Internal network. Listed companies or large enterprises have their own internal networks, which are simply intranets. Social Security Bureau, full name of Social Insurance Fund Administration, is called Social Insurance Fund Management Center in some urban areas. In addition, many areas have merged the Personnel Bureau with the Social Security Center, collectively known as the Human Resources and Social Security Bureau, which is divided into two levels: city and district, mainly dealing with five insurances and one fund (namely, endowment insurance, medical insurance, maternity insurance, work injury insurance, unemployment insurance, housing provident fund), etc., and is a social insurance agency.