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In a hierarchical telecommunications network the backhaul portion of the network comprises the intermediate links between the core network, or backbone network and the small subnetworks at the "edge" of the entire hierarchical network. In contracts pertaining to such networks, backhaul is the obligation to carry packets to and from that global network. A non-technical business definition of ''backhaul'' is the commercial wholesale bandwidth provider who offers quality of service (QOS) guarantees to the retailer. It appears most often in telecommunications trade literature in this sense, whereby the backhaul connection is defined not technically but by who operates and manages it, and who takes legal responsibility for the connection or uptime to the Internet or 3G/4G network. See also hotspot contracts below. In both the technical and commercial definitions, backhaul generally refers to the side of the network that communicates with the global Internet, paid for at wholesale commercial access rates to or at an ethernet exchange or other core network access location. Sometimes middle mile networks exist between the customer's own LAN and those exchanges. This can be a local WAN or WLAN connection, for instance Network New Hampshire Now and Maine Fiber Company run tariffed public dark fiber networks as a backhaul alternative to encourage local and national carriers to reach areas with broadband and cell phone that they otherwise would not be serving. These serve retail networks which in turn connect buildings and bill customers directly. 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 Internet service provider's network (via a point of presence). The term backhaul may be used to describe the entire wired part of a network, although some networks have wireless instead of wired backhaul, in whole or in part, for example using microwave bands and mesh network and edge network topologies that may use a high-capacity wireless channel to get packets to the microwave or fiber links. A telephone company is very often the ISP providing backhaul, although for academic R&E networks or large commercial networks or municipal networks, it is increasingly common to connect to a public broadband backhaul. See national broadband plans from around the world, many of which were motivated by the perceived need to break the monopoly of incumbent commercial providers. The US plan for instance specifies that all community anchor institutions should be connected by gigabit fiber optics before the end of 2020. == Definition == Visualizing the entire hierarchical network as a human skeleton, the core network would represent 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 stations to the corresponding base station controllers. *Connecting DSLAMs to the nearest ATM or Ethernet aggregation node. *Connecting a large company's site to a metro Ethernet network. *Connecting a submarine communications cable system landing point (which is usually in a remote location) with the main terrestrial telecommunications network of the country that the cable serves. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Backhaul (telecommunications)」の詳細全文を読む スポンサード リンク
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