diff --git a/runtest.sh b/runtest.sh
index 7828800..d30fa21 100755
--- a/runtest.sh
+++ b/runtest.sh
@@ -61,7 +61,7 @@ run_iperf() {
   local args=("-c" "$target" "-J" "-t" "10")
 
   if [ "$mode" = "udp" ]; then
-    args+=("-u")
+    args+=("-u" "-b" "$BANDWIDTH")
   fi
 
   if [ "$direction" = "down" ]; then
diff --git a/settings.env.default b/settings.env.default
index 23a3e5f..45cfae0 100644
--- a/settings.env.default
+++ b/settings.env.default
@@ -13,6 +13,7 @@ LEAD_TIME=90s
 INTERFACE=wlan0
 PING_COUNT=25
 PING_TARGET=1.1.1.1
+BANDWIDTH=
 
 MAX_RETRIES=5
 RETRY_DELAY=10  # seconds