Multicast Grooming Algorithm in Waveband Switching Optical Networks

In optical Wavelength-Division-Multiplexing (WDM) networks, multicast becomes more and more popular to provide high-speed communication between one point and multiple points. At the same time, the ports of Optical Cross-Connect (OXC) are greatly enhanced with the increasing number of wavelengths in fibers, and then the waveband switching technique is proposed to save the ports and reduce the cost of OXC. However, current waveband grooming algorithms are all limited in unicast. To achieve the multicast communication and meanwhile save the ports of OXC, we need to solve the multicast grooming, routing and wavelength/waveband assignment problem which is the HP-hard. In this paper, we propose a heuristic algorithm named Integrated Multicast Waveband Grooming (IMWG) based on Multicast Layered Auxiliary Graph (MLAG) that includes a Virtual Topology Layer (VTL) and multiple Waveband-Plane Layers (WPLs) to support the single-hop, multi-hop and hybrid multicast waveband grooming. For each demand, IMWG first computes a single-hop or multi-hop grooming waveband-tree on VTL. If the grooming waveband-tree cannot be found on VTL, IMWG computes a new waveband-tree on WPL. If the new waveband-tree cannot be found on WPL, IMWG computes a hybrid grooming waveband-tree on MLAG. Simulation results show that, compared with other algorithms, IMWG is able to obtain better performances.

I. Introduction

With the large increase of service requirements in the Internet, multicast applications become more and more popular. Multicast applications provide communications between one point (source node) and multiple points (destination nodes), such as in video distribution and multiparty conferences. In order to achieve multicast communication, a feasible multicast-tree from the source node to all detonation nodes needs to be established to transmit the traffic for each multicast demand. In optical Wavelength-Division-Multiplexing (WDM) networks, multicast in optical layer has got more attention in recent years to achieve high-speed and reliable multicast communication [1]–[4], where the multicast-tree in optical layer is also called light-tree that is established based on wavelength channels, or waveband-tree that is established based on waveband channels.