Link aggregation schemes (e.g., EtherChannel) provide a resilient mechanism for fault tolerance, load balancing and scalable bandwidth by grouping a set of physical network interfaces into a logic link aggregation (LAG). Traffic on the logic link is evenly distributed in steady state and dynamically adjusted in response to system events to avoid traffic polarization and black-holing, which would otherwise eliminate the primary benefits of link aggregation.
While dynamic load distribution is essential to cope with link failure and operational changes, the corresponding hardware reprogramming imposes a major challenge on large scale campus and datacenter switch design. As the number of ports in the switch system increases, both the computational load and the frequency of hardware reprogramming grow exponentially, and hence adversely affect the reliability and system responsiveness of link aggregation schemes.