In order to address poor bandwidth-utilization in circuit-switched WRONs, various techniques for optical packet-switching (OPS) have been explored, but needing complex technologies, such as real-time header extraction/insertion, packet alignment, etc. An intermediate solution between the WRONs and OPS networks – the optical burst-switched (OBS) network – has been explored, where several packets are clubbed together at ingress nodes to form optical bursts, which are transmitted with the headers sent as control packets ahead of each bursts. With this prior resource-reservation scheme at en-route nodes before burst arrivals, OBS networks overcome the challenges of OPS networks, while improving bandwidth utilization as compared to WRONs. We first present the node architectures, followed by header-processing schemes and switch designs for OPS networks. Next we present the basic concepts of OBS networking and describe the necessary network protocols, including burst assembly scheme, just enough time (JET) signaling, resource-reservation and routing schemes. (145 words)
Dynamic Wavelength Grouping for Quality of Service in Optical Packet Switching