> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]] On Behalf Of Michael Sokolov
> Sent: Wednesday, March 18, 2009 10:56 AM
> To: [email protected]
> Subject: Re: [time-nuts] French Time offset
>
> "Lux, James P" <[email protected]> wrote:
>
> > Things get done for funny reasons: After all, the physical size of
> > France is why ATM "cells" (packets) are 53 bytes (48 byte payload)
> > instead of either 32 byte or 64 byte payloads.
>
> Huh? Can you please elaborate? I thought the 48 octets of
> payload were a compromise between the camp that wanted 32 and
> the camp that wanted 64.
>
> MS,
> who has implemented the whole ATM/AAL5 stack in software
> (looking at cell headers and all) for SDSL.
>
53 bytes was the longest you could do and not require echo suppression for a
path across France. The US is so huge, they had already bit the bullet on
needing echo suppression, so they wanted longer packets, to reduce the header
overhead (as a percentage). There were also some "timing jitter" requirements,
and how much buffering was considered reasonable for "real time" response in
voice applications.
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