NAT performance

jeffrey.zhou · ‎05-11-2003

Although in the Cisco document, the NAT session limit is bounded by the amount of available DRAM in the router. But I found large number of NAT sessions will cause high CPU utilization. In Cisco 7206 NPE 200, when the NAT sessions reach 12000 entries, the CPU will be up to 99%. In Cisco 7206VXR NSE-1, When the number of NAT sessions reach 19000, the CPU utilization will be up to 95%. In these cases, the router CPU reach its limit prior to the memory reaching its limit. So is it normal in above cases?

raymong · ‎05-12-2003

If you have over 30,000 entries and are receiving packets at a rate of 1000 packets per second, you will likely see cpu utilization close to 100%. Otherwise, it could be a problem with the IOS you are running.

jeffrey.zhou · ‎05-12-2003

Hi Raymong,

Would you please let me know that which platform or processor engine your figures get from? In my case, at the peak time, the router are receiving about 2000 packets per second and have about 20000 entries, and it get from the 7206 VXR with NSE-1.