System and method for hierarchical metering in a virtual router based network switch

Abstract

A virtual routing platform includes a line interface a plurality of virtual routing engines (VREs) to identify packets of different packet flows and perform a hierarchy of metering including at least first and second levels of metering on the packet flows. A first level of metering may be performed on packets of a first packet flow using a first metering control block (MCB). The first level of metering may be one level of metering in a hierarchy of metering levels. A second level of metering on the packets of the first packet flow and packets of a second flow using a second MCB. The second level of metering may be another level of metering in the hierarchy. A cache-lock may be placed on the appropriate MCB prior to performing the level of metering. The first and second MCBs may be data structures stored in a shared memory of the virtual routing platform. The cache-lock may be released after performing the level of metering using the MCB. The cache-lock may comprise setting a lock-bit of a cache line index in a cache tag store, which may identify a MCB in the cache memory. The virtual routing platform may be a multiprocessor system utilizing a shared memory having a first and second processors to perform levels of metering in parallel. In one embodiment, a virtual routing engine may be shared by a plurality of virtual router contexts running in a memory system of a CPU of the virtual routing engine. In this embodiment, the first packet flow may be associated with one virtual router context and the second packet flow is associated with a second virtual router context. The first and second routing contexts may be of a plurality of virtual router contexts resident in the virtual routing engine.