The design methods for logical topologies with consideration both traffic demand and hop count of physical route in IP over WDM networks

In recent years, many logical topology designing methods in IP over WDM networks have been researched in which HLDA (Heuristic Logical Topology Design Algorithm) and MLDA (Minimum-Delay Logical Topology Design Algorithm) are considered as basic algorithms using overlay architecture model in IP over WDM networks [1]. HLDA and MLDA set up the lightpath between the pair of nodes based on only its traffic demand. In this paper, we propose two algorithms, SHFLDA (Single Hop-Free Logical Topology Design Algorithm) and SHCLDA (Single Hop-Constraint Logical Topology Design Algorithm). They set up the lightpath between the pair of nodes based on both the traffic demand and the hop count of the minimum hop route for this pair of nodes. SHFLDA gets the low network congestion and SHCLDA gets the low average delay. There is a comparison of four parameters: the total traffic volume on the lightpaths established, the network congestion, the total traffic demand and the percentage of used wavelengths in the network in SHFLDA and SHCLDA. Our simulation results indicate that SHCLDA is more effective than SHFLDA if the scale of network is large and vice versa.