[address-policy-wg] scaling # of prefixes Re: Proposal 2011-02 moving to Last Call

On Fri, 30 Sep 2011, Turchanyi Geza wrote:

> I realy would like to know what makes you so optimistic? While you think 
> so that a few hundred thousands more routes doesn!t really matter?
>
> Which kind of routers/line cards could support this at wire speed? Any
> summary of convergence issues in large scale network?

As far as I know, Cisco 7600 with XL PFC, Juniper MX, Cisco ASR 9k, CRS 
etc, all handle 1M or more routes, or at least a mix of 0.5M IPv4 and 
0.25k IPv6 routes. I don't see why number of IPv6 routes would converge a 
lot slower than number of IPv4 routes.

> Am I missed some new technology that is already implemented allmost
> everywhere?

Prefix independent convergence, ie BGP prefix points to loopback which 
points to outgoing interface. When you need to converge your IGP you just 
rewrite the loopback pointers.

This doesn't help EBGP of course, but number of routes are increasing 
slower tham moores law, so as long as the router vendors implement RIB 
processing in modern hw (not PPC :P), RIB handling is fine.

Still, a lot of platforms can only program approximately 10k prefixes per 
second into hw, so increasing number of prefixes by hundreds of thousands 
means tens of seconds of increased convergence times for EBGP.

-- 
Mikael Abrahamsson    email: swmike at swm.pp.se