Centralized vs. Distributed Connection Management Schemes under Different Traffic Patterns in Wavelength-Convertible Optical Networks

Centralized and Distributed methods are two connection management schemes in wavelength convertible optical networks. In the earlier work, the centralized scheme is said to have lower network blocking probability than the distributed one. Hence, much of the previous work in connection management has focused on the comparison of different algorithms in only distributed scheme or in only centralized scheme. However, we believe that the network blocking probability of these two connection management schemes depends, to a great extent, on the network traffic patterns and reservation times. Our simulation results reveal that the performance improvement (in terms of blocking probability) of centralized method over distributed method is inversely proportional to the ratio of average connection interarrival time to reservation time. After that ratio increases beyond a threshold, those two connection management schemes yield almost the same blocking probability under the same network load. In this paper, we review the working procedure of distributed and centralized schemes, discuss the tradeoff between them, compare these two methods under different network traffic patterns via simulation and give our conclusion based on the simulation data

JA(G)OBS Simulator: Implementation of the main features of the routing protocol

Projecte final de carrera fet en col.laboració amb Instituto Universitário de Lisboa. Departamento de Ciências e Tecnologias da InformaçãoEnglish: Optical Burst Switching (OBS) is an optical switching paradigm that has been re-gaining attention in the last few years after its boom around the year 2000. This paradigm is able to bring together the present technology (avoiding the optical buffer technology hurdles) and what is envisaged for future networks (packet-based optical switching). However it lacks a well-defined control plane that can keep up with quality of service (QoS) demands by Internet applications and end-to-end connectivity among multiple switching domains controlled by a single control instance. Generalized Multi-Protocol Layer Switching (GMPLS) is a technology that can give the missing link to OBS. It is the extension of the Multi-Protocol Layer Switching (MPLS) which was designed for IP networks to introduce fast forwarding and Traffic Engineering (TE). GMPLS evolves from MPLS to deal with non-IP networks, e.g. SDH and WDM. However, it does not handle OBS so far. This Master Thesis contributes towards this GMPLS-OBS interoperability by the development of some features to the Java Event-Driven Simulator of the GMPLS-OBS architecture called JA(G)OBS. This thesis comes up in sequence of another UPC-ISCTE Master Thesis of João Baião from September 2010, who implemented some of the basic features of the GMPLS Signaling protocol in the simulator. In particular, this Master Thesis will focus on the implementation of the GMPLS Routing protocol basic features in the simulator and to deploy a Graphical User Interface (GUI) for the simulator. The GMPLS Routing protocol considered in the simulator is the Open Shortest Path First with Traffic Engineering (OSPF-TE) which is one of the standards of GMPLS routing