Ports are the basic building blocks of an FC network. Ports on the switch can be one of the following types:
1. N_port: An end point in the fabric. This port is also known as thenodeport. Typically, it is a host port (HBA) or a storage array port that is connected to a switch in a switched fabric.
2. NL_port: A node port that supports the arbitrated loop topology. Thisport is also known as the node loop port.
3. E_port: An FC port that forms the connection between two FC switches.This port is also known as the expansion port. The E_port on an FC switch connects to the E_port of another FC switch in the fabric through a link, which is called an Inter-Switch Link (ISL). ISLs are used to transfer host-to-storage data as well as the fabric management traffic from one switch to another. ISL is also one of the scaling mechanisms in SAN connectivity.
4. F_port: A port on a switch that connects an N_port. It is also known as afabric port and cannot participate in FC-AL.
5. FL_port: A fabric port that participates in FC-AL. This port is connectedto the NL_ports on an FC-AL loop. AFL_port also connects a loop to a switch in a switched fabric. As a result, all NL_ports in the loop can participate in FC-SW. This configuration is referred to as a public loop. In contrast, an arbitrated loop without any switches is referred to as a private loop. A private loop contains nodes with NL_ports, and does not contain FL_port.
6. G_port: A generic port that can operate as an E_port or an F_port and determines its functionality automatically during initialization.