IDS Connector Communication

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Message Flows for Connector to Connector Communication

Connector Self-description Request

Data_Interaction_pre_v5_Split_Con_Desc

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.

Contract_Negotiation

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

Data_Interaction_pre_v5_Split_Res_Art_Desc

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

Key	Value
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	-

Key	Value
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.

Key	Value
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

Key	Value
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	ids:RejectionReason

Key	Value
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	-

Key	Value
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

Key	Value
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.

Key	Value
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	ids:RejectionReason

Key	Value
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: The response message is of type ids:DescriptionResponseMessage see ta-002

Key	Value
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	-

Key	Value
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

Key	Value
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.

Key	Value
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	ids:RejectionReason

Key	Value
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: That the response message is of type ids:ArtifactResponseMessage. see ta-002

Key	Value
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	-

Key	Value
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

Key	Value
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	-

Key	Value
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	-

Key	Value
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

Key	Value
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	-

Key	Value
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	-

Key	Value
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	-

Key	Value
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: That the response message is of type ids:ContractAgreementMessage. see ta-002

Key	Value
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.

Key	Value
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	-

Key	Value
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	-

Key	Value
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	-

Key	Value
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

Key	Value
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	-

Key	Value
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	Return an ids:ContractRejectionMessage.
Terms	-

Key	Value
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

Key	Value
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	-