Re: Coincidence...

[Koen De Vleeschauwer <koen () EU net>]

> At 02:48 PM 07-05-97 -0700, Michael Dillon wrote:
> > I though that ATM cell sizes were so small in order to better support
> > real-time voice and video. 
>
> The original ATM compromise was designed to avoid screwing up echo
> cancellation on the last mile loops which is very sensitive to delay and
> hard to adjust since it is old fashioned analog hardware and not digital.
> That is one of the more difficult aspects of the new xDSL technology is
> dealing with echo cancellation and crosstalk in those crummy old two-wire
> circuits.
Part of the story. US, Japanese and European telco manufacturers had different
perceptions of 'optimal' atm cell size. Depending upon the mix voice/video/data
different results were obtained; believe 32 and 64 byte were mentioned.
The powers that be decided upon a compromise and chose a value 'in the middle'
causing everyone to redesign their equipment. The compromise value was not a 
power of two. Must have been '89 or thereabouts.

regards,

Koen

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