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

Hello Mike,

OK, then we see both the same, just the interpretation is different. Lets
see the details.

On Fri, Sep 30, 2011 at 10:09 AM, Mikael Abrahamsson <swmike at swm.pp.se>wrote:

> 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?
>>
>
So the hardwired limit of 0.5M IPv4 routes and 0.25k IPv6 does not allow a
few hundred thousands more IPv6 routes at all (not even would allow an 0.25M
IPv6 limit) -- and speed of processing is an other issue...

>
> 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.
>

Agreed. Convergence is an issue!!!

>
> --
> Mikael Abrahamsson    email: swmike at swm.pp.se
>
>
In summary: we do not have the technology which would allow a very liberal
PI allocation policy, therefore a very liberal PI allocation policy is not
possible now.

Strict limits must be kept.

Thanks,

Géza
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