When responding to a question about interoperability between FirstNet and Canadian carriers, Sambar said that “interoperability can be achieved in a number of ways.” However, the notion of core-to-core interoperability with other LTE providers could pose some security issues, he said.

“When you get down to cores interoperating together, our concern is that it becomes a very slippery slope,” Sambar said.

Most of the debate regarding core-to-core interoperability has centered around Verizon, which last month announced plans to develop a dedicated public-safety LTE core, as well as providing first responders with the same type of priority/preemption capabilities that AT&T will offer FirstNet subscribers. However, establishing core-to-core interoperability with Verizon likely would mean that FirstNet would have to enable the same functionality to hundreds of other carriers that serve the U.S. market, Sambar said.

“Are we all comfortable that some of them use Chinese hardware in their network?” Sambar said. “Are we comfortable interoperating with cores that use Chinese equipment, because we told FirstNet that we’re not using any Chinese-made equipment in our core? If we interoperate with one core, do we need to make it available to any reputable wireless company’s core?

“China Telecom, as an example, operates an MVNO network here in the United States, and they use spectrum and capacity from T-Mobile and Sprint is my understanding, based on Internet research I did. Are we comfortable with the FirstNet core for public safety interoperating with a China Telecom MVNO? Those are questions that we have to start to ask ourselves, if we start going down this path of interoperable cores.

“I think FirstNet’s decision—through the process of investigation and the use of the Boulder lab—was that opens up a can of worms; it becomes very dangerous. And, when you create seams in a network, that’s when you have vulnerabilities, and we don’t want vulnerabilities in the network. So, that’s why it’s being constructed the way it is. It’s a FirstNet issue in the end—FirstNet, NTIA, the Department of Commerce, the FCC, etc.—but as it stands today, we have a significant security concerns.”