The physical interface through which storage devices, hosts, loops, and fabrics are connected. Common port identifiers include: F_Port for a port which provides a point-to-point connection between devices on a Fibre Channel SAN; N_Port for the end-point (a server or storage node) in a Fibre Channel fabric; E_Port for an expansion port, which is used to connect one switch to another switch; NL_Port for a node loop port, which is the end-point in an arbitrated loop (it connects a node to the loop); and FL_Port for a fabric loop port, which connects nodes (such as NL_Ports) that do not reside on the same loop.