Fibre Channel
Encyclopedia
Fibre Channel, or FC, is a gigabit
-speed network technology primarily used for storage networking. Fibre Channel is standardized in the T11 Technical Committee of the InterNational Committee for Information Technology Standards (INCITS
), an American National Standards Institute
(ANSI)–accredited standards committee. Fibre Channel was primarily used in the supercomputer
field, but now, has become the standard connection type for storage area network
s (SAN) in enterprise storage
. Despite its name, Fibre Channel signaling can run on both twisted pair
copper
wire
and fiber-optic
cable
s.
Fibre Channel Protocol (FCP) is a transport protocol (similar to TCP
used in IP networks) which predominantly transports SCSI commands over Fibre Channel networks.
system then in use for similar roles. HIPPI used a massive 50-pair cable with bulky connectors, and had limited cable lengths. When Fibre Channel started to compete for the mass storage market its primary competitor was IBM's proprietary Serial Storage Architecture
(SSA) interface. Eventually the market chose Fibre Channel over SSA, rather than give IBM control over the next generation of mid- to high-end storage technology. Fibre Channel was primarily concerned with simplifying the connections and increasing distances, as opposed to increasing speeds. Later, designers added the goals of connecting SCSI disk storage, providing higher speeds and far greater numbers of connected devices.
It also added support for any number of "upper layer" protocols, including ATM
, and IP
, with SCSI being the predominant usage.
The following table shows Fibre Channel speed variants:
* - Throughput for duplex connections
are connected together. A port in Fibre Channel terminology is any entity that actively communicates over the network, not necessarily a hardware port
. This port is usually implemented in a device such as disk storage, an HBA on a server or a Fibre Channel switch
.
layering, but is split similarly into 5 layers, namely:
Layers FC0 through FC2 are also known as FC-PH, the physical layers of Fibre Channel.
Fibre Channel routers operate up to FC4 level (i.e. they may operate as SCSI routers), switches up to FC2, and hubs on FC0 only.
Fibre Channel products are available at 1, 2, 4, 8, 10, 16 and 20 Gbit/s; these protocol flavors are called accordingly 1GFC, 2GFC, 4GFC, 8GFC, 10GFC, 16GFC, or 20GFC. The 16GFC standard was approved by the INCITS T11 committee in 2010, and those products are expected to become available in 2011. Products based on the 1GFC, 2GFC, 4GFC, 8GFC and 16GFC standards should be interoperable and backward compatible. The 1GFC, 2GFC, 4GFC, 8GFC designs all use 8b/10b encoding
, while the 16GFC standard uses 64b/66b encoding
. Unlike the 10GFC and 20GFC standards, 16GFC provides backward compatibility with 4GFC and 8GFC.
The 10 Gbit/s standard and its 20 Gbit/s derivative, however, are not backward compatible with any of the slower speed devices, as they differ considerably on FC1 level in using 64b/66b encoding
instead of 8b/10b encoding
, and are primarily used as inter-switch links.
The following types of ports are defined by Fibre Channel:
(*Note: The term "trunking" is not a standard Fibre Channel term and is used by vendors interchangeably. For example: A trunk (an aggregation of ISLs) in a Brocade device is referred to as a Port Channel by Cisco. Whereas Cisco refers to trunking as an EISL.)
Modern Fibre Channel devices support SFP transceiver, mainly with LC
fiber connector. Older 1GFC devices used GBIC
transceiver, mainly with SC
fiber connector.
Fibre Channel switches can be divided into two classes. These classes are not part of the standard, and the classification of every switch is a marketing decision of the manufacturer:
A fabric consisting entirely of one vendor is considered to be homogeneous. This is often referred to as operating in its "native mode" and allows the vendor to add proprietary features which may not be compliant with the Fibre Channel standard.
If multiple switch vendors are used within the same fabric it is heterogeneous, the switches may only achieve adjacency if all switches are placed into their interoperability modes. This is called the "open fabric" mode as each vendor's switch may have to disable its proprietary features to comply with the Fibre Channel standard.
Some switch manufacturers offer a variety of interoperability modes above and beyond the "native" and "open fabric" states. These "native interoperability" modes allow switches to operate in the native mode of another vendor and still maintain some of the proprietary behaviors of both. However, running in native interoperability mode may still disable some proprietary features and can produce fabrics of questionable stability.
s are available for all major open systems
, computer architectures, and buses, including PCI
and SBus
. Some are OS dependent. Each HBA has a unique World Wide Name
(WWN), which is similar to an Ethernet MAC address
in that it uses an Organizationally Unique Identifier
(OUI) assigned by the IEEE. However, WWNs are longer (8 byte
s). There are two types of WWNs on a HBA; a node WWN (WWNN), which can be shared by some or all ports of a device, and a port WWN (WWPN), which is necessarily unique to each port.
are tools which collect, analyze, decode, store signals so people can view the high-speed waveforms at their leisure.
Gigabit
The gigabit is a multiple of the unit bit for digital information or computer storage. The prefix giga is defined in the International System of Units as a multiplier of 109 , and therefore...
-speed network technology primarily used for storage networking. Fibre Channel is standardized in the T11 Technical Committee of the InterNational Committee for Information Technology Standards (INCITS
INCITS
The InterNational Committee for Information Technology Standards, or INCITS , is an ANSI-accredited forum of IT developers. It was formerly known as the X3 and NCITS....
), an American National Standards Institute
American National Standards Institute
The American National Standards Institute is a private non-profit organization that oversees the development of voluntary consensus standards for products, services, processes, systems, and personnel in the United States. The organization also coordinates U.S. standards with international...
(ANSI)–accredited standards committee. Fibre Channel was primarily used in the supercomputer
Supercomputer
A supercomputer is a computer at the frontline of current processing capacity, particularly speed of calculation.Supercomputers are used for highly calculation-intensive tasks such as problems including quantum physics, weather forecasting, climate research, molecular modeling A supercomputer is a...
field, but now, has become the standard connection type for storage area network
Storage area network
A storage area network is a dedicated network that provides access to consolidated, block level data storage. SANs are primarily used to make storage devices, such as disk arrays, tape libraries, and optical jukeboxes, accessible to servers so that the devices appear like locally attached devices...
s (SAN) in enterprise storage
Enterprise storage
In computing, an enterprise storage is the computer storage designed for large-scale, high-technology environments of the modern enterprises. When comparing to the consumer storage, it has higher scalability, higher reliability, better fault tolerance, and much higher initial price.From the...
. Despite its name, Fibre Channel signaling can run on both twisted pair
Twisted pair
Twisted pair cabling is a type of wiring in which two conductors are twisted together for the purposes of canceling out electromagnetic interference from external sources; for instance, electromagnetic radiation from unshielded twisted pair cables, and crosstalk between neighboring pairs...
copper
Copper
Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...
wire
Wire
A wire is a single, usually cylindrical, flexible strand or rod of metal. Wires are used to bear mechanical loads and to carry electricity and telecommunications signals. Wire is commonly formed by drawing the metal through a hole in a die or draw plate. Standard sizes are determined by various...
and fiber-optic
Fiber-optic communication
Fiber-optic communication is a method of transmitting information from one place to another by sending pulses of light through an optical fiber. The light forms an electromagnetic carrier wave that is modulated to carry information...
cable
Cable
A cable is two or more wires running side by side and bonded, twisted or braided together to form a single assembly. In mechanics cables, otherwise known as wire ropes, are used for lifting, hauling and towing or conveying force through tension. In electrical engineering cables are used to carry...
s.
Fibre Channel Protocol (FCP) is a transport protocol (similar to TCP
Transmission Control Protocol
The Transmission Control Protocol is one of the core protocols of the Internet Protocol Suite. TCP is one of the two original components of the suite, complementing the Internet Protocol , and therefore the entire suite is commonly referred to as TCP/IP...
used in IP networks) which predominantly transports SCSI commands over Fibre Channel networks.
History
Fibre Channel started in 1988, with ANSI standard approval in 1994, as a way to simplify the HIPPIHIPPI
HIPPI is a computer bus for the attachment of high speed storage devices to supercomputers. It was popular in the late 1980s and into the mid-to-late 1990s, but has since been replaced by ever-faster standard interfaces like SCSI and Fibre Channel.The first HIPPI standard defined a 50-wire...
system then in use for similar roles. HIPPI used a massive 50-pair cable with bulky connectors, and had limited cable lengths. When Fibre Channel started to compete for the mass storage market its primary competitor was IBM's proprietary Serial Storage Architecture
Serial Storage Architecture
Serial Storage Architecture is a serial transport protocol used to attach disk drives to servers. It was invented by Ian Judd of IBM in 1990...
(SSA) interface. Eventually the market chose Fibre Channel over SSA, rather than give IBM control over the next generation of mid- to high-end storage technology. Fibre Channel was primarily concerned with simplifying the connections and increasing distances, as opposed to increasing speeds. Later, designers added the goals of connecting SCSI disk storage, providing higher speeds and far greater numbers of connected devices.
It also added support for any number of "upper layer" protocols, including ATM
Asynchronous Transfer Mode
Asynchronous Transfer Mode is a standard switching technique designed to unify telecommunication and computer networks. It uses asynchronous time-division multiplexing, and it encodes data into small, fixed-sized cells. This differs from approaches such as the Internet Protocol or Ethernet that...
, and IP
Internet Protocol
The Internet Protocol is the principal communications protocol used for relaying datagrams across an internetwork using the Internet Protocol Suite...
, with SCSI being the predominant usage.
The following table shows Fibre Channel speed variants:
| NAME | Line-Rate (GBaud Baud In telecommunications and electronics, baud is synonymous to symbols per second or pulses per second. It is the unit of symbol rate, also known as baud rate or modulation rate; the number of distinct symbol changes made to the transmission medium per second in a digitally modulated signal or a... ) |
Throughput (Fullduplex) (MB Megabyte The megabyte is a multiple of the unit byte for digital information storage or transmission with two different values depending on context: bytes generally for computer memory; and one million bytes generally for computer storage. The IEEE Standards Board has decided that "Mega will mean 1 000... ps)* |
Availability |
| 1GFC | 1.0625 | 200 | 1997 |
| 2GFC | 2.125 | 400 | 2001 |
| 4GFC | 4.25 | 800 | 2005 |
| 8GFC | 8.5 | 1600 | 2008 |
| 10GFC Serial | 10.52 | 2550 | 2004 |
| 10GFC Parallel | 12.75 | ||
| 16GFC | 14.025 | 3200 | 2011 |
| 20GFC | 21.04 | 5100 | 20?? |
Fibre Channel topologies
There are three major Fibre Channel topologies, describing how a number of portsComputer port (software)
In computer programming, port has a wide range of meanings.A software port is a virtual/logical data connection that can be used by programs to exchange data directly, instead of going through a file or other temporary storage location...
are connected together. A port in Fibre Channel terminology is any entity that actively communicates over the network, not necessarily a hardware port
Computer port (hardware)
In computer hardware, a port serves as an interface between the computer and other computers or peripheral devices. Physically, a port is a specialized outlet on a piece of equipment to which a plug or cable connects...
. This port is usually implemented in a device such as disk storage, an HBA on a server or a Fibre Channel switch
Fibre Channel switch
In the computer storage field, a Fibre Channel switch is a network switch compatible with the Fibre Channel protocol. It allows the creation of a Fibre Channel fabric, that is currently the core component of most storage area networks . The fabric is a network of Fibre Channel devices which...
.
- Point-to-Point (FC-P2P). Two devices are connected directly to each other. This is the simplest topology, with limited connectivity.
- Arbitrated loopArbitrated loopArbitrated loop, also known as FC-AL, is a Fibre Channel topology in which devices are connected in a one-way loop fashion in a ring topology. Historically it was a lower-cost alternative to a fabric topology. It allowed connection of many servers and computer storage devices without using then...
(FC-AL). In this design, all devices are in a loop or ring, similar to token ring networking. Adding or removing a device from the loop causes all activity on the loop to be interrupted. The failure of one device causes a break in the ring. Fibre Channel hubs exist to connect multiple devices together and may bypass failed ports. A loop may also be made by cabling each port to the next in a ring.- A minimal loop containing only two ports, while appearing to be similar to FC-P2P, differs considerably in terms of the protocol.
- Only one pair of ports can communicate concurrently on a loop.
- Maximum speed of 8GFC.
- Switched fabric (FC-SW). All devices or loops of devices are connected to Fibre Channel switchFibre Channel switchIn the computer storage field, a Fibre Channel switch is a network switch compatible with the Fibre Channel protocol. It allows the creation of a Fibre Channel fabric, that is currently the core component of most storage area networks . The fabric is a network of Fibre Channel devices which...
es, similar conceptually to modern EthernetEthernetEthernet is a family of computer networking technologies for local area networks commercially introduced in 1980. Standardized in IEEE 802.3, Ethernet has largely replaced competing wired LAN technologies....
implementations. Advantages of this topology over FC-P2P or FC-AL include:- The switches manage the state of the fabric, providing optimized interconnections.
- The traffic between two ports flows through the switches only, it is not transmitted to any other port.
- Failure of a port is isolated and should not affect operation of other ports.
- Multiple pairs of ports may communicate simultaneously in a fabric.
| Attribute | Point-to-Point | Arbitrated loop | Switched fabric |
|---|---|---|---|
| Max ports | 2 | 127 | ~16777216 (224) |
| Address size | N/A | 8-bit Bit A bit is the basic unit of information in computing and telecommunications; it is the amount of information stored by a digital device or other physical system that exists in one of two possible distinct states... ALPA |
24-bit port ID |
| Side effect of port failure | Link fails | Loop fails (until port bypassed) | N/A |
| Mixing different link rates | No | No | Yes |
| Frame delivery | In order | In order | Not guaranteed |
| Access to medium | Dedicated | Arbitrated | Dedicated |
Layers
Fibre Channel does not follow the OSI modelOSI model
The Open Systems Interconnection model is a product of the Open Systems Interconnection effort at the International Organization for Standardization. It is a prescription of characterizing and standardizing the functions of a communications system in terms of abstraction layers. Similar...
layering, but is split similarly into 5 layers, namely:
- FC4 — Protocol Mapping layer, in which application protocols, such as SCSISCSISmall Computer System Interface is a set of standards for physically connecting and transferring data between computers and peripheral devices. The SCSI standards define commands, protocols, and electrical and optical interfaces. SCSI is most commonly used for hard disks and tape drives, but it...
or IPInternet ProtocolThe Internet Protocol is the principal communications protocol used for relaying datagrams across an internetwork using the Internet Protocol Suite...
, are encapsulated into a PDUProtocol data unitIn telecommunications, the term protocol data unit has the following meanings:#Information that is delivered as a unit among peer entities of a network and that may contain control information, address information, or data....
for delivery to FC2. - FC3 — Common Services layer, a thin layer that could eventually implement functions like encryptionEncryptionIn cryptography, encryption is the process of transforming information using an algorithm to make it unreadable to anyone except those possessing special knowledge, usually referred to as a key. The result of the process is encrypted information...
or RAIDRAIDRAID is a storage technology that combines multiple disk drive components into a logical unit...
redundancy algorithms; - FC2 — Network layer, defined by the FC-PI-2 standard, consists of the core of Fibre Channel, and defines the main protocolsFibre Channel network protocolsCommunication between devices in a fibre channel network uses different elements of the Fibre Channel standards. The following sections introduce the main concepts and show how a combination of primitives and frames is required....
; - FC1 — Data Link layer, which implements line coding of signals;
- FC0 — PHY, includes cabling, connectorsFibre Channel electrical interfaceThe Fibre Channel electrical interface is one of two related standards that can be used to physically interconnect computer devices. The other standard is a Fibre Channel optical interface, which is not covered in this article....
etc.;
Layers FC0 through FC2 are also known as FC-PH, the physical layers of Fibre Channel.
Fibre Channel routers operate up to FC4 level (i.e. they may operate as SCSI routers), switches up to FC2, and hubs on FC0 only.
Fibre Channel products are available at 1, 2, 4, 8, 10, 16 and 20 Gbit/s; these protocol flavors are called accordingly 1GFC, 2GFC, 4GFC, 8GFC, 10GFC, 16GFC, or 20GFC. The 16GFC standard was approved by the INCITS T11 committee in 2010, and those products are expected to become available in 2011. Products based on the 1GFC, 2GFC, 4GFC, 8GFC and 16GFC standards should be interoperable and backward compatible. The 1GFC, 2GFC, 4GFC, 8GFC designs all use 8b/10b encoding
8B/10B encoding
In telecommunications, 8b/10b is a line code that maps 8-bit symbols to 10-bit symbols to achieve DC-balance and bounded disparity, and yet provide enough state changes to allow reasonable clock recovery. This means that the difference between the count of 1s and 0s in a string of at least 20 bits...
, while the 16GFC standard uses 64b/66b encoding
64b/66b encoding
In data networking and transmission, 64b/66b is a line code that transforms 64-bit data to 66-bit line code to provide enough state changes to allow reasonable clock recovery and facilitate alignment of the data stream at the receiver....
. Unlike the 10GFC and 20GFC standards, 16GFC provides backward compatibility with 4GFC and 8GFC.
The 10 Gbit/s standard and its 20 Gbit/s derivative, however, are not backward compatible with any of the slower speed devices, as they differ considerably on FC1 level in using 64b/66b encoding
64b/66b encoding
In data networking and transmission, 64b/66b is a line code that transforms 64-bit data to 66-bit line code to provide enough state changes to allow reasonable clock recovery and facilitate alignment of the data stream at the receiver....
instead of 8b/10b encoding
8B/10B encoding
In telecommunications, 8b/10b is a line code that maps 8-bit symbols to 10-bit symbols to achieve DC-balance and bounded disparity, and yet provide enough state changes to allow reasonable clock recovery. This means that the difference between the count of 1s and 0s in a string of at least 20 bits...
, and are primarily used as inter-switch links.
Ports
- node ports
- N_port is a port on the node (e.g. host or storage device) used with both FC-P2P or FC-SW topologies. Also known as Node port.
- NL_port is a port on the node used with an FC-AL topology. Also known as Node Loop port.
- F_port is a port on the switch that connects to a node point-to-point (i.e. connects to an N_port). Also known as Fabric port. An F_port is not loop capable.
- FL_port is a port on the switch that connects to a FC-AL loop (i.e. to NL_ports). Also known as Fabric Loop port.
- E_port is the connection between two fibre channel switches. Also known as an Expansion port. When E_ports between two switches form a link, that link is referred to as an inter-switch link (ISL).
- D_port is a diagnostic port, used solely for the purpose of running link-level diagnostics between two switches and to isolate link level fault on the port, in the SFP, or in the cable.
- EX_port is the connection between a fibre channel router and a fibre channel switch. On the side of the switch it looks like a normal E_port, but on the side of the router it is a EX_port.
- TE_port * a Cisco addition to Fibre Channel, now adopted as a standard. It is an extended ISL or EISL. The TE_port provides not only standard E_port functions but allows for routing of multiple VSANVSANIn computer networking, a virtual storage area network is a collection of ports from a set of connected Fibre Channel switches, that form a virtual fabric. Ports within a single switch can be partitioned into multiple VSANs, despite sharing hardware resources...
s (Virtual SANs). This is accomplished by modifying the standard Fibre Channel frame (vsan tagging) upon ingress/egress of the VSAN environment. Also known as Trunking E_port. - VE_Port an INCITSINCITSThe InterNational Committee for Information Technology Standards, or INCITS , is an ANSI-accredited forum of IT developers. It was formerly known as the X3 and NCITS....
T11 addition, FCIP interconnected E-Port/ISL, i.e. fabrics will merge. - VEX_Port a INCITSINCITSThe InterNational Committee for Information Technology Standards, or INCITS , is an ANSI-accredited forum of IT developers. It was formerly known as the X3 and NCITS....
T11 addition, is a FCIP interconnected EX-Port, routing needed via lsan zoning to connect initiator to a target.
- general (catch-all) types
- Auto or auto-sensing port found in Cisco switches, can automatically become an E_, TE_, F_, or FL_port as needed.
- Fx_port a generic port that can become a F_port (when connected to a N_port) or a FL_port (when connected to a NL_port). Found only on Cisco devices where oversubscription is a factor.
- GL_port on a switch can operate as an E_port, FL_port, or F_port. Found on QLogic switches.
- G_port or generic port on a switch can operate as an E_port or F_port. Found on Brocade, McData, and QLogic switches.
- L_port is the loose term used for any arbitrated loop port, NL_port or FL_port. Also known as Loop port.
- U_port is the loose term used for any arbitrated port. Also known as Universal port. Found only on Brocade switches.....
(*Note: The term "trunking" is not a standard Fibre Channel term and is used by vendors interchangeably. For example: A trunk (an aggregation of ISLs) in a Brocade device is referred to as a Port Channel by Cisco. Whereas Cisco refers to trunking as an EISL.)
Optical carrier medium variants
| Fiber modality | Speed (MByte/s) | Transmitter | Medium variant | Distance |
|---|---|---|---|---|
| Single-Mode Fiber Single-mode optical fiber In fiber-optic communication, a single-mode optical fiber is an optical fiber designed to carry only a single ray of light . Modes are the possible solutions of the Helmholtz equation for waves, which is obtained by combining Maxwell's equations and the boundary conditions... |
1600 | 1310 nm longwave light | 1600-SM-LC-L | 0.5 m - 10 km |
| 1490 nm longwave light | 1600-SM-LZ-I | 0.5 m - 2 km | ||
| 800 | 1310 nm longwave light | 800-SM-LC-L | 2 m - 10 km | |
| 800-SM-LC-I | 2 m - 1.4 km | |||
| 400 | 1310 nm longwave light | 400-SM-LC-L | 2 m - 10 km | |
| 400-SM-LC-M | 2 m - 4 km | |||
| 400-SM-LL-I | 2 m - 2 km | |||
| 200 | 1550 nm longwave light | 200-SM-LL-V | 2 m - 50 km | |
| 1310 nm longwave light | 200-SM-LC-L | 2 m - 10 km | ||
| 200-SM-LL-I | 2 m - 2 km | |||
| 100 | 1550 nm longwave light | 100-SM-LL-V | 2 m - 50 km | |
| 1310 nm longwave lightFC-PH lists 1300nm (see clause 6.1 and 8.1) | 100-SM-LL-L 100-SM-LC-L |
2 m - 10 km | ||
| 100-SM-LL-I | 2 m - 2 km | |||
| Multimode Fiber Multi-mode optical fiber Multi-mode optical fiber is a type of optical fiber mostly used for communication over short distances, such as within a building or on a campus... |
1600 | 850 nm shortwave lightFC-PI-5 Clause 6.4FC-PI-4 Clause 6.4The older FC-PH and FC-PH-2 list 850nm (for 62.5µm cables) and 780nm (for 50µm cables)(see clause 6.2, 8.2, and 8.3) | 1600-M5F-SN-I | 0.5 m - 125 m |
| 1600-M5E-SN-I | 0.5 m - 100 m | |||
| 1600-M5-SN-S | 0.5 m - 35 m | |||
| 1600-M6-SN-SFC-PI-5 Annex A | 0.5 m - 15 m | |||
| 800 | 800-M5F-SN-I | 0.5 m - 190 m | ||
| 800-M5E-SN-I | 0.5 m - 150 m | |||
| 800-M5-SN-S | 0.5 m - 50 m | |||
| 800-M6-SN-S | 0.5 m - 21 m | |||
| 400 | 400-M5F-SN-I | 0.5 m - 400 m | ||
| 400-M5E-SN-I | 0.5 m - 380 m | |||
| 400-M5-SN-I | 0.5 m - 150 m | |||
| 400-M6-SN-I | 0.5 m - 70 m | |||
| 200 | 200-M5E-SN-I | 0.5 m - 500 m | ||
| 200-M5-SN-I | 0.5 m - 300 m | |||
| 200-M6-SN-I | 0.5 m - 150 m | |||
| 100 | 100-M5E-SN-IPC-PI-4 Clause 8.2 | 0.5 m - 860 m | ||
| 100-M5-SN-IPC-PI Clause 8.2 | 0.5 m - 500 m | |||
| 100-M6-SN-I | 0.5 m - 300 m | |||
| 100-M5-SL-I | 2 m - 500 m | |||
| 100-M6-SL-IFC-PH Annex C and Annex E | 2 m - 175 m |
| Multimode fiber | Fiber Diameter | FC media designation |
|---|---|---|
| OM1 | 62.5 µm | M6 |
| OM2 | 50 µm | M5 |
| OM3 | 50 µm | M5E |
| OM4 | 50 µm | M5F |
Modern Fibre Channel devices support SFP transceiver, mainly with LC
Optical fiber connector
An optical fiber connector terminates the end of an optical fiber, and enables quicker connection and disconnection than splicing. The connectors mechanically couple and align the cores of fibers so that light can pass...
fiber connector. Older 1GFC devices used GBIC
GBIC
A gigabit interface converter is a standard for transceivers, commonly used with Gigabit Ethernet and fibre channel in the 1990s...
transceiver, mainly with SC
Optical fiber connector
An optical fiber connector terminates the end of an optical fiber, and enables quicker connection and disconnection than splicing. The connectors mechanically couple and align the cores of fibers so that light can pass...
fiber connector.
Fibre Channel infrastructure
- directors offer a high port-count in a modular (slot-based) chassis with no single point of failure (high availability).
- switches are typically smaller, fixed-configuration (sometimes semi-modular), less redundant devices.
A fabric consisting entirely of one vendor is considered to be homogeneous. This is often referred to as operating in its "native mode" and allows the vendor to add proprietary features which may not be compliant with the Fibre Channel standard.
If multiple switch vendors are used within the same fabric it is heterogeneous, the switches may only achieve adjacency if all switches are placed into their interoperability modes. This is called the "open fabric" mode as each vendor's switch may have to disable its proprietary features to comply with the Fibre Channel standard.
Some switch manufacturers offer a variety of interoperability modes above and beyond the "native" and "open fabric" states. These "native interoperability" modes allow switches to operate in the native mode of another vendor and still maintain some of the proprietary behaviors of both. However, running in native interoperability mode may still disable some proprietary features and can produce fabrics of questionable stability.
Fibre Channel Host Bus Adapters
Fibre Channel HBAHost adapter
In computer hardware, a host controller, host adapter, or host bus adapter connects a host system to other network and storage devices...
s are available for all major open systems
Open system (computing)
Open systems are computer systems that provide some combination of interoperability, portability, and open software standards. The term was popularized in the early 1980s, mainly to describe systems based on Unix,...
, computer architectures, and buses, including PCI
Peripheral Component Interconnect
Conventional PCI is a computer bus for attaching hardware devices in a computer...
and SBus
SBus
SBus is a computer bus system that was used in most SPARC-based computers from Sun Microsystems and others during the 1990s...
. Some are OS dependent. Each HBA has a unique World Wide Name
World Wide Name
A World Wide Name or World Wide Identifier is a unique identifier which identifies a particular Fibre Channel, Advanced Technology Attachment or Serial Attached SCSI target...
(WWN), which is similar to an Ethernet MAC address
MAC address
A Media Access Control address is a unique identifier assigned to network interfaces for communications on the physical network segment. MAC addresses are used for numerous network technologies and most IEEE 802 network technologies, including Ethernet...
in that it uses an Organizationally Unique Identifier
Organizationally Unique Identifier
An Organizationally Unique Identifier is a 24-bit number that is purchased from the Institute of Electrical and Electronics Engineers, Incorporated Registration Authority...
(OUI) assigned by the IEEE. However, WWNs are longer (8 byte
Byte
The byte is a unit of digital information in computing and telecommunications that most commonly consists of eight bits. Historically, a byte was the number of bits used to encode a single character of text in a computer and for this reason it is the basic addressable element in many computer...
s). There are two types of WWNs on a HBA; a node WWN (WWNN), which can be shared by some or all ports of a device, and a port WWN (WWPN), which is necessarily unique to each port.
Development tools
When developing and/or troubleshooting the Fibre Channel bus, examination of hardware signals can be very important to find problems. Logic analyzers and bus analyzersBus analyzer
A bus analyzer is a computer bus analysis tool, often a combination of hardware and software, used during development of hardware or device drivers for a specific bus, for diagnosing bus or device failures, or reverse engineering....
are tools which collect, analyze, decode, store signals so people can view the high-speed waveforms at their leisure.
Sources
- Clark, T. Designing Storage Area Networks, Addison-Wesley, 1999. ISBN 0-201-61584-3
Further reading
- RFC 2625 - IP and ARP over Fibre Channel
- RFC 2837 - Definitions of Managed Objects for the Fabric Element in Fibre Channel Standard
- RFC 3723 - Securing Block Storage Protocols over IP
- RFC 4044 - Fibre Channel Management MIBManagement information baseA management information base is a virtual database used for managing the entities in a communications network. Most often associated with the Simple Network Management Protocol , the term is also used more generically in contexts such as in OSI/ISO Network management model...
- RFC 4625 - Fibre Channel Routing Information MIB
- RFC 4626 - MIB for Fibre Channel's Fabric Shortest Path First (FSPF) Protocol