ISO 18425:2013

Overview

ISO 18425:2013 - Space data and information transfer systems: Spacecraft Onboard Interface Services (SOIS) - Subnetwork Packet Service - defines the service specification and service interfaces for SOIS-compliant onboard subnetworks. Published by ISO and adopted from CCSDS 851.0‑M‑1, this standard specifies what the Subnetwork Packet Service must provide (not how it must be implemented over particular onboard data links). ISO 18425:2013 is intended to be used together with the SOIS Green Book and other CCSDS documentation to achieve interoperable onboard networking for space missions.

Key topics and requirements

• Service definition and interfaces: Formalizes the packet service API and the interaction model between onboard applications and subnetwork services.
• Scope limitation: Specifies the service only - implementation methods for specific physical or link-layer technologies are out of scope and are to be defined per mission, agency, or CCSDS protocols.
• Quality of Service (QoS): Describes QoS-related service capabilities to support differentiated handling of traffic within an onboard subnetwork.
• Security considerations: Identifies security as a topic to be addressed in service deployment (see standard for applicable guidance).
• Service primitives and parameters: Defines the primitives (operations) and parameters through which higher-level software interacts with the subnetwork packet service.
• Management Information Base (MIB): Provides a MIB specification and guidance for management and monitoring of the subnetwork packet service.
• Conformance and documentation: Includes a Service Conformance Statement Proforma for vendors and missions to declare compliance.

Applications and who uses it

ISO 18425:2013 is used to achieve interoperable and reusable onboard networking components across spacecraft and multi-agency missions:

• Spacecraft system architects - for specifying onboard network services and integration points.
• Onboard network and software engineers - to implement SOIS-compliant service interfaces and map them to specific link-layer protocols.
• Mission planners and integrators - to ensure cross-support and interoperability between spacecraft, ground segments, and agencies.
• Equipment vendors - to develop compliant network modules, routers, and interfaces that meet CCSDS/ISO expectations. Practical use cases include enabling TCP/IP-based applications over a single subnetwork, providing common QoS mechanisms for telemetry/telecommand/data-handling, and supporting multi-agency cross-support scenarios.

Related standards

• CCSDS 851.0‑M‑1 (December 2009) - Source Recommended Practice adopted by ISO as ISO 18425:2013.
• Spacecraft Onboard Interface Services Green Book - Principles and context to be applied together with ISO 18425:2013.
• CCSDS mission- or link-specific protocol documents - specify the concrete protocols that implement the service for particular onboard data links.

Keywords: ISO 18425:2013, SOIS, Subnetwork Packet Service, spacecraft onboard interface services, CCSDS, QoS, MIB, onboard subnetwork, packet service, interoperability.