diff --git a/tc/tc_core.c b/tc/tc_core.c
index fb898766..8c3a2acc 100644
--- a/tc/tc_core.c
+++ b/tc/tc_core.c
@@ -45,12 +45,12 @@ unsigned tc_core_tick2time(unsigned tick)
 	return tick/tick_in_usec;
 }
 
-long tc_core_time2ktime(long time)
+unsigned tc_core_time2ktime(unsigned time)
 {
 	return time * clock_factor;
 }
 
-long tc_core_ktime2time(long ktime)
+unsigned tc_core_ktime2time(unsigned ktime)
 {
 	return ktime / clock_factor;
 }
diff --git a/tc/tc_core.h b/tc/tc_core.h
index b2a16bc3..b1ede1ed 100644
--- a/tc/tc_core.h
+++ b/tc/tc_core.h
@@ -9,8 +9,8 @@
 int  tc_core_time2big(long time);
 unsigned tc_core_time2tick(unsigned time);
 unsigned tc_core_tick2time(unsigned tick);
-long tc_core_time2ktime(long time);
-long tc_core_ktime2time(long ktime);
+unsigned tc_core_time2ktime(unsigned time);
+unsigned tc_core_ktime2time(unsigned ktime);
 unsigned tc_calc_xmittime(unsigned rate, unsigned size);
 unsigned tc_calc_xmitsize(unsigned rate, unsigned ticks);
 int tc_calc_rtable(unsigned bps, __u32 *rtab, int cell_log, unsigned mtu, unsigned mpu);