The back bone is a line for the transfer of larger amounts of data. It gathers the data of the systems it is connected to. Locally, it connects Local Area Networks (LAN) so that a Wide Area Network (WAN) can be created. Within the LAN, the back bone is used to efficiently bridge distances (between buildings). Within the WAN, the back bone pools the paths of the network to a remote connection line. The connection points are named notes.