Fibre Channel

Description Glossary RFCs Publications Obsolete RFCs


Protocol suite:
Protocol type:Data link layer protocol.
SNMP MIBs: ( ( ( ( (
Working groups: imss, Internet and Management Support for Storage.
ipfc, IP over Fibre Channel.
ips, IP Storage.
Links: Fibre Channel Industry Association

RFC 4439:

Fibre Channel is logically a bidirectional point-to-point serial data channel, structured for high performance. Fibre Channel provides a general transport vehicle for higher-level protocols such as Small Computer System Interface (SCSI) command sets, the High- Performance Parallel Interface (HIPPI) data framing, IP (Internet Protocol), IEEE 802.2, and others.

Physically, Fibre Channel is an interconnection of multiple communication points, called N_Ports, interconnected either by a switching network, called a Fabric, or by a point-to-point link. A Fibre Channel "node" consists of one or more N_Ports. A Fabric may consist of multiple Interconnect Elements, some of which are switches. An N_Port connects to the Fabric via a port on a switch called an F_Port. When multiple FC nodes are connected to a single port on a switch via an "Arbitrated Loop" topology, the switch port is called an FL_Port, and the nodes' ports are called NL_Ports. The term Nx_Port is used to refer to either an N_Port or an NL_Port. The term Fx_Port is used to refer to either an F_Port or an FL_Port. A switch port, which is interconnected to another switch port via an Inter-Switch Link (ISL), is called an E_Port. A B_Port connects a bridge device with an E_Port on a switch; a B_Port provides a subset of E_Port functionality.

Many Fibre Channel components, including the Fabric, each node, and most ports, have globally-unique names. These globally-unique names are typically formatted as World Wide Names (WWNs). WWNs are expected to be persistent across agent and unit resets.

Fibre Channel frames contain 24-bit address identifiers, which identify the frame's source and destination ports. Each FC port has both an address identifier and a WWN. When a Fabric is in use, the FC address identifiers are dynamically assigned by a switch. Each octet of a 24-bit address represents a level in an address hierarchy, with a Domain_ID being the highest level of the hierarchy.

Each switch in a Fabric is assigned one or more unique Domain_IDs using a two-step process. First, one switch, called Principal Switch, is selected from the switches of a Fabric. Then, the Principal Switch assigns Domain_IDs to the other switches of the Fabric. Address assignment within a domain is performed by the switch to which that Domain_ID is granted.

Fibre Channel frame:

0001020304050607 0809101112131415 1617181920212223 2425262728293031
Fibre channel frame header
Data :::

SOF, Start of Frame. 32 bits.
Indicates the start of the frame.

Fibre channel frame header. 24 bytes.

Data. Variable length, 0 to 2112 bytes.

CRC. 32 bits.
Uses the same 32-bit polynomial used in FDDI and is specified in ANSI X3.139 Fiber Distributed Data Interface.

EOF, End of Frame. 32 bits.
Indicates the end of the frame.



[RFC 3643] Fibre Channel (FC) Frame Encapsulation.

[RFC 4044] Fibre Channel Management MIB.

[RFC 4338] Transmission of IPv6, IPv4, and Address Resolution Protocol (ARP) Packets over Fibre Channel.

[RFC 4438] Fibre Channel Name Server MIB.

[RFC 4439] Fibre Channel Fabric Address Manager MIB.

[RFC 5324] MIB for Fibre-Channel Security Protocols (FC-SP).


Obsolete RFCs:

[RFC 2625] IP and ARP over Fibre Channel.

[RFC 2837] Definitions of Managed Objects for the Fabric Element in Fibre Channel Standard.

[RFC 3831] Transmission of IPv6 Packets over Fibre Channel.

Description Glossary RFCs Publications Obsolete RFCs