diff --git a/Demo/Common/ethernet/FreeTCPIP/net/clock-arch.h b/Demo/Common/ethernet/FreeTCPIP/net/clock-arch.h
index cde657b62..73d32e20a 100644
--- a/Demo/Common/ethernet/FreeTCPIP/net/clock-arch.h
+++ b/Demo/Common/ethernet/FreeTCPIP/net/clock-arch.h
@@ -36,7 +36,7 @@
 
 #include "FreeRTOS.h"
 
-typedef unsigned long clock_time_t;
+typedef portTickType clock_time_t;
 #define CLOCK_CONF_SECOND configTICK_RATE_HZ
 
 #endif /* __CLOCK_ARCH_H__ */