On the support of minimum service rates for input queue switches

The fast growth of the Internet has made popular applications with diverse and stringent transmission requirements. In order to meet this demand, packet switches today are designed to include the support of quality of service (QoS) as a powerful product differentiator. Customized packet handling on a flow by flow basis, ensuring switching objectives such as guaranteed throughput and bounded switching delays, is a goal likely to affect the entire switch architecture. The core of a packet switch, the switch fabric, is typically available as a single chip or chip set. These chip sets currently do not support QoS features, such as minimum packet service rates. This paper addresses an important feature of an input queue packet switch in the support of QoS: minimum service rates. We develop a framework for evaluating a switch fabric to support minimum service rate guarantees, and apply it to two well know switch fabric schedulers. In conjunction with a robust simulation environment, we verify that specific algorithms to ensure minimum service rates are needed. We develop several algorithms for this purpose and evaluate tradeoffs between service rate guarantees and throughput.