ATM routers

Unanswered Question
Jun 8th, 2007

Hi all, can anyone tell me why people would have a wan link from there site that uses ATM? and what are the benifits ?

I have this problem too.
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mohammedmahmoud Fri, 06/08/2007 - 03:34


Access links to CE routers, or WAN links was delivered formerly via Leased lines which was very expensive. Further on circuit switching or packet switching methods was massively used in a variety of flavors, mainly FR, X.25, ATM, Ethernet and PPP.

ATM, is similar to packet switching, but uses fixed length cells (53Bytes - 48 bytes of data and 5 bytes of header information) instead of variable length packets. Data is divided into fixed-length cells and then transported across virtual circuits, which is best for simultaneous use of Voice and data, its main drawback is that overhead can be considerable, but one of its main advantages is that it supports high speeds (ATM provides data link layer services that run over SONET (Synchronous Optical Networking) Layer 1 links - Fiber links), where you can have up to OC-192 (STM64)rates.

On slow links (2 Mbit/s and below). ATM still makes sense, and this is why so many ADSL systems use ATM as an intermediate layer between the physical link layer and a Layer 2 protocol like PPP or Ethernet.

Please do check this link for more general details:

I hope that i've been informative.

HTH, please do rate all helpful replies,

Mohammed Mahmoud.


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