OpenFlow-Based Server Load Balancing Gone Wild
Source: Princeton University
Today's data centers host online services on multiple servers, with a front-end load balancer directing each client request to a particular replica. Dedicated load balancers are expensive and quickly become a single point of failure and congestion. The OpenFlow standard enables an alternative approach where the commodity network switches divide traffic over the server replicas, based on packet-handling rules installed by a separate controller. However, the simple approach of installing a separate forwarding rule for each client connection (Or "Microflow") leads to a huge number of rules in the switches and a heavy load on the controller.