[73815] in North American Network Operators' Group

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Re: RIPE "Golden Networks" Document ID - 229/210/178

daemon@ATHENA.MIT.EDU (Alex Bligh)
Sat Sep 4 15:24:32 2004

Date: Sat, 04 Sep 2004 20:23:19 +0100
From: Alex Bligh <alex@alex.org.uk>
Reply-To: Alex Bligh <alex@alex.org.uk>
To: John Bender <johnbender@speakeasy.net>,
	Iljitsch van Beijnum <iljitsch@muada.com>
Cc: NANOG <nanog@merit.edu>, Alex Bligh <alex@alex.org.uk>
In-Reply-To: <20040902160944.111d6721@localhost>
Errors-To: owner-nanog-outgoing@merit.edu




--On 02 September 2004 16:09 -0700 John Bender <johnbender@speakeasy.net> 
wrote:

> This would not be as problematic if dampening could be applied to a path
> rather than a prefix, since an alternate could then be selected.  But
> since this would require modifications to core aspects of BGP (and
> additional memory and processor requirements) it does not seem a likely
> solution.

Hmmm....

So returning to the illustration Rodney gave Randy about the .foo
domain, are we saying that if the .foo domain's DNS is anycast,
then as (just from statistics of multiple paths) prefix flaps (as
opposed to flaps of individual paths) are going to be more likely [*],
route dampening adversely affects such (anycast) sources more than
straight unicast?

Or, looking at it the other way around, if in a heavily plural
anycast domain prefix route changes (as opposed to route changes
of individual paths) are more common than "normal" routes [*] (albeit
without - dampening aside - affecting reachability), does this mean
route dampening disproportionately harms such routes?

i.e. is the answer to Randy "because such networks [might] have
a higher tendency to use anycast.

* = note untested assumption

Alex

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