Purdue Model & ICS Architectures

Purdue Enterprise Reference Architecture (PERA), or the Purdue model, is a 1990s reference model for enterprise architecture, developed by Theodore J. Williams and members of the Industry-Purdue University Consortium for Computer Integrated Manufacturing.

ICS functions

The image to the right shows a typical ICS architecture, following the Purdue model and stretched out across the industrial and enterprise networks of an organization. Within the ICS architecture shown in the preceding screenshot, the following main types of devices within the three main sections of the architecture can typically be distinguished:

• The Enterprise Zone is predominantly IT space. Devices, systems, and equipment typically found here are computer-related, such as servers, workstations, and laptops, as well as mobile devices such as phones, tablets, handhelds, and others. These devices are connected together with various Ethernet equipment and media, including switches, wireless access points, routers, firewalls, and the cables that connect all of these devices (Category 6 (Cat6)/Cat6e media).

• The Industrial Demilitarized Zone (IDMZ) functions as a barrier between the Enterprise Zone and the Industrial Zone and is typically implemented as a collection of virtualization hardware, firewalls, and switches.

• In the Industrial Zone, we can find a variety of regular off-the-shelf IT equipment, along with proprietary and specialized hardware that is used to run the production process. In an upcoming section, ICS architecture, we will discuss some of the more common systems that can be found in the Industrial Zone.

The ultimate goal of an ICS is to create a product or run a process. This goal is achieved by implementing distinct functions within the ICS that, when combined, allow for control, visibility, and management of the production or process control. We will now look at typical functions found within an ICS.