Impact of graph theoretic network parameters on the design of regular virtual topologies for optical packet switching

The design of regular virtual topologies to facilitate optical packet switching in networks with arbitrary physical topologies is studied in this paper. Due to the intractable nature of the problem, two different artificial intelligence based heuristics are used to find favourable solutions expeditiously. The impact that the spread of the degree of physical topology nodes has on the quality of solutions obtained is investigated. Two important counter-intuitive findings emerge from this paper. Firstly, increasing the spread of the nodal degree in the physical topology leads to an improvement in the quality of initial non-optimised (or random) solutions. Secondly and conversely, increasing the spread of nodal degree has a detrimental impact on the final optimised solutions obtained. Both these surprising conclusions are explained by introducing novel estimates for the initial cost and the margin for improvement on this cost. The results produced in this paper are interesting and are applicable to the design of regular virtual topologies in generic physical topologies and additionally, suggest principles that are applicable to the wider area of telecommunication network design.