Network coverage can be divided into the following three categories: personal area networks (LANs), metropolitan area networks (MAN), and wide area networks (WANs), which I will explain below.
Local Area Network (LAN). A local area network is a network that covers a small area, usually confined to a building, office, campus, or within an organization. It connects devices such as computers, servers, printers, routers, etc., located within a relatively small geographical area. LAN coverage is typically between a few meters and several kilometers and can be achieved by Ethernet, Wi-Fi, or other LAN technologies. LAN provides high-speed transmission rate, low latency, and high security, and is suitable for scenarios such as internal collaboration, resource sharing, and data transmission.
Metropolitan Area Network (MAN). A metro network is a network that covers a city or a geographically large area. The scope of a metropolitan area network is larger than that of a local area network, but smaller than that of a wide area network. It usually consists of multiple local area networks, connected by fiber optics, wireless connections, or other communication lines. Metro networks typically cover a range of tens to hundreds of kilometers and can connect multiple office locations, campuses, communities, and more. Metro networks offer high bandwidth and transmission rates for collaboration and data communication between regional institutions, departments, or educational institutions.
Wide Area Network (WAN). A wide area network is a network that spans a large geographical area and can cover a national, intercontinental, or even global scale. A WAN is composed of multiple metropolitan area networks or local area networks, and realizes long-distance connections through the Internet, private lines, satellite communications, etc. WAN coverage can range from hundreds to thousands of kilometers or even beyond. WANs provide high-capacity bandwidth and high-speed transmission for data communication, remote access, and telecommuting on a global scale.
In summary, there is a certain hierarchy between the coverage of these three types of networks. Smaller networks can act as sub-networks of larger networks, connected to each other through Internet Protocol (IP) and routers to form a larger network structure. For example, multiple LANs can be connected by routers to form a metropolitan area network, and multiple metropolitan area networks can be connected through backbone networks to form a wide area network.