CESNET among World Leaders in CEF Networks Design and Operation

CESNET is probably in a best position among the world leaders in long-span CEF Network design and operation now. This is a result of some four-year development supported by universities, Academy of Sciences and by the nearly all dark fibre owners in the Czech Republic.

Current development of National Research and Education Networks worldwide is heading towards optical networks run by customers themselves (Customer Empowered Fibre network, CEF). CESNET set off on this trail as one of the first organizations at a time when only several supported this trend; CESNET prepared a 323 km long 2.5 Gbps Prague–Brno line by leasing optical fibres in 1999 and started operation of this circuit in February 2000. As a result, two kinds of gigabit transmission lines existed in the CESNET2 production network: leased dark fibre lines equipped with transmission devices controlled by the CESNET staff, and leased gigabit transmission services controlled by telco operators. It was found out that leasing dark fibres should be strongly preferred for costs reasons. Moreover, using own transmission equipment brings very important advantages concerning the future network design and control. Such networks offer not only the best effort services but also services needed for real-time applications (remote connection to expensive or unique research devices, remote presence, remote collaborative environment, etc.).

Since 2002, intensive efforts have been made to convert the CESNET2 NREN to dark fibres. In contrary to other contemporary CEF networks worldwide, we opted to significantly decrease the number of regeneration or amplification devices placed in housing points (so-called huts) in field along the dark fibre line. Instead of commonly used fibre lines with spans between huts of about 80 km, very long multiple fibre span (about 150–200 km each) lines or single-span lines (up to about 300 km) have been deployed. This hut-skipping technique reduces the operation expenses (OPEX) and is very important if lack of highly experienced optical staff prevails. Consequently, the architecture of NRENs (placing the PoPs within university premises) as well as of other CEF Networks can be adapted to minimize the number of huts used.

Experiments with EDFA amplifiers carried out during the first half of 2002 brought us two lines using a state-of-the-art technology called NIL (Nothing-In-Line): a 189 km line between Prague and Pardubice and a slightly shorter one between Prague and Ústí, both with transfer rates of 1 Gbps (a 2.5 Gbps rate was tested as well) in the CESNET2 production network. The results achieved were presented at the TERENA TNC2002 conference. At the end of 2002, CESNET leased over 1,000 km of fibre pairs. In 2003, CESNET established collaboration with a supplier to construct optical fibre first-mile lines. The CESNET2 production network upgrade to customer empowered dark fibres was mostly completed in 2003. Now, in October 2004,

• CESNET uses 3643 km of dark fibre, including 3160 km in the CESNET2 nationwide production network
• most of these fibres are lighted as long-span lines; as far as we know, CESNET has a world-leading position in design and operation of long-span CEF Networks
• CESNET-made PC Light equipment using optical modules evaluated for lighting a single-span Praha–Brno testbed line proved as a significantly cheaper and more suitable alternative to commercially available stand-alone optical amplifiers
• all gigabit lines of the Czech Republic NREN are dark fibre lines empowered by CESNET (the last leased gigabit service delivered by a telco operator has terminated)
• CESNET has deployed six single-fibre intercity lines (over 350 km in total) with transmission speeds of 100 Mbps, especially suited to connecting smaller nodes to the network
• an international 1 GE dark fibre line Brno–Bratislava to the Slovak NREN SANET is operational
• an international 1 GE dark fibre line Ostrava–Bielsko-Biala to the Polish NREN Pionier is operational
• a dark fibre 1 GE NIL 235 km line Brno–Ostrava is operational in the CESNET production network,
• a dark fibre 10 GE NIL 302 km line has undergone successful laboratory tests in laboratory and is prepared for deployment.

The actual load of CESNET2 lines can be found on http://www.cesnet.cz/provoz/zatizeni/.

More information about the CESNET optical networking research is available on http://www.ces.net/doc/2003/research/optnet.html.

The CESNET association was established by the universities and the Academy of Sciences of the Czech Republic in order to operate a national network for science and research. It is financed from the funds of the Government Council for Science and Research and of its members. At present, it operates the national optical gigabit network CESNET2 and works together with Canada, the Netherlands and the U.S.A. on the building of the global lambda network GLIF (Global Lambda Integrated Facility), the Czech part of which is called CzechLight. Thanks to its research activities in the field of telecommunications and Internet technologies, CESNET is the representative of the Czech Republic in the European project GÉANT, in which it takes an active part.