ISO 21080-2016 PDF

Full title and description

Space data and information transfer systems — Licklider transmission protocol (LTP) for CCSDS. This International Standard specifies the CCSDS Licklider Transmission Protocol (LTP) profile and related service elements to provide optional reliability and segmentation mechanisms for use over space and ground packet delivery services in the CCSDS framework.

Abstract

ISO 21080:2016 defines a Recommended Standard for the CCSDS Licklider Transmission Protocol (LTP). LTP provides an application-level transfer service that offers optional reliability mechanisms on top of an underlying packet-delivery service, intended primarily for the space environment (deep-space and disrupted/delay-prone links) but also usable over ground networks when appropriate.

General information

• Status: Published (International Standard, confirmed stage).
• Publication date: July 2016.
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 49.140 (Space data and information transfer systems).
• Edition / version: Edition 1 (2016).
• Number of pages: 57.

Scope

Specifies the CCSDS profile of RFC 5326 for use in space data and information transfer systems. It is intended for use over current and envisaged packet delivery services used in the space environment (including CCSDS conventional packet telecommand and telemetry). For space links it is typically deployed over a CCSDS data link that supports Encapsulation Packets so that individual LTP segments map to single encapsulation packets; it may also operate over a variety of ground-network services used for cross-support.

Key topics and requirements

• Definition of LTP segment types and their roles (data segments, report segments, report-acknowledgment, cancel and cancel-acknowledgment segments).
• Concept of red (reliable) and green (unreliable) parts of a transmission block and mandatory/optional checkpoints for reliable delivery.
• Use of self-delimiting numeric values (SDNVs) and other binary encodings appropriate for constrained space links.
• Procedures for segmentation, retransmission, reception reporting, and session completion tailored to long-delay and disrupted links.
• CCSDS-specific profile and ambiguity resolutions of RFC 5326, and consideration of security extensions (RFC 5327) where applicable.
• Interoperation guidance with CCSDS Bundle Protocol implementations (DTN use) and registration of engine identifiers for unique addressing.

Typical use and users

Used by space agencies, satellite and spacecraft communication system designers, ground-segment and mission-operations engineers, and developers of Delay-Tolerant Networking (DTN) software (e.g., bundle protocol convergence-layer implementers). Typical deployments include deep-space probes, planetary communications, near-Earth missions with intermittent connectivity, and testbeds that require reliable transfer over highly challenged links.

Related standards

Key related documents include the CCSDS recommended standard for LTP (CCSDS 734.1-B-1, the CCSDS profile of RFC 5326), the original IETF specifications (RFC 5326 — LTP specification and RFC 5327 — security extensions), and CCSDS/ISO standards for the Bundle Protocol (ISO 21323:2016) and other CCSDS data-link profiles that LTP typically runs over.

Keywords

LTP, Licklider Transmission Protocol, CCSDS, space data links, delay-/disruption-tolerant networking (DTN), bundle protocol, SDNV, segmentation, retransmission, checkpoints.

FAQ

Q: What is this standard?

A: ISO 21080:2016 is the ISO-adopted Recommended Standard that specifies the CCSDS Licklider Transmission Protocol (LTP) profile for space data and information transfer systems (Edition 1, published July 2016).

Q: What does it cover?

A: It covers the protocol structures, segment types, reliable-delivery mechanisms (red/green parts and checkpoints), encoding conventions (SDNV), session procedures (segmentation, retransmit, reporting), and CCSDS-specific profiling of the IETF LTP specification to ensure interoperability in space missions.

Q: Who typically uses it?

A: Space agencies, spacecraft communications engineers, ground-station and mission-operations teams, and implementers of DTN/bundle-protocol stacks that need a convergence-layer protocol suited to long-latency or disrupted links.

Q: Is it current or superseded?

A: The published edition is ISO 21080:2016 (Edition 1). As with ISO standards, it is subject to periodic review; users should check their national or ISO catalogue for any later amendments or confirmations. The 2016 edition remains the referenced ISO publication.

Q: Is it part of a series?

A: It sits within the family of CCSDS/ISO space data and information transfer systems standards and is commonly used together with CCSDS/ISO Bundle Protocol specifications and lower-layer CCSDS link-layer profiles to form interoperable DTN-capable stacks (for example, ISO 21323:2016 for the CCSDS Bundle Protocol).

Q: What are the key keywords?

A: LTP, Licklider Transmission Protocol, CCSDS, delay-tolerant networking, bundle protocol, space data links, SDNV, reliable transfer.