A node (Latin nodus, ‘knot’) is a critical element of any computer network. It can be defined as a point in a network at which lines intersect or branch, a device attached to a network[1], or a terminal or other point in a computer network where messages can be created, received, or transmitted.[2]
A node can be any device connected to a computer network. Nodes can be computers, personal digital assistants (PDAs), cell phones, switches, routers or various other networked devices.
A node is a connection point, either a redistribution point or an end point, for data transmission. In general, a node has programmed or engineered capability to recognize and process or forward transmissions to other nodes.
If the network in question is the Internet, every node must have a MAC address or Data Link Control address[3] if it is at least a data link layer device, as defined in the OSI model.
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.
In telecommunications, a node is a specific location in a telecommunication network. 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.