Future network should be able to eficiently serve Most existing telecommunication wide area networks (WAN) packet-based networks, such as the Internet. In this paper, based and Metropolitan Area Networks (MAN) have an SDH based. on results from COST 266, we explore characteristics of Optical electronically circuit switched transport core. Connection setBurst switching (OBS) and Optical Packet Switching (OPS).up or tear down may require days or weeks, and switching as Both node and Area Network (MAN) are well as inultiplexing/demultiplexiilg always requires complex discussed. A unique joint comparative performance evaluation of optical/electro,optical (oEIo) conversions, tile contention resolution in OBS and OPS are presented, as well as which controls set-up and tear-down of connections. Work on networks, and their performance. automatically switched optical network (ASON) and Xeywords: burst switching, packet switching, contention generalised multi-protocol label switching (GMPLS) takes place within ITU and IETF, respectively. Resulting Optically of Quality of Service (QoS) differentiation in OBS,OPS operators and vendors =e working on an optical Control plane, resolution, node design, Qualie of Service, simuldios -7ih International Conference on Telecommunications -ConTEL 2003 ISBN: 953-184-052-0, June 11-13, 2003, Zagreb, Croatia 775 Circuit Switched (OCS) networks can offer explicit transfer guarantees, since circuit establishments are confirmed. However, this generates a delay at least equal to the round-trip time, typically several ms. Even though OCS networks will offer more flexibility than today's solution, the access to the optical bandwidth is still provided with fihrdwavelength granularity. Future networks should he able to serve a client layer that includes packet-based networks, such as the Internet, which may have a highly dynamic connection pattern with a significant portion of bursty traffic between the communicating pairs. In this case, OCS transport may not be flexible enough. It would require over-dimensioning of the number of connections and of the bandwidth reservation of each connection, to avoid excessive delay and extensive buffering at the ingress routers. Here is when Optical Packet Switching (OPS) and Optical Burst Switching (OBS) come into play, with the goal of reducing delays and improving the utilization of the network's resources through statistical multiplexing. This comes at the expense of not being able to offer explicit transfer guarantees. However, suitable node design and proper dimensioning of network resources may enable support of most services over the same network. Moreover, OPS and OBS may share the WDM layer with an OCS scheme, serving applications with need for explicit transfer guarantees. In the first part of this paper we present a strictly non-blocking node design suitable for OPS/OBS. Then, we show how the node-design can he simplified, with the drawback that it becomes blocking. We then elaborate on how the performance of this blocking node can approximate the ...
