Memory needed to handle BGP routing table

[wmurphyccla]

Can someone recommend a router platform that has enough memory to handle BGP routing tables and has switching capabilities.

[mheusinger]

Hi,

256 MB memory should be more than enough for now. It depends however on the number of peers (increased number of BGP pathes). Roughly as a rule of thumb: 40 MB BGP table, 40 MB routing table, 40 MB CEF table. A 3800 would for sure be able to handle this under "normal" conditions.

What exactly do you mean with switching capabilities? What are your exact requirements (ports, bandwidth, etc.)?

Regards, Martin

[wmurphyccla]

Thank you for your response. We are looking at maybe 2 to 3 peers. We currently have on order through our ISP two 3750 layer3 switches which was recommended by them. We recently had a meeting with our current ISP and inform them that we wanted to run BGP between the two ISP's and they said the 3750 didn't have enough memory to handle the BGP routing table. These units will sit outside of our firewall which will have our outside DNS and a couple of other firewalls for other services we provide. These units (routers) will be our gateway to the internet. One ISP is provide 9meg and the other 15meg.

[ilya.varlashkin]

it might be some magic with 3800, but on 7206 with 256MB RAM installed getting full table from single peer leaves me only humble 6MB free. It could be that large IGP or IOS image for 7206 also took significant amount of memory, but 256MB doesn't feel so much safe these days for full-bgp.

[tdrais]

Memory wise you could even use a 2800 to do this. They can go to 768 or even a gig. It will all depend on how big your interfaces are and how much traffic you actually intend the router to pass.

We use 3825 with 512m at some location and take 2 full bgp table with no issues running fractional E3.

I suspect 256m would be enough but the memory upgrade was fairly cheap.

Make sure you order advancedipservices since you don't get BGP with ipbase.

If you are going to need a lot of switch ports it will become cheaper to buy a separate switch rather than one of the internal modules.