A mathematical model for wavelength assignment in wavelength division multiplexing mesh networks with wavelength reuse

Abstract

This letter presents a mathematical model that minimizes the number of wavelengths required for wavelength assignment in a wavelength-reusable multi-carrier-distributed (WRMD) wavelength division multiplexing mesh network. None of the source nodes in the WRMD network is equipped with laser diodes. It receives carrier wavelengths from a multi-carrier light source or reuses carrier wavelengths from other established lightpaths. The loop problem may occur in mesh topologies when a source node selects a reused carrier wavelength from a destination lightpath node, if we consider only flow conservation constraints, which are usually adopted in conventional network design. We solve the loop problem by formulating constraints that reflect the special characteristics of the WRMD network. To support the development of heuristic algorithms towards large-scale networks, our mathematical model, which can provide reference values including upper and lower bounds, is useful for benchmarks.

A routing and wavelength assignment scheme in multi-carrier-distributed optical mesh networks with wavelength reuse

“…First, the number of required wavelengths in the RWA scheme is compared with that of the fixed route (FR) scheme [12], which considers the fixed routes of optical carrier connections and requested lightpaths. Second, the number of required wavelengths by the RWA scheme is compared.…”

“…In order to evaluate the effectiveness of the RWA scheme, the number of required wavelengths is investigated. The number of required wavelengths in the ILP approach is compared with that of the FR scheme [12], which does not take into account the routing of optical carrier connections and requested lightpaths in the WRMD mesh network. The FR scheme is used as a reference scheme as it is only an existing scheme for the WRMD mesh network.…”

“…Therefore, the mesh topology makes distributing optical carriers and assigning wavelengths much more complex than the ring topology [11]. A mathematical model for wavelength assignment to minimize the number of required wavelengths for the WRMD mesh network was introduced in [12]. This model provides reference values, including upper and lower bounds, which are useful for benchmarking purposes.…”

“…This model provides reference values, including upper and lower bounds, which are useful for benchmarking purposes. However, the schemes of both [4] and [12] are unable to change the routes of optical carrier connections and requested lightpaths since they are fixed. In practical cases, all routes of optical carrier connections and requested lightpaths are required to be designed to minimize the number of wavelengths.…”

“…In practical cases, all routes of optical carrier connections and requested lightpaths are required to be designed to minimize the number of wavelengths. The work in [4][5][6][7][8][9][10][11][12] provided only a wavelength assignment scheme. The routing of optical carrier connections and requested lightpaths was not considered.…”