[ppml] Just say *NO* to PI space -- or howto make it less destructive

[Pekka Savola]

On Tue, 25 Apr 2006, Howard, W. Lee wrote:
> Matthew Petach wrote:
>>> dynamicity.  Huston's study indicated that there are folks whose BGP
>>> announcements flap (due to TE) intentionally 1000's of times a day.
>> BGP flap dampening is already well understood for limiting the impact
>> of flapping routes on your CPU, if that's a concern; it has no bearing
>> on address allocation policy decisionmaking.
>
> Dampening works, for the value of "works" which equals "suppressing 
> new (better?) information about the path to a network," which is 
> often equal to "misrouting data because a new path was not 
> calculated."  If, following this proposed policy, aggressive 
> dampening becomes commonly required by operators to maintain their 
> networks, it might have a bearing on support for this policy.

The effects of dampening depend a lot on where it's applied.  Towards 
a customer end-site?  In outgoing advertiement to your peers and 
upstreams for your own customers?  By transit operators?  By all the 
ASs for their incoming Internet/peering feeds?

IMHO, flap damping closest to the source is the best approach because 
a multihomed site wouldn't lose connectivity, but unfortunately that 
isn't applied that often... or Geoff wouldn't have observed the 
advertisement flapping problems..

-- 
Pekka Savola                 "You each name yourselves king, yet the
Netcore Oy                    kingdom bleeds."
Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings