Re: [Bier] WGLC: draft-ietf-bier-non-mpls-bift-encoding

Hi Senthil,
I believe the ‘Domain-wide unique’ is the key value of Non-MPLS encapsulation.
Allocation BIFT-id locally on each node is an extra cost, not only in data-plane, but also in control-plane.

That has been concluded in RFC8296 section 2.2.1.1:
   In non-MPLS networks, a BIFT-id MUST be assigned for every
   combination of <SD, SI, BSL> that is to be used in that network.  The
   correspondence between a BIFT-id and a particular <SD, SI, BSL>
   triple is unique throughout the BIER domain and is known to all the
   BFRs in the BIER domain.

The draft we are discussing is to define the above ‘correspondence’  rule.

Jingrong

From: BIER [mailto:bier-bounces@ietf.org] On Behalf Of Senthil Dhanaraj
Sent: Monday, January 28, 2019 5:19 PM
To: Greg Shepherd <gjshep@gmail.com>
Cc: BIER WG <bier@ietf.org>
Subject: Re: [Bier] WGLC: draft-ietf-bier-non-mpls-bift-encoding

Support !
However, i would like to get couple of clarifications with respect to the BIFT-id in non-MPLS networks..

1.

Excerpts from section 2.2.1.1 from RFC8296

   In an MPLS network, since the BIFT-id is an MPLS label, its value may

   be changed as a BIER packet goes from BFR to BFR.  In a non-MPLS

   network, since the BIFT-id is domain-wide unique, it is not expected    // Senthil

   to change as a BIER packet travels.

Senthil// I believe, we do not want to mandate that the BIFT-id must be domain-wide-unique in case of non-MPLS networks (for the sake of flexibility).
              If its *not* domain-wide-unique, then the BIFT-id may change in BFR's as the BIER packet travels from BFIR to BFER.
              Authors & Fellow BIER'ers, let me know what do you think ?

2.

draft-ietf-bier-non-mpls-bift-encoding-01 proposes two encoding methods for BIFT-id and is mentioned that, both of the encoding options are to derive "domain-wide-unique: BIFT-id's.

I believe, option-2, that is  "6. The Non-MPLS Static IBU-SI BIFT Encoding", is flexible and can be used for non-domain-wide-unique BIFT-id's also.

If we agree that, we should allow "non-domain-wide-unique" BIFT-id's for non-MPLS networks, can we re-phrase the text in draft-ietf-bier-non-mpls-bift-encoding-01 to specify that, such an encoding option can be used for non-domain-wide-unique cases as well ?

Thanks,
Senthil

On Sat, Jan 26, 2019 at 1:43 AM Greg Shepherd <gjshep@gmail.com<mailto:gjshep@gmail.com>> wrote:

Change of subject. This is WGLC for:

https://datatracker.ietf.org/doc/draft-ietf-bier-non-mpls-bift-encoding/

Same two week timer.

Thanks

On Fri, Jan 25, 2019 at 10:13 AM Greg Shepherd <gjshep@gmail.com<mailto:gjshep@gmail.com>> wrote:
Please read and reply to this thread with your vote for/against adoption of:

https://datatracker.ietf.org/doc/draft-ietf-bier-non-mpls-bift-encoding/

..as a BIER WG document.

This starts a two week counter.

Thanks,
Chairs
(Shep)
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