System and method for adaptively balancing network traffic over router output ports

A method and system for determining an output port upon which to transmit a packet in a router having a plurality of output ports adapted to be coupled with an adjacent router. In one embodiment, a list is created of output ports that are coupled with the adjacent router, and the list is modified based on network traffic. A port is selected from the list of ports, and the packet is transmitted over the selected port. In one example, the list is modified continuously as a background process based on network traffic. The list may be modified by determining a port which is under-utilized, determining a port which is over-utilized, and substituting in the list one or more instances of the port which is over-utilized with one or more instances of the port which is under-utilized. In this manner, a router can adaptively and evenly distribute the packet transmission traffic over the output ports.