Re: [mpls] Comments about draft-xiong-mpls-path-segment-sr-mpls-interworking and difference between Path Segment and BSID

Dhruv Dhody <> Thu, 12 September 2019 10:18 UTC

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From: Dhruv Dhody <>
Date: Thu, 12 Sep 2019 15:47:23 +0530
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Cc: Loa Andersson <>, Tarek Saad <>,,
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Subject: Re: [mpls] Comments about draft-xiong-mpls-path-segment-sr-mpls-interworking and difference between Path Segment and BSID
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Hi Quan,

Thanks for your mail and further discussion.

It is not about Path SID v/s Binding SID, both are needed and each serve a
specific purpose.

The comment I made during 105 was that you are using Path SID to do the
function of Binding SID!

where you say -

  The border nodes should
  install the following MPLS data entries for Path segments:

    incoming label: i-Path
       outgoing label: the SID list of the next domain or link + next i-Path

Here you are not using Path SID for OAM/PM but for the functionality of
Binding SID! That seems like a wrong thing to do!


On Thu, Sep 12, 2019 at 12:35 PM <> wrote:

> Hi  all,
> I noticed you proposed comments at the IETF#105 MPLS meeting to the draft
> "draft-xiong-mpls-path-segment-sr-mpls-interworking". Your comment and
> review is very appreciated!
> The Path Segment defined in draft-ietf-spring-mpls-path-segment has been
> proposed and adopted in Spring WG.
> The Path Segment is a path identification for Performance measurement and
> Bidirectional path correlation and End-to-end Path Protection.
> The draft "draft-xiong-mpls-path-segment-sr-mpls-interworking" mainly
> focus on the SR and MPLS Interworking with Path Segment to provide
> end-to-end bidirectional VPN service in inter-domain scenario.
> I noticed the Binding SID is also used in inter-domain scenario. I think
> the main difference is as follows:
> Binding SID indicates a SID List. Selected path by replace the Binding SID
> to a SID List. Path Segment indicates a path, it can realize
> OAM,PM,protection. Selected path by path segment correlation.
> Binding SID can not replace path segment in bidirectional path, OAM, PM
> and protection etc. If we use Binding SID, the per-segment or per-domain
> OAM/PM/protection can not be achieved.
> I just start the discussion and comments and suggestions are very welcome!
> Best Regards,
> Quan