2002 - cesnet

of these amplifiers has caused some troubles (e.g., short-time failures) whichcan be difficult to detect. The amplifiers offer no possibility for continuousmonitoring of the signal quality (e.g., through SNMP) and they can be controlledonly using a panel or a serial console (however, it is necessary to interrupttheir operation). The manufacturer has been looking for a possible solution;however, it would be rather complicated to operate more EDFA amplifiers withoutcomplete diagnostics and a management system.LiberecR44SDH AliatelSDH AliatelHradec KrálovéR45SDH TelecomPardubiceOstravaR48Ústí n. L.SW21R32EDFAEDFAEDFAR46ZlínSW21R32SW28ONSR50OlomoucPrahaR40EDFAR41ONSONSONSR42 R43BrnoR84R85R21SW4DWDM AliatelDWDM AliatelTeliaONSR53České BudějoviceNIX.CZGÉANTR5PlzeňR52EDFAONSLSR – Label Switch RouterPE – Provider Edge RouterEDFA amplifierCisco ONS 15104POS STM-161000BaseFXE3 serialATM E3dark fiberFigure 3.3: Existing topology of CESNET2 networkAt present, we are preparing an optical line from Brno to Bratislava with theSANET network. We plan to use the Catalyst 3524 and CWDM-GBIC as an amplifier,at a wavelength of 1,550 nm (the lowest signal attenuation). CWDM-GBIChas a higher optical output (approx. 30 dB), longer operating distance (approx.100 km) and it is even cheaper than the standard GBIC-ZX.CESNET2 makes use of the Cisco GSR 12016 routers with redundant key components(power supply, processors, switching arrays). In the middle of the year,we launched two external routers Cisco OSR 7609 (R84, R85), connected to the20 High-speed National Research Network and its New Applications 2002