diff --git a/a8/tcplistener.h b/a8/tcplistener.h
index 10a3697..85bbc16 100644
--- a/a8/tcplistener.h
+++ b/a8/tcplistener.h
@@ -35,12 +35,13 @@ namespace a8
         void Close();
         bool IsActive();
         template <typename T>
-        void RegisterSessionClass()
+        void RegisterSessionClass(int max_packet_len)
         {
             on_create_client_socket_ =
-                [] (a8::TcpSession** p)
+                [max_packet_len] (a8::TcpSession** p)
                 {
                     *p = new T;
+                    (*p)->SetMaxPacketLen(max_packet_len);
                 };
         }
         bool SendClientMsg(unsigned short sockhandle, const char *buff, int buffLen);