This book is about the load-balanced router, a router architecture that is scalable and can guarantee a full capacity. A load-balanced router consists of two stages. First, a load-balancing stage spreads arriving packets equally among linecards. Then, a forwarding stage transfers packets from the linecards to their final destination. A load-balanced router does not use any centralized scheduler, as most current router architectures. Therefore, it can scale while providing the throughput guarantees needed by network operators. It this book, we show how to implement the load-balanced router using a single passive optical switch fabric with no reconfigurations, while current routers commonly need switch fabrics with fast reconfiguration times. Further, we introduce a simple distributed algorithm that can avoid packet reordering, a common problem of load-balanced architectures. Finally, we present a practical switch fabric architecture that would enable load-balanced routers to scale to higher numbers of interfaces. We conclude by showing that the load-balanced router can help provide the scalability and capacity guarantees needed in the Internet.
