[bess] [Technical Errata Reported] RFC8584 (7811)

RFC Errata System <rfc-editor@rfc-editor.org> Thu, 15 February 2024 20:32 UTC

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From: RFC Errata System <rfc-editor@rfc-editor.org>
Cc: laburdet.ietf@gmail.com, bess@ietf.org, rfc-editor@rfc-editor.org
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Message-Id: <20240215203243.C2A181E58A6@rfcpa.amsl.com>
Date: Thu, 15 Feb 2024 12:32:43 -0800
Archived-At: <https://mailarchive.ietf.org/arch/msg/bess/0hRVY-hI3y8hypde3vqHiTw52zM>
Subject: [bess] [Technical Errata Reported] RFC8584 (7811)
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The following errata report has been submitted for RFC8584,
"Framework for Ethernet VPN Designated Forwarder Election Extensibility".

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You may review the report below and at:
https://www.rfc-editor.org/errata/eid7811

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Type: Technical
Reported by: Luc André Burdet <laburdet.ietf@gmail.com>

Section: 3.2.  HRW Algorithm

Original Text
-------------
   Where:

   o  DF(V) is defined to be the address Si (index i) for which
      Weight(V, Es, Si) is the highest; 0 <= i < N-1.

   o  BDF(V) is defined as that PE with address Sk for which the
      computed Weight is the next highest after the Weight of the DF.
      j is the running index from 0 to N-1; i and k are selected values.


Corrected Text
--------------
   Where:

   o  DF(V) is defined to be the address Si (index i) for which
      Weight(V, Es, Si) is the highest; 0 <= i <= N-1.

   o  BDF(V) is defined as that PE with address Sk for which the
      computed Weight is the next highest after the Weight of the DF.
      j is the running index from 0 to N-1; i and k are selected values.


Notes
-----
Paul Kyzivat raised a point while reviewing EVPN Port-Active draft, that really points to a possible algorithm errata in RFC8584 ;

Basically, when evaluating the DF for HRW, 
>      * DF(Es) is defined to be the address Si (index i) for which
>        Weight(Es, Si) is the highest; 0 <= i < N-1.

Here,

if N=1, no remotes:  0 <= i < 0    -- ERROR

if N=2, 1 peer:  0 <= i < 1  -> possible values are only 0 meaning index 1 (the peer)’s weight is not considered.
Logically, this should be 0 <= i <= N-1    or    0 <= i < N ?

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RFC8584 (draft-ietf-bess-evpn-df-election-framework-09)
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Title               : Framework for Ethernet VPN Designated Forwarder Election Extensibility
Publication Date    : April 2019
Author(s)           : J. Rabadan, Ed., S. Mohanty, Ed., A. Sajassi, J. Drake, K. Nagaraj, S. Sathappan
Category            : PROPOSED STANDARD
Source              : BGP Enabled ServiceS
Area                : Routing
Stream              : IETF
Verifying Party     : IESG

[bess] [Technical Errata Reported] RFC8584 (7811) RFC Errata System