Multiple Path Selection Algorithm using Prime Number
Jae-Young Kim, Byungjun Ahn, Jungsik Kim · 2006
A novel algorithm for next-hop selection over a set of equal cost multiple paths (ECMP) in a router is presented, which provides for load sharing among multiple routes. The main idea of proposed algorithm called prime number modulo-N load balance (PMN-LB) is that the remainders are distributed equally when the multiples of a number are divided by prime number. Based on this specific property, PMN-LB assigns incoming flows to a next-hop selected. The hashed value of flow is divided by the number of multiple paths. If a next-hop pointed the remainder is available, this next-hop selected to forward packet. But if not, the prime number not less than the number of available multiple paths divides the hashed value and a next-hop is selected using this remainder. If the previous calculation is failed, the hashed value is divided by the number of available multiple paths. The disruption characteristic is remarkably improved using prime number division scheme. The lookup performance of PMN-LB is an optimal O(1) and disruptive behavior is between 0.125 and 0.500 in case N is the number of next-hops and N is equal to eight. As compared with other algorithm decided which next-hop to use, the performance of PMN-LB like modulo-N is an optimal O(1), disruptive behavior of PMN-LB is better than that of modulo-N and that of hash-threshold algorithm. But highest random weight (HRW)'s disruptive behavior with 1/N is better than that of PMN-LB. The load balancing between next-hops is nearly good