Re: [mpls] MPLS-RT review draft-shen-mpls-egress-protection-framework-06

"lizho.jin" <> Thu, 19 October 2017 15:07 UTC

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Date: Thu, 19 Oct 2017 23:05:23 +0800
From: "lizho.jin" <>
To: Yimin Shen <>
Cc: loa <>, "" <>, "'Carlos Pignataro (cpignata)'" <>, 'Eric Gray' <>, Ignas Bagdonas <>, mpls-chairs <>, "" <>
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Subject: Re: [mpls] MPLS-RT review draft-shen-mpls-egress-protection-framework-06
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Hi Yimin
Thanks for the reply. See inline below.

On 10/18/2017 00:33Yimin Shen<> wrote:
Hi, Lizhong

Thanks very much for your kind review! Please see inline for our response.

Yimin Shen
Juniper Networks

From: "lizho.jin" <>
Date: Friday, October 13, 2017 at 1:03 PM
To: loa <>, "<>
Cc: "'Carlos Pignataro (cpignata)'" <>, 'Eric Gray' <>, Ignas Bagdonas <>, mpls-chairs <>, "<>
Subject: Re: MPLS-RT review draft-shen-mpls-egress-protection-framework-06
Resent-From: <>
Resent-To: <>, Jeyananth <><><><><><>
Resent-Date: Friday, October 13, 2017 at 1:04 PM

Hi, Authors
I've been asked to do MPLS-RT review. Overall this kind of egress protection is much easy to deploy, and the mechanism is useful, and technically sound. 
It is ready to consider for WG adoption. And I still have some questions as below:
1. section 1. " example of such extension is [RSVP-EP]."
Typo? It should be RSVP-TE?

[yshen] This is supposed to refer to draft-ietf-teas-rsvp-egress-protection, which is missing in the reference section. We will add it.

2. section 5.9. The protected egress {E, P} which is called a "context ID" is actually an anycast address, right? The terminology of "anycast" used here will be much clear, but it depends on you to choose.

[yshen] The section 5.9 describes context ID strictly from reachability’s perspective. We want to avoid the word “anycast”, because a context ID should not be used in anycast. IOW, it should not be the destination address in any IP headers.

3. section 5.12. It seems bypass tunnel sharing or facility backup scenario missed in this section.

[yshen] The section 5.12 does talk about bypass sharing at the beginning. Bypass sharing is also talked about in some other sections. This framework does not use facility backup. 
[Lizhong] this section talks about the label swapping operation on PLR, and I do not see similar words for bypass tunnel sharing. I consider the bypass tunnel sharing as similar mechanism of facility backup, is that correct?

4. section 8. "On PE3, a context label 100 is assigned to the context ID, "
The label 100 should be assigned to the RSVP-TE tunnel with address of context ID, not only to the context ID, since one-to-one backup is used in this example.

[yshen] The context label is assigned to the context ID. If any RSVP tunnel is destined to the context ID, yes, it will automatically get bound to the context label as well.  
[Lizhong] It seems I understand you meaning. If there are two RSVP-TE bypass tunnel to the same context ID, then same context label will be used for the two RSVP-TE bypass tunnel, right? In that case, how about the upstream label in P2MP LSP? It is not possible for the P to distinguish different upstream labels assigned from different ingress if there are two P2MP share one of the same egress. 

5. section 8.1. "R1 computes a bypass path to while avoiding PE2. "
Could you give more explicit way to achieve above without RSVP-TE protocol extensions?

[yshen] Section 5.10 and 5.11.

On 9/28/2017 01:14,Loa Andersson<> wrote: 
Carlos, Eric, Ignas and Lizhong 

You have been selected as MPLS-RT reviewers for draft-shen-mpls-egress- 

Note to authors: You have been CC'd on this email so that you can know 
that this review is going on. However, please do not review your own 

Reviews should comment on whether the document is coherent, is it 
useful (ie, is it likely to be actually useful in operational networks),  
and is the document technically sound? 

We are interested in knowing whether the document is ready to be 
considered for WG adoption (ie, it doesn't have to be perfect at this 
point, but should be a good start). Please remember that it often is 
easier to progress the document when it has become a working group 
document. All comments in the MPLS-RT review needs to be addressed, 
but please think carefully about whether a comment is gating the 
adoption or could just as easily be addressed after the adoption. 

Reviews should be sent to the document authors, WG co-chairs and WG 
secretary, and CC'd to the MPLS WG email list. If necessary, comments 
may be sent privately to only the WG chairs. 

If you have technical comments you should try to be explicit about what 
needs to be resolved before adopting it as a working group document, and 
what can wait until the document is a working group document and the 
working group has the revision control. 

Are you able to review this draft by October 13, 2017? Please respond 
whether you are available to do the review in a timely fashion. 

Thanks, Loa 
(as MPLS WG co-chair) 

Loa Andersson                        email: 
Senior MPLS Expert 
Huawei Technologies (consultant)     phone: +46 739 81 21 64