FICON (Fibre Connection) is the
IBM proprietary name for the
ANSI
The American National Standards Institute (ANSI ) 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 organi ...
''FC-SB-3 Single-Byte Command Code Sets-3 Mapping Protocol'' for
Fibre Channel (FC)
protocol
Protocol may refer to:
Sociology and politics
* Protocol (politics), a formal agreement between nation states
* Protocol (diplomacy), the etiquette of diplomacy and affairs of state
* Etiquette, a code of personal behavior
Science and technolog ...
. It is a FC layer 4 protocol used to map both IBM's antecedent (either
ESCON
ESCON (Enterprise Systems Connection) is a data connection created by IBM, and is commonly used to connect their mainframe computers to peripheral devices such as disk storage, tape drives and IBM 3270 display controllers. ESCON is an opt ...
or parallel
Bus and Tag
Bus and Tag is an "IBM standard for a computer peripheral interface", and was commonly used to connect their mainframe computers to peripheral devices such as line printers, disk storage, magnetic tape drives and IBM 3270 display controllers. ...
)
channel
Channel, channels, channeling, etc., may refer to:
Geography
* Channel (geography), in physical geography, a landform consisting of the outline (banks) of the path of a narrow body of water.
Australia
* Channel Country, region of outback Austral ...
-to-control-unit cabling infrastructure and protocol onto standard FC services and infrastructure. The topology is
fabric
Textile is an umbrella term that includes various fiber-based materials, including fibers, yarns, filaments, threads, different fabric types, etc. At first, the word "textiles" only referred to woven fabrics. However, weaving is not th ...
utilizing
FC switches or directors. Valid rates include 1, 2, 4, 8 and 16 Gigabit per second data rates at distances up to 100 km.
FICON was introduced in 1998 as part of fifth generation of IBM System/390 mainframes. After 2011 FICON replaced ESCON in new IBM mainframe deployments because of FICON's technical superiority (especially its higher performance) and lower cost.
Protocol internals
Each FICON channel port is capable of multiple concurrent data exchanges (a maximum of 32) in full duplex mode. Information for active exchanges is transferred in Fibre Channel sequences mapped as FICON ''Information Units'' (IUs) which consist of one to four Fibre Channel frames, only the first of which carries 32 bytes of FICON (FC-SB-3) mapping protocol. Each FICON exchange may transfer one or many such IUs.
FICON channels use five classes of IUs to conduct information transfers between a channel and a control unit. They are: Data, Command, Status, Control, and lastly Link Control. Only a channel port may send Command or Command and Data IUs, while only a control unit port may send Status IUs.
As with prior Z channel protocols, there is a concept of a channel to control unit "connection". In its most primitive form, a connection is associated with a single channel program. In practice, a single channel program may result in the establishment of several sequential connections. This normally occurs during periods where data transfers become dormant while waiting for some type of independent device activity to complete (such as the physical positioning of tape or a disk access arm). In such cases, the connection may be closed by action of the device's control unit with the signaling of appropriate status. When the control unit is ready to resume such an interrupted connection, it signals the channel to reconnect and resume the interrupted channel program. By closing temporarily dormant connections, channel and control unit facilities may be better utilized to serve other active channel programs and certain protocol timeouts that might otherwise occur may be avoided.
FICON uses two Fibre Channel exchanges for a channel control unit connection one for each direction. So while a Fibre Channel exchange is capable of carrying a command and response on a single exchange, and all other FC-4 protocols work that way, the response to a FICON IU is always on a different exchange from the IU to which it is a response. The two exchanges that implement a connection are called an exchange pair (Note that the concept of the two exchanges being related exists only at the FC-4 layer). While other FC-4s have a single "data structure type" code that characterizes their IUs in Fibre Channel frame headers, FICON has two. One is for IUs from channel to control unit; the other for control unit to channel.
Except for some initialization dialogue that requires stronger synchronization, FICON uses Fibre Channel class of service 3 (Datagram). Thus, at the Fibre Channel physical (FC-2 and below) level, the communication is connectionless, frames and sequences may arrive out of order, and there is no acknowledgement of arrival. But all of that exists at the FC-4 level.
Additional CRC
The integrity of customer data carried within one or more IUs is protected by a running 32-bit
cyclic redundancy check (CRC) contained in the last frame of an IU classified as an ending IU within each data transfer. This is in addition to the standard Fibre Channel CRC used to verify the integrity of each individual FC frame. As such, the FICON CRC has the capability of detecting missing or out of sequence frames/IUs.
Cables
FICON may employ Fibre Channel fiber optic cables with either ''short'' wavelength (multi-mode; 62.5 or 50 micrometer core) or ''long'' wavelength (single mode; 9 micrometer core). Long wavelength is used in the majority of applications owing to its superior optical power budget and bandwidth. FICON cannot use ''Copper'' Fibre Channel cables.
Usage
FICON is used exclusively with computers based on the IBM
z/Architecture
z/Architecture, initially and briefly called ESA Modal Extensions (ESAME), is IBM's 64-bit complex instruction set computer (CISC) instruction set architecture, implemented by its mainframe computers. IBM introduced its first z/Architecture ...
(current descendant of
System/360,
System/370
The IBM System/370 (S/370) is a model range of IBM mainframe computers announced on June 30, 1970, as the successors to the System/360 family. The series mostly maintains backward compatibility with the S/360, allowing an easy migration path ...
, etc.), commonly called
mainframes. FICON and its predecessors are the only protocols sufficient to communicate with traditional mainframe peripheral devices, especially for
z/OS
z/OS is a 64-bit operating system for IBM z/Architecture mainframes, introduced by IBM in October 2000. It derives from and is the successor to OS/390, which in turn was preceded by a string of MVS versions.Starting with the earliest:
* ...
. However, most mainframe operating systems also support
FCP (
SCSI command set over Fibre Channel).
FICON is technically quite similar to more popular storage protocols, such as FCP. Both FICON and FCP share levels 1–3 of Fibre Channel specifications. Some administrators argue that FICON offers somewhat easier troubleshooting in mainframe environments, but the inherent technical advantages and disadvantages between FICON and FCP are much alike. Some mainframe-specific setups, such as
GDPS
In computing, a Parallel Sysplex is a cluster of IBM mainframes acting together as a single system image with z/OS. Used for disaster recovery, Parallel Sysplex combines data sharing and parallel computing to allow a cluster of up to 32 systems t ...
, require FICON (or its predecessor ESCON). Mainframe-attached storage, such as IBM's System Storage
DS8000
The IBM DS8000 series (early IBM System Storage DS8000 series) is an IBM storage media platform with hybrid flash and hard disk storage for IBM mainframes and other enterprise grade computing environments.
Description
This series formerly desi ...
, often supports both protocols. The storage is divided into fixed block storage volumes (accessed with FCP) and mainframe-specific
CKD/ECKD storage volumes (accessed with FICON and/or ESCON).
Devices
Disk storage products that can be attached via FICON include:
*
EMC Symmetrix
The Symmetrix system was an EMC's enterprise storage array. It combined dozens of hard drives into a single virtual device that was then shared on a local area network. It was the flagship product of EMC in the 1990s and 2000s.
History
Sym ...
, DMX and VMAX families
*
Hewlett Packard Enterprise
The Hewlett Packard Enterprise Company (HPE) is an American multinational information technology company based in Spring, Texas, United States.
HPE was founded on November 1, 2015, in Palo Alto, California, as part of the splitting of the ...
XP Storage family
* Hitachi Vantara
Virtual Storage Platform
Virtual Storage Platform is the brand name for a Hitachi Data Systems line of computer data storage systems for data centers. Model numbers include G200, G400, G600, G800, G1000, G1500 and G5500
History
Hitachi Virtual Storage Platform, also kno ...
* Hitachi Vantara
Virtual Storage Platform G1000
* Hitachi Vantara
Virtual Storage Platform G1500/F1500
* Hitachi Vantara
Virtual Storage Platform 5000
*
IBM Enterprise Storage Server
The IBM Enterprise Storage Server (ESS) or the ''Shark'' is an enterprise storage array from IBM.
History
Originally, in 1998 IBM released the IBM 2105 Versatile Storage Server (VSS). It did not meet commercial success and the successor came in ...
(Shark)
* IBM
Storage DS6000 and DS8000
*
INFINIDAT InfiniBox
*
StorageTek
Storage Technology Corporation (StorageTek or STK, earlier STC) was a data storage technology company headquartered in Louisville, Colorado. New products include data retention systems, which it calls "information lifecycle management" (ILM).
...
FlexLine V2Xf/V2X4f SVA
Tape storage facilities include:
* Advanced TS Migrations, Co. zAppliance Solutions VTL and zPDT data exchange
* Bus-Tech(EMC) MAS and MDL Virtual Tape Library
* EMC Disk Library for mainframe (DLm)
* IBM 3584 UltraScalable Tape Library (TS3500)
* IBM TS7680G ProtecTIER Deduplication Gateway for System z
* IBM Virtual Tape Server (VTS)
*
Luminex Mainframe Virtual Tape (MVT) and CGX Solutions
*
Oracle StorageTek SL3000 and SL8500 Tape Library
* Oracle StorageTek Virtual Storage Manager
* Tributary Systems Storage Director
Hardware Security Module (HSM) products that support FICON include:
* Thales payShield 9000
Switches/directors that support FICON include:
* NOKIA (formerly Alcatel-Lucent) 1830 PSS
* Brocade DCX family
* Brocade M-Series (McDATA)
* Cisco MDS 9000 Series
* EMC Connectrix family (made by Brocade or Cisco)
Managed File Transfer products that support FICON include:
* Alebra Technologies Parallel Data Mover
*
Luminex Mainframe Data Integration (MDI) Platform
Other older FICON switching platforms are still in use. These include the McDATA 6064, CNT UMD, and CNT (Inrange) FC/9000. Inrange was acquired by CNT in 2003, CNT was acquired by McDATA in 2005, and in 2007 McDATA was in turn acquired by
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 ...
. Approximately 80% of FICON directors and switches installed in mainframe environments were Brocade products at the time. McDATA was well established in the mainframe directors space, manufacturing the 9032-3 and 9032-5 ESCON directors for IBM, as well as the FICON Bridge Card.
[Steve Guendert. "A Comprehensive Guide for Migrating from ESCON to FICON"] Brocade has many co-patents with IBM for FICON and ESCON technology.
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, ...
was a relative newcomer to this space, with their first FICON director coming out in 2003.
Other manufacturers producing FICON-compatible equipment include
Optica Technologies, and
InfoPrint Solutions Company, which offers high-volume printers that can attach via FICON.
References
{{Reflist
Fibre Channel
IBM System/360 mainframe line