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Re: [RRG] Geoff Huston's article on BGP stability, update statistics and damping
> From: Robin Whittle <email@example.com>
> Geoff Huston has a new article "Damping BGP":
> "... the busiest 1% of prefixes responsible for 24% of the routing
> updates for the month."
While I agree that whatever's causing this ought to be fixed, there are some
points we need to not lose sight of.
First, fixing this would be a *one-time* improvement in the growth curve for
the update rate (versus long-term time). I.e. you'd see a flat spot (or a
drop) in the curve, after which it would resume its previous growth.
Second, 25% is not peanuts, but it's also not an order of magnitude, and
eliminating these wouldn't get us into a whole new operating region. I don't
know what the current growth rate for BGP updates is, but if it's anything
like the growth rate of the table itself (as one might reasonably assume it
is), 25% is not a long calendar time.
Again, it ought to be fixed, but let's not kid ourselves that this is the
solution to our problems.
I completely agree with you. If the RRG wants to reduce the path hunting
problem, a better approach would be to look at BGP extensions like EPIC
that allow routers to avoid transmitting unnecessary messages. This is a
longer term approach than tuning the damping mechanisms but would
probably be very useful. Another longer term direction could be to
develop interdomain routing protocols that are not entirely based on
path vector like BGP. A possible approach is HLP.
EPIC is described in
Jaideep Chandrashekar, Zhenhai Duan, Zhi-Li Zhang,
Jeff Krasky, Limiting Path Exploration in BGP, IEEE INFOCOM 2005,
HLP is described in
L. Subramanian, M. Caesar, C. Tien Ee, M. Handley, M. Mao, S. Shenker,
I. Stoica, “HLP: A Next Generation Interdomain Routing Protocol,”
http://inl.info.ucl.ac.be , Universite catholique de Louvain, Belgium
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