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

["Zhenlong Cui" <[e-mail]>]

Hi Shahram,

   Give you an example....

   OAM must operate on MPLS-TP nodes that are branch points on point-to-
   multipoint (P2MP) trees include ring topology. That means that the branch
   points must be possible to drop & continue the received OAM frame.
   
   If the Down-MEP is configured at ingress i/f(LSP Terminal Point) as shown 
   below figure, then the received OAM frame will be blocked by ingress i/f 
   and can't transmit to downstream link.
   
   I think it is a problem.

                         --------------------------
                        |                     -----|
                        |                    | N/A |
                        |                 ->-|     |->-------------LSP (Downstream link)
                        |                |   | Out |
                        |                |   | i/f |
                        |                |    -----|
                        |-----           |    -----|
                        | MEP |    ----  |   | N/A |
                        |     |   |    |-    |     |
              LSP----->-| In  |->-| FW |--->-| Out |->----UNI
                        | i/f |   |    |-    | i/f |
                        |-----     ----  |    -----|
                        |                |    -----|
                        |                |   | N/A |
                        |                |   |     |
                        |                 ->-| Out |->----UNI
                        |                    | i/f |
                        |                     -----|
                         --------------------------

Best regards,
Zhenlong

> -----Original Message-----
> From: Shahram Davari [mailto:[e-mail]]
> Sent: Thursday, March 14, 2013 3:53 AM
> To: Zhenlong Cui; 'Gregory Mirsky'; [e-mail]
> Cc: [e-mail]; [e-mail]; [e-mail]; [e-mail]
> Subject: RE: [mpls] On Up and Down MEP in MPLS-TP (RE: 2nd working group last call ondraft-ietf-mpls-tp-mip-mep-map)
> 
> Hi,
> 
> I don't really understand what you are trying to say. Can you provide an example.
> 
> Thx
> SD
> 
> -----Original Message-----
> From: Zhenlong Cui [mailto:[e-mail]]
> Sent: Wednesday, March 13, 2013 11:45 AM
> To: 'Gregory Mirsky'; Shahram Davari; [e-mail]
> Cc: [e-mail]; [e-mail]; [e-mail]; [e-mail]
> Subject: RE: [mpls] On Up and Down MEP in MPLS-TP (RE: 2nd working group last call ondraft-ietf-mpls-tp-mip-mep-map)
> 
> Hi Shahram,
> 
> Some, at least in case of ring topology, the LSP UP-MEP is a necessity.
> 
> As you know, a intermediate node on a ring network have to supports Swap & POP processing.
> There are some OAM models should be taken into consideration for intermediate node, as follows:
> 
> (1) Set Down-MEP only
>  If we support the down-mep only and set down-mep at Down I/F(swap point), OAM will not be transmitted to downstream node.
> 
> (2) Set Down-MIP and UP-MIP
>  For support the LSP Protection at the intermediate node, the MEP must be set at the POP Point.
> 
>  Note:
>   MPLS-TP recovery in a ring must protect unidirectional P2MP transport paths as specified in RFC 5654.
> 
> (3) Set Down-MIP and UP-MEP
>  This model can solve above model's issues.
> 
> 
> Best regards,
> zhenlong
> 
> 
> ________________________________________
> From: [e-mail] [mailto:[e-mail]] On Behalf Of Gregory Mirsky
> Sent: Wednesday, March 13, 2013 3:56 AM
> To: Shahram Davari; [e-mail]
> Cc: [e-mail]; [e-mail]; [e-mail]; [e-mail]
> Subject: [mpls] On Up and Down MEP in MPLS-TP (RE: 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]] On Behalf Of Shahram Davari
> Sent: Tuesday, March 12, 2013 11:30 AM
> To: [e-mail]
> Cc: [e-mail]; [e-mail]; [e-mail]; [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]]
> Sent: Tuesday, March 12, 2013 11:20 AM
> To: Shahram Davari
> Cc: [e-mail]; [e-mail]; [e-mail]; [e-mail];
> [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]] On Behalf Of
> >Shahram Davari
> >Sent: Wednesday, March 06, 2013 11:30 AM
> >To: Loa Andersson; [e-mail]
> >Cc: <[e-mail]>; [e-mail];
> >[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]] On Behalf Of
> >Loa Andersson
> >Sent: Tuesday, February 26, 2013 3:02 AM
> >To: [e-mail]
> >Cc: <[e-mail]>; [e-mail];
> >[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])
> >
> >This working group last call ends March 13, 2013.
> >
> >/Loa
> >for the MPLS working group co-chairs
> >--
> >
> >
> >Loa Andersson                        email: [e-mail]
> >Senior MPLS Expert                          [e-mail]
> >Huawei Technologies (consult)        phone: [phone]
> >_______________________________________________
> >mpls mailing list
> >[e-mail]
> >https://www.ietf.org/mailman/listinfo/mpls
> >
> >
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> >
> >
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> 
> 
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