[c-nsp] me3600x-cx FIB-to-RIB prefix count discrepancy

[Vitkovský Adam]

Hi folks,

I have noticed an interesting discrepancy in the number of IPv4 prefixes in FIB compared to RIB prefix count. 
For example on one box: 
there are 9253 VPN prefixes (sum from all VRFs). 
global routing table has 834 prefixes. 
together that is 10087 prefixes. 
however TCAM shows 11621 prefixes. 

So the delta is 1534 prefixes (cca 13%) which is quite a lot. 

On a non-production box the sum of global + VRF prefixes is 1487 though TCAM shows 1510. 
-delta is 23 prefixes (cca 1.5%). 


And I can't figure out where I should be looking for these delta prefixes. 
I thought it might be something with the backup paths but those doesn't fit the counts anyhow. 
It's hard to do any capacity planning as I can't predict how the RIB counts are gonna be translated into FIB counts. 
I'd appreciate any pointers. 



adam