Route table growth and hardware limits...talk to the filter

Sat Sep 8 15:57:17 UTC 2007

On Sat, Sep 08, 2007 at 09:17:16AM -0400, Jared Mauch wrote:
> On Sat, Sep 08, 2007 at 08:22:24AM -0400, William Allen Simpson wrote:
[snip]
> >  I do not agree the filters as originally proposed are "too aggressive".
> >  Traffic engineering with one's peers is all very well and good, but at
> >  the second AS (or overseas) it's not acceptable.
> 
> 	I think this is the most important point so far.  There are a lot
> of providers that think that their announcements need to be global
> to manage link/load balancing with their peers/upstreams.  Proper use
> of no-export (or similar) on the more specifics and the aggregate
> being sent out will reduce the global noise significantly.
> 
> 	Perhaps some of the providers to these networks will nudge them
> a bit more to use proper techniques.

Any policing effort will require co-ordination and to be stated 
publicly (here and elsewhere) that it is a Good Thing.  At a previous
employer, I managed the network-wide memory carefully for years
with such filtering techniques and received intense pushback from 
remote networks that were broken.  The obvious lack of clue, lack 
of care, contstant arguments and pushback was so disgusting that 
it contributed to me departing that position.  

>From direct experience of chasing and hounding on my own time, 
apathy far outweighed ignorance most of the time.  The fact that 
you can trivially operate more effectively using the same basic 
toolset (synrchonized and well-maintained prefix lists at the 
start) needed to clean up your external announcements was ignored.
A direct cookbook provided and lots of folks will still think 
you are asking too much of them.

Some large transit providers also encourage customers to deaggregate
and just announce prefixes in use rather than aggregate allocations
as a so-called security measure.  The ongoing pollution is also 
a way to both squeeze competators out of the marketplace and 
abuse longest match as a revenue stream.  The mental image that 
came to me of the so-called tier 1s is a multi-party game of 
chicken, where the exhaustion of routing slots in their own gear 
is the point of collision.  Or maybe a a series of cartoon planes 
in a nose dive contest to see who can pull up closest to the last 
second is more appropriate, as the crunch is inevitable.

Cheers!

Joe

-- 
             RSUC / GweepNet / Spunk / FnB / Usenix / SAGE