Re: delayed multihoming/mobility set-up

[Iljitsch van Beijnum <iljitsch@muada.com>]

On 18-nov-03, at 0:14, Masataka Ohta wrote:

> > If we assume that we are using BGP for the EGP routing updates, we 
> > have the Ahuja/Labovitz route cancellation effect. If I remember 
> > correctly, their research showed that 40% of re-routing takes 2-4 
> > minutes (I am taking this out of my head).

> That is a reason why global routing table should be shrinked.

I'm afraid these two issues aren't really related. The reason that BGP 
rerouting can take so long is that the RFC mandates a 90 second hold 
time, but Cisco and presumably others use an even longer default hold 
time of 180 seconds. Operators are often reluctant to change the 
default.

Once the BGP session goes down there is of course the issue of updating 
all the related routes, which can also take some time depending on the 
number of routes that ran over the neighbor. But this is usually a 
matter of seconds (think a one digit number).

> It, instead, is the reference for BGP++.

We already have BGP4+, but now we need BGP++?