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Memory requirements on a 3640 to run BGP4 and CEF

I'm looking for opinions on the necessary memory to run BGP4 for external routing and using CEF for a dual T-1 connection on a 3640 router. We have another route in running on a Cisco 7205 that we will also configure for BGP4, so we will end up with both routes holding two sets of addresses, plus the DMZ.

The dual-T connection will be the only product running on the 3640.

Cisco Employee

Re: Memory requirements on a 3640 to run BGP4 and CEF

at least 128MB.

If you can put more, go for more than 128MB.

Re: Memory requirements on a 3640 to run BGP4 and CEF

Well, I don't know about that. It really depends on what the specifics are of the network.

For example, it is definitely true that you need a lot of memory if you really want to handle the entire BGP route table. But enterprises need to do such a thing only rarely - usually defaults work just fine. Another thing that soaks up a lot of memory is having a lot of BGP peers, but generally enterprise routers will have no more than a few. Finally, your CEF table will be larger depending on how many adjacencies and forwarding entries you have, but both of these things can be managed.

I've used 2500's with 8MB RAM as dual-connected BGP routers running CEF, and it's worked just fine. Obviously the BGP table was very small and so were the CEF tables. It depends on how well you manage those tables and whether you really need them to be large.