In atelecommunications network, alink is acommunication channel that connects two or more devices for the purpose ofdata transmission. The link may be a dedicatedphysical link or avirtual circuit that uses one or more physical links or shares a physical link with other telecommunications links.
A telecommunications link is generally based on one of several types of information transmission paths such as those provided bycommunication satellites, terrestrialradio communications infrastructure andcomputer networks to connect two or more points.
The termlink is widely used in computer networking to refer to the communications facilities that connectnodes of a network.[1]
Sometimes the communications facilities that provide the communication channel that constitutes a link are also included in the definition oflink.
Apoint-to-point link is a dedicated link that connects exactly two communication facilities (e.g., twonodes of a network, an intercom station at an entryway with a single internal intercom station, a radio path between two points, etc.).
Broadcast links connect two or more nodes and supportbroadcast transmission, where one node can transmit so that all other nodes can receive the same transmission.Classic Ethernet is an example.
Also known as amultidrop link, a multipoint link is a link that connectstwo or more nodes. Also known as general topology networks, these includeATM andFrame Relay links, as well asX.25 networks when used as links for anetwork-layer protocol likeIP.
Unlike broadcast links, there is no mechanism to efficiently send a single message to all other nodes without copying and retransmitting the message.
Apoint-to-multipoint link (or simply amultipoint) is a specific type of multipoint link which consists of a central connection endpoint (CE) that is connected to multiple peripheral CEs. All of the peripheral CEs receive any transmission of data that originates from the central CE while any transmission of data that originates from any of the peripheral CEs is only received by the central CE.
Links are often referred to by terms that refer to the ownership or accessibility of the link.
Aforward link is the link from a fixed location (e.g., abase station) to a mobile user. If the link includes acommunications relay satellite, the forward link will consist of both anuplink (base station to satellite) and a downlink (satellite to mobile user).[2]
Thereverse link (sometimes called areturn channel) is the link from a mobile user to a fixed base station.
If the link includes acommunications relay satellite, the reverse link will consist of both anuplink (mobile station to satellite) and adownlink (satellite to base station) which together constitute a halfhop.
This article incorporatespublic domain material fromFederal Standard 1037C.General Services Administration. Archived fromthe original on 2022-01-22. (in support ofMIL-STD-188). This article incorporatespublic domain material fromDictionary of Military and Associated Terms.United States Department of Defense.
