Networking hardware, also known as network equipment or computer networking devices, are physical devices which are required for communication and interaction between devices on a computer network. Specifically, they mediate data in a computer network. Units which are the last receiver or generate data are called hosts or data terminal equipment. Networking devices may include gateways, routers, network bridges, modems, wireless access points, networking cables, line drivers, switches, hubs, and repeaters; and may also include hybrid network devices such as multilayer switches, protocol converters, bridge routers, proxy servers, firewalls, network address translators, multiplexers, network interface controllers, wireless network interface controllers, ISDN terminal adapters and other related hardware. Wireless networking has become increasingly popular, especially for portable and handheld devices. Other networking hardware used in computers includes data center equipment (such as file servers, database servers and storage areas), network services (such as DNS, DHCP, email, etc.) as well as devices which assure content delivery.