ATM v/s SONET

[Bharat Ranjan <bharatr () microsoft com>]

> Vendors such as Fore are starting to offer OC-3c/12/c and OC-48c (future)
> interfaces on their ATM switches. Using these interfaces, the switches can be
> connected together in a ringlike fashion. A service offered when connected in
> a ring is called Fast Failover Recovery, or something along that line. This
> service provides functionality that is identical to SONET
> protection-switching. Basically, bandwidth is reserved around the ring for
> protection scenarios. When the ATM switches detect failure (fiber cut, node
> failure, etc.), they recreate the VP around the opposite direction of the
> ring using the reserved bandwidth. This is done at the ATM level, versus the
> physical level for SONET. As expected, the switchover time is in seconds
> versus the milliseconds for SONET.
>
> For networks that carry data that is not sensitive to this increased
> switchover time, does it make sense to use SONET at all? The question comes
> down to why do you need a SONET ring when then same functionality and speed
> is provided by the ATM ring?


         mm mm   sssss  nnnnnn   * Bharat Ranjan              *
        m  m  m s       nnnnnnn  * Network Engineer           *
        m  m  m  sssss  nn   nn  * MSN Network Services       *
        m     m       s nn   nn  * (206)-936-0471             *
        m     m  sssss  nn   nn  * bharatr () microsoft com      *
        *******************************************************
        * The opinions/ideas in this memo are not necessarily *
        * those of Microsoft Corp.                            *
        *******************************************************
>
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