Backhaul

Definitions

Backhaul refers to connections between a core system and a subsidiary node. An example of backhaul is the link between a network — which could be the Internet or an internetwork that can connect to the Internet — and the cell tower base stations that route traffic from wireless to wired systems. Two backhaul technologies well-suited for mobile Internet access are fiber optic cable and point-to-point microwave radio relay transmissions.

Backhaul is "the installation of a dedicated line that transmits a signal to and from an Internet backbone . . . ."

How it works

In a hierarchical telecommunications network the backhaul portion of the network comprises the intermediate links between the core, or backbone, of the network and the small subnetworks at the "edge" of the entire hierarchical network. For example, while cell phones communicating with a single cell tower constitute a local subnetwork, the connection between the cell tower and the rest of the world begins with a backhaul link to the core of the telephone company's network (via a point of presence).

Visualizing the entire hierarchical network as a human skeleton, the core network would be the spine, the backhaul links would be the limbs, the edge networks would be the hands and feet, and the individual links within those edge networks would be the fingers and toes.

In situations where installing communications cables is impractical, fixed wireless infrastructure may be used to provide the needed backhaul. Microwave technologies, for example, are used in a number of applications to extend coverage to areas not served by fiber-optic or other wire links.