Re: [Idr] IDR agenda item

Robert, 

To be clear, the message from the authors is not to present the pros or
cons of add-paths - those comments should be saved for draft
Advertisement of Multiple Paths in BGP.

I feel that our abstract is clear to state that when turning on Add
Paths there are things that must be considered: This document describes
implementation and operational
   best practices for ADD-PATH in order to facilitate the introduction
   of ADD-PATH to existing networks and to ensure interoperability

It's not the focus of the draft to recommend how to solve a set of
problems.  Perhaps we should be more definitive in our statements in
saying so.

Bert

-----Original Message-----
From: idr-bounces@ietf.org [mailto:idr-bounces@ietf.org] On Behalf Of
Robert Raszuk
Sent: Monday, March 22, 2010 1:38 PM
To: idr@ietf.org
Subject: Re: [Idr] IDR agenda item

Hi,

> IDR Meeting:
> Date: 3/22 time: 15:20-1720:
>
> 15:30-16:00
> draft-uttaro-idr-add-paths-guidelines-00 Roberto Fragassi

As I will not be able to attend IDR meeting tomorrow as it overlaps with

PPSP WG meeting I would like to provide a comment on this draft to the
list.

The draft makes a number of statements which imply that distribution of 
multiple bgp paths edge to edge using add-paths extension is the only 
tool to address fast connectivity restoration, load balancing or to 
eliminate route oscillation.

What I think is important is that a fresh reader not mistakenly think 
that this is the only solution and that increase of network wide BGP 
state is the only option possible to address above applications.

The alternative design approach which does address all of the above 
applications is possible without use of add-paths, by just proper 
construction of the SP's network hierarchy. While such hierarchy of pop 
and core based design may not be applicable to all providers it is 
clearly applicable to vast majority of them therefor providing a 
reference or at least mentioning awareness to it in such document seems 
beneficial.

References:

http://www.nanog.org/meetings/nanog48/presentations/Tuesday/Raszuk_To_Ad
dPaths_N48.pdf

http://www.apricot2010.net/__data/assets/pdf_file/0005/18905/Routing_01_
Conf-Hall-2_0900-1030_Routing_Robert-Raszuk.pdf

Also for those networks which may end up requiring distribution of more 
then best path and for a number of reasons may not be able to upgrade 
both RRs and their all PEs/ASBRs there is alternative proposal which 
this draft does not reference.

URL:  tools.ietf.org/id/draft-raszuk-diverse-bgp-path-dist-01.txt

Therefor if the goal of this drat is to document how practically one 
would be to address reduction of routing churn, faster connectivity 
restoration, better load sharing and a mechanism for graceful 
maintenance i think that for the future reader providing the above 
alternative may be truly beneficial.

Many thx,
R.
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