[Cake] zoom traffic analysis

Dave Taht dave.taht at gmail.com
Sun Apr 19 15:58:14 EDT 2020

I did take apart a bit of zoom traffic the other day, over two hops of
fq_codel'd wifi to the nudome from comcast. It does appear they put
voice and video on separate tuples, both multiplexing over port 8801.
Over roughly a 10ms interval with a redundant packet.

Or: it could be rtsp information or some other sort of control traffic.

no diffserv markings are used.

either way, our fq is going to kick in here, and that's interesting.
It's also really remarkable how low bandwidth videoconferencing is and
how good the framerate is, nowadays. even the video flows are really
well paced out. (note that they "should" be for stuff coming from the
internal, and *might* be from stuff coming from them due to the
sideffects of using fq_codel on inbound shaping)

cap here: http://flent-fremont.bufferbloat.net/~d/zoom2.cap

I do miss the days where traffic like this wasn't so encrypted!

Make Music, Not War

Dave Täht
CTO, TekLibre, LLC
Tel: 1-831-435-0729

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