View source for Backhaul

In a hierarchical [[telecommunications network]] the '''[[backhaul]]''' portion of the network comprises the intermediate links between the [[core network]], or [[Backbone network|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.

Other examples include:

*Connecting wireless [[base station]]s to the corresponding [[base Station subsystem|base station controllers]].
*Connecting [[DSLAM]]s to the nearest [[Asynchronous Transfer Mode|ATM]] or [[Ethernet]] aggregation node.
*Connecting a large company's site to a [[metro Ethernet]] network.
*Connecting a [[submarine communications cable]] system [[cable landing point|landing point]] (which is usually in a remote location) with the main terrestrial telecommunications network of the country that the cable serves.

The choice of backhaul technology must take account of such parameters as capacity, cost, reach, and the need for such resources as [[frequency spectrum]], [[optical fiber]], wiring, or [[Right-of-way (transportation)|rights of way]]. Backhaul technologies include:

*Point-to-point [[microwave radio relay]] transmission (terrestrial or, in some cases, by satellite)
*[[Point-to-multipoint communication|Point-to-multipoint]] microwave access technologies, such as [[LMDS]], [[Wi-Fi]], [[WiMAX]], etc., can also be used for backhauling purposes
*[[DSL]] variants, such as [[ADSL]] and [[SHDSL]]
*[[PDH]] and [[Synchronous optical networking|SDH/SONET]] interfaces, such as (fractional) E1/T1, E3, T3, STM-1/OC-3, etc.
*[[Ethernet]]

Backhaul capacity can also be leased from another network operator, in which case the choice of technology is generally made by this other network operator.

==Vendors==

* [[Ericsson]]
* [[Ceragon]]
* [[Motorola]]
* [[Proxim Wireless]]
* [[Harris Stratex Networks]]
* [[Nokia Siemens Networks]]

==See also==
*[[Last mile]]
*[[Return channel]]

==External links==

* [http://www.netevents.tv/docuplayer.asp?docid=104 Debate: The Backhaul Battle Who Will Win? - Video] 40 minutes, wide ranging.
* [http://www.telecommagazine.com/International/article.asp?HH_ID=AR_2351 Over the Backhaul]