[Idr] Re: Fwd: I-D Action: draft-wang-idr-dpf-00.txt

["Wang, Kevin" <[e-mail]>]

Hi Robert and Gyan,

Thanks for your feedback! Your observation is correct that IGP Flex Algo could achieve the same. BGP DPF can be though as a BGP counterpart of IGP Flex Algo to some extent (though not precisely).

As explained in the “Introduction” section of this draft, BGP DPF is designed for the current IP fabric environment where EBGP is usually the only protocol used for routing. Section 5 of RFC 7938 explains why DC fabrics use EBGP as the sole routing protocol.

Thanks,
Kevin

From: Gyan Mishra <[e-mail]>
Date: Tuesday, December 2, 2025 at 7:43 AM
To: Robert Raszuk <[e-mail]>
Cc: idr@ietf. org <[e-mail]>, lsr <[e-mail]>
Subject: [Idr] Re: Fwd: I-D Action: draft-wang-idr-dpf-00.txt

I agree with Robert that you could use RFC 9502 IGP Flex Algo in IP networks to build disjoint planes as desired.

You could also use SRv6 with IGP Flex Algo with SR RFC 9350 which uses IPv6 data plane and build your disjoint planes.

Thanks

Gyan

On Tue, Dec 2, 2025 at 6:32 AM Robert Raszuk <[e-mail]<mailto:[e-mail]>> wrote:
Hi,

In respect to the subject draft ... why would you not use IGP Flexible Algorithm for it ?

Are you going to port now years of work from IGP to BGP to achieve the same ?

Besides, in a non-blocking fabric latency is really not a factor. So you want to logically partition it to make it blocking them worry about what travels on which such logical plane ? Is this a reasonable direction ?

Thx,
R.

---------- Forwarded message ---------
From: <[e-mail]<mailto:[e-mail]>>
Date: Mon, Dec 1, 2025 at 10:49 PM
Subject: I-D Action: draft-wang-idr-dpf-00.txt
To: <[e-mail]<mailto:[e-mail]>>


Internet-Draft draft-wang-idr-dpf-00.txt is now available.

   Title:   BGP Deterministic Path Forwarding (DPF)
   Authors: Kevin Wang
            Michal Styszynski
            Wen Lin
            Mahesh Subramaniam
            Thomas Kampa
            Diptanshu Singh
   Name:    draft-wang-idr-dpf-00.txt
   Pages:   18
   Dates:   2025-12-01

Abstract:

   Modern data center (DC) fabrics typically employ Clos topologies with
   External BGP (EBGP) for plain IPv4/IPv6 routing.  While hop-by-hop
   EBGP routing is simple and scalable, it provides only a single best-
   effort forwarding service for all types of traffic.  This single
   best-effort service might be insufficient for increasingly diverse
   traffic requirements in modern DC environments.  For example, loss
   and latency sensitive AI/ML flows may demand stronger Service Level
   Agreements (SLA) than general purpose traffic.  Duplication schemes
   which are standardized through protocols such as Parallel Redundancy
   Protocol (PRP) require disjoint forwarding paths to avoid single
   points of failure.  Congestion avoidance may require more
   deterministic forwarding behavior.

   This document introduces BGP Deterministic Path Forwarding (DPF), a
   mechanism that partitions the physical fabric into multiple logical
   fabrics.  Flows can be mapped to different logical fabrics based on
   their specific requirements, enabling deterministic forwarding
   behavior within the data center.

The IETF datatracker status page for this Internet-Draft is:
https://datatracker.ietf.org/doc/draft-wang-idr-dpf/<https://urldefense.com/v3/__https://datatracker.ietf.org/doc/draft-wang-idr-dpf/__;!!NEt6yMaO-gk!EP_lEYmqbOUApQqqOz-ZuP9CsojS2gbvLvgQfxoYTXPXtS-0yjfv8ElqZwJBCRfOLFY6nymWoR5eJlshPeG9$>

There is also an HTML version available at:
https://www.ietf.org/archive/id/draft-wang-idr-dpf-00.html<https://urldefense.com/v3/__https://www.ietf.org/archive/id/draft-wang-idr-dpf-00.html__;!!NEt6yMaO-gk!EP_lEYmqbOUApQqqOz-ZuP9CsojS2gbvLvgQfxoYTXPXtS-0yjfv8ElqZwJBCRfOLFY6nymWoR5eJjgsy_TY$>

Internet-Drafts are also available by rsync at:
rsync.ietf.org::internet-drafts


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