Delay-Constrained Admission and Bandwidth Allocation for Long-Reach EPON

Abstract

Next generation Passive Optical Network (PON)technology has been evolving to consolidate the metro andaccess networks in order to offer enhanced capacity, highsplit ratio and reduced deployment cost per subscriber.However, transmission of the signals to long distances up to100km leads to increased propagation delay whereas highsplit ratio may lead to long cycle times resulting in largequeue occupancies and long packet delays. In this article, wepresent a delay-constrained admission control mechanismand adapt this scheme to our previously proposed bandwidthallocation technique, namely Periodic GATE Optimization(PGO). We call this new scheme Delay-Constrained PeriodicGATE Optimization (DC-PGO). DC-PGO is designed to runfor multiple service classes as it inherits the advantages ofPGO by periodically building and solving an ILP formulationat the OLT in order to obtain the appropriate creditvalues for the overloaded ONUs. At the ONU side, DCPGOruns an admission control scheme before pushing thearriving packets in the sub-queues. The admission controlscheme uses statistical information consisting of the localdata at the ONU and the previously received GATE messagesfrom the OLT. Through simulations, we show that DC-PGOenhances the performance of multi-threaded polling in longreachEthernet PON when packets of differentiated serviceclasses arrive with pre-specified delay requirements.