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Computer networking devices are units that mediate data

Data

The term data refers to qualitative or quantitative attributes of a variable or set of variables. Data are typically the results of measurements and can be the basis of graphs, images, or observations of a set of variables. Data are often viewed as the lowest level of abstraction from which...

 in a computer network

Computer network

A computer network, often simply referred to as a network, is a collection of hardware components and computers interconnected by communication channels that allow sharing of resources and information....

. Computer networking devices are also called network equipment, Intermediate Systems (IS) or InterWorking Unit (IWU). Units which are the last receiver or generate data are called host

Server (computing)

In the context of client-server architecture, a server is a computer program running to serve the requests of other programs, the "clients". Thus, the "server" performs some computational task on behalf of "clients"...

s or data terminal equipment

Data terminal equipment

Data Terminal Equipment is an end instrument that converts user information into signals or reconverts received signals. These can also be called tail circuits. A DTE device communicates with the data circuit-terminating equipment...

.

List of computer networking devices

Common basic networking devices:

• 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
  OSI model
  The Open Systems Interconnection model is a product of the Open Systems Interconnection effort at the International Organization for Standardization. It is a prescription of characterizing and standardizing the functions of a communications system in terms of abstraction layers. Similar...
  
  .
• Bridge: a device that connects multiple network segment
  Network segment
  A network segment is a portion of a computer network. The nature and extent of a segment depends on the nature of the network and the device or devices used to interconnect end stations.-Ethernet:...
  
  s along the data link layer
  Data link layer
  The data link layer is layer 2 of the seven-layer OSI model of computer networking. It corresponds to, or is part of the link layer of the TCP/IP reference model....
  
  . Works on OSI layer 2
  OSI model
  The Open Systems Interconnection model is a product of the Open Systems Interconnection effort at the International Organization for Standardization. It is a prescription of characterizing and standardizing the functions of a communications system in terms of abstraction layers. Similar...
  
  .
• Switch
  Network switch
  A network switch or switching hub is a computer networking device that connects network segments.The term commonly refers to a multi-port network bridge that processes and routes data at the data link layer of the OSI model...
  
  : 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
  OSI model
  The Open Systems Interconnection model is a product of the Open Systems Interconnection effort at the International Organization for Standardization. It is a prescription of characterizing and standardizing the functions of a communications system in terms of abstraction layers. Similar...
  
  .
• Hub
  Ethernet hub
  An Ethernet hub, active hub, network hub, repeater hub or hub is a device for connecting multiple Ethernet devices together and making them act as a single network segment. A hub works at the physical layer of the OSI model. The device is a form of multiport repeater...
  
  : connects multiple Ethernet segments together making them act as a single segment. When using a hub, every attached all the objects, compared to switches
  Network switch
  A network switch or switching hub is a computer networking device that connects network segments.The term commonly refers to a multi-port network bridge that processes and routes data at the data link layer of the OSI model...
  
  , which provide a dedicated connection between individual nodes. Works on OSI layer 1
  OSI model
  The Open Systems Interconnection model is a product of the Open Systems Interconnection effort at the International Organization for Standardization. It is a prescription of characterizing and standardizing the functions of a communications system in terms of abstraction layers. Similar...
  
  .
• Repeater
  Repeater
  A repeater is an electronic device that receives asignal and retransmits it at a higher level and/or higher power, or onto the other side of an obstruction, so that the signal can cover longer distances.-Description:...
  
  : device to amplify or regenerate digital signals received while sending them from one part of a network into another. Works on OSI layer 1
  OSI model
  The Open Systems Interconnection model is a product of the Open Systems Interconnection effort at the International Organization for Standardization. It is a prescription of characterizing and standardizing the functions of a communications system in terms of abstraction layers. Similar...
  
  .

Some hybrid network devices:

• Multilayer Switch
  Multilayer switch
  A multilayer switch is a computer networking device that switches on OSI layer 2 like an ordinary network switch and provides extra functions on higher OSI layers.- Layer 3 Switching :...
  
  : a switch
  Network switch
  A network switch or switching hub is a computer networking device that connects network segments.The term commonly refers to a multi-port network bridge that processes and routes data at the data link layer of the OSI model...
  
   which, in addition to switching on OSI layer 2
  OSI model
  The Open Systems Interconnection model is a product of the Open Systems Interconnection effort at the International Organization for Standardization. It is a prescription of characterizing and standardizing the functions of a communications system in terms of abstraction layers. Similar...
  
  , provides functionality at higher protocol layers.
• Protocol Converter
  Protocol converter
  A Protocol Converter is a device used to convert standard or proprietary protocol of one device to the protocol suitable for the other device or tools to achieve the interoperability...
  
  : a hardware
  Hardware
  Hardware is a general term for equipment such as keys, locks, hinges, latches, handles, wire, chains, plumbing supplies, tools, utensils, cutlery and machine parts. Household hardware is typically sold in hardware stores....
  
   device that converts between two different types of transmissions
  Transmission (telecommunications)
  Transmission, in telecommunications, is the process of sending, propagating and receiving an analogue or digital information signal over a physical point-to-point or point-to-multipoint transmission medium, either wired, optical fiber or wireless...
  
  , such as asynchronous and synchronous transmissions.
• Bridge Router (B router): CombineS router and bridge functionality and are therefore working on OSI layers 2 and 3
  OSI model
  The Open Systems Interconnection model is a product of the Open Systems Interconnection effort at the International Organization for Standardization. It is a prescription of characterizing and standardizing the functions of a communications system in terms of abstraction layers. Similar...
  
  .

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
  Proxy server
  In computer networks, a proxy server is a server that acts as an intermediary for requests from clients seeking resources from other servers. A client connects to the proxy server, requesting some service, such as a file, connection, web page, or other resource available from a different server...
  
  : computer network service
  Network service
  Network services are the foundation of a networked computing environment. Generally network services are installed on one or more servers to provide shared resources to client computers.- Network services in LAN :...
  
   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
  Network address translation
  In computer networking, network address translation is the process of modifying IP address information in IP packet headers while in transit across a traffic routing device....
  
  : 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
  Multiplexer
  In electronics, a multiplexer is a device that selects one of several analog or digital input signals and forwards the selected input into a single line. A multiplexer of 2n inputs has n select lines, which are used to select which input line to send to the output...
  
  : 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 WLAN
• Modem
  Modem
  A modem is a device that modulates an analog carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information. The goal is to produce a signal that can be transmitted easily and decoded to reproduce the original digital data...
  
  : 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
  Terminal adapter
  - ISDN :In ISDN terminology, a terminal adapter or TA is a device that connects a terminal to the ISDN network.The TA therefore fulfills a similar function to the ones a modem has on the POTS network, and is therefore sometimes called an ISDN modem...
  
   (TA): a specialized gateway
  Gateway (telecommunications)
  In telecommunications, the term gateway has the following meaning:*In a communications network, a network node equipped for interfacing with another network that uses different protocols....
  
   for ISDN
• Line Driver
  Line driver
  In electronics, a line driver is an amplifier used to improve the strength of an analog or digital signal at its source by driving the input to the transmission line with a higher than normal signal level. This increases the quality of a transmission over a long run of cable...
  
  : a device to increase transmission distance by amplifying the signal. Base-band networks only.