IDS Connector Communication


Message Flows for Connector to Connector Communication

Connector Self-description Request

To get the self-description of the Provider Connector, an ids:DescriptionRequestMessage is sent without the property ids:RequestedElement. This indicates that the Consumer wants to request the self-description of the Provider Connector and not of a specific element. The Provider validates this request and, if the message processing is successful, returns an ids:DescriptionResponseMessage containing the Provider Connector's self-description. In case of any errors during the message processing, the Provider returns an ids:RejectionMessage with a ids:RejectionReason indicating the error's cause.

Usage Contract Negotiation

The message flow of the usage contract negotiation is described in following sequence diagram.

First, the Data Consumer sends an ids:ContractRequestMessage containing a suggested contract (an instance of ids:ContractRequest) to the Data Provider. This ids:ContractRequest can differ from the Provider's previous contract offer. The Data Provider then processes the request and responds with an appropriate response message. Processing means to first validate the request and then check if the contract request's content of the Data Consumer complies with the contract offer by the Provider.

The Provider can do a counteroffer in form of an ids:ContractOfferMessage containing an ids:ContractOffer. Then, the Consumer Connector may respond with a counteroffer in form of an ids:ContractMessage as well. This can go back and forth an arbitrary number of times until one of the parties either rejects or accepts the contract, or an error occurs. In case of a rejection or an error, an ids:ContractRejectionMessage that contains the rejection's reason is sent to the other party. If the contract is accepted, an ids:ContractAgreementMessage including the ids:ContractAgreement is returned.

In this description, it is assumed that the Provider Connector is the one that ultimately gives in and sends the ids:ContractAgreementMessage. If it was the other way around, the sequence after the optional block onwards would also be defined the other way around.

As soon as the Consumer receives the ids:ContractAgreementMessage, it processes the agreement. While processing, the consumer checks whether the received agreement contains the correct assigner and whether it fits the suggested rules that where sent within the ids:ContractRequest or ids:ContractOffer. If the agreement is not valid, an error occurs, or if the Consumer rejects the agreement, an ids:ContractRejectionMessage is returned.

Furthermore, the Consumer has the option to restart the negotiation process sending an ids:ContractOfferMessage with a modified ids:ContractOffer at any time. As marked as (1) in the sequence diagram, this would cause the process to jump to the offer exchange part again. If instead, the agreement is accepted, and the processing is successful, the Consumer returns an ids:ContractAgreementMessage including the ids:ContractAgreement to the Provider to confirm the validity. If the Provider receives this ids:ContractAgreementMessage, it finalizes the exchange from its side and marks the agreement as confirmed. Optionally, the contract agreement is sent to the Clearing House within an ids:LogMessage. If an error occurs during processing, the Consumer is informed via an ids:ContractRejectionMessage. On success, the communication concludes with the Provider sending an ids:MessageProcessedNotificationMessage to the Consumer, this is optional. The Consumer concludes with saving the agreement and setting the confirmed status to true.

Requesting Data

Based on the self-description of the Provider Connector and a negotiated contract, the Consumer Connector is able to request data. For this, the Consumer Connector sends an ids:DescriptionRequestMessage with the URI of the selected resource as the ids:RequestedElement to the Provider Connector. The Provider Connector first validates the message and then returns the metadata of the requested resource to the Consumer via an ids:DescriptionResponseMessage. In case of unsuccessful processing, the Provider returns an ids:RejectionMessage instead.

The Consumer Connector expects an ids:DescriptionResponseMessage as the response containing the metadata of the requested resource (an instance of ids:Resource). The Consumer validates the message and then stores the resource. In case of any occurring error, the communication is suspended. If not, the Consumer Connector is then able to choose a specific artifact that should be consumed.

In the third step, the Consumer Connector sends an ids:ArtifactRequestMessage including a set ids:RequestedArtifact and a reference to the applicable contract agreement as the ids:TransferContract to the Provider Connector. The Provider validates the message and the transfer contract. If an error occurs during processing, the Provider responds with an ids:RejectionMessage to the Consumer. If the message is valid, the Provider returns an ids:ArtifactResponseMessage containing the data. The Consumer Connector expects this ids:ArtifactResponseMessage and stores or further processes the attached data.

Note, that even though the diagram shows the artifact request is located right after one description request, there can be more than one request for a resource's self-description before sending an artifact request. Also, there can be more than one artifact request executed as long as the artifact URI is known, and an applicable contract agreement exists.

Example for Combining the Flows

One way to combine the flows is to first use the Connector Self-description Request sequence to request the self-description of the Provider Connector. The Consumer can then browse the offers of the Provider. After that, based on the requirements, it defines a contract request and starts the Usage Contract Negotiation flow. If this is successful, the Consumer is allowed to request specific data via the Requesting Data Flow.

Conformance Requirements for the Connector to Connector Communication

KeyValue

ID

ta-001

Product

Connector

Strictness level

MUST

Prerequisites

The self-description of a specific Connector is needed.

Behaviour

Send an ids:DescriptionRequestMessage to this specific Connector. The property ids:RequestedElement is not set.

Terms

-

KeyValue

ID

ta-002

Product

Connector

Strictness level

MUST

Prerequisites

Connector receives an ids:DescriptionRequestMessage without the property ids:RequestedElement.

Behaviour

Validation of the received message.

Terms

Validation in this case means to ensure:

  • The message is not empty.

  • The message has the expected syntax.

  • The message contains a valid DAT.

  • The message version is supported.

KeyValue

ID

ta-003

Product

Connector

Strictness level

MUST

Prerequisites

Connector receives an ids:DescriptionRequestMessage without the property ids:RequestedElement. This message is successfully validated.

Behaviour

Get the self-description of type ids:InfrastructureComponent of the receiving Connector and return it within an ids:DescriptionResponseMessage to the requesting Connector.

Terms

see ta-002

KeyValue

ID

ta-004

Product

Connector

Strictness level

MUST

Prerequisites

Connector receives an ids:DescriptionRequestMessage without the property ids:RequestedElement set. This message is not successfully validated, or an error occurs during processing.

Behaviour

Return an ids:RejectionMessage containing the appropriate ids:RejectionReason.

Terms

KeyValue

ID

ta-005

Product

Connector

Strictness level

MUST

Prerequisites

The metadata of a specific offered resource is needed. The resource URI is known.

Behaviour

Be able to send an ids:DescriptionRequestMessage to the offering Connector. The property ids:RequestedElement is filled with the specific resource URI.

Terms

-

KeyValue

ID

ta-006

Product

Connector

Strictness level

MUST

Prerequisites

Connector receives an ids:DescriptionRequestMessage with a resource URI as ids:RequestedElement.

Behaviour

Validation of the received message.

Terms

see ta-002

KeyValue

ID

ta-007

Product

Connector

Strictness level

MUST

Prerequisites

Connector receives an ids:DescriptionRequestMessage with a resource URI as ids:RequestedElement. This message is successfully validated.

Behaviour

Get the metadata of the requested resource that is provided by the receiving Connector and send it within an ids:DescriptionResponseMessage to the requesting Connector.

Terms

The requested resource is the one with the matching resource URI.

KeyValue

ID

ta-008

Product

Connector

Strictness level

MUST

Prerequisites

Connector receives an ids:DescriptionRequestMessage with a resource URI as ids:RequestedElement. This message is not successfully validated, or an error occurs during processing.

Behaviour

Return an ids:RejectionMessage containing the appropriate ids:RejectionReason.

Terms

KeyValue

ID

ta-009

Product

Connector

Strictness level

MUST

Prerequisites

Connector receives an ids:DescriptionResponseMessage as a response to an ids:DescriptionRequestMessage.

Behaviour

Validation of the received message.

Terms

Validation in this case means to ensure:

KeyValue

ID

ta-010

Product

Connector

Strictness level

MUST

Prerequisites

The data of a specific artifact offered by a specific Connector is needed. The artifact URI is known. An applicable contract agreement has been negotiated.

Behaviour

Be able to send an ids:ArtifactRequestMessage to this specific Connector. The property ids:RequestedArtifact is filled in with the specific artifact URI. The property ids:TransferContract is filled with a reference to the applicable contract agreement.

Terms

-

KeyValue

ID

ta-011

Product

Connector

Strictness level

MUST

Prerequisites

Connector receives an ids:ArtifactRequestMessage with an artifact URI as ids:RequestedArtifact. The property ids:TransferContract is filled with a reference to the applicable contract agreement.

Behaviour

Validation of the received message.

Terms

see ta-002

KeyValue

ID

ta-012

Product

Connector

Strictness level

MUST

Prerequisites

Connector receives an ids:ArtifactRequestMessage with an artifact URI as ids:RequestedArtifact. The property ids:TransferContract is filled with a reference to the applicable contract agreement. Validation of the message is successful.

Behaviour

Get the data from the requested artifact and send it within an ids:ArtifactResponseMessage to the requesting entity.

Terms

The requested artifact is the one with the matching artifact ID.

KeyValue

ID

ta-013

Product

Connector

Strictness level

MUST

Prerequisites

Connector receives an ids:ArtifactRequestMessage with an artifact URI as ids:RequestedArtifact. The property ids:TransferContract is filled with a reference to the applicable contract agreement. Validation of the message is not successful, or an error occurs during processing.

Behaviour

Return an ids:RejectionMessage containing the appropriate ids:RejectionReason.

Terms

KeyValue

ID

ta-014

Product

Connector

Strictness level

MUST

Prerequisites

Connector receives an ids:ArtifactResponseMessage containing the requested data as the response to an ids:ArtifactRequestMessage.

Behaviour

Validation of the received message.

Terms

Validation in this case means to ensure:

KeyValue

ID

ta-015

Product

Connector

Strictness level

MUST

Prerequisites

A contract agreement needs to be negotiated with a specific Connector.

Behaviour

Be able to send an ids:ContractRequestMessage containing an ids:ContractRequest to this specific Connector.

Terms

-

KeyValue

ID

ta-016

Product

Connector

Strictness level

MUST

Prerequisites

Connector receives an ids:ContractRequestMessage containing an ids:ContractRequest.

Behaviour

Validate received message and check if the contract can be agreed upon.

Terms

see ta-002

KeyValue

ID

ta-017

Product

Connector

Strictness level

MUST

Prerequisites

Connector receives an ids:ContractRequestMessage containing an ids:ContractRequest. The validation of the message and the contract request is successful.

Behaviour

Return an ids:ContractAgreementMessage containing an ids:ContractAgreement to the requesting Connector.

Terms

-

KeyValue

ID

ta-018

Product

Connector

Strictness level

MUST

Prerequisites

Connector receives an ids:ContractRequestMessage containing an ids:ContractRequest. The validation of the message and/or the contract request is not successful, and/or an error occurs during processing.

Behaviour

Return an ids:ContractRejectionMessage containing the appropriate ids:RejectionReason.

Terms

-

KeyValue

ID

ta-019

Product

Connector

Strictness level

MUST

Prerequisites

Connector receives an ids:ContractOfferMessage containing an ids:ContractOffer.

Behaviour

Validation of the received message.

Terms

see ta-002

KeyValue

ID

ta-020

Product

Connector

Strictness level

MUST

Prerequisites

Connector receives an ids:ContractOfferMessage containing an ids:ContractOffer. The validation of the message and the contract offer is successful.

Behaviour

Return an ids:ContractAgreementMessage containing an ids:ContractAgreement to the requesting Connector.

Terms

-

KeyValue

ID

ta-021

Product

Connector

Strictness level

MUST

Prerequisites

Connector receives an ids:ContractOfferMessage containing an ids:ContractOffer. The validation of the message and/or contract offer is not successful, and/or an error occurs during processing.

Behaviour

Return an ids:ContractRejectionMessage containing the appropriate ids:RejectionReason.

Terms

-

KeyValue

ID

ta-022

Product

Connector

Strictness level

MUST

Prerequisites

Connector receives an ids:ContractOfferMessage containing an ids:ContractOffer. The validation is successful. The contract should not be rejected, but a counter offer should be sent.

Behaviour

Return an ids:ContractOfferMessage containing an ids:ContractOffer to the requesting Connector.

Terms

-

KeyValue

ID

ta-023

Product

Connector

Strictness level

MUST

Prerequisites

Connector that has sent an ids:ContractRequestMessage or an ids:ContractOfferMessage receives an ids:ContractAgreementMessage containing an ids:ContractAgreement as a response.

Behaviour

Validation of the received message.

Terms

Validation in this case means to ensure:

KeyValue

ID

ta-024

Product

Connector

Strictness level

MUST

Prerequisites

Connector that has sent an ids:ContractRequestMessage or an ids:ContractOfferMessage receives an ids:ContractAgreementMessage containing an ids:ContractAgreement as a response.

Behaviour

Check the contract agreement.

Terms

Checking the contract agreement means to:

  • Check if the assigner is the expected one.

  • Check if the rules of the contract agreement match the offered ones.

KeyValue

ID

ta-025

Product

Connector

Strictness level

MUST

Prerequisites

Connector that has sent an ids:ContractRequestMessage or an ids:ContractOfferMessage receives an ids:ContractAgreementMessage containing an ids:ContractAgreement as a response. The validation is successful, and the checks result in accepting the contract agreement.

Behaviour

Return an ids:ContractAgreementMessage containing the ids:ContractAgreement to the other Connector to confirm the contract agreement.

Terms

-

KeyValue

ID

ta-026

Product

Connector

Strictness level

MUST

Prerequisites

Connector that has sent an ids:ContractRequestMessage or an ids:ContractOfferMessage receives an ids:ContractAgreementMessage containing an ids:ContractAgreement as a response. The validation is not successful, an error occurs, or the contract agreement should be rejected.

Behaviour

Return an ids:ContractRejectionMessage containing the appropriate ids:RejectionReason.

Terms

-

KeyValue

ID

ta-027

Product

Connector

Strictness level

MUST

Prerequisites

Connector that has sent an ids:ContractRequestMessage or an ids:ContractOfferMessage receives an ids:ContractAgreementMessage containing an ids:ContractAgreement as a response. The validation is successful. Some modifications to the contract are pending.

Behaviour

Return an ids:ContractOfferMessage containing an ids:ContractOffer to the other Connector.

Terms

-

KeyValue

ID

ta-028

Product

Connector

Strictness level

MUST

Prerequisites

Connector receives an ids:ContractAgreementMessage containing an ids:ContractAgreement. The Connector has not sent an ids:ContractRequestMessage or an ids:ContractOfferMessage before.

Behaviour

Validation of the received message.

Terms

see ta-002

KeyValue

ID

ta-029

Product

Connector

Strictness level

MAY

Prerequisites

Connector receives an ids:ContractAgreementMessage containing an ids:ContractAgreement. The Connector has not sent an ids:ContractRequestMessage or an ids:ContractOfferMessage before. The validation of the message is successful.

Behaviour

Send an ids:MessageProcessedNotificationMessage with the filled ids:CorrelationMessage to the Consumer Connector.

Terms

-

KeyValue

ID

ta-030

Product

Connector

Strictness level

MUST

Prerequisites

Connector receives an ids:ContractAgreementMessage containing an ids:ContractAgreement. The Connector has not sent an ids:ContractRequestMessage or an ids:ContractOfferMessage before. The validation of the message is not successful, or an error occurs during processing.

Behaviour

Terms

-

KeyValue

ID

ta-031

Product

Connector

Strictness level

MAY

Prerequisites

Connector that has sent an ids:ContractAgreementMessage containing the ids:ContractAgreement to the other party to confirm the contact agreement receives an ids:MessageProcessedNotificationMessage as a response.

Behaviour

Validation of the received message.

Terms

see ta-002

KeyValue

ID

ta-32

Product

Connector

Strictness level

MAY

Prerequisites

Connector that has sent an ids:ContractAgreementMessage containing the ids:ContractAgreement to the other party to confirm the contract agreement receives an ids:MessageProcessedNotificationMessage as a response. The validation is successful.

Behaviour

Communication concludes.

Terms

-

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