What is Converged Plantwide Ethernet (CPwE)?
Converged Plantwide Ethernet (CPwE) is a reference architecture developed by Rockwell Automation and Cisco for building industrial networks that are secure, scalable and manageable. It combines IT and OT networks into one coherent Ethernet architecture.
The aim is to enable reliable, real-time communication within industrial environments, with support for automation applications, data analytics and integration with the enterprise environment.
🧱 Key components of CPwE
| Component | Description |
|---|---|
| Cell/Area Zones | Local segments grouping production assets (such as PLCs and sensors) |
| Industrial DMZ | Buffer zone between IT and OT networks with strictly controlled access |
| Layer 2/3 Switching | Segmentation and routing via managed switches and VLANs |
| Firewalls & ACLs | Industrial Firewall rules to control traffic between zones |
| Redundancy | Multiple connections (e.g. via REP or PRP) for high availability |
| Remote Access | Secured VPN or jump servers for remote access to OT systems |
🎯 Why use CPwE?
- ✅ Segmentation of critical processes and equipment
- ✅ Real-time communication between OT devices
- ✅ Integration with MES, Historian and cloud analytics
- ✅ Layered security following the Defense in Depth principle
- ✅ Scalability to multiple plants or lines
- ✅ Compliance with standards such as IEC 62443, NIS2 and ISO 27001
🔐 Security within CPwE
| Layer | Security measures |
|---|---|
| Physical layer | Secure access to network hardware |
| Network layer | VLANs, ACLs, Firewalls, NAT, deep packet inspection |
| Application layer | Whitelisting of permitted applications, patch management |
| User layer | Roles, access control, multi-factor authentication (MFA) |
| Monitoring layer | Logging, SIEM, IDS/IPS, anomaly detection |
⚠️ Common mistakes in CPwE deployments
- ❌ No clear segmentation between IT and OT traffic
- ❌ Unused ports left open or undocumented
- ❌ Remote Access without strong authentication or logging
- ❌ Misconfiguration of ACLs or VLANs
- ❌ No monitoring of the Industrial DMZ (IDMZ)
- ❌ No integration with central Incident Response procedures
🧯 Cyber incidents within CPwE
Cyber incidents can occur in CPwE as a result of:
- Attacks on vulnerable OT components via the IT network
- Malware spreading across poorly segmented VLANs
- Misconfiguration of routers/firewalls leaving access open
- Data theft via Historian or remote engineer access
- DDoS attacks blocking switch capacity or HMI traffic
A well-implemented CPwE prevents this through microsegmentation, monitoring and control.
🔁 CPwE vs. traditional OT network
| Traditional OT network | Converged Plantwide Ethernet (CPwE) |
|---|---|
| Outdated, flat network topology | Segmented, scalable architecture |
| Limited integration with IT | Standard IT integration with secure boundary zones |
| No or limited security | Defense in Depth with ACLs, firewalls and DMZs |
| Difficult to manage | Centrally manageable using modern tools and best practices |
🏗️ CPwE in practice
Typical applications of CPwE include:
- Real-time data transport between PLC, SCADA, Historian and MES
- Integration of sensor data with data analytics platforms
- Secure remote maintenance via DMZ jump servers
- Centralisation of logging and monitoring within the OT network
📌 In summary
Converged Plantwide Ethernet is the standard for building reliable, secure and integrated industrial networks.
It delivers scalability, visibility and security in modern production environments, and forms a foundation for Industry 4.0.