Load balancing with minimal flow remapping for network processors

Maintaining high performance in parallel processing routers while preserving packet ordering within the flows is a difficult problem. To preserve packet ordering, hashing at the flow level has been used to distributed packet processing workload among the router processing units. Even though it preserves ordering, hashing alone may cause significant workload imbalance and thus adaptive methods are usually needed. In this paper, we present an input port selection scheme that can be augmented with the adaptive Highest Random Weight (adaptive HRW) method. The adaptive HRW is a hash-based method that works at the flow level and is used to balance packet processing workload among the router processing units. When imbalance occurs, the adaptive HRW method triggers all input ports to re-balance their workload among the processing units. When augmented the selection scheme, the adaptive HRW method should be able to identify the subset of input ports responsible for the imbalance. The simulation results show that deploying the selection scheme with the adaptive HRW significantly reduces the number of flows remapped while balancing the packet processing workload among the router processing units.