Selfish routing

Sat Apr 26 21:22:58 UTC 2003

Thus spake <alex at yuriev.com>
> > Ah, but there are times when suboptimal paths have spare capacity
> > but you are dropping packets on the optimal path(s) due to
> > congestion.  An "unselfish" routing model would allow you to use
> > _all_ available capacity in the network before packets get dropped.
>
> Make optimal path have more capacity.

If your lead time for ordering circuits is <1 day and your cost for excess
bandwidth is zero, that's certainly a viable strategy.  Most of us, even
facilities-based carriers, don't live in that dreamland.

> No need for FastPath(tm) or any other market hype.
> Case closed.

Please distinguish between startups desperately marketing OSPF under a
trademark, and tier 1 carriers who use _significantly different_ routing
strategies and won't even acknowledge it without an NDA.

> "My outbound is your inbound"
> "I always can control my outbound"
> "Therefore, you cannot control your inbound"
> "Therefore, your claims of 'traffic management' is marketing hype"

A carrier can't exercise fine-grained control over what traffic levels their
peers/customers/upstreams send them, but it is possible to react in
real-time to varying traffic levels and prevent congestion (within your own
network) from flash crowds, link outages, peer flaps, etc.

Capcity, even in our current bandwidth glut, is expensive.  If you can
maintain the same performance level with less capacity, you keep more
profits at the end of the day -- and that's the real goal, not design
purity.

S

Stephen Sprunk         "God does not play dice."  --Albert Einstein
CCIE #3723         "God is an inveterate gambler, and He throws the
K5SSS        dice at every possible opportunity." --Stephen Hawking