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

Sat Sep 4 19:23:19 UTC 2004

--On 02 September 2004 16:09 -0700 John Bender <johnbender at 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