Well,
 
In my experience it depends on the model of router.  I had a 3640 (granted, it's old) with 128MB that was just fine until a couple of months ago, now it's not enough.  For one BGP table you will have to have at least 256MB in a 36xx router.  Our 720xVXR routers currently have 256MB in them as well, but we've already ordered upgrades to 1GB with new NPE-G1s...
 
- Erik
 

From: Mark Bojara [mailto:mark@aboutit.co.za]
Sent: Monday, January 03, 2005 8:23 AM
To: nanog@merit.edu
Subject: minimum requirements for a full bgp feed

Hello All,

If I wish to purchase a Cisco router that handles a full internet BGP feed what are the minimum specs I should be looking at?

Regards
Mark Bojara