Plenty of local commercial ISPs function in large cities, but most of the existing country-wide cable lines are held by small number of large operators such as former "monopolist", the state-controlled Rostelecom and the railways-affiliated Transtelecom, which operates country biggest DWDM fiber backbone. Cell phone coverage with the digital services such as GPRS is almost ubiquitous. In year 2007 the Golden Telecom company has constructed a massive Wi-Fi network in Moscow for commercial use which is recognized as the largest urban wireless network in the world. The Black Sea coast of Russia has become an important area for the fiber-optic networks, as it served as a backbone of communication during the Winter Olympic Games in 2014. On October 2010 mobile operator MegaFon has selected Huawei NE5000E routers to construct backbone nodes for a 40-Gbit/s IP/MPLS network in Russia' s largest cities, including Moscow and St. Petersburg, Huawei says. Meanwhile, Megafon also announced the opening of what it touts as Russia's largest data center in Samara. In 2011 Rostelecom started implementation of WDM-based equipment on the backbone network for data transmission in the Republic of Dagestan. Due to WDM introduction the fiber-optic communication lines bandwidth increased to 2.5 Gbit/s. Rostelecom invested about 48 million rubles in the project. Until 2011 the backbone network in Russia was based on DWDM technology with a capacity of 10 and 40 Gbit/s. The operator started projects to expand the capacity of the Transit Europe – Asia transit line at two independent branches. Communication lines are under construction within a second phase of the TEA backbone "High Speed Backbone Transit Europe-Asia". The construction of the first branch completed in 2011 (Khabarovsk – Stockholm). The second branch (Khabarovsk – Frankfurt) was completed in 2013. In addition, the expanded backbones are in the route of Khabarovsk – Nakhodka – Tokyo and Khabarovsk – Hong Kong, where equipment of 100G WDM is also applied. Presently, MasterTel, based in Moscow and Saint Petersburg, is an ISP that provides high speed fiber-optic lines of up to 10Gbit/s per second to consumers and businesses. In 2012, the Russian Federation announced an ambitious target of providing 90% of households with "ultrafast" connection speeds of at least 100 megabits per second by 2018. The responsibility has been given to Rostelcom, which is tasked with connecting about 4 million rural settlements by installing 200,000 km of fiber-optic cable.