BGP Error Handling (Fwd: [GROW] WGLC: draft-ietf-grow-ops-reqs-for-bgp-error-handling-04)

[Rob Shakir <rjs () rob sh>]

Hi NANOGers,

Back at NANOG51 in Miami, I gave a presentation relating an IETF draft relating to improving the robustness of BGP-4 to 
meet the requirements of current operational deployments, and there was some good discussion following this. This 
document was then presented to the IETF IDR and GROW (Global Routing Operations WG), and we have since iterated the 
document to make it significantly clearer, and describe the desired operational behaviour.

This work was particularly on the back of the issues that were seen in the Internet DFZ relating to malformed AS_PATH, 
invalid AS4_PATH, and the problematic RIPE NCC large optional-transitive advertisement.

The discussion, and the requirements outlined have helped influence a number of new standards developments in BGP:

- An IDR BGP error handling draft [0] is in progress to standardise the "treat-as-withdraw" behaviour, which allows 
session resets to be avoided based on erroneous BGP UPDATEs where possible.

- Further drafts relating to extending ROUTE REFRESH [1] and Graceful Restart [2] have been proposed to allow recovery 
from inconsistent RIB states, and reduced impact to forwarding when a session reset cannot be avoided respectively.

- The work that Tom Scholl, Richard Steenbergen, John Scudder, and David Freedman did on the ADVISORY message has been 
extended to handle some error handling cases, as well as the original use case [3].

The working group last call represents final agreement prior to publishing this work, which is valuable since it 
provides a framework of requirements which future developments are intended to solve. 

I would encourage anyone who has an interest in this area to review the document, and let the GROW mailing list (grow 
() ietf org) know whether the requirements describe meet their use case, and/or any comments or deviations that should 
be noted.

Many thanks in advance for doing so - there are a number of network scenarios that I think will be operationally 
improved by implementing this work.

Kind regards,
r.


Begin forwarded message:

> From: Christopher Morrow <christopher.morrow () gmail com>
> Subject: [GROW] WGLC: draft-ietf-grow-ops-reqs-for-bgp-error-handling-04
> Date: 11 June 2012 21:21:49 GMT+01:00
> To: grow-chairs () tools ietf org, "grow () ietf org grow () ietf org" <grow () ietf org>
>
> Hello GROW-WG folk,
> Please take this message as the start of a 2 week, ending 6/25/2012
> (June 25, 2012) WGLC for the subject draft, link to current version:
>  <http://www.ietf.org/internet-drafts/draft-ietf-grow-ops-reqs-for-bgp-error-handling-04.txt>
>
> Abstract:
> "BGP-4 is utilised as a key intra- and inter-Autonomous System routing
>   protocol in modern IP networks.  The failure modes as defined by the
>   original protocol standards are based on a number of assumptions
>   around the impact of session failure.  Numerous incidents both in the
>   global Internet routing table and within Service Provider networks
>   have been caused by strict handling of a single invalid UPDATE
>   message causing large-scale failures in one or more Autonomous
>   Systems.
>
>   This memo describes the current use of BGP-4 within Service Provider
>   networks, and outlines a set of requirements for further work to
>   enhance the mechanisms available to a BGP-4 implementation when
>   erroneous data is detected.  Whilst this document does not provide
>   specification of any standard, it is intended as an overview of a set
>   of enhancements to BGP-4 to improve the protocol's robustness to suit
>   its current deployment."
>
> -Chris
> co-chair
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