ATM v/s SONET

Wed Oct 2 23:19:32 UTC 1996

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>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 at microsoft.com      *
	*******************************************************
	* The opinions/ideas in this memo are not necessarily *
	* those of Microsoft Corp.                            *
	*******************************************************
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