On 13 June 2011 18:32, Sprecher, = Nurit (NSN - IL/Hod HaSharon) <nurit.sprecher@nsn.com> wrote:

Hi,

I would like = to second Sasha.

End-t= o-end PW protection (with diverse paths) does not scale, and put hard restr= ictions on the utilization of the resources. =A0

MPLS-TP PWs are carried acro= ss the network inside MPLS-TP LSPs. Therefore, an obvious way to provide pr= otection for a PW is to protect the LSP that carries it.=A0

If the PW is a multi-segment= PW, then LSP recovery can only protect the PW in individual segments.=A0 T= his means that a single LSP recovery action cannot protect against a failur= e of a PW switching point (an S-PE).

When = protecting against an AC or T/S-PE failure by dual connectivity, PW redunda= ncy mechanisms provide means for the PEs to coordinate over which LSP the t= raffic of the PW is carried.

I als= o doubt why there is a need for additional mechanism.

Best regards,=

Nurit=

=A0

From:= pwe3-bounces@ietf.org [mailto:pwe3-bounces@ietf.org] On Behalf= Of ext Alexander Vainshtein
Sent: Monday, June 13, 2011 3:43 PM
To: ma.yuxia@zte.com.cn
Cc: mpls@ietf.org; pwe3@ietf.org
Subject: Re: [PWE3] [mpls] Seeking feedback on I-D "MPLS-TP Lin= earProtection Applicability to MS-PW"

=A0

Dear Ma and all,

Addin= g the PWE3 WG to my response.

=A0

The PW redundancy mechanism su= pports linear protection of MS-PWs as one of many additional application us= e cases:

Appen= dix A of the PW redundancy Bit draft describes 5 application uses cases in addition to MS-PW with single-homed= CEs (which is listed there as use case 5).

And i= t is equally applicable to IP/MPLS and MPLS - with the help of =A0the Static PW Status Messages draft( if, f= or whatever reason, you do not want =A0to, or cannot, use RFC = 4447).

=A0
Hence I doubt the need for yet another PW redundancy =A0mechanism with = narrow scope of applicability.

=A0
Regards,
=A0=A0=A0=A0 Sasha

=A0

From:= mpls-bounces@ietf.org [mailto:mpls-bounces@ietf.org] On Behalf= Of ma.yuxia@z= te.com.cn
Sent: Monday, June 13, 2011 3:25 PM
To: mpls@ietf.org
Subject: Re: [= mpls] Seeking feedback on I-D "MPLS-TP Linear Protection Applicability= to MS-PW"

=A0
Hi all,

The linear protection mechanism for LSP and PW(including MS-PW) should be the same and= it is valuable to describe it clearly.

BTW, there is a typo, it is "T-PE= Z" instead of "T-PE B". <= /span>

=A0"
=A0 Figure 1 illustrates such a scenario, where two MS-PWs are
=A0 established between T-PE A and T-PE B, over S-PEs 1-2 and 3-4
=A0 respectively. Each PW segment is established over an LSP (e.g. PW-
=A0 s12 over LSP12).
=A0"
-----Original Message-----
From: Daniel Cohn
Sent: Tuesday, May 17, 2011 4:14 PM
To: mpls
Su= bject: Seeking feedback on I-D "MPLS-TP Linear Protection
Applicabi= lity to MS-PW"
Importance: High

Hi MPLSers,

I uploade= d "MPLS-TP Linear Protection Applicability to MS-PW" I-D
(http://tools.ietf.org/html/draft-cohn-mpls-tp-pw-protect= ion-00)

The abstract goes:

One of the requirements of the = MPLS transport profile [RFC 5654] is
to provide linear protection for tr= ansport paths, which include both
LSPs and PWs. The functional architect= ure described in [SurvivFwk]
is applicable to both LSP and PWs, however [LinearProt] does not
explici= tly describe mechanisms for PW protection in MPLS-TP.

This document extends the applicability of the linear protection
mechani= sm described in [LinearProt] to MPLS-TP segmented PWs
(MS-PWs) as defin= ed in [RFC 6073].

Could you please review it and send feedback to th= e mailing list or
directly to the author?

Looking forward to your feedback,

D= aniel
This e-mail message is intended for the recipient= only and contains information which is CONFIDENTIAL and which may be propr= ietary to ECI Telecom. If you have received this transmission in error, ple= ase inform us by e-mail, phone or fax, and then delete the original and all= copies thereof.

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