Overview
ISO/IEC 14776-223:2008 (FCP-3) specifies the Fibre Channel Protocol for SCSI (third version). It defines how SCSI commands, data and status are transported over Fibre Channel using FC-FS-2 Exchanges and Information Units (IUs). The standard maps the SCSI Architecture Model-3 (SAM-3) services onto Fibre Channel link and FC-4 services, covering addressing, exchanges, I/T nexus events, and confirmed completion and recovery behaviors for SCSI over Fibre Channel.
Key Topics
- FCP Information Units (IUs): Formats and usage for FCP_CMND, FCP_DATA, FCP_XFER_RDY, FCP_RSP and FCP_CONF - how commands, data bursts and responses are encapsulated.
- FC-FS-2 frame header fields: Definitions and use of fields such as r_ctl, d_id, s_id, f_ctl, seq_id, ox_id and rx_id for reliable SCSI transport over Fibre Channel.
- I/O and exchange behavior: FCP I/O operations, bidirectional vs unidirectional commands, precise delivery, retransmission rules and confirmed completion of operations.
- Process and port login: PRLI (Process Login), PRLO (Process Logout), Process Login parameters and discovery of FCP capabilities.
- Link and FC‑4 services: FC-4 link service usage, Sequence Retransmission Request (SRR), FCP_RJT rejects and Name Server registration for FC-4 objects.
- Task management & recovery: Task retry identification, clearing effects of task management, I_T nexus loss notifications and Transport Reset events.
- SCSI mode pages and timers: FCP-specific SCSI mode parameters (e.g., Disconnect‑Reconnect, Port Control) and operational timers such as E_D_TOV, R_A_TOV, RR_TOV, REC_TOV and ULP_TOV for error detection and resource recovery.
Applications
ISO/IEC 14776-223:2008 is essential for organizations implementing or integrating SCSI over Fibre Channel in enterprise storage and SAN environments:
- Storage array firmware and host bus adapter (HBA) developers implementing FCP-3 IU formats and exchange semantics.
- SAN architects and integrators ensuring interoperability between hosts, switches and targets.
- QA and interoperability test teams validating compliance with FC-FS-2 frame usage, PRLI/PRLO behavior and timer/ recovery handling.
- Systems software authors (multipathing, device drivers) that depend on precise SCSI-over-Fibre-Channel semantics and task management behaviors.
- Network designers tuning performance (burst sizes, mode pages) and reliability for high-throughput storage deployments.
Related Standards
- SCSI Architecture Model-3 (SAM-3) - mapping of SCSI services referenced by FCP-3.
- FC-FS-2, FC-LS, FC-AL-2 - Fibre Channel framing, link and arbitrated loop service documents referenced by FCP-3.
- Other parts of the ISO/IEC 14776 SCSI over Fibre Channel series.
Keywords: ISO/IEC 14776-223:2008, FCP-3, Fibre Channel Protocol for SCSI, SCSI over Fibre Channel, FC-FS-2, FCP Information Units, SAN, storage networking, PRLI, PRLO, World Wide Name (WWN).
Open preview (PDF)Information technology — Small Computer System Interface (SCSI) — Part 223: Fibre Channel Protocol for SCSI, Third Version (FCP-3)
