2002 - cesnet

Cisco GSR 12008GE-GBIC-ZXlinkCisco 7500GE-GBIC-ZXEDFAfiber 180 kmboosterFigure 4.8: Testing configuration for GE, with booster onlyCisco GSR 12008GE-GBIC-ZXlinkCisco 7500GE-GBIC-ZXEDFAfiber 180 km EDFAbooster preamplifier optical filterFigure 4.9: Testing configuration for GE, with booster and preamplifierCisco GSR 12008GE-GBIC-ZXlinksplitterCisco 7500GE-GBIC-ZXEDFAEDFAfiber 180 kmbooster preamplifier optical filterRamanpumpFigure 4.10: Test configuration for GE, with booster, preamplifierand Raman pumpThe Prague–Pardubice line was further monitored in order for us to identify thebehaviour of optical amplifiers under the conditions of a long-term operation.The line reported very good results and we therefore decided to continue andinstall two EDFA 24 dBm boosters on another line, Prague–Ústí n. L., again usingthe Gigabit Ethernet technology.There were some problems reported on this line – the card in the new Cisco7609 router behaved in a non-standard manner after its connection to the linewith optical amplifiers, resulting in a loss of the connectivity. It turned out laterthat this was caused by short-term signal dropouts (30 ms), which occured dueto an error in the firmware of Keopsys optical amplifiers. Keopsys and Ciscodebugged their software and at present, both lines are free of errors.During the second half of the year, we also began to make a more intensive useof Optisim and Artis simulating programs, particularly for the simulation of tests58 High-speed National Research Network and its New Applications 2002