Reliable multicast for control in distributed routers

Growing traffic volumes and demands for new services rapidly increase the requirements imposed on network systems, such as BP routers. We argue that a decentralized modular system design would improve the scalability, flexibility, and reliability of future routers. We have designed and implemented such a distributed router, based on physical separation between control and forwarding elements. One challenge with the design concerns the internal communication between the elements constituting the router. This paper presents performance measurements of different internal transaction mechanisms between the control and forwarding planes. In particular, an existing protocol for reliable multicast has been integrated and evaluated in our experimental prototype. The prototype consists of one control element and up to 16 forwarding elements, interconnected by an internal control network based on Ethernet switches.