A more thorough explanation:

A local-exchange network is a system that provides telephone service on a local basis. It includes switches, local loops, transport trunks, billing databases, and operator services. Switches direct calls to the appropriate destination, local loops connect telephones to the switches, and transport trunks carry calls from switch to switch.

For example, when you make a phone call to your neighbor, the call goes through the local-exchange network. The switch directs the call to your neighbor's phone through the local loop, and the transport trunk carries the call to your neighbor's switch.

There are federal requirements that a local-exchange carrier who controls a local-exchange network permit competition by selling some access, including unbundled access, to its local-exchange network. This means that other companies can use the local-exchange network to provide telephone service in the same area.