool do_resample = true);
+    virtual void resample_kbps();
 // internal only
 public:
     /**
diff --git a/trunk/src/app/srs_app_utility.cpp b/trunk/src/app/srs_app_utility.cpp
index 3af39035a..66c4525fa 100644
--- a/trunk/src/app/srs_app_utility.cpp
+++ b/trunk/src/app/srs_app_utility.cpp
@@ -1119,9 +1119,7 @@ void srs_api_dump_summaries(std::stringstream& ss)
                 << __SRS_JFIELD_ORG("net_send_bytes", ns_bytes) << __SRS_JFIELD_CONT
                 << __SRS_JFIELD_ORG("srs_sample_time", nrs->sample_time) << __SRS_JFIELD_CONT
                 << __SRS_JFIELD_ORG("srs_recv_bytes", nrs->rbytes) << __SRS_JFIELD_CONT
-                << __SRS_JFIELD_ORG("srs_recv_kbps", nrs->rkbps) << __SRS_JFIELD_CONT
                 << __SRS_JFIELD_ORG("srs_send_bytes", nrs->sbytes) << __SRS_JFIELD_CONT
-                << __SRS_JFIELD_ORG("srs_send_kbps", nrs->skbps) << __SRS_JFIELD_CONT
                 << __SRS_JFIELD_ORG("conn_sys", nrs->nb_conn_sys) << __SRS_JFIELD_CONT
                 << __SRS_JFIELD_ORG("conn_sys_et", nrs->nb_conn_sys_et) << __SRS_JFIELD_CONT
                 << __SRS_JFIELD_ORG("conn_sys_tw", nrs->nb_conn_sys_tw) << __SRS_JFIELD_CONT