What Does Fabric Port (F_Port) Mean?
The fabric port (F_port) is a fabric switch port used to connect an N_port to a switch in a fiber channel topology. It uses a fiber channel point-to-point (FC-P2P) topology - a structure connecting two fiber channel devices. An F_port can only be connected to one N_port or to a peripheral device such as a host or disc operating as an N_port. An N_port is a node port connecting a node to a fiber channel switch.
A fiber channel (FC) is a high-speed network technology for connecting high speed storage devices to computers. An FC also connects numerous computer systems and is ideal for connecting servers. One of the main purposes of an FC is to deliver a reliable interface for a remote operating system (OS) requiring a high bandwidth.
There are also an FL_port connecting switches and loops. The FL_port is called a fabric loop port and connects to the NL_port.
Techopedia Explains Fabric Port (F_Port)
The F_port is typically a channel to the FC fabric for frames transmitted and received by an N_port. A frame is a data unit transmitted or received between network points. A fiber channel frame can usually contain up to 2112 bytes per unit.
A fiber channel switch is a network switch used one at a time or in large multi-switch configurations. A switch port can be an F_Port, FL_Port or E_Port. A switch is a composed of various important modules such as:
- A router
- A fabric controller
- An address manager
- One or more switch ports
- A path selector
- A switch construct which has multiplexed frame switching , circuit switching or both
The fiber channel provides a network of many-to-many communication, redundancy, device name look up and security. It primarily transmits small computer system interface (SCSI) commands using fiber channel networks like storage area network (SAN). The fiber channel standards are defined by the American National Standards Institute (ANSI). An F_port supports class 1, class 2 and class 3 services.
The F_port end is where an external N_port is attached to the fabric. It contains the FC-PH transport element. FC-PH includes layers FC0 through FC2 of the fiber channel physical layers, which are:
- FC4: This is the protocol mapping layer in which application protocols, such as Internet protocol (IP) or SCSI are condensed into a protocol data unit (PDU) for delivery to FC2 (fiber channel 2)
- FC3: This is a common services layer - a thin layer which eventually could implement functions like redundant array of independent disks (RAID) or encryption redundancy algorithms.
- FC2: This is a network layer containing the core of fiber channel and defining the main protocols by the FC-PI-2 standard.
- FC1: This is the data link layer, which applies the line coding of signals.
- FC0: This is the physical layer (PHY), which includes connectors and cabling.