There is no tool to produce throughput graphs from capture files. Yes, there’s always Ethereal, but even that can only display the graphs, but it can’t export the data to be plotted by some other program. tcptrace of course can produce graphs, but … well, it produces them in an - attention, please - xplot data file. That data format just sucks, cannot be read by anything but this stupid xplot, and those bloody xplot programs simply don’t work. I actually fixed a bug in the Java xplot version with locale settings (last updated somewhat 2001), but big plot files are simply not plotted - the program hangs then. That the default output format is white on black and that it is - of course - not scriptable is not really worth mentioning, is it?
And because I need throughput graphs I wrote my own tool. extsniff is available now, and produces nice gnuplot style data files from pcap files. Compiles under Windows and Linux, and just does the fucking job.
I am actually tempted to extend extsniff to produce TCP RTT (round trip time) graphs, too … but, well, that’s too time-consuming right now.