Subject: [Idr] I-D Action: draft-ietf-idr-rfd-usable-00.txt

From: [email-masked]
Date: Mon, 18 Jun 2012 09:18:03 -0700

A New Internet-Draft is available from the on-line Internet-Drafts directories.
 This draft is a work item of the Inter-Domain Routing Working Group of the IETF.

	Title           : Making Route Flap Damping Usable
	Author(s)       : Cristel Pelsser
                          Randy Bush
                          Keyur Patel
                          Pradosh Mohapatra
                          Loughborough University
	Filename        : draft-ietf-idr-rfd-usable-00.txt
	Pages           : 9
	Date            : 2012-06-18

Abstract:
   Route Flap Damping (RFD) was first proposed to reduce BGP churn in
   routers.  Unfortunately, RFD was found to severely penalize sites for
   being well-connected because topological richness amplifies the
   number of update messages exchanged.  Many operators have turned RFD
   off.  Based on experimental measurement, this document recommends
   adjusting a few RFD algorithmic constants and limits, to reduce the
   high risks with RFD, with the result being damping a non-trivial
   amount of long term churn without penalizing well-behaved prefixes'
   normal convergence process.

The IETF datatracker status page for this draft is:
https://datatracker.ietf.org/doc/draft-ietf-idr-rfd-usable

There's also a htmlized version available at:
http://tools.ietf.org/html/draft-ietf-idr-rfd-usable-00

Internet-Drafts are also available by anonymous FTP at:
ftp://ftp.ietf.org/internet-drafts/

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From: Saku Ytti <[email-masked]>
Date: Mon, 18 Jun 2012 20:47:29 +0300

I would love to see optional local-pref based penalty instead of suppression.

As an operator I'm less concerned of RE usage than I am pulling
connectivity when competitor still offers connectivity. But when there
are multiple options, penalizing unstable route would be nice.

On 18 June 2012 19:18,  <[email-masked]> wrote:
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-- 
  ++ytti

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From: Randy Bush <[email-masked]>
Date: Tue, 19 Jun 2012 17:14:08 +0900

> are multiple options, penalizing unstable route would be nice.

what you are saying makes sense to my ops side.  but, from the intro

   The goal is to, with absolutely minimal change, ...

and the doc merely suggests a change in some constants.  your suggestion
would go considerably further.

i am not strongly against it, more worried that it opening pandora's
box.  what do others think?

randy

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From: Paul WALL <[email-masked]>
Date: Tue, 19 Jun 2012 01:50:43 -0700

> I would love to see optional local-pref based penalty instead of

+1

Drive Slow, Drive Low (the LP)

Paul Wall

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From: Shane Amante <[email-masked]>
Date: Tue, 19 Jun 2012 11:11:26 -0600

>> I would love to see optional local-pref based penalty instead of

IMO, suppress is nice, particularly when you've got to deal with legacy platforms w/out a lot of CPU, and no (short-term) plans to upgrade.  Unfortunately, LP will mean addt'l churn in the AS as LP is adjusted upward/downward as the penalty increases and decreases.  In addition, given the number of "applications" that LP is currently being used for, (e.g.: BGP Traffic Engineering), and _planned_ to be used for, (e.g.: SIDR origin and path validation, BGP persistence, etc.), I wonder if such manipulation of LP is even practical wrt RFD?  Instead, what about MED-based penalty -- at least to mitigate this latter concern?

Regardless, I can see the utility of LP or MED-based penalty and as long as it's just an optional knob to be enabled, then I wouldn't mind seeing it included in a future rev of the draft, for those that wish to [explicitly] enable it.

-shane