WDM metropolitan sectioned ring for Storage Area Networks extension with symmetrical and asymmetrical traffic

As storage area networks (SANs) are increasingly replacing traditional direct-attached storage (DAS) in many large data centers, many studies are considering extending SANs over large distances. SANs in a metropolitan wavelength-division multiplexing (WDM) scenario create asymmetrical traffic and hot-node scenarios. This paper proposes a sectioned WDM metropolitan ring network as a suitable extension for SANs. Two node architectures are considered, one uses two fixed transmitters and the other uses a tuneable transmitter. A tunable receiver is used with both architectures. For the two fixed-transmitters node architecture, two versions of medium access control (MAC) protocol are introduced. Simulation is carried out under both symmetrical and asymmetrical traffic sources. Performance of the sectioned ring is compared with that of the SAN ring network architecture proposed in [1].