Overview
ISO/IEC 14776-263:2018 - Information technology - Small Computer System Interface (SCSI) - Part 263: SAS Protocol Layer - 3 (SPL-3) - defines the rules and behaviour for exchanging SCSI information over a serial interconnect (Serial Attached SCSI, SAS). As part of the SCSI family of standards, SPL-3 specifies architecture, state machines, naming/identifier formats and protocol procedures that ensure reliable, interoperable communication between SAS devices, controllers and expanders.
Key topics and technical requirements
The standard covers technical topics and implementation requirements including:
- Architecture and layering
- Definition of physical links (phys), logical links, ports (narrow/wide), domains and service delivery subsystems.
- Link and connection management
- Connection lifecycle, persistent connections, advancing credit and data transmit/receive state machines.
- Device and expander models
- Expander device topology, expander interfaces and internal components (routing, connection manager/router and broadcast handling).
- Discovery and configuration
- Discover process, configuration subprocess, route table handling and topology constraints for auto-configuration and path discovery.
- Naming and identifiers
- SAS addresses, NAA formats, port and phy identifiers, hashed addresses and device naming conventions for unique identification.
- Events and fault handling
- Reset sequences (soft/hard reset), I_T nexus loss, power loss handling and event-related behaviours.
- Routing and broadcast mechanics
- Expander routing attributes, route tables, broadcast propagation and routing restrictions.
- State machines and UML conventions
- Formal state machine definitions for transmit/receive paths, timers, counters and message semantics.
These areas define mandatory protocol behavior that implementers must follow to achieve interoperability across SAS devices.
Applications
ISO/IEC 14776-263:2018 is applied where robust, high-performance serial SCSI transport is required:
- Designing and implementing SAS host bus adapters (HBAs), RAID controllers and storage controllers.
- Developing SAS expanders, enclosures and backplanes for storage arrays.
- Firmware and device driver development for enterprise storage systems, servers and SAN/NAS appliances.
- Interoperability testing, certification, conformance testing and test-lab validation of SAS devices.
- System integration involving SAS–SATA bridging, multipath routing and enterprise data center storage architectures.
Who should use this standard
- Storage hardware engineers and firmware developers
- System architects and integrators in enterprise storage
- Test laboratories and QA teams performing protocol conformance
- Product managers and technical leads specifying SAS implementations
Related standards
- Other parts of the ISO/IEC 14776 SCSI family that define alternate transport protocols and higher-level command sets for SCSI over different interconnects.
Keywords: ISO/IEC 14776-263:2018, SAS Protocol Layer 3, SPL-3, Serial Attached SCSI, SCSI standard, expander, SAS address, persistent connections, discover process.
Open preview (PDF)Information technology — Small computer system interface (SCSI) — Part 263: SAS protocol layer - 3 (SPL-3)
