8583 IMP

The 8583 IMP is a planned implementation of an Interface Message Processor (IMP) to support authorisation, clearing and settlement of card payments. Compared to the other two IMPs (SEPA and SIC), the 8583 IMP must support pull, not push, payment instruments.

In a card payment transaction, the first step is an authorisation from the payee PSU to the payer’s PSP. The authorisation must be routed in real-time through the FEX to the 8583 IMP and over to the Router. If Tapestry is run as the payer’s PSP, then the Router must call the Ledger to make an authorisation on the payer’s payment account.

If Tapestry is run as the PSP for the payee PSU, then the Router must forward the authorisation request over to the payment infrastructure of the relevant payment scheme such as Visa or Mastercard. The authorisation request would thus pass the FEX and the 8583 IMP twice making this a performance critical activity.

Whether Tapestry could be adapted to support credit transfer payments such as for the SEPA and SIC IMPs as well as card payments with the 8583 IMP is an open question and to be explored in further research and development work.