Subject: [Mpls-interop] comment on framework documents

From: Lou Berger <[email-masked]>
Date: Tue, 18 Nov 2008 14:48:40 -0600

So this is a comment that spans:
    draft-blb-mpls-tp-framework-01
    draft-busi-mpls-tp-oam-framework-00
    draft-sprecher-mpls-tp-survive-fwk-00.txt

and is directed to all the authors of those documents (and whoever 
else feels like responding.)

Item 1: Hierarchy required to support LSP Tandem Connection monitoring

As I read the requirements, the monitoring of an LSP segment (a.k.a, 
MPLS-TP LSP Tandem Connection)	requires the establishment of MEPs at 
the end-points of the LSP segment.  This in turn requires the use of 
an additional label between the MEPs, i.e., LSP hierarchy.

I believe this is a correct description of the data plane impact of 
LSP segment/Tandem Connection monitoring.  Does anyone disagree?

* Presuming I didn't get it wrong, I think the use of hierarchy in 
support of monitoring needs to be reflected in the MPLS-TP and OAM 
framework documents. *

Item 2: Hierarchy required on protected LSP tandem connection

The requirements (req#46)state that OAM must be used (and not control 
plane) to signal protection, and that recovery reference points are 
defined at the same location as the OAM MEPs.

When combined with item 1, this means that hierarchy must be used on 
the *working* path of a protected LSP segment.  Does anyone disagree?

* Presuming I didn't get it wrong, I think the use of hierarchy **on 
the working path*** in support of monitoring needs to be reflected in 
the MPLS-TP Survivability document. *

Any comments or objections?

Thanks,
Lou

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From: "BUSI ITALO" <[email-masked]>
Date: Tue, 18 Nov 2008 21:48:59 +0100

Lou,

Thanks for commenting. I almost agree with you.

See my comments in line marked with [ib]

Italo 

> -----Original Message-----
> From: [email-masked] 
> [mailto:[email-masked]] On Behalf Of Lou Berger
> Sent: Tuesday, November 18, 2008 2:49 PM
> To: MEAD team
> Subject: [Mpls-interop] comment on framework documents
> 

[ib] I agree. I think that we just need to clarify that there is a 1:1
relationship between the two LSPs.

> support of monitoring needs to be reflected in the MPLS-TP and OAM 

[ib] We have some description about that in the OAM framework and an
open issue about whether this solution construct needs to be described
within the OAM framework.
I understand you think it should.
Do you think we need to spell this out more explicitly?

> the *working* path of a protected LSP segment.  Does anyone disagree?

[ib] I agree. I think this is required also for the *protection* LSP
segment.

> the MPLS-TP Survivability document. *

[ib] I agree that the survivability framework should reflect this.

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From: George Swallow <[email-masked]>
Date: Tue, 18 Nov 2008 15:54:09 -0500

Italo -

Why do you limit this to 1:1?  Certainly 1:1 is permitted, but why not N:1
as well?

...George

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From: Lou Berger <[email-masked]>
Date: Tue, 18 Nov 2008 16:41:56 -0600

Italo,
         See responses below.

>relationship between the two LSPs.

I agree with George, why not n:1.

>Do you think we need to spell this out more explicitly?

The reason that I think it needs to be spelled out in the framework 
is the data plane impact.  To me this makes it a fundamental part of 
mpls-tp and therefore warrants being mentioned at the framework level.

>[ib] I agree. I think this is required also for the *protection* LSP

true. I assumed this was a given, but it's worth being equally explicit.

>[ib] I agree that the survivability framework should reflect this.

Much thanks.

Lou

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From: "Sprecher, Nurit (NSN - IL/Hod HaSharon)" <[email-masked]>
Date: Wed, 19 Nov 2008 03:46:36 +0100

George,
I think you meant to 1:n, one TC for N LSPs isn't it?
Best regards,
Nurit

-----Original Message-----
From: [email-masked]
[mailto:[email-masked]] On Behalf Of ext George Swallow
Sent: Tuesday, November 18, 2008 22:54
To: BUSI ITALO; Lou Berger; MEAD team
Subject: Re: [Mpls-interop] comment on framework documents

Italo -

Why do you limit this to 1:1?  Certainly 1:1 is permitted, but why not
N:1
as well?

...George