Subscription and Notification Pattern

Introductory text

Functional Variants of the Subscription and Notification Pattern

Two distinct business requirements for Subscription and Notification Pattern: Updating of previously shared Evidence or being informed about an Event

Technically also two different approaches to Notification: Sending updated Data of a defined Evidence type or Event Notifications that contain only the identification data and the event type. Technical approach and business requirement do not relate one two one, giving rise to potential hybrid approaches.

Event The reference Architecture for the DE4A projects focusses the Subscription and Notification Pattern on Event Notification, which can be combines with the Lookup Pattern to cover the updating previously shared evidence use case. [23-04-2021: tables below still represent a hybrid approach and need rework]

Business Process

Event Subscription

Business Process (picture)

Activity Table

Activity / UC	Role	Type*	Description
Trigger initiate subscription	eProcedure	User	The eProcedure leads at the side of the data-evaluator to either the registration of the represented company or the registration of a branch of the represented company (the parent-company of the branch). A successful registration of the company or the branch of the company leads to a subscription to business events of the represented company. This is needed to assess impact of these business events on service delivery to the company or the branch. The  subscription process can also be triggered for technical reasons: for instance to resend subscription requests because an error occurred at DO-side.
Initiate subscription	DE	Service	Initiate subscription: Collect data and formulate subscription need: company identifier all events of subset/type of events (specific event catalogue)? tbd type of action: subscribe period of subscription? tbd Forward to Data requestor (if applicable) Note: subscriber should unsubscribe and re-subscribe if participant-id changes. To be able to do so, subscriptions have to be registered at the DE.
Trigger cancel subscription	eProcedure / Public service / Notification	Service	Potential triggers to cancel a subscription are: Public service: the delivery of an public service can lead to the need to cancel the subscription (the public service has ended, e.g. a multi-year subsidy procedure, the country can decide to cancel the  branch-office registration). eProcedure: the user can also withdraw from service and thereby initiating cancellation of the subscription? Notification: after receiving a notification the assessment can be that the subscription is no longer needed (exception flow). Technical reasons: for instance an error at the DO-side could lead to the need to resend the request to cancel a subscription.
Cancel subscription	DE	Service	Cancel subscription: Collect data and formulate cancel subscription need: company identifier all events of subset/type of events (specific event catalogue)? tbd type of action: cancel subscription specific end-date of the subscription? tbd Forward to Data requestor (if applicable)
Lookup event provider routing information	DR	Service	Lookup information on competent authority that facilitates subscription service (metadata tbd) (should data requestor resolve participant id dynamically? Not needed, participant id is stable enough)
Inform National Coordinator that un-subscription was not successful	DR	User	In case of the cancellation of a subscription there is a slight chance the participant ID of DO has changed: a manual process deals with this (unhappy) flow.
Send (un)subscription request	DR	Service	Send the request to subscribe or unsubscribe to the DT.
Forward (un)subscription error	DR	Service	Forward (un)subscription error message received from DT to DE
Investigate reason for (un)subscription error	DE	User	Analyse error and take appropriate actions (error could be on side of DE of DO) (exception so no need to model this in detail)
Forward confirmation	DR	Service	Forward the confirmation on the (un)subscription request (received from the DT) to the DE.
Log (un)subscription information	DE	Service	The confirmation is logged to complete the audit trail. Note: register in a way that it is easily readable (optional: include subscription id).
Validate (un)subscription request	DT	Service	Technical validation including forwarding to data owner. Technical exception out of scope
Evaluate (un)subscription request	DO	Service	Functional check of request to subscribe: does company exists, are type of events/subscription supported, is DE authorized. Functional check of request to unsubscribe: does subscription exists. If the request does not pass the functional check, the request is rejected.
Prepare (un)subscription error message	DO	Service	Collect the content (mainly the link to the request and the error message) and send it to DT
Send (un)subscription error message	DT	Service	Forward to DR
Register (un)subscription	DO	Service	Data owner creates/ends the DE’s subscription on the company’s events. Remarks: If messages resemble BRIS messages that would avoid extra work to be done; because this mechanism is in already in place Harmonised set of business events possibly needed. Register on evidence type: tbd
Confirm (un)subscription	DO	Service	Create a confirmation: (un)subscription result (success), timestamp, link to (un)subscription request and send to DT (if applicable)
Send (un)subscription confirmation	DT	Service	Send confirmation to DR Log confirmation

• A / M = Automated or Manual

Messages

Message ‘Subscription request’

Element	Description	Example value
Legal Person Identifier	Identification of the company following the eIDAS regulation: country code / country code / company identifier	RO/AT/90000471
Requested action	Indicates whether a subscription or the cancellation of a subscription is requested by the sender: ‘subscribe’ or ‘unsubscribe’	subscribe
Participant ID	The OOP TS participant identifier that identifies the organisation that is the subscriber (and thus will receive business event notifications)	SE000000013
TBD: event catalogue	The domain of events the subscription is
TBD: subscription period	The date of beginning and ending (optional) of the subscription

Message ‘Subscription confirmation’

Element	Description	Example value
Legal Person Identifier
Subscription timestamp
Subscription result	Subscription successful ; subscription cancellation successful
Subscription request reference
Subscription reference	Local identifier of the subscription. Not needed but can be useful in exception flows

Message ‘Subscription error’

Element	Description	Example value
Legal Person Identifier
Request type	Subscribe / unsubscribe
Error timestamp
Error message	Subscribe: company unknown, (participant not authorized) Unsubscribe: company unknown, company not active, subscription unknown, subscription not active
Subscription request reference

Design decisions

Explicit request and preview

The nature of the subscription and notification pattern leads to a different use of the explicit request and preview as stated in the SDG-regulation:

• Notification is performed without a user transaction, making real-time explicit request and preview impossible.
• Fraud prevention outweighs user centricity, making explicit request and preview less opportune.
• The public nature of company data relaxes the need of explicit request and preview.

Implementing an explicit request for future notifications introduces the burden of creating and maintaining an explicit request administration, with for instance options to retract a previously given explicit request

Design decision: for the Business event notification explicit request and preview as defined in the SDG-regulation is not applicable.

Positioning of subscription registration

For the location of the subscription registration certain options can be considered:

• Fully at the data providing MS: The subscription is registered at the data providing member state. The DE sends messages to the DO via DR and DT to manage the subscription (subscribe, cancel subscription).

• Splitted between data provider and data consuming MS: It is a possibility to split the register; the DO then only registers which MS subscribe to a certain company, and the DC MS registers which DE subscribe to the company. The process flow would be: (1) a central component at the DT registers which DE’s subscribe to which subjects of which data owners; (2) the DT registers as a MS for this company; (3) the DO registers which MS subscribes to which company and sends notifications to the DT (4) the DT distributes the notification to all DE.
• At a central component: The DE4A-architecture implements the four-corner model, a central subscription register would conflict with this principle. Moreover, a subscription is a direct relation between a DO and a DE regarding a subject, there will be no added value to place such a subscription in an external, central component.

Design decision: The registration of subscriptions is placed within the data providing member state. DP MS is free to choose in which environment this is (DT, DO or another environment). The assumption for the design of the S&N pattern is that the subscription registration is fully placed in the environment of the DO.

Evidence exchange and subscription request

The main flow of the DBA-pilot is that the intermediation pattern triggers the subscription and notification pattern. Part of the intermediation pattern is the exchange of evidence: DE requests a specific evidence type from a specific company from the DO. In the happy flow the DE subscribes to receive notifications regarding this company. This trigger can be implemented in different ways:

• As a part of the request for evidence. The evidence exchange request then consists at least of: company identifier, requested evidence type, DE identifier, subscribe y/n.

• In a separate subscription request message: after a user consent to the preview and a successful completion of the registration process a separate subscription message is send.

Design decision: the subscription request is not combined with the evidence exchange request but is sent after successful registration of the company/branch.

Combining the subscription request with the evidence exchange would be too early in the process. It would lead to (possibly a relative high number of) requests to cancel the subscription if no consent was given or the registration was not successful. This would also introduce the risk of unauthorised subscriptions and notifications if the cancellation fails.

Event Notification

Business Process (picture)

Activity / UC	Role	Type	Description
Trigger Change in registered company	Company representative / SP	User	An event regarding the company triggers the notification process. This event can be initiated by: a representative of the company itself, e.g.: merger, change of owner. a public service, e.g.: change of postal code, death of representative, court of law ruling.
Change company registration	DO	User	Standard process of the Data Owner - Business Register - to process changes in company registration as a result of the business event.
Identify DE4A event	DO	Service	The DO determines the DE4A Business event name. Note that the DO must have a mapping of it's own business events to the list of DE4A business events.
Check subscription	DO	Service	Check the subscription register for subscribers to the company that is the subject of the business event: No active subscriptions: end of process Active subscriptions found: continue notification process
Extract evidence	DO	Service	Delete this step. (sending evidence or changed data is another type of notification process)
Prepare notification message and subscriber list	DO	Service	Make a list of the subscribers to notify and create the payload of the notification, mainly the DE4A business event name and the timestamp the event took place.
Resolve service metadata	DT	Service	Move from a list of subscribers to single notifications (one for each subscriber) and lookup the routing information for each notification.
Resolve subscriber participant ID and inform National Coordinator	DT	User	If address / DE participant id is not found in the metadata, manual action is needed: contact DE / MS of participant id to analyse the exception and take appropriate measures.
Request from DE to resend event notifications	DE	User	Exception flow for missed notifications (failed or non-failed): if a DE misses notifications a resend of notifications can be requested.
Resend past event notifications	DT	User	The resending of previously sent notifications requires a manual action at the DT.
Send event notification	DT	Service	Send notification, receive the acknowledgement that the notification has been received by the DR and update the audit log with both the event notification and the acknowledgement.
Validate event notification	DR	Service	DR performs a technical validation of the event notification and forward it to the DE. A technical exception flow is out of scope of this process description. Log received message as part of audit trail?
Determine event response	DE	Service	Check the notified business event and determine the action to be taken. Note that every determination result is logged as a part of the audit trail or for internal reasons: Company identifier Notified event Request id Determined response Timestamp of determination
Request unsubscription	DE	Service	When the company cannot be identified or is no longer active. Afterwards this will have to be analysed this to find the cause of this apparently wrong subscription and to take appropriate measures.
Dismiss event	DE	Service	The business event is not relevant for the DE and is dismissed. No further actions need to be taken.
Update company information	DE	Service	THe lookup pattern is triggered to request a new copy of the Company Registration Evidence.
Identify business responses and notify responsible party	DE	User	Notify responsible party or organizational unit (that then contacts the company if needed). Depends on process, case by case, if this can be automated or manually.

Note:

• A functional response from DE to DO, for example to inform that appropriate actions have been taken, are out of scope of DE4A / OOP TS (it is part of BRIS requirements though). Check.
• Notifications from DE to DO (resulting from changes in the branch registration) are out of scope of DE4A / OOP TS.

Messages

Message ‘Business event notification’

Element	Description	Example value
Legal Person Identifier	Identification of the company following the eIDAS regulation: country code / country code / company identifier
Business event identification	The identification of the business event (list of value: OOP TS business event catalogue)
Business event timestamp	Date and time of business event
Subscription reference	Identification of the subscription as registered at DO (local id) which can be used in communication between DO and DE. Not essential but can be useful in exception flows

Process Realization

?All on one Page or do we create sub-pages for Business Process and Process Realization?

Used by the following use cases

DBA (UC2)

Application collaborations

TBD