Access protocols for an efficient optical packet-switched metropolitan area ring network supporting IP datagrams

Novel distributed medium access protocols for a time-slotted WDM metro ring employing optical packet switching and supporting variable-length data packets such as IP datagrams directly in the optical layer are proposed in this paper. In the underlying control-channel based network architecture, much more nodes than available wavelengths may be accommodated and each node is equipped with three transmitters (two fixed-tuned and one tunable) and two fixed-tuned receivers. The new access control scheme relies on a frame-based slot reservation strategy including reservation of successive slots for data packets longer than the given slot size, and immediate access for packets shorter than the slot length. Thus, an efficient EP-over-WDM metro network with simple receiver hardware is obtained.