Re: [mpls] Updated drafts - draft-kini-mpls-ring-frr-facility-backup, draft-kini-mpls-fast-lsp-alert

hi,Autumn
here I only ask a question for this E-FRR solution.
for example as the following:
   +-------L1--------L2---------L3--------L4-------+
    |                                                      |
 L10                                                  L5
  |                                                      |
 +-------L9--------L8---------L7--------L6-------+
we suppose there are two working LSP , One LSP: L10-L9-L8-L7-L6,
another LSP: L10-L1-L2-L3-L4.
now if the failure happened between L8 and L7. according to your solution.
L8 and L7 would send fast alert message to each node of bypass Tunnel
: L8-L9-L10-L1-L2-L3-L4-L5-L6-L7;
when node L10 received fast alert message from L8 or L7, for working LSP:
L10-L9-L8-L7-L6, will swich into e-backup tunnel: L10-L1-L2-L3-L4-L5-L6;
while for another LSP: L10-L1-L2-L3-L4 , how  do it know the failure don't 

affect the working LSP and can't need to switch into e-backup tunnel?
whether there is include LSP ID information which will be affected by 
the failure in the fast alert message packet? or the solution will adapt
new method to judge which LSP will be affected by the failure?

maybe my understanding be wrong?

best regards
liu

Autumn Liu <autumn.liu@ericsson.com> 
发件人:  mpls-bounces@ietf.org
2010-07-28 06:35

收件人
Greg Mirsky <gregimirsky@gmail.com>, Julien Meuric 
<julien.meuric@orange-ftgroup.com>
抄送
"mpls@ietf.org" <mpls@ietf.org>
主题
Re: [mpls] Updated drafts       - 
draft-kini-mpls-ring-frr-facility-backup, draft-kini-mpls-fast-lsp-alert

Hi Greg and Julien 

Thanks for pointing this out. The draft can be applied to the case when 
segment protection is utilized as defined in 4873. We will update the 
draft accordingly.

Regards,
Autumn

From: mpls-bounces@ietf.org [mailto:mpls-bounces@ietf.org] On Behalf Of 
Greg Mirsky
Sent: Monday, July 26, 2010 1:37 PM
To: Autumn Liu
Cc: mpls@ietf.org
Subject: Re: [mpls] Updated drafts - 
draft-kini-mpls-ring-frr-facility-backup, draft-kini-mpls-fast-lsp-alert

Dear Autumn,
thank you for adding specific case to our discussion. In my view 
protecting segment L10-L1-L2-L3-L4-L5 (e-backup tunnel) is shared by all 
backup tunnels that traverse the ring through nodes L10-L9-L8-L7-L6-L5. 
This e-backup tunnel is the e-backup tunnels for all working 
sections/segments (in case of link and node protection) of an LSP 
L10-...-L8-..-L5. I'd re-state my question to authors whether they've 
considered re-using RSVP-TE objects and subobjects defined in RFC 4873. If 
mechanisms and objects defined in RFC 4873 not sufficient, why RFC 4873 
not referenced in the draft Efficient Facility Backup FRR.

Regards,
Greg

On Mon, Jul 26, 2010 at 12:16 PM, Autumn Liu <autumn.liu@ericsson.com> 
wrote:
Hi Greg,

 +-------L1--------L2---------L3--------L4-------+
  |                                                      |
 L10                                                  L5
  |                                                      |
 +-------L9--------L8---------L7--------L6-------+

Not all PLRs. Using the diagram in draft as an example.
Bypass 1 (to protect link between L8 and L7) : 
L8-L9-L10-L1-L2-L3-L4-L5-L6-L7 
Bypass 2 (to protect node failure on L8) : L9-L10-L1-L2-L3-L4-L5-L6-L7

e-backup tunnel L10-L1-L2-L3-L4-L5 can be used instead for both cases 
without getting traffic u-turned.

Regards,
Autumn

From: Greg Mirsky [mailto:gregimirsky@gmail.com] 
Sent: Monday, July 26, 2010 12:03 PM
To: Autumn Liu
Cc: Julien Meuric; Sriganesh Kini; mpls@ietf.org 

Subject: Re: [mpls] Updated drafts - 
draft-kini-mpls-ring-frr-facility-backup, draft-kini-mpls-fast-lsp-alert

Dear Autumn,
I'm quite surprised to read your reply to Julien. My understanding of your 
proposal is that all PLRs share the same u-PLR for given ring segment of 
LSP. Please correct me if my understanding is different from authors 
intention.
I'd like to add to Julien's comment that RFC 4873 seems relevant to your 
solution as well as RFC 4872. And I'd ask the same question as Julien in 
regard to not referencing RFC 4873.

Regards,
Greg

On Mon, Jul 26, 2010 at 11:30 AM, Autumn Liu <autumn.liu@ericsson.com> 
wrote:
Hi Julien,

draft-kini-mpls-ring-frr-facility-backup describes a mechanism to let the 
primary LSP be aware of what the bypass LSP for corresponding protected 
facility. If my understanding is correct, the association mechanism 
defined in 4872 is used to associate the primary and backup LSPs. This is 
not good enough for the problem the draft is trying to address since each 
link/node along the primary LSP may have different bypass LSPs.

Regards,
Autumn

-----Original Message-----
From: mpls-bounces@ietf.org [mailto:mpls-bounces@ietf.org] On Behalf Of 
Julien Meuric
Sent: Monday, July 26, 2010 10:40 AM
To: Sriganesh Kini
Cc: mpls@ietf.org
Subject: Re: [mpls] Updated drafts - 
draft-kini-mpls-ring-frr-facility-backup, draft-kini-mpls-fast-lsp-alert

Hi Sriganesh.

The mechanism described in draft-kini-mpls-ring-frr-facility-backup
reminds me of end to end recovery (or more specifically end to end 
protection), as enabled by RFC 4872. That is all the more similar because 
the association mechanism is already defined in there, with a dedicated 
RSVP-TE object. RFC 4872 is Standard Track: is there any rational for not 
considering it?

Regards,

Julien

Le 26/07/2010 18:59, Sriganesh Kini a écrit :
> FYI - These updated version of these drafts were presented today at
> IETF78.
> http://tools.ietf.org/html/draft-kini-mpls-ring-frr-facility-backup-01
> http://tools.ietf.org/html/draft-kini-mpls-fast-lsp-alert-01
> Thanks
>
> - Sri
>
>
> _______________________________________________
> mpls mailing list
> mpls@ietf.org
> https://www.ietf.org/mailman/listinfo/mpls
>
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