A computer network is composed of end devices, network media, and intermediary devices connected together. The number of computers that can be connected depends on the type of network, which is classified by geographical size as a personal area network (PAN), local area network (LAN), campus area network (CAN), metropolitan area network (MAN), wide area network (WAN), wireless local area network (WLAN), or peer-to-peer network. In a client/server network, servers provide centralized services and resources to client devices, while in a peer-to-peer network all devices can act as both clients and servers sharing resources directly.