Fallback and Recovery Specification (FRS)

DG TAXUD – EXCISE COMPUTERISATION PROJECT REF: ECP2-FITSDEV2-SC03-FRS
FALLBACK AND RECOVERY SPECIFICATION (FRS) VERSION: 3.11-EN
Solution elements
5 Solution elements
Solution elements are the basic components of the overall business responses that relate
to the identified exceptions. Whenever one of these exceptions is encountered, the related
generic responses apply, regardless of the specific aspects of the exception.
This chapter presents generic solution elements to build the business responses to EMCS
exceptions.
5.1 Prevention of exceptions
PR01 Pre-validation of entered information
PR02 Ensure permanent availability of EMCS applications
PR03 Atomicity of EBP processing
PR04 Use of timers
PR05 Enqueue message for further automatic recovery
PR06 Business acknowledgement
PR07 Follow-up „open‟ information
As a general rule, it is easier to prevent an exception from happening than to try to solve
it after it has occurred. Therefore, when there are indications that some means exist to
prevent an exception or reduce its consequences, these means are to be identified and
become a part of the solution.
A prevention solution element is characterised by:
� a place of prevention that identifies the responsibility of the measure; prevention
should be performed as close as possible to the source of the cause and to the possible
point of correction;
� a type of prevention such as assistance and control of input at user interface, integrity
control at receipt of a message, control of internal consistency before sending a
message, etc.
A major characteristic of EMCS is that it mainly consists of automatic sequences of
processes entrusted to different IT systems and that are automatically chained.
Consequently, there is generally no intermediate actor enabled to verify to correct
movement information during the processing of a use case.
At the end of a use case, the new information must be known and consistent amongst all
involved locations throughout the whole system.
Consequently, there must be general mechanisms to:
� ensure that only correct data are entered into the system;
� ensure that the normal sequence of states is respected.
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