Netflow

ip route-cache flow or ip flow ingress?

ip route-cache flow will enable flows on the physical interface and all sub-interfaces associated with it.
ip flow ingress will enable flows on individual sub-interfaces, as opposed to all of them on the same interface.

Ref: http://www.plixer.com/blog/general/ip-route-cache-flow-or-ip-flow-ingress-which-do-i-use/
http://www.cisco.com/en/US/docs/ios/12_2t/12_2t15/feature/guide/ft_nfsub.html
http://www.cisco.com/en/US/prod/collateral/iosswrel/ps6537/ps6555/ps6601/prod_white_paper0900aecd80406232.html