Memory requirement for BGP

[cool.cisco]

Hi,

I am new to BGP, I have one 3745 router and 1 ISP,

I have already registered an AS Number.

The load is at present there is one Internet service provider connected and after some time another will be connected on the other router and both will connect via ebgp and hsrp..

What is the cisco recommendation...

Is should be 7200 series??????????????

Ram requirement?????????

Its urgent would appreciate your all feedbacks...

Thanks,

[peterledwidge]

Here is a useful link

http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/bgp.htm

And below will give you an idea of the memory requirements for a full BGP routing table.

Best to discuss with your options with your chosen service provider.

BGP table version is 157414430, main routing table version 157414430

175931 network entries using 19880203 bytes of memory

351543 path entries using 16874064 bytes of memory

60643/30167 BGP path/bestpath attribute entries using 6549444 bytes of memory

43823 BGP AS-PATH entries using 1111700 bytes of memory

1555 BGP community entries using 77004 bytes of memory

0 BGP route-map cache entries using 0 bytes of memory

0 BGP filter-list cache entries using 0 bytes of memory

BGP using 44492415 total bytes of memory

BGP activity 4157413/3960160 prefixes, 136839096/136466191 paths, scan interval

60 secs

HTH

Peter

[cool.cisco]

Thanks for the wonderful link and explanation...

But my basic question remains the same will 3745 router will bw sufficient in my scenerio.

Thanks

Irshad

[Danilo Dy]

Hi,

I've worked with multiple BGP implementation, different scenarios and different Cisco Router Series.

In my experience you need 256MB of memory to received all 140K plus internet prefixes. I think they will used up to 140MB as well.

If you are only connected to 1 ISP, you can ask them to advertise default-route to you. In this case 128MB is enough. I can't remember exactly, but I think I implemented BGP in a 64MB router where my upstream ISP only advertised default-route to me. But most ISP now recommends 128MB minimum even if they will only advertised default-route to you.

I used a 3745 router in one of my implentation, with 256MB and receiving 140K plus prefixes. I don't experience any problem

The most important here is the memory. I implemented BGP in 2600 and 3600 series with 128MB, but receiving default-route from my upstream ISP.

Regards.