IDS Connector Communication
Message Flows for Connector to Connector Communication
Connector Self-description Request
![](https://docs.internationaldataspaces.org/~gitbook/image?url=https%3A%2F%2Fuser-images.githubusercontent.com%2F76526301%2F116513994-ad57ba80-a8ca-11eb-912c-24ed6b824bcd.png&width=768&dpr=4&quality=100&sign=3a0f83fe&sv=1)
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.
![](https://docs.internationaldataspaces.org/~gitbook/image?url=https%3A%2F%2Fuser-images.githubusercontent.com%2F76526301%2F117145269-4434e300-adb3-11eb-900e-2055b771af04.png&width=768&dpr=4&quality=100&sign=3020392c&sv=1)
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
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 |
Terms | - |
Key | Value |
---|---|
ID | ta-002 |
Product | Connector |
Strictness level | MUST |
Prerequisites | Connector receives an ids:DescriptionRequestMessage without the property |
Behaviour | Validation of the received message. |
Terms | Validation in this case means to ensure:
|
Key | Value |
---|---|
ID | ta-003 |
Product | Connector |
Strictness level | MUST |
Prerequisites | Connector receives an ids:DescriptionRequestMessage without the property |
Behaviour | Get the self-description of type |
Terms | see ta-002 |
Key | Value |
---|---|
ID | ta-004 |
Product | Connector |
Strictness level | MUST |
Prerequisites | Connector receives an ids:DescriptionRequestMessage without the property |
Behaviour | Return an ids:RejectionMessage containing the appropriate |
Terms |
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 |
Terms | - |
Key | Value |
---|---|
ID | ta-006 |
Product | Connector |
Strictness level | MUST |
Prerequisites | Connector receives an ids:DescriptionRequestMessage with a resource URI as |
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 |
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 |
Behaviour | Return an ids:RejectionMessage containing the appropriate |
Terms |
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:
|
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 |
Terms | - |
Key | Value |
---|---|
ID | ta-011 |
Product | Connector |
Strictness level | MUST |
Prerequisites | Connector receives an ids:ArtifactRequestMessage with an artifact URI as |
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 |
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 |
Behaviour | Return an ids:RejectionMessage containing the appropriate |
Terms |
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:
|
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 |
Terms | - |
Key | Value |
---|---|
ID | ta-016 |
Product | Connector |
Strictness level | MUST |
Prerequisites | Connector receives an ids:ContractRequestMessage containing an |
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 |
Behaviour | Return an ids:ContractAgreementMessage containing an |
Terms | - |
Key | Value |
---|---|
ID | ta-018 |
Product | Connector |
Strictness level | MUST |
Prerequisites | Connector receives an ids:ContractRequestMessage containing an |
Behaviour | Return an ids:ContractRejectionMessage containing the appropriate |
Terms | - |
Key | Value |
---|---|
ID | ta-019 |
Product | Connector |
Strictness level | MUST |
Prerequisites | Connector receives an ids:ContractOfferMessage containing an |
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 |
Behaviour | Return an |
Terms | - |
Key | Value |
---|---|
ID | ta-021 |
Product | Connector |
Strictness level | MUST |
Prerequisites | Connector receives an ids:ContractOfferMessage containing an |
Behaviour | Return an ids:ContractRejectionMessage containing the appropriate |
Terms | - |
Key | Value |
---|---|
ID | ta-022 |
Product | Connector |
Strictness level | MUST |
Prerequisites | Connector receives an ids:ContractOfferMessage containing an |
Behaviour | Return an ids:ContractOfferMessage containing an |
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 |
Behaviour | Validation of the received message. |
Terms | Validation in this case means to ensure:
|
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 |
Behaviour | Check the contract agreement. |
Terms | Checking the contract agreement means to:
|
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 |
Behaviour | Return an ids:ContractAgreementMessage containing the |
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 |
Behaviour | Return an ids:ContractRejectionMessage containing the appropriate |
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 |
Behaviour | Return an ids:ContractOfferMessage containing an |
Terms | - |
Key | Value |
---|---|
ID | ta-028 |
Product | Connector |
Strictness level | MUST |
Prerequisites | Connector receives an ids:ContractAgreementMessage containing an |
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 |
Behaviour | Send an ids:MessageProcessedNotificationMessage with the filled |
Terms | - |
Key | Value |
---|---|
ID | ta-030 |
Product | Connector |
Strictness level | MUST |
Prerequisites | Connector receives an ids:ContractAgreementMessage containing an |
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 |
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 |
Behaviour | Communication concludes. |
Terms | - |
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