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

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