In this chapter, we will be taking a closer look at the Purdue Enterprise Reference Architecture (PERA), or Purdue model for short. The Purdue model is an industry best practice and a widely adopted concept model for ICS network segmentation and is used extensively to explain ICS architectures.

This chapter also includes an explanation of the Converged Plantwide Ethernet (CPwE) architectures. CPwE is a collaborative effort between Cisco and Rockwell Automation to publish ICS network architectures that cohere to industry best practice design and security recommendations. The architectures are tested and validated for functionality and performance by both companies.

The following topics will be covered in this chapter:

• The Purdue Enterprise Reference Architecture
• ICS Purdue model adoption - CPwE
• ICS network segmentation
• ICS network levels/layers
• The CPwE industrial network security framework