Industrial Automation Networks

Cisco IoT Solution Brief

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Improve Operational Efficiency

Introduction to the Cisco Industrial Automation Networking Solution

For over a decade, manufacturers seeking to drive operational improvements from their production systems and assets have used Cisco’s Industrial Automation Networking solution to drive convergence and digitization.

Industry 4.0 and industrial Internet of Things (IIoT) initiatives are driving improvements in manufacturers’ production processes and supply chains and enhancing their products’ value. These initiatives require visibility and access to the data of the industrial automation and control systems (IACS) in production environments.

This solution provides not only a reference architecture blueprint, but tested and validated design and implementation guidance so IT and OT teams can confidently drive convergence and digitization of production environments. The guidance is based on extensive testing with operational IACS systems and in collaboration with many of those vendors. It is used by IT/OT partners and system integrators to accelerate deployments.

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Cisco® is the leader in industrial networking and cybersecurity. We are leveraging Cisco’s extensive portfolios of products and technology to easily deploy, manage, and secure these ever larger and critical networks and the data that flows through the IIoT.

Cisco Validated Designs (CVDs) provide the core network foundation that meet the needs of operations and IT. This solution brief is a high-level overview of the reference architecture described in the “Networking and Security in Industrial Automation Environments” CVD.

Converged networks providing secure connectivity throughout the plant

Production environments have been adopting standard networking for more than 15 years, transitioning from proprietary, niche networking technologies of the past. This solution provides an architecture and new networking approaches to help with the transition to standardized networks and realize the promise of ubiquitous connectivity. The key use cases this solution incorporates include:

      Connectivity for IACS devices, including sensors, actuators, and controllers’ and assets such as robots, machines, tools, and process skids

      Support for plant-wide applications such as manufacturing execution systems, supervisory control and data acquisition (SCADA), historians, and asset managers

      Network access for on-premises personnel to manage the plant and access remote resources as needed

      Visibility and continuous monitoring by IT and OT personnel of the network and security status of the IACS devices and communication

      Remote access to production assets and applications to improve uptime

      Enable IoT applications with edge computing such as predictive analytics and maintenance, digital twin, and machine learning and optimization

      Secure access of IACS for data acquisition as well as integration with enterprise or cloud-based predictive maintenance, optimization applications, and data warehouses

Key requirements

The solution supports systems and environments that are critical to companies where downtime and network issues quickly have significant impact on revenue, reputation, and product quality. Therefore, key requirements the solution delivers include:

      High availability for all key industrial automation systems and services

      Real-time, deterministic application support with low network latency and jitter for the most challenging applications, such as motion control

      Converged network to support communication from sensor to cloud

      Support for a range of IACS vendors and protocols

      Ease of use as IACS networks are often deployed, configured, and managed by non-IT personnel with limited Ethernet and IP networking skill

      Reliance on open standards to ensure vendor choice and protection from proprietary constraints

      Secure production environments with:

      Visibility of devices and communication throughout the manufacturing zones

      Protection from key threats by implementing the industrial demilitarized zone (IDMZ) and zone-based segmentation according to industrial security policies

      Detection of threats including malware and malicious traffic

      Detection of abnormal process modifications such as unexpected variable changes or program uploads to automation devices

      Response to security risks through integration with security management applications

      Availability of precise time across the site to support motion applications and schedule-of-events data collection

      Scalable from small (tens to hundreds of IACS devices) to very large (thousands to 10,000s) deployments

      Support for long operational lifecycles—often production environments and assets are not upgradeable for years or decades, therefore equipment and software updates may be very limited and newer network deployments must account for older devices with limited networking capability

Target audience

To successfully connect and secure the industrial environment, all stakeholders must work together; OT understands the industrial environment—the devices, the protocols, and the business processes, IT understands the IP network, and the security team understands threats and vulnerabilities. By working together, they can leverage existing networking and security technologies, tools, and expertise to protect the industrial network without disrupting production safety and uptime. This solution is intended to be used by IT, OT, and security teams and their relevant partners and system integrators.

Operations will appreciate the ease of use and simple deployment, as well as the broad support of various IACS vendors and protocols with OT-designed tools. IT network managers will appreciate the ability to apply skills, technology, and applications already deployed in the enterprise when looking to integrate production environments. Security teams will have visibility into industrial assets and security events with context enriched by control engineers.

Industrial ecosystem integration

Most industrial environments are supported by a wide range of vendors and suppliers. It is not atypical to see hundreds if not thousands of suppliers for companies’ operational environments. The solution not only supports a large range of vendor equipment and the industrial protocols they support, but the design and implementation guidance has been developed with key vendors over more than 15 years and is deployed at thousands of facilities around the world. The solution integrates expertise from Cisco, the market leader in industrial networking and cybersecurity technologies, with that from the OT ecosystem. The solution is used in environments that support all the major IACS platform vendors including Rockwell Automation, Schneider Electric, Siemens, Emerson, Honeywell, Mitsubishi, and Omron, among many others.

This solution provides both IT and OT teams with the foundation to confidently collaborate and deploy secure, converged industrial automation networks and cybersecurity.

Industrial Automation reference architecture

The underpinning of the solution is the IA reference architecture, which depicts key functions of the manufacturing environment and relevant network security capabilities. The reference architecture is the core map to the design and implementation guidance provided by the solution.

Plant logical framework

This solution applies the Purdue model as a base framework for the architecture to help give context and align with industry concepts and standards. The Purdue model describes industrial or production levels of control used to describe how automation and control technologies are applied. The Purdue model is shown in Figure 1.

Figure 1.           Depiction of the Purdue model

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The Purdue model is useful in that it breaks down key functions of industrial applications. The network requirements for these applications drive key considerations and capabilities for the solution described later in this paper.

Industrial Automation reference architecture

The IA reference architecture overlays the typical devices, applications, network infrastructure and security technology onto the Purdue framework to give context to the design and implementation guidance. The architecture is focused around three key networking areas: The Cell/Area Zone supporting the core IACS embedded in the production environment functional zones, the Industrial/Manufacturing Zone supporting plant-wide applications and services, and the IDMZ providing key segmentation between production and enterprise systems.

Figure 2.           Industrial Automation architecture map

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Cell/Area Zone

The Cell/Area Zone, a functional area within a plant or factory, is the foundation of the reference architecture. Most plants will have 10s if not 100s of functional areas. This is the network that connects sensors, actuators, drives, controllers, robots, machines, and any other IACS devices that need to communicate in real-time (I/O communication). It represents Levels 0-2 of the Purdue model. Most importantly, Cell/Area Zone networks support the critical automation and control functions that keep the plant operating and producing quality products.

Fundamentally, the Cell/Area Zone is a Layer 2, access network; a subnet, a broadcast domain, a VLAN and/or an SSID. Programmable logic controllers (PLCs) communicate with their assigned sensors, actuators, and other IACS devices within a Cell/Area Zone. The solution outlines key design considerations and recommended implementations for these networks, both wired (Ethernet) and wireless (Wi-Fi). The solution covers topics such as IACS traffic flows, topology, resiliency, industrial protocol support, multicast management, VLANs and trunking, IP addressing considerations, quality of service (QoS), time synchronization, security and segmentation, among many others. More often than not, Cell/Area Zone networks are deployed and managed by the operational organization.

Most importantly, the solution identifies how to seamlessly integrate these networks into a larger plant network design. This is critical to provide access to the rich data and information found in the IACS devices while maintaining their core operational requirements.

Figure 3.           Cell/Area Zone map

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Industrial Zone

Along with the Cell/Area Zones, the Industrial Zone incorporates all the key applications and functions that support a production facility. The Industrial Zone supports site-wide applications and services required to maintain operational integrity of the production environment, including manufacturing execution systems, asset managers, historians, and SCADA systems, along with technical services such as time services, network management, security and identity services (for example, AAA), and wireless LAN control, among many others. To preserve smooth plant operations and functioning of the Cell/Area Zone IACS applications and the overall plant network, and in alignment with standards such as IEC 62443, the IDMZ provides clear, logical segmentation and protection from levels 4 and 5, or the enterprise and external networks, users, and applications.

Besides supporting the site-wide applications, the Industrial Zone network also provides interconnectivity from these applications to the IDMZ, as well as between Cell/Area Zones for inter-zone traffic. Whereas the Cell/Area Zone can be thought of as Layer 2 access networks, the Industrial Zone network supports Layer 3 routing and includes distribution and core network infrastructure. Additionally, it supports access networks for site-wide applications that operate on plant micro-data center servers.

For many customers, the Industrial Zone network also represents the IT and OT demarcation of responsibility, where IT operates the data center servers and applications and the core/distribution network infrastructure. As the distribution network infrastructure straddles the two zones, Industrial and Cell/Area, deployment and management of this part of the network requires close collaboration between IT and OT. For example, resilient distribution network infrastructure and configuration is important for the site-wide applications as well as the IACS systems in the Cell/Area Zone. Therefore, distribution infrastructure is part of both Cell/Area and Industrial Zone design and implementation guidance to help ensure successful IT and OT collaboration.

Figure 4.           Industrial Zone map

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Industrial Demilitarized Zone

Although not part of Purdue reference model, the industrial automation solution includes an IDMZ between the industrial and enterprise zones. The IDMZ is deployed within plant environments to separate the enterprise networks and the operational domain of the plant environment. Downtime in the IACS network can be costly and have a severe impact on revenue, so the operational zone cannot be impacted by any outside influences. The IDMZ helps ensure that. Network access is not permitted directly between the enterprise and the plant; however, data and services are required to be shared between the zones, thus the IDMZ provides architecture for the secure transport of data.

The main function of the IDMZ is to provide firewall-based segmentation and protection for the Industrial Zone. The firewall tightly controls and inspects the flow of data, files, and user access between the zones. In addition to the firewall, the IDMZ supports services such as file transfers, software upgrades, remote access servers, and proxied data services. Due to the focus on cybersecurity and firewalls, the IDMZ is typically deployed and managed by IT (versus OT).

Figure 5.           Industrial Demilitarized Zone map

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Capabilities required for industrial automation

Industrial applications at their core are focused on maintaining stability, continuity, and integrity of industrial processes. At the core is a loop of sensors, controllers, and actuators that must be maintained to safely operate the industrial automation and control processes. Additionally, a number of other applications need to gather information to display status, maintain history, and optimize the industrial process operations. These systems are often deployed by OT system integrators without the support of the IT organization and operated by OT personnel that lack IT capabilities and expertise. This solution outlines how to achieve a set of key requirements to support the installation and operations of the industrial systems described below.

Resiliency and availability

Uptime is a key consideration for any production environment. Industrial applications often operate continuously for weeks, months, or years and any downtime, especially unplanned, results in significant loss of production output and costs, directly impacting the bottom line. The network infrastructure is critical to those industrial applications, therefore this solution considers a number of resiliency mechanisms.

Industrial network topologies are often constrained by the layout of the facility and equipment and high cost of cabling. Therefore, the solution supports use of ring and redundant star network topologies that ensure network connectivity is maintained even if a key connection is lost. Additionally, considerations are also made for non-resilient topologies such as linear or star for customers choosing to forego this capability.

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Network resiliency protocols are needed to take advantage of the redundant paths in the network topologies. The solution supports a number of protocols and outlines their capabilities as well as deployment challenges to help customers choose the right topology and resiliency protocol for their industrial applications. The list of protocols includes Spanning Tree Protocol (STP), Resilient Ethernet Protocol (REP), Media Redundancy Protocol (MRP), Parallel Redundancy Protocol (PRP), High-availability Seamless Redundancy (HSR), and EtherChannel.

A key consideration is redundancy at critical networking functions to decrease the impact of network equipment failure. The solution considers “stacking” of networking equipment as well as the Hot-Standby Resiliency Protocol to maintain routing capabilities.

In any industrial environment, equipment failures, including to the network infrastructure, have to be dealt with quickly to reduce the amount of downtime. Fast replacement of failed network infrastructure is supported through the use of replaceable flash-memory in the network infrastructure as well as via automated network management applications.

Support for a wide variety of industrial automation and control protocols

The IACS protocols used support the critical communications required to keep the plant operational. These protocols include ODVA, Inc.’s Common Industrial Protocol (CIP™) and EtherNet/IP™, PROFINET®, Modbus® TCP, CC-Link™, and OPC UA™, among others. The solution specifically focuses on supporting these protocols.

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The support starts with detailed descriptions of the typical traffic flows including characteristics such as latency, jitter, and sensitivity to loss. This background is especially important for IT networking experts to understand the nature of the solution guidance and recommendations. For example, often these protocols use a mix of unicast, multicast, and broadcast traffic, all of which need to be reflected in network configuration. Therefore, the solution outlines how to deploy QoS in the network to prioritize critical traffic while also supporting other less-sensitive traffic.

In addition, more and more IACS systems require distribution of precise time. Precise time is used for sensitive applications, such as high-speed motion, but also for schedule-of-events to precisely track the order and timing of events in the system. As more applications consume precise time, sitewide distribution becomes important to maintain a single, synchronized sense of time across all the devices and systems.

Another key consideration is how the network infrastructure integrates into the IACS it supports. Therefore, much of the network infrastructure supports IACS protocols for monitoring and management purposes. The solution provides design and implementation guidance for these features.

Lastly, cybersecurity infrastructure and technology that understands, monitors, and protects IACS devices and communication is critical. This technology is capable of analyzing the IACS protocols in-line (in other words, without having to build an expensive out-of-band collection network to mirror the traffic to a central security platform) and thereby monitors for threats and anomalies as well as protects the systems. This is a significant enhancement of the cybersecurity stance for production environments.


Production environments vary in size drastically, from small deployments (tens to hundreds of IACS devices) to very large deployments (thousands to tens of thousands of IACS devices) and the solution is designed to accommodate that variability. The solution reference architecture with Cell/Area Zones interconnected to distribution and core is the classic model for a scalable, repeatable network design. Key IA solution features include:

      Cell/Area Zones with support for Layer 2 VLANs to scale production environments and meet IACS application requirements

      Distribution and core network infrastructure supporting Layer 3 to interconnect Cell/Area Zones with each other and the Manufacturing Zone

      Support for plant-wide applications (for example, SCADA, historian, and MES) and network and security services (for example, DHCP, DNS, timing, and security)

Easy to configure, implement, and manage

Historically, production environments and the IACS in them have been the sole responsibility of the operational organizations, such as plant managers and control engineers. But as Ethernet and IP networks have become the standard for IACS systems, IT departments are increasingly engaging with plant managers and control engineers to leverage the knowledge and expertise in standard networking technologies for the benefit of plant operations. Nonetheless, ease of configuration, implementation, and management are key considerations as often IT or OT personnel or partners may be involved in deploying the network and security infrastructure. The solution identifies and uses a number of key features and concepts to assist both IT and OT in this critical activity. Key IA solution features include:

      Templates and macros to ease configuration of network infrastructure with critical concepts such as segmentation (for example, VLANs and ACLs), QoS, and multicast management, among others

      Support plug-n-play for network infrastructure for easy and fast repair and installation

      Support for both IT and OT network management tools to give all relevant personnel access to tailored network monitoring and management features.


Over the years, manufacturers around the world have been connecting their industrial environments to enterprise networks to automate production and gain operational advantages. Organizations are now deploying IoT technologies to migrate to Industry 4.0, optimize production, and build new generations of products and services. This deeper integration between IT, cloud, and industrial networks requies cybersecurity capabilities that can protect the production environment and assets and maintain operations.

This solution represents the leading cybersecurity approach for production environments, encompassing a defense-in-depth model driven by the leading cybersecurity and networking technology provider conjoined with operational and IT expertise. Cybersecurity in industrial as well as enterprise areas relies upon solid process as much as on key technology. The IA solutions focuses on supporting key cybersecurity processes.

Figure 6.           Cybersecurity processes supported

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To support the cybersecurity processes, the solution starts with the reference architecture that describes critical segmentation concepts such as the IDMZ.

Rugged, access network infrastructure (switches and wireless access points) with industry leading cybersecurity capabilities is the foundation for securing the industrial network. The access network is where IACS devices connect and initial cybersecurity considerations are applied. The access network identifies what is connected and applies initial segmentation concepts (for example, VLANs and TrustSec) to protect the IACS devices. The connection processes (for example, DHCP for IP addresses) are secured and the IACS devices communicate with each other. This communication and its content are monitored. Network and security telemetry data are collected and sent to various network and cybersecurity applications. Key cybersecurity features in the network infrastructure include:

      Secure boot, secure memory, secure access (for example, TACACS AAA services), and secure software update features to protect the network infrastructure and ensure integrity of the hardware and software

      IEC 62443-4-1 and 4-2 industrial cybersecurity certifications for Cisco Industrial Ethernet (IE) 3x000 switches

      Support for secure network access by end devices via IEEE 802.1x and MAC authentication bypass

      Support for protection of key network-based services and protocols, for example DHCP, DNS, resiliency protocols, LLDP, SNMP, and so on

      Support for advanced cybersecurity protocols such as access control lists (ACLs), Netflow, TrustSec and MACsec

      Support for Cisco Cyber Vision OT-focused cybersecurity sensors (Cisco IE3400, Cisco IC3000 Industrial Compute Gateway, Cisco IR1101 Integrated Services Router, and Cisco Catalyst 9300)

More sophisticated segmentation and protection is applied with industry leading commercial and industrial firewalls. These are deployed to key “conduits” within the network architecture: the IDMZ between the Cell/Area Zone and the wider plant network, or as secure access for critical legacy assets that require specialized protection. All the same cybersecurity features noted above for network infrastructure are available, with the addition of the following features:

      Support for full stateful traffic inspection including a range of IACS protocols

      Support for advanced cybersecurity protocols such as Multi-Level Access Controls, NetFlow, TrustSec, and MACsec

      Full “lights-out” traffic bypass to maintain IACS communication (industrial firewall only)

      Managed by IT security tools such as Firepower Management Center and OT-focused on-box user interface for configuration and management

The solution outlines key design and implementation of cybersecurity applications that play critical roles for both the IT and OT organizations to monitor and maintain the security of IACS and plant-wide applications. These include:

      Cisco Cyber Vision analyses application flows on the industrial network to build a detailed asset inventory and communication map. This helps security teams spot vulnerabilities to patch, identify malware and intrusions, and list all the assets to defend. Because Cisco Cyber Vision decodes IACS protocols, it gives OT engineers real-time insights on the actual industrial process status and raise alarms on unexpected process modifications such as variable changes or controller modifications.

      Cisco Stealthwatch uses NetFlow telemetry data from the network to provide visibility into communication flows and has many machine learning algorithms that can help an IT security professional detect possible malware propagation in the network. Cisco Stealthwatch does not have the specific IACS protocol analysis and support found in Cisco Cyber Vision.

      Cisco Identity Services Engine (ISE) is a network access controller (NAC) dedicated to creating and enforcing network security policies. It enables software-based device-level segmentation to manage network access control at scale. The solution describes design and deployment for industrial networks.


The IACS end devices and network infrastructure may be located in physically disparate locations and in non-controlled or even harsh environmental conditions such as extreme temperature, humidity, vibration, noise, explosiveness, or electronic interference. The solution relies upon Cisco’s Industrial Ethernet switches, firewalls, and edge computing designed to operate in these rugged conditions. All the Cisco equipment runs the operating system and software based on the commercial grade versions making them easier to deploy and manage for IT organizations.

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The solution not only includes a range of ruggedized equipment, but also includes guidance and recommendations for considerations such as connectivity (for example, cabling guidance).


The Cisco Industrial Automation solution and relevant product technologies are an essential foundation to securely connect and digitize industrial and production environments to achieve significantly improved business operation outcomes. The Cisco solution overcomes top customer barriers to digitization and Industry 4.0 including security concerns, inflexible legacy networks, and complexity. The solution provides a proven and validated blueprint for connecting IACS and production assets, improving industrial security, and improving plant data access and operating reliability. Following this best practice blueprint with Cisco market-leading technologies will help decrease deployment time, decrease risk, decrease complexity, and improve overall security and operating uptime.

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