Fibre Channel over Ethernet

Last updated

Fibre Channel over Ethernet (FCoE) is a computer network technology that encapsulates Fibre Channel frames over Ethernet networks. This allows Fibre Channel to use 10 Gigabit Ethernet 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. [1]

Contents

Combined storage and local area network Storage FCoE.png
Combined storage and local area network

Functionality

FCoE transports Fibre Channel directly over Ethernet 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.

Traditionally, data centers used both Ethernet for TCP/IP networks and Fibre Channel for SANs, each having different and mostly incompatible interfaces/connections and interconnects/wiring and thus requires separate cabling/wiring and interconnects such as switching hardware for each. With the advent of FCoE, SANs that would have traditionally used Fibre Channel is consolidated with Ethernet and becomes another network protocol running on the Ethernet fabric, alongside traditional traffic such as IP. FCoE operates on top of the data link layer in the OSI model which contrasts with most other well-known protocols that may use Ethernet, such as (for a storage-related example) iSCSI, which runs on top of TCP over IP. As a consequence, FCoE is not routable at the IP layer and will not work across routed IP networks such as the Internet.

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 (dcb) Task Group.

Fibre Channel required three primary extensions to deliver the capabilities of Fibre Channel over Ethernet networks:

"Converged" network adapter Converged Network Adapter.png
"Converged" network adapter

Computers can connect to FCoE with converged network adapters (CNAs), which contain both Fibre Channel host bus adapter (HBA) and Ethernet network interface controller (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 storage area networks (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:

Frame format

FCoE Frame Format Frame FCoE.png
FCoE Frame Format

FCoE is encapsulated over Ethernet with the use of a dedicated Ethertype, 0x8906. A single 4-bit field (version) satisfies the IEEE sub-type requirements. The 802.1Q tag is optional but may be necessary in a given implementation. [2] The SOF (start of frame) and EOF (end of frame) are encoded as specified in RFC   3643. 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 Ethertype of 0x8914.

Timeline

In October 2003, Azul Technology developed early version and applied for a patent. [3]

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). [4] [5]

In April 2008, an early implementor was Nuova Systems, a subsidiary of Cisco Systems, which announced a switch. [6] [7] Brocade Communications Systems also announced support in 2008. [8] After the late-2000s financial crisis, however, any new technology had a hard time getting established. [9] [10]

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. [1]

In May 2010, the FC-BB-5 standard was published as ANSI/INCITS 462-2010. [11] Some additional work was done in the INCITS. [12]

Data center switches from Force10 and Dell PowerConnect supported FCoE and in June 2013, Dell Networking, which is the new brand-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. [13]

See also

Related Research Articles

<span class="mw-page-title-main">SCSI</span> Set of computer and peripheral connection standards

Small Computer System Interface is a set of standards for physically connecting and transferring data between computers and peripheral devices, best known for its use with storage devices such as hard disk drives. SCSI was introduced in the 1980s and has seen widespread use on servers and high-end workstations, with new SCSI standards being published as recently as SAS-4 in 2017.

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 network. iSCSI facilitates data transfers over intranets and to manage storage over long distances. It can be used to transmit data over local area networks (LANs), wide area networks (WANs), or the Internet and can enable location-independent data storage and retrieval.

<span class="mw-page-title-main">InfiniBand</span> Network standard

InfiniBand (IB) is a computer networking communications standard used in high-performance computing that features very high throughput and very low latency. It is used for data interconnect both among and within computers. InfiniBand is also used as either a direct or switched interconnect between servers and storage systems, as well as an interconnect between storage systems. It is designed to be scalable and uses a switched fabric network topology. By 2014, it was the most commonly used interconnect in the TOP500 list of supercomputers, until about 2016.

Fibre Channel (FC) 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 (SAN) in commercial data centers.

<span class="mw-page-title-main">Host adapter</span> Computer hardware device

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 connecting SCSI, SAS, NVMe, Fibre Channel and SATA devices. Devices for connecting to FireWire, USB and other devices may also be called host controllers or host adapters.

In computer networking, cut-through switching, also called cut-through forwarding is a method for packet switching systems, wherein the switch starts forwarding a frame before the whole frame has been received, normally as soon as the destination address and outgoing interface is determined. Compared to store and forward, this technique reduces latency through the switch and relies on the destination devices for error handling. Pure cut-through switching is only possible when the speed of the outgoing interface is at least equal or higher than the incoming interface speed.

ATA over Ethernet (AoE) is a network protocol developed by the Brantley Coile Company, designed for simple, high-performance access of block storage devices over Ethernet networks. It is used to build storage area networks (SANs) with low-cost, standard technologies.

IPFC stands for Internet Protocol over Fibre Channel. It governs a set of standards created in January 2006 for address resolution (ARP) and transmitting IPv4 and IPv6 network packets over a Fibre Channel (FC) network. IPFC makes up part of the FC-4 protocol-mapping layer of a Fibre Channel system.

<span class="mw-page-title-main">QLogic</span> American network device manufacturer

QLogic Corporation was an American manufacturer of networking server and storage networking connectivity and application acceleration products, based in Aliso Viejo, California through 2016. QLogic's products include Fibre Channel adapters, converged network adapters for Fibre Channel over Ethernet (FCoE), Ethernet network interface controllers, iSCSI adapters, and application-specific integrated circuits (ASICs). It was a public company from 1992 to 2016.

Internet Fibre Channel Protocol (iFCP) is a gateway-to-gateway network protocol standard that provides Fibre Channel fabric functionality to Fibre Channel devices over an IP network. It is officially ratified by the Internet Engineering Task Force. Its most common forms are in 1 Gbit/s, 2 Gbit/s, 4 Gbit/s, 8 Gbit/s, and 10 Gbit/s.

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 portfolio will be detailed on the Dell Networking page.

<span class="mw-page-title-main">ATTO Technology</span> Storage connectivity product manufacturer

ATTO Technology, Inc. is a manufacturer of storage connectivity products for data-intensive computing. ATTO manufactures Fibre Channel and SAS/SATA host bus adapters, RAID adapters, Fibre Channel switches, protocol conversion bridges, storage controllers, MacOS iSCSI initiator software and acceleration software with storage interface connectivity to SATA, SAS, Fibre Channel, Thunderbolt devices, Ethernet and NVMe.

<span class="mw-page-title-main">Storage area network</span> Network which provides access to consolidated, block-level data storage

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 servers so that the devices appear to the operating system as direct-attached storage. A SAN typically is a dedicated network of storage devices not accessible through the local area network (LAN).

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.

Fibre Channel over IP is an Internet Protocol (IP) created by the Internet Engineering Task Force (IETF) for storage technology.

<span class="mw-page-title-main">LIO (SCSI target)</span> Open-source version of SCSI target

In computing, Linux-IO (LIO) Target is an open-source implementation of the SCSI target that has become the standard one included in the Linux kernel. Internally, LIO does not initiate sessions, but instead provides one or more Logical Unit Numbers (LUNs), waits for SCSI commands from a SCSI initiator, and performs required input/output data transfers. LIO supports common storage fabrics, including FCoE, Fibre Channel, IEEE 1394, iSCSI, iSCSI Extensions for RDMA (iSER), SCSI RDMA Protocol (SRP) and USB. It is included in most Linux distributions; native support for LIO in QEMU/KVM, libvirt, and OpenStack makes LIO also a storage option for cloud deployments.

<span class="mw-page-title-main">Dell M1000e</span> Server computer

The Dell blade server products are built around their M1000e enclosure that can hold their server blades, an embedded EqualLogic iSCSI storage area network and I/O modules including Ethernet, Fibre Channel and InfiniBand switches.

<span class="mw-page-title-main">Converged network adapter</span> Computer input/output device

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, it "converges" access to, respectively, a storage area network and a general-purpose computer network.

<span class="mw-page-title-main">SCST</span>

SCST is a GPL licensed SCSI target software stack. The design goals of this software stack are high performance, high reliability, strict conformance to existing SCSI standards, being easy to extend and easy to use. SCST does not only support multiple SCSI protocols but also supports multiple local storage interfaces and also storage drivers implemented in user-space via the scst_user driver.

Storage security is a specialty area of security that is concerned with securing data storage systems and ecosystems and the data that resides on these systems.

References

  1. 1 2 "Fibre Channel: Backbone - 5 revision 2.00" (PDF). American National Standard for Information Technology International Committee for Information Technology Standards Technical Group T11. June 4, 2009. Archived from the original (PDF) on December 29, 2009. Retrieved May 5, 2011.
  2. "Fibre Channel – Backbone 5, 7.7 FCoE frame format" (PDF). T11. 4 June 2009. Archived from the original (PDF) on December 29, 2009. Retrieved 2015-01-06.
  3. Alex E. Henderson; John William Hayes; Walter E. Croft; Linda Elaine Eaton (October 21, 2003). "Transporting fibre channel over ethernet". US Patent and Trademark Office. US Patent 20080028096 granted January 31, 2008
  4. Austin Modine (October 17, 2007). "QLogic hypes ′network consolidation′ with FCoE". The Register.
  5. PrimeNewswire (October 16, 2007). "QLogic, NetApp and Nuova Systems Demonstrate Industry′s First Converged Network With Fibre Channel Over Ethernet". TMC News.
  6. Paul Shread (April 10, 2008). "Cisco Buys Nuova as FCoE Heats Up". Enterprise Storage Forum. Retrieved May 5, 2011.
  7. "Cisco Announces Intent to Acquire Remaining Interest in Nuova Systems". Press release. Cisco Systems. April 8, 2008. Archived from the original on March 4, 2012. Retrieved May 5, 2011.
  8. Dave Rowell (March 19, 2008). "Cisco, Brocade See One Big Happy Fabric". Enterprise Storage Forum. Retrieved May 5, 2011.
  9. Drew Robb (March 29, 2011). "FCoE Struggles to Gain Traction". Enterprise Storage Forum. Retrieved May 5, 2011.
  10. Henry Newman (April 25, 2011). "FCoE Gets Lost in Vendor Stupidity". Enterprise Storage Forum. Retrieved May 5, 2011.
  11. "Information technology - Fibre Channel - Backbone - 5 (FC-BB-5)". ANSI/INCITS 462-2010. International Committee for Information Technology Standards (formerly NCITS). May 13, 2010. Official standard.
  12. "Fibre Channel over Ethernet". T11 web site. Retrieved May 23, 2013.
  13. Dell Networking S-Series switches overview, visited 26 May 2013