Fibre Channel


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Related to Fibre Channel: Fibre Channel over Ethernet

Fibre Channel

(storage, networking, communications)
An ANSI standard originally intended for high-speed SANs connecting servers, disc arrays, and backup devices, also later adapted to form the physical layer of Gigabit Ethernet.

Development work on Fibre channel started in 1988 and it was approved by the ANSI standards committee in 1994, running at 100Mb/s. More recent innovations have seen the speed of Fibre Channel SANs increase to 10Gb/s. Several topologies are possible with Fibre Channel, the most popular being a number of devices attached to one (or two, for redundancy) central Fibre Channel switches, creating a reliable infrastructure that allows servers to share storage arrays or tape libraries.

One common use of Fibre Channel SANs is for high availability databaseq clusters where two servers are connected to one highly reliable RAID array. Should one server fail, the other server can mount the array itself and continue operations with minimal downtime and loss of data.

Other advanced features include the ability to have servers and hard drives seperated by hundreds of miles or to rapidly mirror data between servers and hard drives, perhaps in seperate geographic locations.

Fibre Channel Industry Association (FCIA).

Fibre Channel

A high-speed transport technology used to build storage area networks (SANs). Although Fibre Channel can be used as a general-purpose network carrying ATM, IP and other protocols, it has been primarily used for transporting SCSI traffic from servers to disk arrays. The Fibre Channel Protocol (FCP) serializes SCSI commands into Fibre Channel frames and uses IP for in-band SNMP network management (see SNMP). For more about storage networks, see SAN.

Specifications
Using singlemode or multimode fibers, Fibre Channel can be configured point-to-point (FC-P2P), as a switched topology (FC-SW) or in an arbitrated loop (FC-AL) with or without a hub, which can connect up to 127 nodes (see below). Transmission rates up to 12.75 Gbps in each direction are supported.

Fibre Channel uses the Gigabit Ethernet physical layer and IBM's 8B/10B encoding method, where each byte is transmitted as 10 bits. Fibre Channel provides both connection-oriented and connectionless services. Following are the class and functional levels. See FCIP, FCoE, IP storage and Director-class switch.


Connection-oriented services
 Class 1    With acknowledgment, full bandwidth
 Class 4    Virtual connections, QoS,
             fractional bandwidth
 Class 6    Uni-directional

 Connectionless services
 Class 2    With acknowledgment
 Class 3    Without acknowledgment


 Node levels
 FC-4  Translation between Fibre Channel and
        command sets that use it: HiPPI, SCSI, IPI,
        SBCCS, IP, IEEE 802.2, audio, video
 FC-3  Common services across multiple ports

 Port levels (FC-PH standard)
 FC-2  Framing and flow control
 FC-1  8B/10B encoding, error detection
 FC-0  Electrical and optical characteristics



Arbitrated Loop
The arbitrated loop is widely used and can connect up to 127 nodes without using a switch. All devices share the bandwidth, and only two can communicate with each other at the same time, with each node repeating the data to its adjacent node. TX means transmit, and RX means receive.







Switch Fabric
A switch fabric is the most flexible topology, enabling all servers and storage devices to communicate with each other. It also provides for a failover architecture in the event a server or disk array ceases to operate.







Point-to-Point
This is the simplest topology connecting two Fibre Channel devices that communicate at full bandwidth.
References in periodicals archive ?
The fact that the majority of tape libraries still come equipped only with a SCSI-based robot for moving media presents a challenge for native Fibre Channel tape users.
Agilent Technologies, the first to introduce 4Gb Fibre Channel controllers with PCI-X and PCI Express, is pleased to support the industry demonstration of 4Gb Fibre Channel technology at the Intel Developer's Forum," said Erik Ottem, Director of Marketing for the Input Output Solutions Division in Agilent's Semiconductor Products Group.
The first 1 Gb/s Fibre Channel SANs were typically simple loop configurations to share data.
Fibre channel plugfests are a vital part of this market transition as it provides vendors a testing forum to prove compatibility between different vendors and older Fibre Channel technology.
When you add to this burgeoning new market the campaign of fear, uncertainty and doubt projected onto iSCSI by the large Fibre Channel vendors, you begin to understand the confusion around iSCSI that appeared this past year.
By using more cost-effective Fibre Channel drives, IT managers will have the capability to run their mission-critical data together with their basic reference data and use the same common Fibre Channel infrastructure.
Fibre Channel has been the protocol of choice for high-end storage needs because of its high throughput, reliability, scalability and the maturity of the applications used to manage and administer it.
The Fibre Channel standard remains as relevant as it was when approved by ANSI in 1993," said Bob Snively, Chair of the INCITS T11 Committee.
Fibre Channel now runs virtually any I/O load through a Fibre Channel adapter with minimal impact on CPU utilization.
Customers have the option of taking advantage of four external Fibre Channel ports or using the adapter as a standard dual-channel product.
Because iSCSI is a native IP-based protocol, data can be transported over the existing Ethernet infrastructure rather than through Fibre Channel or SCSI cabling.
As a Fibre Channel test equipment vendor, Finisar wholeheartedly supports the FCIA SANmark Qualified Test Provider initiative," said Kevin Cornell, Sr.