[c-nsp] BLSR protection on long-haul OC-192 links

[Andrew Gallo]

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On 3/22/2010 2:54 PM, Bit Bucket wrote:
> I'm putting together a regional four-node SONET network that will have two
> long-haul OC-192 fiber links. To provide path diversity, one leg will be
> about 450 miles longer than the other. Termination gear will be Cisco
> ONS-15454s and we will be running GigE circuits (protected) across the
> links. My concern is that with one leg being more than twice the length of
> the other, will BLSR still maintain a "hitless" transition in the event that
> one of the OC-192s fails?
> 
> I asked Cisco this question and we went through several techs before it was
> escalated to their developers, who labbed it out and said it would work.
> This is a little disconcerting, since I seriously doubt I am the first to
> ask this question. Is there anyone out there who has done this and could
> could share their experience with this type of design?
> 
> 
> Thanks -
> _______________________________________________
> cisco-nsp mailing list  cisco-nsp at puck.nether.net
> https://puck.nether.net/mailman/listinfo/cisco-nsp
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Stab in the dark here.... if we assume that latency is caused purely by
photonic delay, at 725Km, the one-way latency would be about 3.45msec,
well within SONET's targetted 50msec switch window.

My calculations:

725Km/.7c = 3.45msec

Or am I way off?  Interesting problem.  Let us know how it goes.


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