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Portion of a network between the backbone and the edge subnetworks

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 network (like for example private networks, LANs, etc.). The most common network type in which backhaul is implemented is a mobile network. A backhaul of a mobile network, also referred to as a mobile backhaul connects a cell site towards the core network. The two main methods of mobile backhaul implementations are fiber based backhaul and wireless point to point backhaul. Other methods, such as copper based wireline, satellite communications and point to multipoint wireless technologies are being phased out as capacity and latency requirements become higher in 4G and 5G networks. 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 Internet exchange point 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 connection. 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). A backhaul may include wired, fiber optic and wireless components. Wireless sections may include using microwave bands and mesh 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 internet service provider providing backhaul, although for academic research and education networks, large commercial networks or municipal networks, it is increasingly common to connect to 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.

Many common wireless mesh network hotspot solutions are supported in open source router firmware including DD WRT, OpenWRT and derivatives. The IEEE 802.21 standard specifies basic capabilities for such systems including 802.11u unknown user authentication and 802.11s ad hoc wireless mesh networking support. Effectively these allow arbitrary wired net connections to be teamed or ganged into what appears to be a single backhaul – a "virtual private cloud". Proprietary networks from Meraki follow similar principles. The use of the term backhaul to describe this type of connectivity may be controversial technically. They invert the business definition, as it is the customer who is providing the connectivity to the open Internet while the vendor is providing authentication and management services.

On very large scale long range networks, including transcontinental, submarine telecommunications cables are used. Sometimes these are laid alongside HVDC cables on the same route. Several companies, including Prysmian, run both HVDC power cables and telecommunications cables as far as FTTx. This reflects the fact that telecommunications backhaul and long range high voltage electricity transmission have many technologies in common, and are almost identical in terms of route clearing, liability in outages, and other legal aspects.