Re: [Idr] [Technical Errata Reported] RFC4271 (5001)

"Alvaro Retana (aretana)" <> Wed, 19 April 2017 18:00 UTC

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From: "Alvaro Retana (aretana)" <>
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Thread-Topic: [Technical Errata Reported] RFC4271 (5001)
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Date: Wed, 19 Apr 2017 18:00:39 +0000
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Subject: Re: [Idr] [Technical Errata Reported] RFC4271 (5001)
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[Cut the distribution.]

idr WG:

I think this report is a lot clearer than the other one John filed (#5000), so I am going to mark this one as “Hold for Document Update” [1].

Just because this report is related to the use of “MAY NOT” I will wait until we resolve the other one just in case.




On 4/19/17, 1:40 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: Technical
Reported by: John Scudder <>

Section: 5

Original Text
   BGP implementations MUST recognize all well-known attributes.  Some
   of these attributes are mandatory and MUST be included in every
   UPDATE message that contains NLRI.  Others are discretionary and MAY
   or MAY NOT be sent in a particular UPDATE message.

Corrected Text
   BGP implementations MUST recognize all well-known attributes.  Some
   of these attributes are mandatory and MUST be included in every
   UPDATE message that contains NLRI.  Others are discretionary and 
   sending them in a particular UPDATE message is OPTIONAL.

The original text uses "MAY NOT" capitalized as if it were an RFC 2119 keyword. However, RFC 2119 does not have any defined meaning for "MAY NOT". In context, it is unlikely the reader would be at risk of misinterpreting the text, but nonetheless it's a misuse of RFC 2119 terminology and difficult to parse if reading closely.

(The replacement text was suggested by Eric Rosen; thanks.)

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.
Category            : DRAFT STANDARD
Source              : Inter-Domain Routing
Area                : Routing
Stream              : IETF
Verifying Party     : IESG