diff --git a/common.h b/common.h
index 403b0e4..28c6ab7 100644
--- a/common.h
+++ b/common.h
@@ -98,7 +98,7 @@ const i32_t max_fail_time=0;//disable
 
 const u32_t heartbeat_interval=1000;
 
-const u32_t timer_interval=500;//this should be smaller than heartbeat_interval and retry interval;
+const u32_t timer_interval=400;//this should be smaller than heartbeat_interval and retry interval;
 
 //const uint32_t conv_timeout=120000; //120 second
 //const u32_t conv_timeout=120000; //for test