Thanks for comments Thomas, agreed.

Cheers,
Jeff

> On Mar 11, 2021, at 22:33, Jakob Heitz (jheitz) <[email protected]> wrote:
> 
> Thanks Thomas.
> I agree to remove the netflow reference.
> 
> Regards,
> Jakob.
> 
> -----Original Message-----
> From: [email protected] <[email protected]> 
> Sent: Sunday, March 7, 2021 10:20 PM
> To: [email protected]; [email protected]; 
> [email protected]; [email protected]; Jakob Heitz (jheitz) 
> <[email protected]>
> Cc: [email protected]
> Subject: RE: [GROW] I-D Action: draft-ietf-grow-as-path-prepending-03.txt
> 
> Dear authors,
> 
> Speaking as a network operator, I think your draft has merit and I agree BGP 
> as-path prepending is misused on the Internet and a best common practice 
> draft is welcomed.
> 
> I like to comment on section 3.4
> https://tools.ietf.org/html/draft-ietf-grow-as-path-prepending-03#section-3.4
> 
> You are referring to the impact of BGP as-path length onto IPFIX.
> 
> To my current knowledge, there are only 4 well known IPFIX entities 
> registered at IANA related to BGP as-path
> 
> https://www.iana.org/assignments/ipfix/ipfix.xhtml
> 
> IE16 bgpSourceAsNumber
> IE17 bgpDestinationAsNumber
> IE128 bgpNextAdjacentAsNumber
> IE129 bgpPrevAdjacentAsNumber
> 
> None of them contain the entire BGP as-path array. Only the first or last BGP 
> ASN of the path array for source and destination IPv4/6 address of the flow.
> 
> The reason to my knowledge is that for UDP transport, which is one of the 
> options to export IPFIX and the most supported, does not support 
> segmentation. Thus limiting IPFIX of the amount data records and values 
> within a record which can be exposed per message even to a lower value than 
> RFC 7011 defines with 65535 bytes as maximum message size.
> 
> https://tools.ietf.org/html/rfc7011#section-10
> https://tools.ietf.org/html/rfc7011#section-10.3.3
> 
> The BGP as-path array could be potentially be exposed with code points from 
> the private enterprise number space. If that would be the case than same 
> operational considerations would apply than in RFC 8549 section 7 described 
> since BGP communities are also array's.
> 
> https://tools.ietf.org/html/rfc8549#section-7
> 
> Therefore I either recommend to remove the IPFIX/Netflow relevant part from 
> the draft or clearly state the scenario where with private enterprise number 
> BGP as-path array is exposed and refer to example implementations as they are 
> nonstandard.
> 
> Best wishes
> Thomas
> 
> -----Original Message-----
> From: GROW <[email protected]> On Behalf Of [email protected]
> Sent: Tuesday, February 9, 2021 1:30 AM
> To: [email protected]
> Cc: [email protected]
> Subject: [GROW] I-D Action: draft-ietf-grow-as-path-prepending-03.txt
> 
> 
> A New Internet-Draft is available from the on-line Internet-Drafts 
> directories.
> This draft is a work item of the Global Routing Operations WG of the IETF.
> 
>        Title           : AS Path Prepending
>        Authors         : Mike McBride
>                          Doug Madory
>                          Jeff Tantsura
>                          Robert Raszuk
>                          Hongwei Li
>                          Jakob Heitz
>    Filename        : draft-ietf-grow-as-path-prepending-03.txt
>    Pages           : 10
>    Date            : 2021-02-08
> 
> Abstract:
>   AS Path Prepending provides a tool to manipulate the BGP AS_Path
>   attribute through prepending multiple entries of an AS.  AS Path
>   Prepending is used to deprioritize a route or alternate path.  By
>   prepending the local ASN multiple times, ASs can make advertised AS
>   paths appear artificially longer.  Excessive AS Path Prepending has
>   caused routing issues in the internet.  This document provides
>   guidance,to the internet community, with how best to utilize AS Path
>   Prepending in order to avoid negatively affecting the internet.
> 
> 
> The IETF datatracker status page for this draft is:
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