A simple table-free distributed routing algorithm for 802.6

The authors propose a simple table-free routing technique for the IEEE 802.6 Distributed Queue Dual Bus (DQDB). It offers the simplicity of high-speed packet switching, such as Batcher-Bayan, techniques to metropolitan-area networks. As in high-speed packet switching networks, it consists of a number of stages. A so-called self-routing technique routes a packet from one end to the other without table processing. By checking only one bit in the routing tag of a message at each stage, a switch knows to which switch the message is to be routed in the next stage. The proposed technique is similar to the knockout switch. However, instead of performing switching in a small area, it covers a much wider (metropolitan) area. Therefore, the technique becomes distributed. The proposed routing technique can be extended to cover a service of point-to-multipoint communications, something which is essential for B-ISDN, while maintaining much of its simplicity. Various issues of sequential delivery, replication, and label management are addressed. A novel technique for simplifying topologies is presented