BS ISO 18441:2021

This standard BS ISO 18441:2021 Space data and information transfer systems. Space link extension. Application program interface for transfer services. Core specification is classified in these ICS categories:

• 49.140 Space systems and operations

1.2.1 ITEMS COVERED BY THIS RECOMMENDED PRACTICE

This Recommended Practice defines the Application Program Interface in terms of:

1. the components that provide the services of the API;

2. the functionality provided by each of the components;

3. the interfaces provided by each of the components; and

4. the externally visible behavior associated with the interfaces exported by the components.

It does not specify:

1. individual implementations or products;

2. the internal design of the components; and

3. the technology used for communications.

This Recommended Practice defines those aspects of the Application Program Interface, which are common for all SLE service types or for a subset of the SLE service types, e.g., all return link services or all forward link services. It also defines a framework for specification of service type-specific elements of the API. Service-specific aspects of the API are defined by supplemental Recommended Practice documents for SLE return link services (references [10], [11], and [12]) and SLE forward link services (references [13] and [14]).

This Recommended Practice for the Application Program Interface responds to the requirements imposed on such an API by the CCSDS SLE transfer service Recommended Standards that were available when this Recommended Practice was released.

1.2.2 CONFORMANCE TO CCSDS RECOMMENDED STANDARDS

This version of the SLE API Recommended Practice conforms to the CCSDS Recommended Standards for Space Link Extension Services, referenced in 1.7, with the exception of the following optional features:

1. The negotiation procedure for version numbers in the BIND operation is not supported. If the responder does not support the version number identified in the BIND Invocation, it responds with a BIND Return containing a negative result and the diagnostic ‘version number not supported’. The responder does not propose an alternative version number.

2. Provider-initiated binding, specified by CCSDS Recommended Standards for return link services is not included in this Recommended Practice. The management parameters that specify the bind initiative are supported to simplify addition of this procedure in later versions.