118 IBM eServer zSeries 900 Technical Guide
3.5 FICON channel in Fibre Channel Protocol (FCP) mode
z900 server FICON Express and FICON features provide support of Fibre Channel and Small
Computer System Interface (SCSI) devices in Linux environments. This support is in
conjunction with the Linux distributions from zSeries Linux distribution partners.
The Fibre Channel (FC) standard was developed by the InterNational Committee of
Information Technology Standards (INCITS), and published as ANSI standards. The zSeries
FCP I/O architecture conforms to the FC standards specified by the INCITS. More detailed
information about the FC standards can be obtained from the following Web sites:
http://www.t10.org
http://www.t11.org
The z900 server FICON Express and FICON feature channels in FCP mode (FCP channel)
provide full fabric attachment of FCP and SCSI devices to Linux images using the Fibre
Channel Protocol. This allows Linux for zSeries and Linux for S/390 operating systems to
access industry-standard FCP and parallel SCSI storage controllers and devices.
z900 server FCP channel full fabric support means that multiple numbers of directors/
switches can be placed between the z900 server and FCP or SCSI device, thereby allowing
many hops through a storage network for I/O connectivity.
Support of FCP full fabric connectivity means that multiple FCP directors on a fabric can
share links and therefore provide improved utilization of inter-site connected resources and
infrastructure. This expanded attachability is intended to provide customers with more
choices for new storage solutions, or the ability to use existing storage devices, which may
leverage existing investments and lower total cost of ownership for their Linux
implementation. This can facilitate the consolidation of UNIX server farms onto zSeries
servers, protecting investments in SCSI-based storage.
For a list of switches, storage controllers, and devices that have been verified to work in a
Fibre Channel network attached to a z900 server FCP channel, and for specific software
requirements to support FCP and SCSI controllers or devices, see:
http://www.ibm.com/servers/eserver/zseries/connectivity
FCP channels are based on the Fibre Channel standards defined by the INCITS, and
published as ANSI standards. FCP is an upper layer fibre channel mapping of SCSI on a
common stack of Fibre Channel physical and logical communication layers. HIPPI, IPI, IP and
FICON (FC-SB-2) are other examples of upper layer protocols.
FCP and SCSI are industry-standard protocols that are supported by a wide range of
controllers and devices which complement the classical zSeries storage attachment
capability through FICON and ESCON channels. The FCP protocol is the base for
industry-standard Fibre Channel networks or Storage Area Networks (SANs).
Fibre Channel networks consist of servers, storage controllers, and devices as end nodes,
interconnected by Fibre Channel switches, directors, and hubs. Switches and directors are
used to build Fibre Channel networks or fabrics; Fibre Channel loops (FC-AL) can be
constructed using Fibre Channel hubs. In addition, different types of bridges and routers can
be used to connect devices with different interfaces (like parallel SCSI). All of these
interconnects can be combined in the same network.
Note: z900 FCP channel full fabric connectivity support is for homogeneous, single switch
vendor fabrics only.

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