Subject: Re: [mpls] Last Call on BCP on ECMP

From: George Swallow <[email-masked]>
Date: Wed, 02 Mar 2005 19:27:26 -0500

Alia -

Thanks for the comments:

> If this is really to be a BCP describing how ECMP and MPLS interact,
> then I'd really like to see a very short section describing the
> possibility that packets may be load-balanced based on the label stack
> as well.

Good addition!  Will do.

> At the time of the OAM label discussion, it was suggested that future
> implementations shouldn't include the reserved labels in any
> processing of the label stack done for load balancing.   Perhaps we
> don't want to capture that here - the idea seemed a bit sensitive at
> the time - though I'd be in favor of it.

The C in BCP is for current.  As this is a future suggestion, and a can
of worms to boot, I think I'll pass.

...George

========================================================================
George Swallow             Cisco Systems                  (978) 936-1398
                           1414 Massachusetts Avenue
                           Boxborough, MA 01719

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From: Alia Atlas <[email-masked]>
Date: Wed, 02 Mar 2005 19:58:18 -0500

George,

>of worms to boot, I think I'll pass.

I agree that it is a can of worms and I'm not advocating making it a should 
or implying that it is generally a current behavior.  At the same time, I'd 
prefer not to lose knowledge of the issue.

Perhaps something simple for a hint such as:
"The processing of the label stack for load balancing may include all MPLS 
labels, including those that are reserved; in such a case, the addition of 
a reserved label, such as the OAM label, may result in a different path 
being taken."

That provides the hint both that most current hardware includes the 
reserved labels and that if it didn't, then OAM might be easier.

What do you think?

Alia

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From: George Swallow <[email-masked]>
Date: Wed, 02 Mar 2005 20:07:59 -0500

> "The processing of the label stack for load balancing may include all
> MPLS labels, including those that are reserved; in such a case, the
> addition of a reserved label, such as the OAM label, may result in a
> different path being taken."

I'll probably word-smith it a bit, but I'm happy to capture the thought.

...George

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From: "Thomas D. Nadeau" <[email-masked]>
Date: Thu, 3 Mar 2005 07:55:53 -0500

> of worms to boot, I think I'll pass.

	I agree. That is something that could have gone into the
OAM requirements draft; this document IMHO is for current
stuff.

	--Tom

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From: Alia Atlas <[email-masked]>
Date: Thu, 03 Mar 2005 08:59:30 -0500

>I'll probably word-smith it a bit, but I'm happy to capture the thought.

Immortal prose it's not :-)
Sounds good.

thanks,
Alia

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From: Alia Atlas <[email-masked]>
Date: Thu, 03 Mar 2005 10:09:27 -0500

We may want another or a different example of a reserved label (such as the 
Router Alert or even Explicit Null)

Alia