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Memory capacity in Cisco 7507 for BGP

In this moment one customer has in a Cisco7507 , 128 MB RAM and currently they have 100000 BGP route entries . How much memory is needed in this Cisco7507 to handle other 100000 BGP route entries ?

The IOS is 12.1.4 Service Provider

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Anonymous
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Re: Memory capacity in Cisco 7507 for BGP

Here is how bgp calculates its memory requirements.

depending on the kind of routes you take in and wheteher they will

be installed in your routing table. Also

the number of neighbour advertising routes to you

comes into play.

say you have 100000 bgp routes coming from only

one neighbour. then the calculation is as below.

(a) number of prefixes (240 bytes per prefix)

(b) number of routes (240 bytes per route)

(c) number of alternate paths (110 bytes per alternate path)

BGP table : 100000 X 240 =24MB

routing table (bgp) 100000 X 240 =24MB

Alt. Paths : 100000 X 110 X N (n=0)=0

total memory requirement = 48MB/s. for 100000 bgp routes.

However your router also have some internal

memory requirement for processor memory

and also each feature and routing protocol configured

also need memory to run and keep thier table.

It would not be ok to simply assume 96MB would hold

another 100 thousand route on this platform without upgrading

memory.

to hold 200000 bgp update, you need

1. 96MB for the route provided single path exist.

2. 64MB IOS memory requirements

3. say another 32MB for all features/IGP routing protocol.

so you'll need about 192MB.

I suggest a memory upgrade to 256MB

MEM-RSP4-256M=, RSP4/RSP4+ 256MB DRAM UPGRADE KIT

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