diff --git a/tc/q_netem.c b/tc/q_netem.c
index f8489e9..2583072 100644
--- a/tc/q_netem.c
+++ b/tc/q_netem.c
@@ -147,6 +147,8 @@
 }
 
 #define NEXT_IS_NUMBER() (NEXT_ARG_OK() && isdigit(argv[1][0]))
+#define NEXT_IS_SIGNED_NUMBER() \
+	(NEXT_ARG_OK() && (isdigit(argv[1][0]) || argv[1][0] == '-'))
 
 /* Adjust for the fact that psched_ticks aren't always usecs
    (based on kernel PSCHED_CLOCK configuration */
@@ -393,7 +395,7 @@
 				explain1("rate");
 				return -1;
 			}
-			if (NEXT_IS_NUMBER()) {
+			if (NEXT_IS_SIGNED_NUMBER()) {
 				NEXT_ARG();
 				if (get_s32(&rate.packet_overhead, *argv, 0)) {
 					explain1("rate");
@@ -407,7 +409,7 @@
 					return -1;
 				}
 			}
-			if (NEXT_IS_NUMBER()) {
+			if (NEXT_IS_SIGNED_NUMBER()) {
 				NEXT_ARG();
 				if (get_s32(&rate.cell_overhead, *argv, 0)) {
 					explain1("rate");