Re: [Idr] [Editorial Errata Reported] RFC4271 (6498)

Susan Hares <> Fri, 07 May 2021 15:54 UTC

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From: "Susan Hares" <>
To: "'Alvaro Retana'" <>, "'Donald Eastlake'" <>, "'RFC Errata System'" <>
Cc: <>, <>, "'Tony Li'" <>, "'Jeffrey Haas'" <>, "'Yakov Rekhter'" <>, "'Keyur Patel'" <>, "'Martin Vigoureux'" <>, "'Susan Hares'" <>, "'John G. Scudder'" <>, "'idr@ietf. org'" <>
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Date: Fri, 7 May 2021 11:53:59 -0400
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Subject: Re: [Idr] [Editorial Errata Reported] RFC4271 (6498)
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No objection. 




From: Alvaro Retana [] 
Sent: Saturday, March 27, 2021 7:17 PM
To: Donald Eastlake; RFC Errata System
Cc:;; Tony Li; Jeffrey Haas; Yakov Rekhter; Keyur Patel; Martin Vigoureux; Susan Hares; John G. Scudder; idr@ietf. org
Subject: Re: [Idr] [Editorial Errata Reported] RFC4271 (6498)




rfc4271 defines “discretionary” as simply the fact that the attribute may or may not be included in all UPDATE messages.  From that point of view, the type is well-known discretionary.


However, using “discretionary” with a required action can also cause confusion.


I think the report is valid — but I also don’t think it should be marked as Verified.  Instead, it should be marked as “Hold for Document Update”.  Does anyone object to this classification?








From: Donald Eastlake  <> <>
Date: March 27, 2021 at 6:58:43 PM
To: RFC Errata System  <> <>
CC: Yakov Rekhter  <> <>et>, Tony Li  <> <>li>,  <> <>om>, Alvaro Retana  <> <>om>, John G. Scudder  <> <>et>, Martin Vigoureux  <> <>om>, Jeffrey Haas  <> <>rg>, Keyur Patel  <> <>om>, Susan Hares  <> <>om>, idr@ietf. org  <> <>rg>,  <> <>
Subject:  Re: [Idr] [Editorial Errata Reported] RFC4271 (6498) 

"SHALL" is the same as "MUST" or "REQUIRED" [RFC2119]. So if it MUST 
be included, how can inclusion be discretionary? 

Donald E. Eastlake 3rd +1-508-333-2270 (cell) 
2386 Panoramic Circle, Apopka, FL 32703 USA 

On Sat, Mar 27, 2021 at 6:39 PM RFC Errata System 
<> wrote: 

The following errata report has been submitted for RFC4271, 
"A Border Gateway Protocol 4 (BGP-4)". 

You may review the report below and at: 

Type: Editorial 
Reported by: Graham Paasch <> 

Section: 5.1.5 

Original Text 
LOCAL_PREF is a well-known attribute that SHALL be included in all UPDATE messages that a given BGP speaker sends to other internal peers. 

Corrected Text 
LOCAL_PREF is a well-known discretionary attribute that SHALL be included in all UPDATE messages that a given BGP speaker sends to other internal peers. 

It is unclear from the text to which of the four path attribute categories LOCAL_PREF belongs. There was even submitted an errata to create a fifth category for this attribute, but it is clear from the definition of the categories, that this attribute is well known discretionary. All routers must be capable of sending or receiving the LOCAL_PREF attribute, however it is up to a routers discretion whether to include that attribute in an UPDATE message. 

This erratum is currently posted as "Reported". If necessary, please 
use "Reply All" to discuss whether it should be verified or 
rejected. When a decision is reached, the verifying party 
can log in to change the status and edit the report, if necessary. 

RFC4271 (draft-ietf-idr-bgp4-26) 
Title : A Border Gateway Protocol 4 (BGP-4) 
Publication Date : January 2006 
Author(s) : Y. Rekhter, Ed., T. Li, Ed., S. Hares, Ed. 
Source : Inter-Domain Routing 
Area : Routing 
Stream : IETF 
Verifying Party : IESG 

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