TABLE OF CONTENTS Noem Merayo
University of Valladolid, Spain
Patricia Fern ndez
University of Valladolid, Spain
Ram n J. Dur n
University of Valladolid, Spain
Rub n M. Lorenzo
University of Valladolid, Spain
Ignacio de Miguel
University of Valladolid, Spain
Evaristo J. Abril
University of Valladolid, Spain
Passive Optical Networks (PONs) are very suitable architectures to face today's access challenges. This technology shows a very cost saving architecture, it provides a huge amount of bandwidth and efficiently supports Quality of Service (QoS). In PON networks, as all subscribers share the same uplink channel, a medium access control protocol is required to provide a contention method to access the channel. As the performance of Time Division Multiplexing Access (TDMA) protocol is not good enough because traffic nature is heterogeneous, Dynamic Bandwidth Allocation (DBA) algorithms are proposed to overcome the problem. These algorithms are very efficient as they adapt the bandwidth assignment depending on the updated requirements and traffic conditions. Moreover, they should offer QoS by means of both class of service and subscriber differentiation. Long-Reach PONs, which combine the access and the metro network into only one by using 100 km of fibre, is an emergent technology able to reach a large number of far subscribers and to decrease the associated costs.
