The following visual map is a illustration for 4 corner network diagram for e-invoicing study.
In an E-Invoicing environment, a typical seller will confirm all transaction details via its own order fulfilment ERP so that the invoice can be generated inside invoice generating system ERP as corner 1. Subsequently the access point will be acting as corner 2 to convert the invoice details into an agreed format set by an international body such as PEPPOL or the national tax administration. Access point in this scenario can be an add-in API developed by technical solution provider following business interoperability specification or independent access point service provider who is servicing customer with an in-house, non-compliance accounting or ERP system to send invoice details for validation to service metadata publisher (SMP).
SMP is a government agency such as network information center to monitor and publish all registered businesses who can send and receive e-invoice. After validation from SMP, it will continue to be validated by the tax administration cloud. Once it is validated by the tax administration, it is a cleared invoice. Notification will be sent to corner 2 and corner 3 respectively. A cleared invoice will be sent to corner 3 which represents the access point of the buyer.
Once corner 3 receives a cleared invoice from corner 2, corner 3 will map the cleared invoice into the format of the buyer invoice processing system or accounts payable. Corner 3 can be an add-in API developed by the buyer accounting or ERP system solution provider or independent service provider that is able to map the cleared invoice into in-house | non-compliant accounting or ERP system.
Corner 4 is the invoice processing system, with the details fully verified and validated by the tax administration, it is an approved invoice and therefore it will eliminate all human intervention, data entry and checking for invoice errors. It helps to process payment faster at the end.