Thursday 19 April 2012

Networking hardware

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Networking hardware or simply Networking equipment typically refers to devices facilitating the use of a computer network. Typically, this includes gateways, routers, network bridges, switches, hubs, and repeaters. Also, hybrid network devices such as multilayer switches, protocol converters and bridge routers. And, proxy servers, firewalls and network address translators. Also, multiplexers, network interface controllers, wireless network interface controllers, modems, ISDN terminal adapters and line drivers. And, wireless access points, networking cables and other related hardware.
Computer networking devices are units that mediate data in a computer network.[1][2] Computer networking devices are also called network equipment, Intermediate Systems (IS)[citation needed] or InterWorking Unit (IWU).[citation needed] Units which are the last receiver or generate data are called hosts or data terminal equipment.[citation needed]
The most common kind of networking hardware today is copper-based Ethernet adapters, helped largely by its standard inclusion on most modern computer systems. Wireless networking has become increasingly popular, however, especially for portable and handheld devices.
Other hardware prevalent within computer networking is datacenter equipment (such as file servers, database servers and storage areas), network services (such as DNS, DHCP, email etc) as well as other specific network devices such as content delivery.
Other diverse devices which may be considered networking hardware include mobile phones, PDAs and even modern coffee machines. As technology grows and IP-based networks are integrated into building infrastructure and household utilities, network hardware becomes an ambiguous statement owing to the increasing number of "network capable" endpoints.List of computer networking devices
  • Gateway: device sitting at a network node for interfacing with another network that uses different protocols. Works on OSI layers 4 to 7.
  • Router: a specialized network device that determines the next network point to which it can forward a data packet towards the destination of the packet. Unlike a gateway, it cannot interface different protocols. Works on OSI layer 3.
  • Bridge: a device that connects multiple network segments along the data link layer. Works on OSI layer 2.
  • Switch: a device that allocates traffic from one network segment to certain lines (intended destination(s)) which connect the segment to another network segment. So unlike a hub a switch splits the network traffic and sends it to different destinations rather than to all systems on the network. Works on OSI layer 2.
  • Hub: connects multiple Ethernet segments together making them act as a single segment. When using a hub, every attached device shares the same broadcast domain and the same collision domain. Therefore, only one computer connected to the hub is able to transmit at a time. Depending on the network topology, the hub provides a basic level 1 OSI model connection among the network objects (workstations, servers, etc.). It provides bandwidth which is shared among all the objects, compared to switches, which provide a dedicated connection between individual nodes. Works on OSI layer 1.
  • Repeater: device to amplify or regenerate digital signals received while sending them from one part of a network into another. Works on OSI layer 1.
Some hybrid network devices:
Hardware or software components that typically sit on the connection point of different networks, e.g. between an internal network and an external network:
  • Proxy server: computer network service which allows clients to make indirect network connections to other network services
  • Firewall: a piece of hardware or software put on the network to prevent some communications forbidden by the network policy
  • Network address translator (NAT): network service provide as hardware or software that converts internal to external network addresses and vice versa
Other hardware for establishing networks or dial-up connections:
  • Multiplexer: device that combines several electrical signals into a single signal
  • Network interface controller a piece of computer hardware to allow the attached computer to communicate by network
  • Wireless network interface controller a piece of computer hardware to allow the attached computer to communicate by LAN
  • Modem: device that modulates an analog "carrier" signal (such as sound), to encode digital information, and that also demodulates such a carrier signal to decode the transmitted information, as a computer communicating with another computer over the telephone network
  • ISDN terminal adapter (TA): a specialized gateway for ISDN
  • Line driver: a device to increase transmission distance by amplifying the signal. Base-band networks only.

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