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Making the Switch: Serial Bus to Ethernet

February 11, 2016

There’s a lot of talk these days about Industrial Ethernet. What it is and what it is not. Part of the misunderstanding is that the standards are very simple, yet stringent.

The simple part of Industrial Ethernet is once you determine your baseline, ‘normal’ traffic’ - any anomaly is apparent. The complexity of Industrial Ethernet is understanding the various standards and protocols.

Read on to see my updated list of requirements and considerations.

In a recent blog, Top Network Security Concerns for 2016, I discussed my concern for vulnerability in the control industry - oil, gas, water, and power. As these systems move from serial port to Ethernet the need to build in a real Visibility Plane is vital.

When working in a factory or production cell environment, there is electromagnetic interference (EMI), meaning devices like motors and mechanical switches can impact the performance and outcome of other equipment. The environmental conditions also need to be factored into introducing equipment, such as humidity, chemical or vaporous airs. IT hardware devices are designed for controlled environments, think of the clean-room data center environment, or look around your office as you’re reading this. 

Here’s a partial list of requirements to consider when designing a network for Industrial Ethernet.

  • Garland_Technology_PC104_top_of_stack_board (1)Redundant power inputs (DC and AC) to prevent single power failure.
    • For constant non switch, non fail functionality
  • Fail safe access methodology.
  • Support for ring topology to provide a redundant backup path.
  • A PC-104 standard sealed rugged, high-strength casing to keep out harmful substances.
  • The ability to withstand shock, drop, and vibration conditions.
    • Like shock and vibration tests in accordance with PLC standards IEC 1131-2, IEC 60068, IEC 60255
    • Harsh external physical environments like wind, rain, sand, IEC 60068
  • Line-swap fast recovery that responds when devices change their port position.
  • DIN Rail mounting - rapid mounting of robust devices by clipping onto a standard DIN Rail.
  • Robust design suitable for industrial applications for ambient conditions like extended temperature range from -40°C up to +70 °C.
  • No fans
  • IP20/IP30/IP67 relative atmospheric humidity up to 95% (non-condensing).
  • Firm and very dependable mechanical stability.
  • Adherence to IEEE802.3 standards on cabling.
  • Proper cable selection for the environment, ie shielded/unshielded; data rate consideration, and 2 Pair vs. 4 Pair.
  • Industrial and Electrical requirements:
    • IEEE 1613 Class 2
    • IEC 61850-3
    • IEC 61000 all parts
    • IEC 60255 most or all parts
    • CSA/UL 60950
  • Electromagnetic Interference requirements like - EMI: EN 50022, EN 50082-2, FCC part15 (class B) IEC 1000-4-2, IEC 1000-4-6, IEC 1000-4-4, EN 61000 and IEEE 1613 (C37.90.x).
    • Faraday casing or shielding for protection from EMF/EMI
  • If required, the ability to internally handle non condensating vaporous and harsh chemical, explosive and or combustible environments:
    • IEC 60068
    • ATEX Hazardous Location Certifications
    • UL, NFPA and FM standards for United States
    • CSA C22.2 and CSA E60079 for Canada
    • EN 500XX and EN 60079 - XX
  • Certification examples CE, cUL60950, cUL 508, cUL 1604 Class1 Div (A,B,C,D) or FM 3611 Class 1 Div2, GL (Germanischer Lloyd) for maritime applications or hazardous locations.
  • High MTBF values (Mean Time Between Failure) from approximately 20 to > 100 years in stressful environments, in comparison with office devices with typically 3 to 5 years in office and home environments.
    • Long lifetime devices and components
  • Safety and RF emissions standards requirements. Security – Robust Physical and Control access.
    • Logical – Network access by only known Devices and Traffic/Protocol Types

 

Looking to add a visibility solution to your industrial deployment, but not sure where to start? Join us for a brief network Design-IT consultation or demo. No obligation - it’s what we love to do.

Defending Industrial Ethernet Network Security Garland Technology

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Heartbeats Packets Inside the Bypass TAP

If the inline security tool goes off-line, the TAP will bypass the tool and automatically keep the link flowing. The Bypass TAP does this by sending heartbeat packets to the inline security tool. As long as the inline security tool is on-line, the heartbeat packets will be returned to the TAP, and the link traffic will continue to flow through the inline security tool.

If the heartbeat packets are not returned to the TAP (indicating that the inline security tool has gone off-line), the TAP will automatically 'bypass' the inline security tool and keep the link traffic flowing. The TAP also removes the heartbeat packets before sending the network traffic back onto the critical link.

While the TAP is in bypass mode, it continues to send heartbeat packets out to the inline security tool so that once the tool is back on-line, it will begin returning the heartbeat packets back to the TAP indicating that the tool is ready to go back to work. The TAP will then direct the network traffic back through the inline security tool along with the heartbeat packets placing the tool back inline.

Some of you may have noticed a flaw in the logic behind this solution!  You say, “What if the TAP should fail because it is also in-line? Then the link will also fail!” The TAP would now be considered a point of failure. That is a good catch – but in our blog on Bypass vs. Failsafe, I explained that if a TAP were to fail or lose power, it must provide failsafe protection to the link it is attached to. So our network TAP will go into Failsafe mode keeping the link flowing.

Glossary

  1. Single point of failure: a risk to an IT network if one part of the system brings down a larger part of the entire system.

  2. Heartbeat packet: a soft detection technology that monitors the health of inline appliances. Read the heartbeat packet blog here.

  3. Critical link: the connection between two or more network devices or appliances that if the connection fails then the network is disrupted.

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