Abstract: A data grid allows large amount of data to be stored and shared among users at geographically different locations. However, when required, data has to be copied to the location where it is needed. This means a lot of network bandwidth will be used for the data transfer. One strategy employed in data grids is to make multiple copies of the data, called replicas, and place them in strategic locations so that the data is not too far from where it might be needed. When data is required, a user now has to choose among the different replicas. Hence, the need for best replica selection to reduce time, effort and resources needed to bring that data to where it is required. Best replica selection tries to estimate the cost involved in copying the data from the alternative replica sites. Most replica cost estimation models use only a few parameters to make the calculations, hence limiting their usage for specific purposes. In this work, we include multiple parameters, taking into account the cha

• Publication Date: 17-Nov-2014
• DOI: 10.15224/978-1-63248-051-4-26
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Abstract: We investigated the performance of RAMAN--EDFA, RAMAN-SOA, EDFA-SOA hybrid Amplifiers in 120 channel WDM systems with each channel having data rate 10 Gbps at reduced channel spacing of 50 GHz. The performance has been compared on the basis of different fiber length at dispersion equal to 2 ps/nm/km in terms of Q- factor, BER and Eye opening. The results showed that RAMAN – EDFA provides the highest Q-factor, lowest BER and maximum eye opening up to distance of 100 km as compared to RAMAN-SOA and EDFA-SOA hybrid amplifiers. RAMAN – EDFA is the best alternative to RAMAN-SOA and EDFA-SOA in high capacity WDM system with reduced channel spacing.

• Publication Date: 17-Nov-2014
• DOI: 10.15224/978-1-63248-051-4-27
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