Overview

Telecommunications networks are generally so large and complex that manually designing a network in a reasonable amount of time is prohibitively difficult. Network designers primarily rely on automated algorithms to determine, for example, how to route traffic through the network, how to protect the traffic, and how to bundle the traffic into wavelengths. In systems with optical bypass, additional algorithms are needed to handle regeneration and to ensure that wavelength contention issues are minimal. The fact that networks have reached a stage where algorithms are essential in producing cost-effective and efficient network designs can be daunting. The good news is that extensive research has been done in this area and much expertise has been gained from live network deployments, resulting in the development of relatively straightforward algorithms that produce very effective network designs.

When designing network algorithms, it is important to consider the size of the problem in terms of the number of network nodes, the amount of traffic carried in the network, and the system specifications. Metro-core networks have tens of nodes whereas backbone networks may have as many as 100 nodes or more. The size of the demand set depends on whether the traffic requires grooming or not. First, consider a backbone network. If all of the traffic is at the wavelength linerate (no grooming needed), there are typically a few hundred to a couple of thousand demands in the network. If all of the traffic is subrate, such that grooming is needed, there could be tens...