CERNET, China Education and Scientific Research Computer Network, is a national academic computer internet invested by the state, managed by the Ministry of Education, and built, managed and operated by universities such as Tsinghua University. CERNET (China Education and Research Network) is a national network center with four levels of management. Regional network center and regional master node; Provincial education and research network; Campus network. The National Network Center is located in Tsinghua University and is responsible for the operation and management of the national backbone network. On June 22nd, 20 13, Hong Kong's South China Morning Post reported that Snowden, a former employee of the US intelligence department, broke the news to the newspaper that the US National Security Agency had continuously attacked Tsinghua University's backbone network.