Patent ID: 7738396

Claim:
An apparatus comprising: a set of interface cards to receive packets of a plurality of packet flows from a network; a plurality of accounting service cards to calculate flow statistics for the packet flows, wherein each of the accounting service cards calculates flow statistics for a subset of the packet flows, and wherein at least one of the plurality of accounting service cards generates packets carrying the calculated flow statistics; and a centralized control unit to receive the packets of the plurality of packet flows from the set of interface cards and distribute the packets of the plurality of packet flows across the plurality of accounting service cards such that packets of common packet flows are distributed to the same one of the plurality of accounting service cards, a tunneling service card that receives the packets carrying the calculated flow statistics for the respective packet flows, aggregates flow statistics from the different accounting service cards, and returns the aggregated flow statistics to the control unit, wherein the centralized control unit forwards the packets that carry the calculated flow statistics to the network via a network tunnel in accordance with forwarding information that associates the packets with next hops along routes through the network.