page_title: Fibre Channel
section_title: Ports
hierarchical_section_title: Fibre Channel / Ports
caption_attribution_description: English: This graphic shows the logical port structure from the physical layer to the ULP.
context_page_description: Fibre Channel is a high-speed data transfer protocol providing in-order, lossless delivery of raw block data. Fibre Channel is primarily used to connect computer data storage to servers in storage area networks in commercial data centers. Fibre Channel networks form a switched fabric because the switches in a network operate in unison as one big switch. Fibre Channel typically runs on optical fiber cables within and between data centers, but can also run on copper cabling.
  There are various upper-level protocols for Fibre Channel, including two for block storage. Fibre Channel Protocol is a protocol that transports SCSI commands over Fibre Channel networks. FICON is a protocol that transports ESCON commands, used by IBM mainframe computers, over Fibre Channel. Fibre Channel can be used to transport data from storage systems that use solid-state flash memory storage medium by transporting NVMe protocol commands.
context_section_description: Fibre Channel ports come in a variety of logical configurations.  The most common types of ports are:
  N_Port (Node port) An N_Port is typically an HBA port that connects to a switch's F_Port or another N_Port.  Nx_Port communicating through a PN_Port that is not operating a Loop Port State Machine.
  F_Port (Fabric port) An F_Port is a switch port that is connected to an N_Port.
  E_Port (Expansion port) Switch port that attaches to another E_Port to create an Inter-Switch Link.
  Fibre Channel Loop protocols create multiple types of Loop Ports:
  L_Port (Loop port) FC_Port that contains Arbitrated Loop functions associated with the Arbitrated Loop topology.
  FL_Port (Fabric Loop port) L_Port that is able to perform the function of an F_Port, attached via a link to one or more NL_Ports in an Arbitrated Loop topology.
  NL_Port (Node Loop port) PN_Port that is operating a Loop port state machine.
  If a port can support loop and non-loop functionality, the port is known as:
  Fx_Port switch port capable of operating as an F_Port or FL_Port.
  Nx_Port end point for Fibre Channel frame communication, having a distinct address identifier and Name_Identifier,providing an independent set of FC-2V functions to higher levels, and having the ability to act as an Originator, a Responder, or both.
  Ports have virtual components and physical components and are described as:
  PN_Port entity that includes a Link_Control_Facility and one or more Nx_Ports.
  VF_Port (Virtual F_Port) instance of the FC-2V sublevel that connects to one or more VN_Ports.
  VN_Port (Virtual N_Port) instance of the FC-2V sublevel. VN_Port is used when it is desired to emphasize support for multiple Nx_Ports on a single Multiplexer (e.g., via a single PN_Port).
  VE_Port (Virtual E_Port) instance of the FC-2V sublevel that connects to another VE_Port or to a B_Port to create an Inter-Switch Link.
  The following types of ports are also used in Fibre Channel:
  A_Port (Adjacent port) combination of one PA_Port and one VA_Port operating together.
  B_Port (Bridge Port) Fabric inter-element port used to connect bridge devices with E_Ports on a Switch.
  D_Port (Diagnostic Port) A configured port used to perform diagnostic tests on a link with another D_Port.
  EX_Port A type of E_Port used to connect to an FC router fabric.
  G_Port (Generic Fabric port) Switch port that may function either as an E_Port, A_Port, or as an F_Port.
  GL_Port (Generic Fabric Loop port) Switch port that may function either as an E_Port, A_Port, or as an Fx_Port.
  PE_Port LCF within the Fabric that attaches to another PE_Port or to a B_Port through a link.
  PF_Port LCF within a Fabric that attaches to a PN_Port through a link.
  TE_Port (Trunking E_Port) A trunking expansion port that expands the functionality of E ports to support VSAN trunking, Transport quality of service (QoS) parameters, and Fibre Channel trace (fctrace) feature.
  U_Port (Universal port) A port waiting to become another port type
  VA_Port (Virtual A_Port) instance of the FC-2V sublevel of Fibre Channel that connects to another VA_Port.
  VEX_Port VEX_Ports are no different from EX_Ports, except underlying transport is IP rather than FC.
caption: A Port has a physical structure as well as logical or virtual structure.  This diagram shows how a virtual port may have multiple physical ports and vice versa.
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