Cross-connect
Updated
A cross-connect is a physical cable, usually fibre, between the equipment of two parties in the same datacenter, installed and billed by the datacenter operator. It is the shortest and most direct way to connect two networks.
In practice
Private delivery into your own racks often ends with a cross-connect. The datacenter installs it on presentation of a letter of authorisation (LOA) from the party that receives the cable.