Bugfix, plot ack_rtt

plot_transmission_timeline.py

         lambda x: ((x * 8) / args.interval) / 10**6
     )
 
-    # remove all not needed columns
+    # set meta values and remove all not needed columns
+    cc_algo = transmission_df["congestion_control"].iloc[0]
+    cc_algo = cc_algo.upper()
+    transmission_direction = transmission_df["direction"].iloc[0]
+
     transmission_df = transmission_df.filter(["goodput", "datetime", "ack_rtt"])
 
     # read serial csv
         left_index=True,
     )
 
-    cc_algo = transmission_df["congestion_control"].iloc[0]
-    cc_algo = cc_algo.upper()
-
-    transmission_direction = transmission_df["direction"].iloc[0]
-
     # transmission timeline
 
     scaley = 1.5