Grid Job Routing Algorithms - Phosphorus

Grid Job Routing AlgorithmsFigure 6.2: PHOSPHORUS testbed performance under PMD impairment for various loads.Currently, network designers utilize two types of amplifiers: semiconductor optical amplifiers (SOAs) anderbium doped fiber amplifiers (EDFAs). SOAs are cheaper and smaller devices than EDFAs; however, they arecharacterized by bigger noise figure and thus bigger n sp values. Typical SOAs are characterized by n sp valuesup to slightly less than 7, while typical EDFAs are characterized by n sp values in the range between 1.5 and 3.Considering Figure 6.2 and Figure 6.4, the ASE noise effect seems negligible at G=17.5 dB with FEC, whilewhen FEC is not used the ASE noise effect becomes an issue even at G=17.5 dB. Generally, the performanceof the network is not satisfactory when FEC is not used and for this reason we won’t analyze it further here. ForG=17.5 dB with FEC, the performance curve rises at n sp = 4, denoting that the network’s throughput divertsfrom 100% in presence of 35 or more such SOAs per path. By increasing G to 20 dB the curve rises at n sp =3,indicating that an average placement of 26 or more SOAs of n sp =3 per path leads to positive blockingprobability, and rises up to 40% for n sp = 5 that corresponds to an average placement of 16 such SOAs perpath. At G=22.5 dB and FEC, the curve rises almost from the beginning (at n sp =2), indicating that an averageplacement of 22 or more such SOAs per lightpath is required to yield to a non zero blocking probability. AtG=25 dB and FEC, more than 20% of the requested connections are blocked, even in presence of a sufficientlylarge number of wavelengths and SOAs with optimal noise figures (for n sp =1.5 we have 16 amplifiers), and 12Project:PHOSPHORUSDeliverable Number: D.5.3Date of Issue: 31/06/07EC Contract No.: 034115Document Code: Phosphorus-WP5-D5.358