Fallback and Recovery Specification (FRS)

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DG TAXUD – EXCISE COMPUTERISATION PROJECT REF: ECP2-FITSDEV2-SC03-FRS FALLBACK AND RECOVERY SPECIFICATION (FRS) VERSION: 3.11-EN Solution elements 5.1.1 PR01: Pre-validation of entered information Any capture of data must be submitted to formal validation at time of keying in, i.e. before any further validation by the system. This is a major requirement of the system. Example: Upon submission of an e-AAD, the application of the consignor includes as many controls as possible to ensure semantic validity of each field (e.g. conformance to business rules) and consistency among fields, possibly by reference to available databases. 5.1.2 PR02: Ensure permanent availability of EMCS applications EMCS is characterised by very strong availability requirements. Some functions such as the submission of an e-AAD have been quoted with a "permanent" availability requirement where a given interruption of the service should not last more than 15 minutes and many other ones with a "high" availability requirement where a given interruption cannot last more than one hour. 5.1.3 PR03: Atomicity of EBP processing Most EBPs described in the FESS [R6] are thought as business transactions, i.e. a set of actions that must be either completed or aborted together. The mechanism is defined at business level, i.e. there is no assumption on the way it shall be implemented. This response does not address specific exceptions but it is a prerequisite that has been used in the discovery of exceptions. Its role is to avoid considering in detail the possible exceptions that arise inside the process and to concentrate on the interconnection of each elementary process with the other ones: incoming and outgoing information exchanges, access to external information, functioning of timers. 5.1.4 PR04: Use of timers Timers are introduced to ensure that a reminder is issued when a specific event has not arisen in due time. The mechanism is defined at business level, i.e. there is no assumption on the way it shall be implemented. This response does not address specific exceptions but it is a prerequisite for some other solution elements. A few major cases are described in the FESS [R6] itself, because they include coordination mechanisms including international information exchanges. Conversely, a range of deadlines are to be defined at national level such as the maximum duration of the storage of a message in a waiting queue when that response is being used (PR05 - enqueue message for further automatic recovery). Example: The storage of a message submitted to business acknowledgement is linked to a maximum waiting time. This waiting time should be associated with a timer to awake the ECP2-FITSDEV2-SC03-FRSv3.11.doc Page 28 of 53
DG TAXUD – EXCISE COMPUTERISATION PROJECT REF: ECP2-FITSDEV2-SC03-FRS FALLBACK AND RECOVERY SPECIFICATION (FRS) VERSION: 3.11-EN Solution elements suspended processing (FB04 - no intervention - wait) and take complementary steps whenever the expected event has not arisen (in that case, return of the business acknowledgement). 5.1.5 PR05: Enqueue message for further automatic recovery A safe storage of information may help in preparing further recovery where it has reached an identified level such as: � arrival of an information exchange regarding a checking failure into a given location; � positive checking of a submitted message; or � just before sending an information exchange. In each case, if the following processing fails, it will be possible to restart from the point of storage to resume the process. This solution element is a prerequisite for the business acknowledgement processing described below (PR06 - business acknowledgement). Example 1: When a submitted draft e-AAD arrives in the MSA of dispatch, it is convenient to securely store it before starting its formal checking; therefore, in case of breakdown during the checking (e.g. sudden unavailability of resources), the checking can be resumed when the failure is corrected. Example 2: When a submitted e-AAD has been found valid but before allocating the ARC, it is convenient to securely store it before starting the allocation of the ARC and performing the related actions; therefore, in case of breakdown during these actions (e.g. sudden unavailability of resources), they can be resumed when the failure is corrected. Example 3: When a valid e-AAD is ready to be sent to the MSA of destination, and in connection with the required business acknowledgement, it is convenient to securely store it before sending it and until the business acknowledgement arrives. This makes it possible to replay the information exchange if neither positive nor negative acknowledgement has been received in a given time limit. 5.1.6 PR06: Business acknowledgement It is important for the EMCS business to ensure that an Information Exchange will not be lost between two MSAs because of a failure or because of a too long transmission delay. This is particularly uneasy to discover. It is therefore essential, at least for the essential Information Exchanges, that the sending MSA has a confirmation that the recipient MSA has correctly received and processed that exchange. The solution element, named business acknowledgement, consists in a positive acknowledgement message (ACK) sent back to the issuing MSA. This message acknowledges that: ECP2-FITSDEV2-SC03-FRSv3.11.doc Page 29 of 53
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Fallback and Recovery Specification (FRS)

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