diff --git a/plot_transmission_timeline.py b/plot_transmission_timeline.py
index 0d3f9c9..a0d7219 100755
--- a/plot_transmission_timeline.py
+++ b/plot_transmission_timeline.py
@@ -156,7 +156,7 @@ if __name__ == "__main__":
 
 
 
-    transmission_df["goodput"] = transmission_df["payload_size"].rolling("{}s".format(args.interval), step="{}s".format(args.interval)).sum()
+    transmission_df["goodput"] = transmission_df["payload_size"].rolling("{}s".format(args.interval)).sum()
     transmission_df["goodput"] = transmission_df["goodput"].apply(
         lambda x: ((x * 8) / args.interval) / 10**6
     )