Traffic Grooming in Unidirectional WDM Rings with Bounded Degree Request Graph

TL;DR

This paper addresses traffic grooming in unidirectional WDM ring networks by developing flexible graph partitioning methods for request graphs with bounded degree, optimizing equipment cost and network adaptability.

Contribution

It introduces a formal model for traffic grooming with bounded degree request graphs and provides solutions for specific degree cases, enhancing flexibility over existing models.

Findings

Solutions for Δ=2 for all C values

Solutions for Δ=3 except C=4

Lower and upper bounds for general cases

Abstract

Traffic grooming is a major issue in optical networks. It refers to grouping low rate signals into higher speed streams, in order to reduce the equipment cost. In SONET WDM networks, this cost is mostly given by the number of electronic terminations, namely ADMs. We consider the case when the topology is a unidirectional ring. In graph-theoretical terms, the traffic grooming problem in this case consists in partitioning the edges of a request graph into subgraphs with a maximum number of edges, while minimizing the total number of vertices of the decomposition. We consider the case when the request graph has bounded maximum degree $\Delta$, and our aim is to design a network being able to support any request graph satisfying the degree constraints. The existing theoretical models in the literature are much more rigid, and do not allow such adaptability. We formalize the problem, and solve the cases $\Delta=2$ (for all values of $C$) and $\Delta = 3$ (except the case C=4). We also provide lower and upper bounds for the general case.