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3945 Memory Allocation for BGP

Jonathan Ridgway


I have seen many 3945's out the box with a memory configuration like 987136K/61440K in "show version", meaning 60MB of I/O memory and 1GB in total. However, I started installing a new 3945 router and it is configured 743424K/305152K, meaning 305MB (30%) of I/O memory and 1GB in total. The problem with this is I need most of the 1GB for the BGP routing table and at the moment BGP won't receive all the routes because I don't have enough memory for it. I am looking to filter routes in the long term but it would be nice to have this router's memory allocation setup correctly, especially since cisco's recommendation is to not go above 25%!

So I tried the command "memory size iomem 5" command to set it down to 5% and then reloaded the router but it remained the same. Also the command "memory size iomem 30" doesn't currently exist in the running config.

The IOS image is c3900e-universalk9-mz.SPA.154-1.T3.bin".

Any suggestions welcome.


1 Reply 1

Vasilii Mikhailovskii
Rising star
Rising star


For IO mem, there is an enhancement report - CSCuh58718 (done in 15.4.3M, 15.5.1T).

In your release, I believe, "memory size iomem " should work for values higher than 201M (in console you might have seen message: "IO memory size too small:  minimum IO memory size is 201M".

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