Re: [mpls] On Up and Down MEP in MPLS-TP (RE: 2nd working group last call ondraft-ietf-mpls-tp-mip-mep-map)

["Shahram Davari" <[e-mail]>]

Greg,

RFC6371 is very high level and does not define whether UP MEP applies to LSP or PW.  Assume there are 2 ingress interfaces A & B. Each interface maps Ethernet traffic to its own PW (PW-A and PW-B). Now assume both these PWs go inside the same LSP that exists Interface C. Now please explain if we were to have an UP-MEP for LSP then on which interface would that LSP UP-MEP reside? Interface A? B? C?

This simple example shows you can't have an LSP UP-MEP.

Thx
SD

From: Gregory Mirsky [mailto:[e-mail]]
Sent: Tuesday, March 12, 2013 11:56 AM
To: Shahram Davari; [e-mail]
Cc: [e-mail]; [e-mail]; [e-mail]; [e-mail]
Subject: On Up and Down MEP in MPLS-TP (RE: [mpls] 2nd working group last call ondraft-ietf-mpls-tp-mip-mep-map)

Dear All,
What would be the most appropriate subject to continue this discussion? I'll give it a try, please feel free to change it.

I think that there's nothing that can preclude from supporting UP MEP on MPLS-TP LSP, according to UP MEP definition of RFC 6371, even when multpiple PWs mapped to that LSP. Same, I think, is the true for  p2mp PW. Note that service, VPWS, is not part of MPLS-TP architecture.

        Regards,
                Greg

-----Original Message-----
From: [e-mail]<mailto:[e-mail]> [mailto:[e-mail]] On Behalf Of Shahram Davari
Sent: Tuesday, March 12, 2013 11:30 AM
To: [e-mail]<mailto:[e-mail]>
Cc: [e-mail]<mailto:[e-mail]>; [e-mail]<mailto:[e-mail]>; [e-mail]<mailto:[e-mail]>; [e-mail]<mailto:[e-mail]>
Subject: Re: [mpls] 2nd working group last call ondraft-ietf-mpls-tp-mip-mep-map

Hideki,

So far no RFC or draft has talked about Down or UP MEP for LSPs. But if you think about it logically LSPs can't have UP-MEP because LSP can carry many PWs and each PW may enter the LSP from a different port/interface.  PWs can have UP-MEP but only for P2P services (VPWS), otherwise they can't have UP-MEP either (same as LSP).

My suggestion is to correct figures and change UP-MEPs to Down-MEPs for LSPs. Also to mention UP-MEP is out of scope.

Thx
SD

-----Original Message-----
From: [e-mail]<mailto:[e-mail]> [mailto:[e-mail]]
Sent: Tuesday, March 12, 2013 11:20 AM
To: Shahram Davari
Cc: [e-mail]<mailto:[e-mail]>; [e-mail]<mailto:[e-mail]>; [e-mail]<mailto:[e-mail]>; [e-mail]<mailto:[e-mail]>; [e-mail]<mailto:[e-mail]>
Subject: Re:Re: [mpls] 2nd working group last call ondraft-ietf-mpls-tp-mip-mep-map

Hi Shahram,

Just one comment.

>I would also argue that LSPs can't have UP-MEPs, since PWs from many ingress ports can enter an LSP  and therefore the LSP can't start on the ingress interface.

I think this depends on implementations.
Any RFC don't restrict to DOWN-MEPs in an LSP.

Anyway, MEP mechanism is out of scope in this draft as you said.

Thanks,
Hideki Endo

>Hi,
>
>Although I mentioned I am Ok with the draft to be advanced to RFC, but after reviewing it in more details it appears that the draft, in spite of its name, does talk about UP-MEP at all and only talks about UP-MIP, while the figures show UP-MEPs for LSPs.  Even if the scope of the draft is UP-MIP, considering that there can't be a MIP without a MEP,  the draft should have some wording regarding UP-MEPs and their applicability to LSPs and PWs. I would also argue that LSPs can't have UP-MEPs, since PWs from many ingress ports can enter an LSP  and therefore the LSP can't start on the ingress interface.
>
>A quick fix at this point is to mention UP-MEP is out of scope and change the figures to only show Down-MEPs. A better fix is to elaborate on UP-MEP and its applicability and placement, etc.
>
>Regards,
>Shahram
>
>
>
>-----Original Message-----
>From: [e-mail]<mailto:[e-mail]> [mailto:[e-mail]] On Behalf Of
>Shahram Davari
>Sent: Wednesday, March 06, 2013 11:30 AM
>To: Loa Andersson; [e-mail]<mailto:[e-mail]>
>Cc: <[e-mail]<mailto:[e-mail]>>; [e-mail]<mailto:[e-mail]>;
>[e-mail]<mailto:[e-mail]>
>Subject: Re: [mpls] 2nd working group last call on
>draft-ietf-mpls-tp-mip-mep-map
>
>My Comments are addressed and I support this draft to be published as Informational  RFC.
>
>Thx
>Shahram
>
>-----Original Message-----
>From: [e-mail]<mailto:[e-mail]> [mailto:[e-mail]] On Behalf Of
>Loa Andersson
>Sent: Tuesday, February 26, 2013 3:02 AM
>To: [e-mail]<mailto:[e-mail]>
>Cc: <[e-mail]<mailto:[e-mail]>>; [e-mail]<mailto:[e-mail]>;
>[e-mail]<mailto:[e-mail]>
>Subject: [mpls] 2nd working group last call on
>draft-ietf-mpls-tp-mip-mep-map
>
>Working Group,
>
>draft-ietf-mpls-tp-mip-mep-map-05.txt has been updated after a previous
>last call, due to the nature a and extent of the updates we have chosen
>to start a 2nd wg last call.
>
>The IETF datatracker status page for this draft is:
>https://datatracker.ietf.org/doc/draft-ietf-mpls-tp-mip-mep-map
>
>There's also a htmlized version available at:
>http://tools.ietf.org/html/draft-ietf-mpls-tp-mip-mep-map-05
>
>A diff from the previous version is available at:
>http://www.ietf.org/rfcdiff?url2=draft-ietf-mpls-tp-mip-mep-map-05
>
>Please send your comments, including approval of the documents and the
>updates to the mpls working group list ([e-mail]<mailto:[e-mail]>)
>
>This working group last call ends March 13, 2013.
>
>/Loa
>for the MPLS working group co-chairs
>--
>
>
>Loa Andersson                        email: [e-mail]<mailto:[e-mail]>
>Senior MPLS Expert                          [e-mail]<mailto:[e-mail]>
>Huawei Technologies (consult)        phone: [phone]
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