Fibre Channel over Ethernet (FCoE) is a

computer network A computer network is a set of computers sharing resources located on or provided by network nodes. The computers use common communication protocols over digital interconnections to communicate with each other. These interconnections are ...

technology that encapsulates Fibre Channel frames over

Ethernet Ethernet () is a family of wired computer networking technologies commonly used in local area networks (LAN), metropolitan area networks (MAN) and wide area networks (WAN). It was commercially introduced in 1980 and first standardized in 1 ...

networks. This allows Fibre Channel to use

10 Gigabit Ethernet 10 Gigabit Ethernet (10GE, 10GbE, or 10 GigE) is a group of computer networking technologies for transmitting Ethernet frames at a rate of 10 gigabits per second. It was first defined by the IEEE 802.3ae-2002 standard. Unlike previous ...

networks (or higher speeds) while preserving the Fibre Channel protocol. The specification was part of the International Committee for Information Technology Standards T11 FC-BB-5 standard published in 2009. Storage FCoE

Functionality

FCoE transports Fibre Channel directly over

while being independent of the Ethernet forwarding scheme. The FCoE protocol specification replaces the FC0 and FC1 layers of the Fibre Channel stack with Ethernet. By retaining the native Fibre Channel constructs, FCoE was meant to integrate with existing Fibre Channel networks and management software. Data centers used Ethernet for TCP/IP networks and Fibre Channel for

storage area network A storage area network (SAN) or storage network is a computer network which provides access to consolidated, block-level data storage. SANs are primarily used to access data storage devices, such as disk arrays and tape libraries from ser ...

s (SANs). With FCoE, Fibre Channel becomes another network protocol running on Ethernet, alongside traditional

Internet Protocol The Internet Protocol (IP) is the network layer communications protocol in the Internet protocol suite for relaying datagrams across network boundaries. Its routing function enables internetworking, and essentially establishes the Internet. ...

(IP) traffic. FCoE operates directly above Ethernet in the network protocol stack, in contrast to

iSCSI Internet Small Computer Systems Interface or iSCSI ( ) is an Internet Protocol-based storage networking standard for linking data storage facilities. iSCSI provides block-level access to storage devices by carrying SCSI commands over a TCP/IP ...

which runs on top of TCP and IP. As a consequence, FCoE is not routable at the IP layer, and will not work across routed IP networks. Since classical Ethernet had no priority-based flow control, unlike Fibre Channel, FCoE required enhancements to the Ethernet standard to support a priority-based flow control mechanism (to reduce frame loss from congestion). The IEEE standards body added priorities in the

data center bridging Data center bridging (DCB) is a set of enhancements to the Ethernet local area network communication protocol for use in data center environments, in particular for use with clustering and storage area networks. Motivation Ethernet is the primary ...

(dcb) Task Group. Fibre Channel required three primary extensions to deliver the capabilities of Fibre Channel over Ethernet networks: * Encapsulation of native Fibre Channel frames into Ethernet Frames. * Extensions to the Ethernet protocol itself to enable an Ethernet fabric in which frames are not routinely lost during periods of congestion. * Mapping between Fibre Channel N_port IDs (aka FCIDs) and Ethernet MAC addresses.

Computers can connect to FCoE with

converged network adapter A converged network adapter (CNA), also called a converged network interface controller (C-NIC), is a computer input/output device that combines the functionality of a host bus adapter (HBA) with a network interface controller (NIC). In other words ...

s (CNAs), which contain both Fibre Channel

host bus adapter In computer hardware, a host controller, host adapter, or host bus adapter (HBA), connects a computer system bus, which acts as the host system, to other network and storage devices. The terms are primarily used to refer to devices for conne ...

(HBA) and Ethernet

network interface controller A network interface controller (NIC, also known as a network interface card, network adapter, LAN adapter or physical network interface, and by similar terms) is a computer hardware component that connects a computer to a computer network. Ear ...

(NIC) functionality on the same physical card. CNAs have one or more physical Ethernet ports. FCoE encapsulation can be done in software with a conventional Ethernet network interface card, however FCoE CNAs offload (from the CPU) the low level frame processing and SCSI protocol functions traditionally performed by Fibre Channel host bus adapters.

Application

The main application of FCoE is in data center

s (SANs). FCoE has particular application in data centers due to the cabling reduction it makes possible, as well as in server virtualization applications, which often require many physical I/O connections per server. With FCoE, network (IP) and storage (SAN) data traffic can be consolidated using a single network. This consolidation can: * reduce the number of network interface cards required to connect to disparate storage and IP networks * reduce the number of cables and switches * reduce power and cooling costs

Frame format

FCoE is encapsulated over Ethernet with the use of a dedicated

Ethertype EtherType is a two-Octet (computing), octet field in an Ethernet frame. It is used to indicate which Communications protocol, protocol is Encapsulation (networking), encapsulated in the payload of the frame and is used at the receiving end by th ...

, 0x8906. A single 4-bit field (version) satisfies the

IEEE The Institute of Electrical and Electronics Engineers (IEEE) is a 501(c)(3) professional association for electronic engineering and electrical engineering (and associated disciplines) with its corporate office in New York City and its operat ...

sub-type requirements. The

802.1Q IEEE 802.1Q, often referred to as Dot1q, is the networking standard that supports virtual local area networking (VLANs) on an IEEE 802.3 Ethernet network. The standard defines a system of VLAN tagging for Ethernet frames and the accompanying pro ...

tag is optional but may be necessary in a given implementation. The SOF (start of frame) and EOF (end of frame) are encoded as specified in . Reserved bits are present to guarantee that the FCoE frame meets the minimum length requirement of Ethernet. Inside the encapsulated Fibre Channel frame, the frame header is retained so as to allow connecting to a storage network by passing on the Fibre Channel frame directly after de-encapsulation. The FIP (FCoE Initialization Protocol) is an integral part of FCoE. Its main goal is to discover and initialize FCoE capable entities connected to an Ethernet cloud. FIP uses a dedicated

of 0x8914.

Timeline

In October 2003, Azul Technology developed early version and applied for a patent. In April 2007, the FCoE standardization activity started. In October 2007, the first public end-to-end FCoE demo occurred at Storage Network World including adapters from QLogic, switches from Nuova Systems, and storage from NetApp (none of the companies involved made any product announcements at the time). In April 2008, an early implementor was Nuova Systems, a subsidiary of

Cisco Systems Cisco Systems, Inc., commonly known as Cisco, is an American-based multinational digital communications technology conglomerate corporation headquartered in San Jose, California. Cisco develops, manufactures, and sells networking hardware, ...

, which announced a switch.

Brocade Communications Systems Brocade is an American technology company specializing in storage networking products, now a subsidiary of Broadcom Inc. The company is known for its Fibre Channel storage networking products and technology. Prior to the acquisition, the compan ...

also announced support in 2008. After the late-2000s financial crisis, however, any new technology had a hard time getting established. In June 2009, the FCoE technology that had been defined as part of the International Committee for Information Technology Standards (INCITS) T11 FC-BB-5 standard was forwarded to ANSI for publication. In May 2010, the FC-BB-5 standard was published as ANSI/INCITS 462-2010. Some additional work was done in the INCITS. Data center switches from

Force10 Dell Force10 (formerly nCore Networks, Force10 Networks), was a United States company that developed and marketed 10 Gigabit and 40 Gigabit Ethernet switches for computer networking to corporate, educational, and governmental customers. It had ...

and

Dell PowerConnect ''The current portfolio of PowerConnect switches are now being offered as part of the Dell Networking brand: information on this page is an overview of all current and past PowerConnect switches as per August 2013, but any updates on current portf ...

supported FCoE and in June 2013,

Dell Networking Dell Networking is the new name for the networking portfolio of Dell. In the first half of 2013, Dell started to re-brand their different existing networking product brands to Dell Networking. Dell Networking will be the new name for the networkin ...

, which is the new

brand A brand is a name, term, design, symbol or any other feature that distinguishes one seller's good or service from those of other sellers. Brands are used in business, marketing, and advertising for recognition and, importantly, to create ...

-name for all networking portfolio of Dell, introduced the S5000 series which can be a fully native FCoE switch with the option to include a native fibre channel module, allowing you to connect the S5000 directly to an FC SAN environment.Dell Networkin
S-Series switches overview
visited 26 May 2013

References

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External links