ISO/IEC 14776-222:2005

Overview

ISO/IEC 14776-222:2005 - "Information technology - Small Computer System Interface (SCSI) - Part 222: Fibre Channel Protocol for SCSI, Second Version (FCP-2)" - defines the Fibre Channel (FC) mapping layer (FC‑4) for transporting SCSI command, data and status across Fibre Channel networks. Using the services of NCITS Project 1311D (FC‑FS), FCP‑2 enables standard SCSI CDBs, data payloads, parameter strings and sense/status information to traverse Fibre Channel fabrics and arbitrated loops, and supports Fibre Channel Classes of Service 1, 2 and 3.

Key topics and technical requirements

• FC‑4 mapping for SCSI (FCP‑2): Rules for encapsulating SCSI command and response units in Fibre Channel frames and sequences.
• FCP Information Units (IUs): Defined IU types such as FCP_CMND, FCP_DATA, FCP_XFER_RDY, FCP_RSP, and FCP_CONF for command/data/response exchange.
• Process Login / Logout: Procedures and parameter pages for PRLI and PRLO to establish FC‑4 associations.
• Link services and error handling: FC‑4 link services (e.g., SRR) plus sequence/exchange level recovery and retransmission behavior.
• Task management and discovery: Mechanisms for task retry identification, task management functions, and discovery of FCP capabilities (World Wide Names, FC‑4 name server objects).
• Mode pages and port control: SCSI mode parameters tailored for Fibre Channel (Disconnect‑Reconnect, Logical Unit and Port Control mode pages).
• Timers and recovery: Defined timers and timeouts (resource allocation, recovery, ULP timeout, etc.) to manage operation and failure recovery.
• Interoperability formats: Use of standard FC frame/sequence headers and fields (R_CTL, S_ID, D_ID, OX_ID/RX_ID, sequence counts) to ensure cross-vendor compatibility.

Practical applications and users

• Who uses it: Storage system architects, SAN engineers, HBA/firmware developers, operating system SCSI driver authors, storage appliance vendors, test and interoperability labs.
• Where it's applied: Designing and implementing SCSI over Fibre Channel for SANs, array controllers, host bus adapters, FC switches and fabric devices, and in interoperability testing to ensure reliable SCSI transport across fabrics and arbitrated loops.
• Benefits: Standardized command/data encapsulation, consistent error recovery and login procedures, and vendor‑neutral interoperability for enterprise storage deployments.

Related standards

• NCITS Project 1311D - Fibre Channel Framing and Signaling (FC‑FS) (used by FCP‑2)
• Other SCSI and Fibre Channel family standards (SCSI‑3/FC‑AL, FC‑PF specifications) - relevant for implementers and interoperability testing.

Keywords: ISO/IEC 14776-222:2005, FCP‑2, Fibre Channel Protocol for SCSI, SCSI over Fibre Channel, FC‑4, FCP_CMND, PRLI, PRLO, SAN, HBA, storage networking.