Design a Network Infrastructure that Meets Performance Needs

By Jessica Forguites, Technical Platform Lead, Rockwell Automation

When designing your industrial network infrastructure, careful planning is required to get the performance needed for today, and in the future, as more devices are integrated into your control system architecture.

When choosing the appropriate industrial switch for your network, there’s a lot to consider and it can be overwhelming with all the options now available — from unmanaged, to lightly managed, and even fully managed switching solutions. So how do you know which is the best choice for your industrial application? Let us help you decide.

How to Select the Right Switch for Your Application

First, you will have to examine your network closely to determine your performance needs. You want to make sure you get the right balance of functionality and ease-of-use at the right price-point for your application.

Unmanaged and managed network switches appear to have common performance characteristics at a port level, but our experience shows this is not the whole story. You’ll validate this the first time you are challenged with adding capacity or migrating legacy equipment to a common network protocol.

Managed switches offer key functionality that’s critical for optimal performance of your network. Port speeds on individual switches are only part of this story as more devices and ports get added over time to connect the unconnected.

This is where scenarios resulting in network bottlenecks occur. Connectivity provides the data needed to optimize processes and increase production. As these applications are brought together, distinctions between performance optimization features emerge.

Now, it’s time to ask yourself whether you are considering the network performance you need to deal with the unexpected?

Scenario One

Imagine you are a production manager, and you receive a call that two production lines are down because of communications errors.

Your maintenance staff clears the faults and restarts the equipment. Ten minutes later, one of the lines shuts down again. Now you call in the experts to look at drawings of your network infrastructure.

You determined that a production line that’s currently shut down for maintenance is connected through the same control cabinet, and the team working on that line has plugged in an Ethernet camera locally to provide a remote expert with a view of a machine fault.

Could this be the source of the communication errors?

Unmanaged switches don’t have any segmentation features and provide no ability to segment devices into their own domain to reduce performance impact risk associated with the unknown.

Because of this, the camera affected existing network loading — resulting in deployment risk and potential unplanned downtime.

Using VLAN features available in lightly and fully managed switches help provide this segmentation. Additionally, quality of service (QoS) features within a lightly managed or managed switch allow prioritization of critical traffic on that switch shared by those two systems.

Scenario Two

Imagine someone plugged an Ethernet camera into your network on the other side of your plant to help troubleshoot with a remote expert.

You’re supporting motion, safety and standard control across a common network infrastructure as part of your operations to optimize costs and resources. You find that other equipment in the facility begins to shut down due to communications faults.

Unmanaged switches and lightly managed switches don’t have QoS policy granularity to support multiple disciplines as described in this scenario. Because the camera is repeatedly sending large image files across the network, the bandwidth of shared communication paths is being completely consumed, and other devices don’t get expected packets and start to experience faults. This all can result in costly downtime.

Using QoS functionality can help. QoS with expanded queue support is available in fully and high-performance-managed switches, supporting prioritization of critical traffic. QoS features in the fully managed line of switches also are optimized to scale across a larger network as described in the scenario.

To further maximize performance, PTP features available on these same families will help safeguard time synchronization service integrity.

These common scenarios can happen to you.

The proper industrial switches, along with our validated Converged Plant-wide Ethernet reference architectures, can help you build a more robust, secure network infrastructure to optimize performance and improve operations.

More scenarios that could help select the appropriate switch can be found in this on-demand webinar about how to select the right switch for your application.

Learn more about industrial network products from Rockwell Automation.

^{The Journal From Rockwell Automation and Our PartnerNetwork™ is published by Putman Media, Inc.}