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Policy Routing Performance Impact


I have a router that is passing traffic between two corporate networks at the rate of about 2M/bit per sec. I would like to implement policy routing on this routing device (4700) with 32MB of mem, 1 ethernet and two FDDIs.

I would have to apply the following:-


ip policy route-map encryp-route-back

The problem is that only 0.001 % of the traffic needs to be policy routed and I am worried about implementing this as all the traffic needs to check the route-maps and be policy routed when only a very small number of packets require the next hop change.

We also have an externded acl on this interface already.

Should I be concerned about this?



Re: Policy Routing Performance Impact

When you implement policy routing all packets coming into the interface will be process switched so policy routing can have an impact on performance for that reason.

Policy-based-routing itself does not affect much performance of the router, but packet forwarding does.

Policy-Based Routing is supported in fast-switching path so the performance impact is minimized.

To activate fast-switching, you need to enable 'ip route-cache policy' on the same interface, where you apply the route-map.

Also, it would be better to keep as few lines in ACL as possible. The shorter ACL is - the less CPU is required to match the packets.

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