Node (networking)
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In communication networks, a node (Latin nodus, ‘knot’) is an active electronic device that is attached to a network, and is capable of sending, receiving, or forwarding information over a communications channel.¹ A node is a connection point, either a redistribution point or a communication endpoint (some terminal equipment).

In network theory, the term node may refer a point in a network topology at which lines intersect or branch².

Computer network nodes

In data communication, a node may either be a data circuit-terminating equipment (DCE) such as a modem, hub, bridge or switch; or a data terminal equipment (DTE) such as a digital telephone handset, a printer or a host computer, for example a router, a workstation or a server.

If the network in question is a LAN or WAN, every node must have a MAC address if it is at least a data link layer device, as defined in the OSI model.

If the network in question is the Internet, many network nodes are host computers, identified by an IP address, and all hosts are nodes. However, datalink layer devices such as switches, bridges and WLAN access points do often have an IP host address (except sometimes for administrative purposes), but are considered as network nodes.

If the network in question is a peer-to-peer or overlay network, nodes that actively route data for the other networked devices as well as themselves are called supernodes.

Telecommunication network nodes

In the fixed telephone network, a node may be a public or private telephone exchange, a remote concentrator or a computer providing some intelligent network service. In cellular data communication, the Home Location Register, Gateway GPRS Support Node (GGSN) and Serving GPRS Support Node (SGSN) are examples of nodes.

In cable television systems (CATV), this term has assumed a broader context and is generally associated with a fiber optic node. This can be defined as those homes or businesses within a specific geographic area that are served from a common fiber optic receiver. A fiber optic node is generally described in terms of the number of "homes passed" that are served by that specific fiber node.

See also

• Host (network)

References

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