Traditional NetFlow exports the IP Next Hop information which is used to provide the end-to-end visibility of flow paths. The NetFlow BGP Next Hop
feature adds BGP next hop information to the data export. This feature also allows service providers to track which service provider the traffic is going through which is useful if you have arrangements with several other service providers for fault-protected delivery of traffic.
Loaded with BGP Next Hop information, service provider NetFlow support allows an ISP to charge customers more per packet when traffic has a more costly destination. In other words, they can pass on some of the cost associated with expensive trans-oceanic links which take advantage of an expensive charge agreement.
Memory Impact
For BGP-controlled routes, the NetFlow BGP Next Hop Support feature adds 16 bytes to each NetFlow flow record. This increases memory requirements by 16 bytes times the number of flow cache entries that have BGP-controlled prefixes.
Performance Impact
Because the BGP next hop is fetched from the CEF path only once per flow, the performance impact of the NetFlow BGP Next Hop Support feature is minimal.
When BGP reporting is necessary, generally calls for autonomous system data aren’t too far behind. Most organizations looking to do NetFlow accounting require these NetFlow elements for their network traffic monitor.
Generally, NetFlow billing is a part of what the service provider is trying to do when they investigate NetFlow BGP support. Reach out to us if you need help setting this up.