Photon Netw Commun (2012) 24:58–70 DOI 10.1007/s11107-011-0367-2 Self-adapted algorithm to provide multi-profile bandwidth guarantees in PONs with symmetric and asymmetric traffic load Tamara Jiménez · Noemí Merayo · Patricia Fernández · Ramón J. Durán · Ignacio de Miguel · Rubén M. Lorenzo · Evaristo J. Abril Received: 8 April 2011 / Accepted: 29 December 2011 / Published online: 20 January 2012 © Springer Science+Business Media, LLC 2012 Abstract A novel bandwidth assignment algorithm in Ethernet Passive Optical Networks with different cover- age, called DySGAB, is proposed to provide subscriber differentiation. In contrast to algorithms which allocate bandwidth based on fixed weighted factors, DySGAB con- tinuously adapts the bandwidth assignation to fulfill the requirements of all profiles, leading to an outstanding per- formance. This auto-adjustment, which has not been imple- mented in any of today’s algorithms, allows the network to evolve automatically to the stipulated values even if they change in real time. As a result, not only does DySGAB ensure the guaranteed bandwidth for every subscriber, but also is independent of the initial bandwidth restrictions, which is an advantageous characteristic for service providers. Keywords Ethernet passive optical network (EPON) · Dynamic bandwidth allocation (DBA) · Automatic adaptation · Service level agreement (SLA) · High coverage 1 Introduction The growth of Internet traffic together with the unprecedented bandwidth requirements of the emerging web applications has made quite necessary the development of new high-band- width access networks. Passive Optical Networks (PONs) are widely regarded as a promising solution for this develop- ment due to its high bandwidth capacity and its cost effec- T. Jiménez (B) · N. Merayo · P. Fernández · R. J. Durán · I. de Miguel · R. M. Lorenzo · E. J. Abril Optical Communications Group, Department of Signal Theory, Communications and Telematic Engineering E.T.S.I. Telecomunicación, University of Valladolid, Campus Miguel Delibes, Paseo de Belén 15, 47011 Valladolid, Spain e-mail: tjimgar@gco.tel.uva.es tiveness. PONs are Point to MultiPoint (P2MP) high capac- ity access networks based on a tree topology between the Optical Line Terminal (OLT) and the Optical Network Units (ONUs). To achieve bidirectional transmission, two different wavelengths are used combined by means of WDM (Wave- length Division Multiplexing) techniques, one for the down- stream direction (from the OLT to the ONUs) and the other for the upstream transmission (from the ONUs to the OLT) [1]. In the downstream direction, the OLT broadcasts the mes- sages to all ONUs, but only the designated ONU will deliver the received traffic to its end users. On the other hand, in the upstream direction, PONs have a multipoint to point topology and all ONUs share the same transmission channel. Therefore, in order to avoid collisions among data from different ONUs, a Medium Access Control (MAC) mechanism is needed in the upstream direction. Dynamic Bandwidth Allocation (DBA) algorithms, based on the TDMA (Time Division Multiplex Access) protocol, are the best choice, as they dynamically distribute the available bandwidth depending on the current demand of ONUs [2–6]. These algorithms implement a status- report mechanism to efficiently allocate the bandwidth, where control messages are necessary to establish the communica- tion between the OLT and ONUs. Furthermore, current access networks have to deal with a multi-profile scenario, where a variety of users with dif- ferent needs exist. In this way, end users contract a Service Level Agreement (SLA) with a provider in which the quality requirements of every supported service, usually related to a minimum guaranteed bandwidth, are specified. This forces the network to differently deal with each SLA subscriber. Consequently, DBA algorithms have to support client differ- entiation to offer a variety of service levels with, for example, different bandwidth guarantees. One typical way to achieve client differentiation is using fixed weights assigned to each ONU according to its SLA. 123