TODO: improve this page (notably, add figures to explain how backhaul and peering/transit get together)
Backhaul is the process of transporting subscribers' data between their location and the core network of the ISP; by extension, it also designate the network infrastructure needed to achieve this task. A backhaul network is sometimes also called a Middle-mile network.
Backhaul can be a difficult problem, especially when a ISP has subscribers at very different locations.
Example of backhaul infrastructures are:
DIY ISPs basically have three classes of solutions for their backhaul:
Which one to choose is heavily dependent on the technology, the geographical and financial scale of the DIY ISP, and the availability of affordable offers from resellers. For instance, a very localised ISP might want to deploy hardware (DSLAM, fiber switches) even if it is quite expensive; on the other end, a regional-scale ISP may not afford to deploy hardware in dozens of locations if there are only a few users connected at each location.