Ongoing discussions within the SWIM communities of interest

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Ongoing discussions within the SWIM communities of interest

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Status

The content on this page is used as input to the Service definition specification. If you are looking for the latest versions please see the specification.

The content on this page will be deleted once the supporting material for the specification is available.


Task Status

This page is part of the ongoing SWIM communities of interest discussions. The content is working material. It should not be treated as final as it is still subject to review, comment and change.


Introduction

Purpose and usage

The purpose of a service definition is to harmonize service implementations.

A service definition is produced by a community of interest. It contains a set of service metadata that defines a type of service.

For example, a service definition may define an AMAN service.

However, the service definition does not provide every piece of metadata about resulting service instances. For example, some service definitions will be technology agnostic and say nothing about the technologies to be used when implementing the service. The metadata is collected throughout the Service Orientation process. Much of it is collected by the end of the design step. This may also include recommendations for some technical aspects e.g. exchange model or a particular binding.

A service definition may be registered in the SWIM Registry. This will allow it to be discovered by service providers. 

A service definition is used by service providers. The service instance they implement is a running service that conforms to the service definition.  A service provider will produce a service description that completes the service metadata, expanding on that that was available in the service definition. The service description refers to the service definition ("standard") that was used as the basis for the service instance (see SWIM-SERV-010 Service standard reference). 

Creation

Bottom-up, top-down, middle-out

The service orientation process is written with a classical top-down approach e.g. starting with operational needs and the identification of a new service if this has not already performed.

A list of identified services is available at https://www.eatmportal.eu/working/rnd/service-overview.

However, it acknowledges that much of the activities can occur based on existing services that are in need of alignment. A service definition can therefore be the result of a community coming together to align a service that its members have already implemented.

It is, of course, also possible to start the service orientation process somewhere in the middle and develop the justification for the services at the same time as implementing it.

Legacy to new

A service definition can be used as a part of the service lifecycle process to support the transition from a legacy service or system to the SWIM environment. The legacy service can be "abstracted" into a service definition that ensures the same requirements are carried forward into the new service as it is implemented and deployed.

Minimum content of service definitions

Interpreting the content

The table below gives the minimum content to be included in a service definition by the issuing community of interest.

The content is to be used by the different service providers. In that regards, the service definition places requirements on the service provider. The goal is for a set of harmonised service instances that conform to the service definition by implementing its requirements.

The more restrictive the service definition is, the fewer choices an implementer has and so the degree of harmonisation will be higher.

Requirement SWIM-SERV-120 - Service standard reference in the EUROCONTROL SWIM Service Description Specification, requires that the deviations and additions to the referenced service definition are listed. This makes it clear to service consumers when the service definition has not been followed. 



Minimum content

IdentifierTitleRequirementExamples/Notes

SWIM-DEFN-010

Service definition coverage

A service definition shall define a single service


Note: This concerns the definition of a service that can be implemented by service providers. It is not used to describe a running service - use a service description in that case.

Note: This requirement uses "define" rather than "describe".

SWIM-DEFN-020

Service definition languageThe textual descriptions in a service definition shall be written in English using the spelling listed as the primary British spelling when conflicting spellings exist.-

SWIM-DEFN-030

Service definition identificationA service definition shall include:
  • a title by which the service definition is known;
  • an edition; and
  • a reference date for use in citing the service definition.

Example:

  • titleAeronautical Data Set Request Service Definition
  • edition0.21
  • reference date2020-09-21

SWIM-DEFN-040

Service identificationA service definition shall include the name of the service.

Example:

  • nameAeronautical Dataset Request

SWIM-DEFN-050

Service abstractA service definition shall include a short textual description summarising the service.

Example:

  • The Aeronautical Dataset Request service allows a service consumer to query the available datasets based on a set of filters and to retrieve datasets that match the filter criteria. The content of the datasets are defined by ICAO Annex 15. The service is part of a series of services that support the concept of aeronautical information product digital data set as defined by ICAO Annex 15.

SWIM-DEFN-085

Service definition providerA service definition shall include the following information about the service definition provider:
  • the name;
  • abbreviated name (if applicable); and
  • description of the organisation responsible for the service definition.


Note: the service definition provider is the community of interest or standards development organisation that developed the service definition.

Example:

  • name: EUROCAE
  • description: ​EUROCAE is the European leader in the development of worldwide recognised industry standards for aviation.


SWIM-DEFN-090

Geographical extent of information

A service definition may include information about the expected geographical coverage of the exchanged information service payload.


Note: the information is intended to help potential service providers understand the service.

Example:

  • The service is expected to provide information for a specific FIR or set of FIRs.

Example:

  • This service shall provide information for the globe.


SWIM-DEFN-095

Intended service providers and consumers

A service definition should include information about the typical service provider type and typical service consumer(s) type.


Note: the list service provider and consumer types is intended to help potential service providers understand the service. The list is not prohibitive. 

Note: service descriptions that describe running services can have a different list.

Example:

  • typical service provider
    • AERONAUTICAL_INFORMATION_SERVICE_PROVIDER
  • typical service consumer
    • AERONAUTICAL_INFORMATION_SERVICE_PROVIDER
    • AIR_TRAFFIC_SERVICE_PROVIDER
    • CIVIL_AIRSPACE_USER
    • MILITARY_AIRSPACE_USER
    • CIVIL_AIR_NAVIGATION_SERVICE_PROVIDER
    • MILITARY_AIR_NAVIGATION_SERVICE_PROVIDER
    • NETWORK_MANAGER
    • PROVIDER_OF_DATA_SERVICES
    • REGULATED_METEOROLOGICAL_SERVICE_PROVIDER

SWIM-DEFN-100

Service categoriesA service definition shall include the service categories to which the service belongs and, if applicable, reference the service categorisation schemes used.

Example:

Example:

SWIM-DEFN-120

Service standard referenceIf the service is based on a service standard the service definition shall include:
  • a reference to the service standard to which the service adheres;
  • a statement on any implemented options of the service standard; and
  • a statement on any deviation from or addition to the service standard.

Example:

  • The service uses the ICAO Digital Data Set Service Definition.

SWIM-DEFN-130

Operational environment

A service definition shall include or refer to information about:

  • the operational needs used in the development of the service; and/or
  • the capabilities offered by the service.

Example:

  • Support the discovery and retrieval of the aeronautical digital data sets as defined by ICAO Annex 15:
    • AIP data set;
    • Obstacle data set;
    • Terrain data set;
    • Airport mapping data set;
    • Instrument flight procedure data set

SWIM-DEFN-140

Service functions

A service definition shall include or refer to information about:

  • the functions expected to be offered by the service in support of its capabilities; and
  • their expected real-world effects.

Example:

  • name: Dataset series query
  • description: Allow a service consumer to query the lists of dataset series matching a series of criteria including type, geographical scope, title
  • real-world effect: the list of matching dataset series objects is returned

SWIM-DEFN-150

Service access and use conditionsA service definition should include or refer to information about the constraints which are expected to be applied to accessing and using the service, including:
  • legal constraints;
  • service policies; and
  • service consumption constraints.

Example:

  • service policy: The service should be free at the point of access.

SWIM-DEFN-160

Security constraintsA service definition should include or refer to information about the security constraints which are expected to apply to accessing and using the service.

Example:

  • The service shall implement authentication mechanisms to ensure access is limited to authorised users.

SWIM-DEFN-180

Quality of serviceA service definition shall include or refer to information about the expected minimum quality of service offered with regards to:
  • performance;
  • reliability; and
  • security.

Example:

  • availability: 99.95 % outside the planned outages Schedule of planned outages

SWIM-DEFN-185

Quality of data

A service definition shall include or refer to information about the expected minimum quality of the data to be provided by the service.


Note: The items used to describe quality of data vary between information domains. They may include, for example, accuracy, resolution and precision.

Example:

  • The data must meet the data quality requirements outlined in the PANS-AIM Data Catalogue. 

SWIM-DEFN-190

Source of information

A service definition should include information about the expected types of sources of the information provided.


Example:

  • regulated meteorological provider

Example

  • AIR_TRAFFIC_SERVICE_PROVIDER


SWIM-DEFN-200

Service validation informationA service definition may include or refer to information about any service prototyping activities that have taken place.

Example

  • The service was prototyped in 2021. The service operations and information definition were tested. However, the quality of service was not tested.

SWIM-DEFN-210

Application message exchange patternA service definition shall include or refer to information about the application message exchange pattern(s) expected to be used by the service.

Example

  • SYNCHRONOUS_REQUEST_RESPONSE

SWIM-DEFN-220

Service behaviour

A service definition shall include or refer to information about the expected typical behaviour of the service.


Note: The requirement covers the minimum content. Handling of unexpected behaviour is possible to define.

Note: A diagram showing how the operations support the typical behaviour can be provided. This can be made available in the model view (SWIM-DEFN-330).

Example:

  • A typical sequence is:
    • (1) The service consumer requests dataset series based on a number of selection criteria, and receives back a list with zero, one or more dataset series objects.
    • (2) The service consumer analyses that list to identify the dataset series he is interested in.
    • (3) The service consumer requests datasets from the selected dataset series, possibly supplying additional selection criteria, and receives back a list of zero, one or more datasets.
    • (4) The service consumer analyses that list to identify the dataset(s) he is interested in.
    • (5) For each dataset of interest
      • (5a) The service consumer requests the file information of the selected dataset, and receives back a list of one or more file objects.
      • (5b) For each file object, the service consumer retrieves the file, and receives back the file content.

SWIM-DEFN-230

Service monitoringA service definition may state whether a service monitoring mechanism is expected to be made available to service consumers.

Example:

  • A service monitoring mechanism is expected to be made available to service consumers.

SWIM-DEFN-240

Service interfacesA service definition shall include or refer to information about the expected exposed service interfaces, including for each service interface,
  • the name of the service interface;
  • a textual description of the service interface including its purpose;
  • an indication that the interface is a provider side interface or a consumer side interface


Note: If no service interfaces are expected, the service implemented can group operations and messages as fit.

Example:

  • nameSearchAndRetrieve
  • descriptionThe interface allows querying metadata and retrieving files.
  • interface provision sidePROVIDER_SIDE_INTERFACE

SWIM-DEFN-250

SWIM Technical Infrastructure Profile

A service definition shall include information about the selected SWIM TI Profile and its version for each service interface.


Note: This can be captured at service level if all of the service interfaces will use the same SWIM TI Profile.

Example:

  • profileSWIM_TI_YP_1_0


SWIM-DEFN-255

SWIM service and network interface binding

A service definition may include for each service interface:

  • a reference to a service interface binding as specified in the selected SWIM TI Profile;
  • a reference to a network interface binding as specified in the selected SWIM TI Profile; and
  • references to additionally supported requirements as specified in the selected SWIM TI Profile.

Example:

  • service interface binding:  WS_LIGHT
  • network interface bindingIPV4_UNICAST
  • additional supportSWIM-TIYP-0092, SWIM-TIYP-0098

SWIM-DEFN-260

Service interface protocols and data format

A service definition may include or refer to information about:

  • the service interface protocols (including name and version); and
  • data format to be used.


NoteProtocols are normally linked to the service interface binding. The information provided here must be consistent with what is selected in SWIM-DEFN-255.

Note: If a data format is listed, it must be consistent with what is allowed by the bindings mentioned in SWIM-DEFN-255.

Example:

  • nameTLS 1.2
  • data format: XML

SWIM-DEFN-270

Service operationsA service definition shall include or refer to information about the expected exposed service operations including:
  • the name of the service operation; and
  • a description of the intent and the results of the service operation.

Example:

  • namequeryDatasets
  • descriptionThe operation accepts criteria about datasets and returns a list with the metadata about the corresponding datasets.

SWIM-DEFN-280

Service messages

A service definition shall include or refer to information about the expected messages that are exchanged by the service including input, output and error messages.

Note: there needs to be at least one message. 

Example:

  • inQueryDatasetsRequest 
  • outQueryDatasetsReply

SWIM-DEFN-290

Information definition (minimum)A service definition shall include or refer to the following information about the exchanged information service payload:
  • the name of the element;
  • the definition of the element;
  • the data type used by the element if applicable; and
  • the semantic correspondence of the element with the AIRM.

Note: Service definitions can use an information exchange schema that is uses the data format selected in SWIM-DEFN-260.

Example:

  • concept:
    • name: Aerodrome
    • definition: A defined area on land or water (including any buildings, installations and equipment) intended to be used either wholly or in part for the arrival, departure and surface movement of aircraft.
    • semantic correspondence: urn:aero:airm:1.0.0:LogicalModel:Subjects:BaseInfrastructure:AerodromeInfrastructure:Aerodrome

Example:

  • reference: see the Model View provided.

SWIM-DEFN-300

Information definition (extended)A service definition should include or refer to information about the exchanged Information service payload including:
  • the cardinality applicable to the element, including whether the element is optional, conditional or mandatory in the exchange;
  • constraints applicable to the element, such as:
    • value ranges;
    • special values;
    • character set restrictions; and
  • the structure and relevant relationships between the elements.

Example:

  • reference: see the Model View provided.

SWIM-DEFN-310

Filter encoding

If information service payload filtering is expected, a service definition shall or refer to information about the filter encoding.



Example:

  • The service consumer should be able to filter information feed based on time and geospatial criteria.

SWIM-DEFN-320

Machine-readable service interface definition

If the service interface binding specifies the use of machine-readable formats, a service definition should include or refer to a service interface definition in a machine-readable format using a standard service definition formalism/language.



Note:  'include' means to embed the machine-readable format into the service definition. It is still a separate artefact.

Example:

  • title: Interface WSDL
  • description: Machine processable description of the service interface
  • reference: public:/2019-09/TOBT_Interface.wsdl

SWIM-DEFN-330

Model viewA service definition may
  • include or refer to a model view, expressed using a formal and standardised notation, that formalises the representation of the business logic of its service interfaces, service operations, service behaviour and exchanged information; and
  • declare the notation used to express the model view.

Example:

  • title: The model view of the service
  • description: The model view of the service
  • reference: public:/2019-09/TOBT_Interface_ModelView.uml

SWIM-DEFN-350

Abbreviations and acronymsA service definition shall include or refer to definitions for all the abbreviations and acronyms used in the service definition.

Example:

  • abbreviation:
    • code: ATM
    • term: Air Traffic Management


Minimum content in graphic form

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