El acceso a la versión del editor puede requerir la suscripción del recurso Access to the published version may require subscription technology is expected to become mature in the medium term, and it may be used as an alternative to current OCS networks, due to its potential advantages in terms of bandwidth allocation granularity. While OBS is being extensively studied in the literature, little attention has been paid to comparative analysis of OBS versus OCS, specially concerning cost analysis. In this paper, we provide a comparative analysis of OBS versus OCS as an evolutionary technology for all-optical rings in the metropolitan access network. This study is specifically targeted towards optimizing the number of optoelectronic (O/E) receivers and wavelengths, with real traffic matrices from the metropolitan rings in the city of Madrid, Spain. Such matrices also include traffic projections of foreseeable broadband services, based on a market analysis from the largest operator in Spain. Our findings show that OCS might be more efficient than OBS in the metro access segment, which is characterized by a highly centralized traffic pattern. However, the more distributed the traffic is the more efficient OBS is. Consequently, OBS might be better suited to metro-core networks, which show a more distributed and dynamic traffic pattern.

Abstract. Services based on packet switched networks are becoming dominant in telecommunication business and both operators and service providers must evolve in order to guarantee the required quality. Increasing bandwidth is no longer a viable solution because of the business erosion for network operators which cannot expect revenues due to the large investments required to satisfy new applications demand of bandwidth. This paper presents devices and a specific architecture of services monitoring platform that allows network operators and service providers to analyze the perceived quality of service and check their service level agreements. Thus, a cost-effective service management, based on direct IP traffic measuring, can be supported on integrated monitoring systems to provide network-centric mechanisms for differentiated quality of service, security and other advanced services.

Network operators have been facing big changes since IP traffic began overwhelming other kinds of data transport. On the other hand, access networks are continuously improving and it is anticipated that bandwidth demands will exponentially increase within next decade to cope with triple-play service requirements. The first level of aggregation, namely metro access networks, can become the bottleneck if no serious modifications are carried out because they were initially designed for circuitoriented services such as analogical voice transmission and they can not keep up with bandwidth demands at reasonable Capital Expenditure efforts. In this paper, the authors present a migration roadmap for metro access networks derived from the results of NOBEL, ePhoton/One and FIRM* European research projects. To achieve it, Dual Bus Optical Ring Network (DBORN), Resilient Packet Ring (RPR) and Optical Circuit Switched Rings (OCSR) architectures have been analyzed both from the technological and the economic point of view in the short and medium term.

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