On dynamically establishing and terminating isochronous message streams in WDM star‐based lightwave networks

Abstract

Complement to our prior work in [21], we address in this paper the problem of dynamically establishing/terminating real‐time message streams in response to call setup/clear requests in single‐hop star‐coupled WDM optical networks.

We consider a network architecture in which N stations are connected to a star coupler with W data channels (W≤N) and one control channel. Each of the W data channels is slotted and shared by the N stations by means of time division multiplexing. The control channel is used for stations to coordinate the call establishment and termination operations. We propose a distributed, dynamic slot allocation scheme to allocate/de‐allocate time slots on the W data channels to message streams, with the objective of meeting message deadlines.

To facilitate slot assignment, the proposed scheme first decomposes each message stream into a set of message sub‐streams, and groups the time slots on each wavelength channel into sub‐channels. In response to a call setup request, the proposed scheme then allocates one or more empty sub‐channels available over the W data channels to a message stream to fulfill its temporal requirement, subject to the source/destination constraints and that the temporal guarantees to existing message streams should not be violated. On the other hand, in response to a call clear request, the proposed scheme releases the slots allocated to the terminated message stream, and merges, if appropriate, empty sub‐channels to facilitate future message stream establishment. We formally prove the properties, and the correctness of, the proposed dynamic slot allocation scheme.