[c-nsp] how many maximum BGP routers can be to reside in one AS？

[Nick Hilliard]

On 26/05/2011 08:58, ying-xiang wrote:
> in another words,is there a limit to be the amount of one AS BGP routers?
> we have a network design will put 2500+ routers running ibgp session
> into a single AS.of course,RR or confederation is required.even so, i am
> not sure it will be done with this design.AFAIK, router’s memory is a
> import thing to consume of bgp route prefix.apart from this,what else
> should get my attention?

2500 routers is quite a large network.  For this size, you will probably 
want to break it down into a number of confederations and create a routing 
policy for each confederation.

It's not really possible to summarise how to do this in a short email, but 
things to look out for are:

- RR cpu load and the number of clients on each RR
- the size of each confederation
- whether or not all your routers need to receive a full routing table
- FIB size on your hardware routers
- your IGP management
- whether you're going to run mpls or not

BGP + RRs + confederations will scale to whatever size you need.

Nick