Backhaul, a term probably derived from the trucking industry, has several usages in information technology.
1) In satellite communication, backhaul is used to mean getting data to a point from which it can be distributed over a network. For example, to deliver a live television program from Chicago to authorized DirecPC satellite terminals around the country, the video signals would have to be backhauled by some means (by optical fiber cable or by another satellite system) to the Hughes DirecPC facility in Germantown, Maryland. From there, it would be uplinked to the Galaxy IV satellite from which DirecPC users could view the broadcast (receive it in a downlink from the satellite at their individual terminals). Backhauling is also used to get non-live audio and video material to distribution points at the major broadcast news organizations for broadcast in the evening or ongoing news.
2) Manufacturers of network switching equipment use the term to mean "getting data to the network backbone" (which is similar to its use in the satellite communication industry). For example, Ascend uses the term to describe how its MAX 2000 switch can be used to interconnect data from a backhaul T-1 line on which mobile and remote office users are connected to an Internet service provider and the backbone of the Internet.
3) According to books we like, backhauling is sending network data over an out-of-the-way route (including taking it farther than its destination) in order to get the data there sooner or because it costs less. This kind of backhauling involves understanding changing network conditions and economics.
4) Backhauling may sometimes be used to mean the use of the back channel on a bidirectional communications line.