Routing algorithm based on optical multi-protocol label switching using wavelength and code division multiplexing

Ahmed Sulyman Salih Musa, University of Texas at El Paso


The evolution of optical networks can be compared to the evolution of electronic transmission systems. Technologies such as Time Division Multiplexing (TDM), Frequency Division Multiplexing (FDM), and Code Division Multiplexing (CDM) are well established in electronic systems, and have an equivalent optical technology that is currently under development. Current optical-electrical-optical (o-e-o) systems utilize optical point-to-point links to provide extremely high data rates between connection points, and electronic switches for data routing. As key optical technologies become available, networks will migrate from o-e-o to an optimal optical-optical-optical (o-o-o) solution. The key optical technologies that help this migration are o-o-o switching and the multiplexing technologies in the optical domain such as Wave Division Multiplexing (WDM) and Optical-CDM. This study describes specific characteristics of optical technology and the requirements they place on routing and path selection. Moreover, a concept for an all-optical circuit-switched network is presented that utilizes near future WDM and Optical-CDM technologies. Mainly this study emphasizes on devising a routing algorithm for all-optical networks that uses these technologies and taking into consideration the optical technology attributes. Routing in all-optical networks needs to be cognizant of different resource types and resource characteristics such as fiber types, fiber linear impairments (attenuation, dispersion, etc.), and fiber nonlinear impairments (four-wave mixing, cross-phase modulation). There are also other types of impairments generated by optical nodes---photonic switches---that also affect the signal quality (Q) or the optical signal to noise ration (OSNR), which is related to the Bit Error Rate. Therefore, both link and switch impairments must be addressed and somehow incorporated into the routing algorithm. However, it is not practical to fully integrate all photonic-specific attributes in the routing process. In turn, new routing parameters and constraints must be defined that reflect the distinct characteristics of photonic networking. These constraints are applied to the design phase of all-optical networks. Thus, these constraints are expressed as a cost (or metric form) that will be used in this algorithm. Furthermore, this algorithm finds the best available circuit based on link and O(3) switch impairments by utilizing the characteristics of the flooding mechanism. To testify the optimality of the proposed algorithm, we consider networks with an arbitrary number of nodes (O(3) switch), and a fixed number of codes and wavelengths on each link. A route between a source or ingress node and destination or egress node can be constructed using a flooding mechanism which distributes messages, consisting of defined metrics, from ingress node to all-egress nodes such that wavelengths and codes used on each established path is not used by the already existing paths. This way, the distinguishable properties of flooding mechanism will be exploited to make it more popular in all-optical backbone networks. (Abstract shortened by UMI.)

Subject Area

Electrical engineering

Recommended Citation

Musa, Ahmed Sulyman Salih, "Routing algorithm based on optical multi-protocol label switching using wavelength and code division multiplexing" (2005). ETD Collection for University of Texas, El Paso. AAI3196415.