Subject: Re: [mpls] [Isis-wg] Request for WG adoption of draft-xu-isis-mpls-elc-00

From: Xuxiaohu <[email-masked]>
Date: Fri, 6 Jun 2014 02:28:56 +0000

Hi Hannes,

It seems that you are not talking about the particular ELC concept as defined in RFC6790 (i..e, the capability of recognizing the ELI and popping that ELI and the following EL). Instead, it seems that you are talking about something else related to the capability of accessing the maximum label stack depth.

As for the granularity of the ELC advertisement (i.e., per-node basis or per-interface-board basis), it has been discussed before. Although the ELC is interface-board related, since it's almost impossible to determine at which interface a packet destined for one of the router's addresses would arrive (e.g., a MPLS packet with the top label being a node segment ID of a given LSR), the feasible way of advertising the ELC is: the egress LSR SHOULD not advertise its ELC unless all of its interface-boards have the ELC. By the way, this is exactly the same way that can be supported by RFC6790, IMHO.

Best regards,
Xiaohu 

> -----Original Message-----
> From: Isis-wg [mailto:[email-masked]] On Behalf Of Hannes Gredler
> Sent: Thursday, June 05, 2014 5:47 PM
> To: Xuxiaohu
> Cc: [email-masked]; <[email-masked]>;
> [email-masked]; [email-masked] list
> Subject: Re: [Isis-wg] Request for WG adoption of draft-xu-isis-mpls-elc-00
> 
> <IS-IS WG chair hat off>
> 
> i'm discomfortable with the *granularity* of the cap-advertisement:
> 
> rather than saying:
> 
> "i can crawl as deep as you like on any of my interfaces"
> 
>   i'd like to announce:
> 
> "i can crawl for EL <N> up to labels deep on interface XYZ"
> 
> 
> /hannes
> 
> On Jun 3, 2014, at 2:17 PM, <[email-masked]>
> <[email-masked]> wrote:
> 
> > Hi,
> >
> > IMHO, before defining the capability, I would be more interrested on seeing
> some progress on a solution for EL over SPRING. A draft exists with multiple
> options, maybe we should wait for one option to have consensus before
> worrying about ELC encoding (quite easy part of the EL for SPRING).
> >
> >
> > Stephane
> >
> > -----Message d'origine-----
> > De : Isis-wg [mailto:[email-masked]] De la part de Xuxiaohu
> > Envoyé : samedi 31 mai 2014 10:05 À : [email-masked] Cc :
> > [email-masked]; [email-masked] Objet :
> > [Isis-wg] Request for WG adoption of draft-xu-isis-mpls-elc-00
> >
> > Hi WG co-chairs,
> >
> > This draft (http://tools.ietf.org/html/draft-xu-isis-mpls-elc-00) describes how
> to advertise the MPLS Entropy Label Capability (ELC) using IS-IS in SPRING
> networks. Since
> (http://tools.ietf.org/html/draft-ietf-isis-segment-routing-extensions-00) has
> been adopted as a WG draft, as co-authors of draft-xu-isis-mpls-elc-00, we hope
> you could consider the WG adoption for this draft as well.
> >
> > Best regards,
> > Xiaohu (on behalf of all-authors)
> >
> > _______________________________________________
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> > https://www.ietf.org/mailman/listinfo/isis-wg
> >
> >
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