handling large numbers of EBGP peers

I've got a router on Mae West with an open peering policy that has
close to 70 peers. I'm currently running gated on a P133 box and have
just increased the size of data structures as the number of peers
grew. We are looking at going to a Cisco 7200 (with NPE200) or 7500
(with RSP4), but I haven't been able to determine weather these
routers will handle this many peers and still have room for expansion.
I've heard that Cisco IOS has a software limit, even if the RSPs can
handle it, but I haven't been able to tell what it was. Are there
routers from other vendors out there handling large numbers of peers?

Our bandwidth is too low to want to consider putting a second router
on the NAP. I've considered providing ebgp multihop peering to other
routers behind this one, but I haven't heard of others doing this sort
of thing on the NAP's before. Of course, there are the route servers,
but I'm more interested in offering direct peering to anyone that
wants it.

I only have full routing tables coming in at 2 places in my network
and might anticipate having 8 - 10 IBGP peer sessions in addition to
external sessions.


The hard limit for BGP peers is currently 200 on 11.X IOS. A 7513 with
and RSP4 will be able to handle that kind of load without a problem and
still have plenly of room for expanison. The only 'HARD LIMIT' issue you
may run into is if you have inbound access-lists on these session, not
including as-path access-lists, it does require quite a bit of interupt
driven CPU usage and you will have a fairly high average. The only
problem with this is that you do not have much processor left for system
processes. This will however hold just five if you use VIP2 based cards
and enable distributed switching.

  My suggestion is that you get a VIP2-40 with 2 PA's, one
FastEthernet, and one (Hssi, depending on what layer II type of connection
you have).

- Aaron Hughes
- UltraNet Communications, Inc.
- aaronh@ultra.net.