CZ-AT-SK Cross-border Fibre Triangle Fundamentally Upgraded

Prague, 20 April 2016. The cross-border dark fibre triangle, built in a collaboration between research and education networks of the Czech Republic (CESNET), Austria (ACOnet) and Slovakia (SANET), has been upgraded to allow transfer of advanced photonic services with a total attainable capacity of 1.6 Tbps.

The new design is based on a dense wave multiplex (DWDM) system with eight channels per line, with each channel capable of transmitting data at up to 200 Gbps. The deployed Czech Light® photonic system was developed as part of CESNET’s research activity.

The triangular topology network is built over cross-border dark fibres at a total length of 519 km, connecting Bratislava, Brno and Vienna. With the total line attenuation of 134 dB, only two intermediate amplifying nodes are used. Variable re-configurable elements with integrated channel monitors are deployed in critical points for remote supervision. Fibre Bragg Gratings (FBG) are used to compensate chromatic dispersion; unlike conventional compensation modules, they will enable further capacity increases in future if coherent transfer systems are used.

The L2 ethernet infrastructure has also been rebuilt above the photonic layer. The current design uses the TRILL technology, ensuring shortest-path routing of L2 frames, even distribution of loads among parallel lines, and fast convergences in the event of changes.

The innovated infrastructure supports data transfer services with a guarantee of very low latency and high availability for academic communities of all the three countries, and is ready for demanding network applications (e.g., precise time transmission, stable frequencies and synchronisation).

CBF Triangle

ACOnet is the Austrian infrastructure for science, research and education, operated by the University of Vienna. ACOnet provides a powerful and robust fibre-optic backbone network using primarily gigabit and 10-gigabit Ethernet technology, with main nodes located at universities in Graz, Innsbruck, Klagenfurt, Linz, Salzburg, and Vienna. ACOnet provides its participating organizations with multi-gigabit internet access, with a special focus on quality national and regional connectivity through public and private peerings, and offering excellent connectivity to the European and global research community via the GÉANT infrastructure. For details visit:

The SANET Association was founded in 1991 by Slovak universities, schools and the Slovak Academy of Sciences as a non-profit organization managing a dark fibre infrastructure, consisting of leased fibres in the national backbone network as well as its own fibres in metropolitan networks. On this infrastructure SANET has been providing multi-gigabit IP services and 2nd layer services for academic, research and education organizations in the Slovak Republic. Since 2002 the association has been actively supporting cross-border connections with surrounding countries using dark fibres. SANET represents Slovakia in the organisations GÉANT and CEENet. For details visit:

The CESNET Association was founded by Czech universities and the Academy of Sciences of the Czech Republic in 1996. It is engaged in research and development in information and communication technologies and builds and develops the CESNET national e-infrastructure for research and education. With its research activities and accomplishments, CESNET represents the Czech Republic in international projects, most notably the pan-European GÉANT network building project and grid projects (, and participates actively in their implementation. The association also works on the use of high-speed networks for sharing multimedia data both through synchronous video conferencing and shared applications, and asynchronous streaming.

Last change: 14.11.2017