Definition

Fibre Channel (FC) port types

What are Fibre Channel (FC) port types?

A Fibre Channel port is a hardware pathway into and out of a node that performs data communications over an FC link. (An FC link is sometimes called an FC channel.) In today's FC environments, three of the most common port types are the N-port, F-port and E-port.

Port

Full name

Port function

N-port

Node port

Node port that connects to an F-port on an FC switch or to an N-port on another node

F-port

Fabric port

Switch port that connects to an N-port on an FC node

E-port

Expansion port

Switch port that connects to another FC switch to create an interswitch link (ISL)

Either a server or a storage system can use an N-port to connect to an FC switch. An FC switch, in turn, can use an F-port to connect to either type of node. An FC switch can also use an E-port to connect to another switch or an FL-port to connect to an arbitrated loop. These are by no means the only types of switches available, but they represent some of the most common.

port names in a Fibre Channel network
Diagram illustrating port names in a Fibre Channel network

An arbitrated loop is an FC topology that uses arbitration to establish a point-to-point circuit for connecting devices in a one-way ring. An arbitrated loop prevents multiple ports from sending frames at the same time. A node in an arbitrated loop uses an NL-port to connect the next node in the loop, often via an FC hub. An FC switch can connect to the arbitrated loop through an FL-port. An arbitrated loop might also include other port types.

Port

Full name

Port function

L-port

Loop port

FC port that contains the functionality necessary to support an arbitrated loop

NL-port

Node loop port

Type of L-port on a node in an arbitrated loop that connects to an NL-port on another node in the loop, often via an FC hub; an NL-port can also connect to an FL-port on an FC switch, either directly or through a hub

FL-port

Fabric loop port

Type of L-port on an FC switch that connects to an arbitrated loop, either through an FC hub or directly to an NL-port

GL-port

Generic loop port

Switch port that can operate as an F-port, E-port or FL-port

Nx-port

Multipurpose node port

Node port that can operate as an N-port or NL-port

Fx-port

Multipurpose fabric port

Switch port that can operate as an F-port or FL-port

In addition to the more common port types, an FC network might incorporate other port types as well, such as the B-port, G-port, EX-port or TE-port. In some cases, a port might be specific to a vendor or to one of that vendor's product lines. For example, the TE-port is specific to the Cisco MDS 9000 family of switches.

Port

Full name

Port function

B-port

Bridge port

Port on a bridge device that connects to an E-port on an FC switch

G-port

Generic port

General-purpose FC port that can operate as an F-port or E-port

EX-port

External E-port

FC port that connects an FC router and FC switch; on the switch side, it looks like a normal E-port, but on the router side, it is an EX-port

TE-port

Trunking E-port

Trunking port that expands E-port functionality to support virtual storage area network (SAN) trunking, the FC trace feature and transport quality of service parameters

See also: SAN switch, Fibre Channel over Ethernet, Fibre Channel director, Fibre Channel adapter, Fibre Channel Arbitrated Loop, non-volatile memory express over Fibre Channel and World Wide Name.

This was last updated in April 2022

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