[c-nsp] Get Cisco CEF hash function

Xavier Nicollet xnicollet at gmail.com
Wed Dec 17 04:25:24 EST 2014


I am using cisco ECMP to load-balance traffic to servers. I am currently
using static IP, but I will soon use BGP.

For instance:
 ip route [VIP-WEB] [REAL-WEB1] weight 20
 ip route [VIP-WEB] [REAL-WEB2] weight 20

I am using cisco 7600, rsp720, and IOS 12.2(33)SRE2 on the test platform.

I am using per per IP balancing, and I have forced seed to 1:

 ip cef load-sharing algorithm universal 00000001
 mls ip cef load-sharing simple

Is there a way to get the exact hash function used by the router ?
This is for monitoring purpose: I'd like to be able to check that each real
server is alive by using different source IP when testing the service

I know I could use
 show ip cef [VIP/32] detail
 show ip cef [VIP/32] internal
 show mls cef exact-route [IPSRC] [VIP]

However, I guess it would be easier to have exact internal hashing
Or is there another way to monitor each real server with such configuration


Xavier Nicollet

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