

Articles
by
H.T. Ewe 
Total Records (
4 ) for
H.T. Ewe 





A. Abid
,
F.M. Abbou
and
H.T. Ewe


Optical Bursts Switching (OBS) is a flexible yet efficient photonic switching paradigm. However, due to their oneway resource reservation mechanism, OBS networks experience high bursts (thus packets) loss rate. In OBS networks, the contention is resolved either by dropping one of the contending bursts, or more efficiently by dropping from one of the contending bursts only the parts that overlap with the other burst. In both situations, only one data source will suffer the data loss in favor to the other. In this study a simple yet effective network resource allocation algorithm is presented. With this algorithm, the dropped segments are selected evenly from both contending data bursts. Furthermore, the truncated data bursts (forwarded or deflected) are guaranteed to be larger than the minimum burstlength allowed by the network specification. Additionally, the algorithm is demonstrated to be practical if used in a mechanism to provide differentiated services to IP packets over an OBS network. A simulation is used to evaluate the performance of the algorithm. 




S.C. Tan
,
F.M. Abbou
,
H.T. Ewe
and
Y.P. Singh


In this study, a new linear formulation for wavelength assignment is presented. The proposed a heuristicbased algorithm
allows to solve wavelength assignment problem in optical network with less computational effort compared with Integer Linear
Programming (ILP) approaches with large size of network. It is found that the proposed heuristic can yield to stable, efficient and reliable results with increasing traffic demands. 




S.C. Tan
,
F.M. Abbou
and
H.T. Ewe


The impact of FourWave Mixing (FWM) is investigated
using the proposed Assign Shortest Path First (ASPF) algorithm for wavelength
assignment in Routing and Wavelength Assignment (RWA) in two different
topologies. The results show that the ASPF algorithm indulges more FWM
crosstalk in a 8 node Ring topology compared with a 8 node Mesh topology
for optical channels of 16 and 32. Careful optical channel capacity, low
FWM crosstalk power in different network topology are strongly desired
for the accomplishment of efficient, costeffective, high capacity WDM
transparent optical network. 




S.C. Tan
,
F.M. Abbou
and
H.T. Ewe


An Antbased algorithm is proposed for Four Wave Mixing (FWM)Aware Wavelength Assignment with the objective to optimize light path connection according to the wavelength clash and wavelength continuity constraints while guaranteeing acceptable signal quality according to FWM crosstalk. Performance results show that the proposed antbased algorithm outperforms the Assign Shortest Path First (ASPF) algorithm. It is found that in the case of Ant algorithm, the induced blocking probability is lower compared to ASPF algorithm in the presence of FWM. 





