Ankara : The Department of Electrical and Electronics Engineering and the Institute of Engineering and Science of Bilkent University, 2008.Thesis (Ph.D.) -- Bilkent University, 2008.Includes bibliographical references leaves 132-139.Increasing demand for bandwidth and proliferation of packet based traffic
have been causing architectural changes in the communications infrastructure.
In this evolution, metro networks face both the capacity and dynamic adaptability
constraints. The increase in the access and backbone speeds result in high
bandwidth requirements, whereas the popularity of wireless access and limited
number of customers in metro area necessitates traffic adaptability. Traditional
architecture which has been optimized for carrying circuit-switched connections,
is far from meeting these requirements. Recently, several architectures have been
proposed for future metro access networks. Nearly all of these solutions support
dynamic allocation of bandwidth to follow fluctuations in the traffic demand.
However, reconfiguration policies that can be used in this process have not been
fully explored yet. In this thesis, dynamic wavelength allocation (DWA) policies
for IP/WDM metro access networks with reconfiguration delays are considered.
Reconfiguration actions incur a cost since a portion of the capacity becomes idle
in the reconfiguration period due to the signalling latencies and tuning times of
optical transceivers. Exact formulation of the DWA problem is developed as a
Markov Decision Process (MDP) and a new cost function is proposed to attain
both throughput efficiency and fairness. For larger problems, a heuristic approach
based on first passage probabilities is developed. The performance of the method
is evaluated under both stationary and non-stationary traffic conditions. The
effects of relevant network and traffic parameters, such as delay and flow size are
also discussed. Finally, performance bounds for the DWA methods are derived.Yetginer, EmrePh.D
