ISO 21080:2016

Overview

ISO 21080:2016 - "Space data and information transfer systems - Licklider transmission protocol (LTP) for CCSDS" - is an ISO-adopted Recommended Standard that formalizes the CCSDS Licklider Transmission Protocol (LTP) for use in the space environment. LTP provides optional reliability mechanisms that operate on top of an underlying packet delivery service (typically a data link). The standard documents service definitions, protocol profiles, conformance requirements and operational guidance for deploying LTP over typical space packet services.

Key topics and technical requirements

• Purpose and scope: Defines the LTP service and protocol for space telemetry and telecommand packet delivery, intended for CCSDS conventional packet telemetry and telecommand.
• Protocol profile: CCSDS profile of RFC 5326 (LTP base specification), including ambiguity resolution and recommended parameter limits.
• Underlying service requirements: LTP assumes an underlying packet delivery service (e.g., CCSDS data link with Encapsulation Packets) and specifies required system services such as reliable storage.
• Service primitives & parameters: Service interface primitives, parameters and client operations (including Service Data Aggregation) are specified for implementers.
• Deployment notes: Guidance for encapsulation so that an LTP segment typically maps to a single CCSDS Encapsulation Packet.
• Conformance & management: Contains conformance proforma (PICS), management information base (MIB) and implementation conformance statement proforma.
• Extensions & security: Notes on likely extensions, LTP security considerations and cross-support operations.
• Normative annexes: Practical implementation guidance (e.g., using CCSDS Space Packet or Encapsulation services), MIB, and conformance templates.

Applications

• Reliable data transfer in space communications, especially for:
  • Deep-space telemetry and telecommand links
  • Delay- and disruption-tolerant transport where optional reliability is needed
  • Satellite-to-ground or inter-spacecraft data transfer over CCSDS packet services
• Enabling interoperability and cross-support among space agencies and ground networks
• Implementing LTP as part of Solar System Internetwork (SSI) or DTN stacks for mission data transport

Who should use this standard

• Spacecraft communications engineers and protocol implementers
• Ground station and mission operations architects
• Satellite integrators and system engineers working on telemetry/telecommand
• Agencies and vendors seeking CCSDS-compliant, interoperable space data transfer solutions

Related standards

• CCSDS Recommended Standards (LTP as CCSDS 734.1-B-1)
• RFC 5326 (Licklider Transmission Protocol base specification)
• CCSDS Space Packet and Encapsulation Packet standards

Keywords: ISO 21080, LTP, CCSDS, Licklider Transmission Protocol, space communications, telemetry, telecommand, space data links, delay-tolerant networking.