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 ======= ___ === Koen De Vleeschauwer, Network Engineer, ====== / / / ___ ____ _/_ ==== EUnet Communications Services BV ===== /--- / / / / /___/ / ===== Singel 540, 1017 AZ Amsterdam, NL ==== /___ /___/ / / /___ /_ ====== Tel. +31 20 5305333; Fax. +31 20 6224657 === ======= [ 24hr emergency number +31 20 4210865 ]