Hi-level eProcurement solution architecture

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Building blocks 

This section explains the different system components and environments. Furthermore, additional information about the system architecture can be found in the ARCHITECTURE OF THE OCDS OPEN SOURCE CENTRAL UNIT OF THE ELECTRONIC PUBLIC PROCUREMENT SYSTEM.

NEPPs

The front-end platforms are web platforms that implement eProcurement system features and provide access for CAs and EOs. The NEPPs interact with the CDU via the API and provides suppliers with temporary credentials to access the auction module hosted on the central unit.

Central Unit

• Business Process Engine - core systems component responsible for execution of commands received and processes inside the system
• CDB - central database, which contains information related to each contracting process
• Chronograph - component that controls the time and operates as a scheduler
• Transport agent - middleware responsible for transferring data (requests and responses) between the System and third-party services and systems
• Form Service - service that allows NEPPs to get actual needed field-set together with existing related information and reference data within one single request to build UI-Form for producing specific type of data-entity by end-user on its side.
• Auth Service - self-contained service for securely transmitting information between parties as a JSON object. This information can be verified and trusted because it is digitally signed.
• Operation Service - self-contained service responsible for identification of the commands between the CDU (BPE) and the NEPPs. 
• Feed Point - platform to organize real-time communication between parties (including NEPPs) for transfering a personalized data as a closed feed,
• Public Point - component that displays CDB records in read-only mode. Only information allowed for publication by the current legislation is displayed.

Document Service

Component responsible for registering, uploading, archiving, organising and control of access to all documents (files), enabling long-term preservation of them in digital format and ensuring that they can be easily retrieved without conversions. Service also provides basic document management functionality for receipt, dispatch, storage and retrieval of documents. Component consist of following:

• Document Repository Management System - server managing the access to the file repository. It controls the access to the files and reads the files from the repository. Requires Internet Connection.
• Document Repository - storage of the files attached to the tender notices, offers, and complaints. Does not require Internet Connection.

Master Data Service

Component is responsible for providing a Data Management, both master and meta. Therefore consumers (such as NEPPs) are able to use centralized dictionary, identification, classification and other kinds of data needed to fulfill data-layer of procurement process according to the data models used.

eAuction environment

• Front-end Auction Servers - cluster of the front-end servers for the eAuction module, which serves eAuction users: displaying individual user’s page; retrieving the current status of the auction from the CDB server, etc.Requires Internet Connection.
• Auction Public Server - front-end eAuction server, installed for the observers. It displays the web page for read-only users, so that everybody can watch how an eAuction is running. Current status of the auction is received from the DB auction server. It does not allow making bids.Requires Internet Connection.
• Back-end Auction Server - back-end eAuction server. It receives bids uploaded through the front-end auction servers, saves them in the auction DB, and executes the logic of the eAuction module. During the auction, it keeps track of the time allocated to each bidder and it determines the sorting order of the bidders at the end of each round according to the award criteria. Does not require Internet Connection.
• Auction DB Management Server - back-end server, which provides correlation between the back-end auction server and the auction DB.Does not require an Internet Connection.
• Auction DB - auction database, which contains information about the auctions in progress and bids provided by every participant.Does not require an Internet Connection.

Web portal

Website that presents procurement information in compliance with legislation, from the CDB through the Portal’s Public. Contains general information pages as well. Requires Internet Connection.

Architecture diagram

Figure 4. High-level diagram of the systems’ architecture