BS ISO 18438:2013 pdf download

BS ISO 18438:2013 pdf download.Space data and information transfer systems- Spacecraft Onboard lnterface Services —Subnetwork Test Service.
This document is one of a family of documcnts specifying the SOIS-compliant services to be provided by onboard subneworks.
The purpose of this document is to define services and service interfaces provided by the SOIS Suhnctwork Test Service. Its scope is to specify the service only and not to specify methods of providing the service over a variety of onboard data links.
This document conforms to the principles set out in the Spacecraft Onhoard Interface Services Green Book lrekrence [All) and is intended to be applied together with it. The protocols which provide this service are to be documented for individual links, and this may be in the purview of individual missions, agencies. or CCSDS. depending on future circumstance.
l..2 APPLICABILITY
This document applies to any mission or equipment claiming to provide a CCSDS SOIScompliant Suhnetwork Test Service.
1.3 RATIONALE
SOIS provide service interface specifications in order to promote interoperability and development reuse via peer-to-peer and venical standardisation.
1.4
The document has live major sections:
— this section. containing administrative information, definitions and references;
– section 2. describing general concepts and assumptions:
— section 3. conlaining the Subnetwork Test Service specification:
section 4. containing the Management Information Base (MIB) for the service:
— section 5. comprising a Service Conformance Statement Proforma. In addition, annex A contains informative references.
protocol data unit PDU): unit of data specified in a protocol and consisting of Protocol Control Information (PCIf and possibly user data.
service: capability of a layer (service provider) together with the layers beneath it. which is provided to the service users.
suhnetwork: an abstraction of a collection of equipment and physical media, such as a local area network or a data bus, which frrms and autonomous whole and can be used to interconnect real systems for the purpose of data transfer.
test service access point (TSAPt: the point at which SOIS lest service is provided by a test service entity to a test service user entity.
test service access point address (TSAP Addressf: a test service address that is used to identify a single TSAP.
liZ.3 Terms Defined in this Recommended Practice
For the purposes of this Recommended Practice, the following definitions also apply. Many other terms that pertain to specific items are defined in the appropriate sections.
channel: identifier for subnetwork resources associated with a resource reservation.
NOTE — A channel can be a list of lime slots in a time division multiplexed system or a bandwidth limit in a bandwidth division multiplexed system. The suhnetwork resources required for the communication may also be defined to allow simultaneous use of non-conflicting resources on suhnetworks that SUppOrt this feature.
data system: addressable entity, situated in a suhnct. which hosts an instance of the subnetwork protocols. subnework services, and subnecwock users.
NOTE — The suhnetwork users are uniquely identifiable in a suhnetwock by a combination of data system address and a protocol ID. A data system is typically a computer or a device.
data system address: identifier which uniquely identifies a data system in a subnetwork.
NOTE — The data system address can be referred to as a destination address or a source address depending on the context o its inocation at the subneLsork service interface.
octet: eight-bit word.
NOTE — An eight-hit word is commonly referred to as a byte.
priority: The transmit precedence of an SDU relative to other SDUs.
quality of service (QoS): ability of a communication system to provide predictable anddifferentiated services.
NOTE – Quality of service for a communication service can be characterised in terms of
important features relevant to that communications service，for example:reliability, transmission rate, effective bandwidth and latency, error rate.
1.6DOCUMENT NOMENCLATURE
The following conventions apply throughout this Recommended Practice:a) The words ‘shall’ and ‘must’ imply a binding and verifiable specification;b)The word ‘should’implies an optional, but desirable, specification;c)The word ‘may’implies an optional specification;
d) The words is’ , ” are’, and ‘will’ imply statements of fact.