BS ISO 20213:2015 pdf download

BS ISO 20213:2015 pdf download.Space data and information transfer systems — Spacecraft onboard interface services — Message transfer service
1.3 RATIONALE
SOIS provides service interface specifications in order to promote interoperability and development reuse via peer-to-peer and vertical standardization.
1.4 DOCUMENT STRUCTURE
This document has six major sections and five annexes:
– this section, containing administrative information, definitions, and references;
– section 2, containing general concepts and assumptions;
– section 3, containing the Message Transfer Service specification;
– section 4, containing the protocol definition, i.e., interoperable protocol between service implementations, so as to allow interoperability between them;
– section 5, containing the Protocol Data Units (PDUs) associated with the protocol definition in section 4;
– section 6, containing the Management Information Base (MIB) for this service;
– annex A, comprising the Service Conformance Statement Proforma;
– annex B, discussing security considerations;
– annex C, containing a list of informative references;
– annex D, containing an example ANSI C Application Programming Interface for
Message Transfer Service;
– annex E, containing an onboard software example of the use of Message Transfer Service, in particular with regard to the suggested interpretation of the adopted Asynchronous Message Service (AMS) primitives.
1.5 CONVENTIONS AND DEFINITIONS
1.5.1 DEFINITIONS
1.5.1.1 General
For the purpose of this document the following definitions apply.
1.5.1.2 Definitions from the Open Systems Interconnection Reference Model This document is defined using the style established by the Open Systems Interconnection (OSI) Basic Reference Model (reference [C1]). This model provides a common framework for the development of standards in the field of systems interconnection.
The following terms used in this Recommended Practice are adapted from definitions given in reference [C1]:
layer: Subdivision of the architecture, constituted by subsystems of the same rank.
protocol data unit: Unit of data specified in a protocol and consisting of Protocol Control Information (PCI) and possibly user data.
service: Capability of a layer (a service provider) together with the layers beneath it,which is provided to the service users.
1.5.1.3 Terms Defined in this Recommended Practice
For the purposes of this Recommended Practice, the following definitions also apply.
application: Component of the onboard software that makes use of the Message Transfer Service.
NOTE – Such components include flight software applications and higher-layer services.message: Discrete unit of data with a defined length that is sent and received atomically between tasks using Message Transfer Service.
1.5.1.4 Definitions from the Asynchronous Message Transfer Recommended Standard
The following terms used in this Recommended Practice are adapted from definitions given in reference [1]: Application AMS (AAMS): Protocol that conveys application data between AMS modules within a single continuum. Meta-AMS (MAMS): Protocol that propagates configuration information that enables the exchange of AAMS PDUs within a single continuum. Remote AMS (RAMS): Protocol the conveys application data between AMS modules in different continua. Meta-AMS PDU (MPDU): PDUs used to effect configuration and discovery procedures.