The Neutral Ground of the Internet: How UNH-IOL Powers Ethernet Compliance with Opal Kelly

If you’ve ever plugged an Ethernet cable into a laptop, a router, or a car and it "just worked," you likely have the University of New Hampshire Interoperability Lab (UNH-IOL) to thank.

For over 37 years, UNH-IOL (iol.unh.edu) has served as the tech industry’s neutral testing ground. From the early days of FDDI to modern 800 Gigabit Ethernet, the lab ensures that devices from fierce competitors—like Broadcom, Intel, and Cisco—can talk to each other without crashing the network.

But ensuring global interoperability requires more than just standard testing; it requires the ability to break things on purpose. To achieve this, UNH-IOL’s Ethernet team turned to Opal Kelly to build a flexible, student-friendly, and scalable test architecture.

UNH-IOL tests for two things: Interoperability (does Device A talk to Device B?) and Conformance (did Device A follow the rules?).

While standard industry equipment from vendors like Keysight or Spirent is excellent for testing performance and scale, it often lacks the flexibility needed for deep conformance testing.

"The niche capabilities we're talking about generally means we have to have tools that do the technology wrong... Getting a piece of silicon to do that is non-trivial." 

— Bob Noseworthy, Principal Engineer, UNH-IOL

To certify a device, UNH-IOL engineers need to act as an "improper PHY"—sending invalid signals, bad framing, or incorrect encoding to ensure the Device Under Test handles errors gracefully. Since standard chips are designed to work correctly, they cannot easily be forced to generate these specific errors.

Previously, the lab relied on standard FPGA evaluation boards. However, these boards frequently went End-of-Life, forcing the team to constantly redesign their test fixtures. They needed a stable, commercially available platform that was lifecycle managed and could serve as the long-term backbone of their test beds.

UNH-IOL standardized on Opal Kelly modules—specifically the XEM7320 and XEM8320—to power their custom conformance tools. These modules serve as the critical bridge between the lab's high-level test scripts and the physical wire.

By leveraging Opal Kelly’s FPGA integration modules, the lab created a highly modular architecture. Rather than designing a new board for every technology, they use a "stack" approach: a consistent Opal Kelly FPGA base paired with swappable "personality boards".

• Adaptability: If the team needs to test automotive Ethernet, they snap on a 100BASE-T1 adapter. If the next test is for fiber, they swap it for an SFP cage board.
  
  
• Scalability: This modularity allows the hardware to be easily moved between groups. A single XEM7320 can migrate from the automotive team to the Gigabit Ethernet team just by changing the adapter, maximizing the lab’s hardware investment.

1. The "Buy vs. Build" Advantage

For a lab staffed with capable engineers, designing a custom FPGA board from scratch was entirely possible. However, the decision to purchase Opal Kelly modules was strategic—driven as much by software as by hardware.

The FrontPanel SDK provided an out-of-the-box USB connection that eliminated months of tedious driver development. For UNH-IOL, the value proposition was simple: Opal Kelly handles the PC-to-FPGA plumbing, allowing their engineers to focus entirely on the Ethernet test logic.

"I basically consider you guys part of my staff. I don't have to solve the problem of the PC-to-FPGA interconnect. You guys and your product have it." 

— Bob Noseworthy, Principal Engineer, UNH-IOL

This partnership model effectively outsources the maintenance of the communication interface. Instead of dedicating internal resources to fixing USB driver bugs or updating Windows compatibility, UNH-IOL relies on Opal Kelly to keep the data pipe open and stable.

2. Empowering a Student Workforce

UNH-IOL operates with a unique workforce model: a small core of about 28 staff engineers manages over 100 undergraduate and graduate student employees. With students graduating and turning over every few years, the lab cannot afford tools with steep learning curves.

FrontPanel proved to be the critical enabler for this evolving workforce. It abstracts away the complex low-level hardware interfacing, allowing students to control the FPGA using languages they are already taught in school.

• Language Flexibility: Students have successfully interfaced with the modules using Python, Java, C++, LabVIEW, and even Rust (via C++ bindings)
  
  
• Immediate Impact: A computer science student comfortable in Java or a computer engineering student knowing Python can write validation scripts in their first semester without needing to understand complex kernel drivers.

"Opal Kelly boards paired with FrontPanel creates a transparent bridge between the FPGA fabric and the PC... It lets students who don't have any experience with FPGAs really hit the ground running."

— Evan Stenger, Senior Engineer, UNH-IOL

This ease of use transforms the educational experience. Students move quickly from learning the basics to contributing real value: writing scripts that automate testing, validating new protocols, and even designing hardware filters

3. Architectural Efficiency: Ditching the MicroBlaze

Moving to Opal Kelly also unlocked significant architectural improvements. In previous designs using Xilinx eval boards, the team had to instantiate a MicroBlaze soft processor just to manage communication over a slow UART connection.

With Opal Kelly, the high-bandwidth USB connection is handled by the FrontPanel IP. This allowed UNH-IOL to:

• Remove the MicroBlaze entirely, saving significant FPGA logic resources.
  
  
• Downsize the FPGA: They moved from large, expensive Kintex-7 parts on eval boards to more efficient Artix-7 FPGAs (XEM7320) while actually increasing their testing capability.
  
  
• Increase Throughput: They can now stream data directly to the PC over USB 3.0, enabling real-time analysis that wasn't possible over UART.

The Result: Automated, Scalable Compliance

Today, UNH-IOL uses this setup to certify everything from 10 Mbps automotive Ethernet to 10 Gigabit fiber. The flexibility of the platform allows them to update their test logic instantly as standards evolve, something impossible with fixed-function ASICs.

By leveraging Opal Kelly, UNH-IOL has successfully transformed their testing capabilities:

• Eliminated "End-of-Life" Anxiety: Previously, the lab relied on evaluation boards (like the Xilinx KC705) that would eventually be discontinued, forcing expensive redesigns. By moving to commercially supported Opal Kelly modules, they secured a stable, long-term hardware platform.
  
  
• Unlocked High-Speed Automation: Replacing legacy UART connections with FrontPanel's USB 3.0 interface allowed the team to stream data continuously to the PC. This enabled automated, "lights-out" testing that can run overnight without human intervention.
  
  
• Accelerated Student Innovation: Interns and student employees now contribute effective production code in their first semester, leveraging Python and Java instead of struggling with complex driver development.
  
  
• Delivered Critical Neutrality: As a non-profit, industry-funded facility, UNH-IOL provides the objective, third-party verification that tech giants rely on. This architecture ensures they can continue to catch the bugs that others miss, keeping the internet running smoothly.

Learn more about the University of New Hampshire Interoperability Lab: Visit UNH-IOL and their use of Opal Kelly solutions in their BitPhyer Tools

Explore the products behind the case study:

• XEM7320 (Artix-7 FPGA Module)
• XEM8320 (Artix UltraScale+ FPGA Module)
• FrontPanel SDK