[sgrossman]

If you are on a system that doesn't have tshark, tcpdump provides the same functionality via the -C <file_size_in_MB> -W <num_files> flags.

e.g. -C 100 -W 200 -w somefile will get you the same circular ring of 200 100MB files.

Also, don't forget to add the -s 0 flag if you want to get the entire payload.