Many-to-Many Traffic Grooming in WDM Mesh Networks

In many-to-many communication, a session consists of group of users (we call them members) where each one of the members transmits its traffic to all other members in the group. This paper studies the problem of provisioning many- to-many sessions with sub-wavelength granularities in WDM mesh networks. Our objective is to minimize the number of transceivers required. We study the problem in networks with and without optical splitting capabilities. For networks without optical splitting capabilities, we use an optimal approach which is an extension of that introduced in [8] for the many-to-one traffic grooming problem. For networks with optical splitting capabilities, we introduce a novel hub-based approach where each session is routed through a many-to-one tree from the members to a central hub node, and then through a multicast tree from the hub node back to the members. At the hub node, network coding is performed by linearly combining the traffic units received from the members. These combinations are then groomed and delivered back to the members using light-tree(s). Numerical results from both approaches are presented and compared.