PEPPOL uses the Transport Infrastructure to connect different eProcurement systems by establishing a set of common business processes and technical standards. This provides an interoperable and secure network connecting all Access Points using the same electronic messaging protocol and formats and applying digital signature technologies to secure message content.
Once connected to the PEPPOL Transport Infrastructure (via a PEPPOL Access Point), public agencies and private enterprises can reach any other eProcurement community also using PEPPOL.
The figure below shows the main components of the PEPPOL Transport Infrastructure:
To understand this diagram imagine that a Danish supplier is sending an eInvoice to a French government agency. The basic operations would be:
The supplier uses their business application to create the invoice.
The supplier's invoice is the sent to their Access Point.
The Access Point looks up the French government agency's delivery point by first checking the PEPPOL Service Metadata Locator (SML) to find the relevant Service Metadata Publisher (SMP). The Service Metadata Publisher provides the correct delivery point for the French government angency's invoices.
The Access Point then delivers the eInvoice (in PEPPOL format) to the French Access Point using a protocol known as START.
The START protocol uses digital certificates to validate and secure the exchange of documents.
The French Access Point then transfers the invoice to the government agency.
The government agency uses their business application to process the invoice.
It is worth noting that the same Transport Infrastructure technology can be used for other types of business transactions – not just eProcurement. PEPPOL provides governance for the European public eProcurement, however the same Transport Infrastructure can support other uses such as exchanging health records, legal documents or freight management information.