Any program that calculates the throughput from the output of tcpdump?

I am currently using tcptrace but am observing some 开发者_开发知识库ridiculous throughputs on a test that I'm running. I am pretty sure something is wrong with the way I am testing but before spending any more time is there any other program I can use to verify this?

EDIT: This is for a router simulator that I am running locally on my system that generates a tcpdump output.

You can use ttcp to measure the TCP performance between two systems.