nanog mailing list archives

Re: Big Temporary Networks


From: Jay Ashworth <jra () baylink com>
Date: Sun, 16 Sep 2012 12:22:57 -0400 (EDT)

----- Original Message -----
From: "Masataka Ohta" <mohta () necom830 hpcl titech ac jp>

Jay Ashworth wrote:
You're saying that *receiving* multicast streams over WLAN works
poorly?

Multicast/broadcast over congested WLAN works poorly, because
there can be no ACK.

That is, multicast/broadcast packets lost by collisions are
never sent again.

Well, yes, but that wasn't what Bill was talking about.  He was talking about
AP's being "nice" to associated clients who are in powersave mode, at the
expensive of all the other connected clients, by buffering multicast packets
until one or more DTIM frames are sent.

We expect live streams to drop a packet here and there; that's what buffering
is for... and why television proper still exists.

Cheers,
-- jra
-- 
Jay R. Ashworth                  Baylink                       jra () baylink com
Designer                     The Things I Think                       RFC 2100
Ashworth & Associates     http://baylink.pitas.com         2000 Land Rover DII
St Petersburg FL USA               #natog                      +1 727 647 1274


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