Backbone network based on optical carrier, developed by EENet, covers most of the Estonian counties and is connected to the European academic network GÉANT that connects over 8000 European research and educational institutions. Optical backbone is used by research institutions, universities, educational and cultural institutions. Newly developed network, started in 2011, will be a significantly faster, more reliable and easily extensible network than the existing one. Two alternative routes will be in operation for all essential segments of the backbone. Using optical cross-border connections, the planned optical backbone will enable closer research cooperation between the Baltic and Nordic countries. This new infrastructure ensures high-quality access to modern data communications for all the Estonian research institutions regardless of their geographical location. EENet's connectivity service is currently used by more than 50 research institutions and universities and ca 250 other academic institutions in Estonia. The new infrastructure ensures high-quality access to modern data communications for all the Estonian research institutions and is essential for Estonian research infrastructure projects (ETAIS, NATARC, CLARIN, Kkobs, SIME etc).