There is an elephant in the industrial infrastructure control room. Much of the equipment within our US critical infrastructure sectors is at risk of aging out, needing replacement or upgrade, yet still in production use.

Securing Legacy Water and WastewaterWhen upgrading to state-of-the-art technology, water and wastewater treatment plants have to assess legacy systems and also project needs for the next 10, 20 or even 30 years. This requires the use of future-proof infrastructure components flexible enough to adapt to network changes or growth.

This means industrial networks, endpoints, control systems and various types of specialized systems and production equipment across a number of industries are in drastic need of replacement or upgrade.  For water and wastewater treatment, the useful life of system components is estimated to be 15-95 years old according to the American Society of Civil Engineers (ASCE) and their report “Failure to Act – The Economic Impact of Current Investment Trends in Water and Wastewater Treatment Infrastructure”

Securing Legacy Water and WastewaterMany of these components were installed in the 1950s for most major cities, long before today’s modern networks, technical advances, application architecture, industrial protocols, cyber security risks, compliance requirements, safety regulations and other factors would have applied.

It was therefore no surprise when, in 2012, a large, growing California metropolis proposed funding for a new power generation and water treatment plant to increase capacity and replace its aging infrastructure.


One of the biggest cities in California is also in the top 10 largest metropolitan areas within the United States based on its size. With a current population of near 1.2 million residents, this city is home to one of the fastest-growing regions in the country. Its city managers could no longer ignore the elephant in their wastewater treatment plant.

In 2012, the city had completed an energy management strategic plan that assessed its wastewater facility’s existing and future power demands and also the condition of existing energy systems. At the time, they identified their current facility equipment age ranged from 20-61 years and had been experiencing increasingly frequent-to-severe breakdowns. Aside from the equipment age, sourcing replacement parts was becoming unviable. Urgency was high to approve funding for a proposed new state-of-the-art cogeneration and wastewater treatment plant to begin services in 2016 and designed to meet 9 regional cities’ needs through 2036.

However, in 2016, despite achieving construction and operational readiness, there were network communication problems plaguing the facility and crippling its PLCs and other systems. After three prior manufacturers had failed, Belden was able to resolve the issues allowing the plant to become fully operational.

Wastewater Treatment Plant Use Case: Key Industrial Networking Requirements:

  • All control and monitoring activities must be seamlessly and securely connected to a central control HMI
  • Processes must run 24 hours a day and 365 days a year without failure
  • Networking equipment should be resistant to threats of possible network malfunction and malware intrusion
  • Rugged Physical product design
  • Hardware redundancy protocol technology and integrated network security

Wastewater processing plant operations require high service and availability from every aspect of the operational design. Therefore an "always up" connection between the master and slave PLCs for power generation was required, and the network architecture design had interconnected switches deployed in a redundant ring.

The benefit of this architecture is that it allows a redundant path to end devices in case of an intermediate link or node failure. However, by its inherent nature this architecture can also generate excessive broadcast traffic when connections are lost or transmission is incomplete.

Securing Legacy Water and WastewaterBelden’s solution architecture for the water treatment plant’s redundant ring using the GarrettCom Magnum 10RX Configurable Router and Security Appliance supporting UDP traffic, Modbus TCP and various types of serial connections.

Many PLCs are not able to handle high volume traffic, connection losses and heavy retransmission demands, and the system can therefore reboot unexpectedly, causing disruption and network unreliability. The switches in the design needed to prevent this traffic from reaching the PLCs and help stabilize the network.UDP and Broadcast Storms   

Necessary sidebar here on UDP and Broadcast storms. One of the mainstay communication protocols used within IP networks is the User Datagram Protocol (UDP). UDP combined with IP provides several modes of communication between end devices; such as Unicast, Multicast and Broadcast. Broadcast communications involve hosts or end-devices sending UDP datagrams to broadcast addresses so that all devices in the network see that message and can act upon it. One of the benefits of using a broadcast is that it reduces the overhead for an end-device seeking to learn the peer IP address. However, UDP has only minimal recovery services and in some cases devices may become overrun with the communications traffic.

A broadcast storm can also be created when a host or end-device receives a broadcast UDP message and is unable to process it. Network communications become unreliable and the L2 switches in this plant’s case didn’t properly terminate the UDP transmissions, causing the storms to be able to reach the PLCs which were therefore intermittently rebooting.

The Solution

Belden personnel proposed a revised architecture after examining many aspects of the wastewater treatment plant’s network architecture and subnet mapping, placement and types of devices and capabilities, serial connections, etc. The weary plant team was welcomed into Belden’s Fremont offices where the test lab could be utilized to validate the architecture using the high performance GarrettCom Magnum 10RX Configurable Router and Security Appliance. This device is highly configurable and has security capabilities built in.

After preparations, the team had completed all the test cases within one day and immediately moved with the decision to replace all switches within the plant facility by the end of that same day. Following implementation they were able to then successfully bring all operations and services online without further broadcast storms and unreliable performance of their PLCs.

Securing Legacy Water and WastewaterThe GarrettCom Magnum 10RX Configurable Router and Security Appliance delivers highly customizable configuration options, high performance and advanced security support for layer 3 networking protocols, firewall, router and VPN.


Research shows that much of our nation’s critical infrastructure is aging out and based on current requirements should have upgrades, replacements, or new facilities created to limit risk of service disruptions, increase public safety, and reduce the risk of cyber security weaknesses. What elephants are tough to ignore within your own industrial networks, endpoints and control systems?

We look forward to hearing from you, and download the SANS 2016 State of ICS Security Survey to see responses and concerns from global ICS professionals’ responses to an in-depth survey by the highly regarded SANS Institute.

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