Generic port (G_Port)

What is a Generic Port (G_Port)?
A generic port (G_Port) is a port that supports either an E_Port or F_Port in a Fiber Channel (FC) switch topology. It can be found on Brocade and McData switches.

The Fiber Channel was developed in 1988 and approved by the American National Standards Institute (ANSI) in 1994. It is a high-speed network technology for transferring data between workstations, mainframes, personal computers, storage devices, supercomputers and other peripheral devices. A primary goal of an FC is to provide a reliable interface for a remote operating system that requires high bandwidth.

A G_Port supports a loop topology in which all connections must be connected and operated at the same speed.

A G_Port can work as an E_Port or F_Port. The E_Port is an inter-switch expansion port that is used to connect two fiber optic switches. An F_Port is a fabric switch port that is used to connect an N_Port to a switch. Both the E_Port and the F_Port are switch ports. A switch port can be an F_Port, FL_Port or E_Port. A switch consists of several important components such as:

An address manager
One or more switch ports
A router for transmitting data packets
A path selector
A fabric controller to control the data transfer
A switch construct with circuit switching, multiplexed frame switching, or both

The functionality of a G_Port is determined when the port is registered. When the G_Port is connected to a node, it works like an F_Port. When the G_Port is connected to an extension, it works like an E_Port.

Most FC networks transmit small computer system interface commands using Fiber Channel networks such as a Storage Area Network (SAN). The SAN is used to connect servers, backup devices and disk arrays and has a very reliable redundant array of independent disks. If one server fails, the additional server can support an array with minimal data loss and downtime.