NASHVILLE, Tenn. — Top network executives from Sprint and C Spire are closely monitoring the developments around software-defined networking (SDN) and network functions virtualization (NFV), but they are in no hurry to deploy the technologies.

Speaking on the CTO panel at the Mobile Carriers Show here last week, Stephen Bye, CTO of C Spire, a regional operator that offers wireless and fiber services in the southeastern U.S., said that SDN is in its infancy and he’s hesitant to deploy it in the network. Specifically, Bye said his company would have to integrate SDN with the carrier’s operations support system, or OSS, to get the benefits of virtualization: “The whole OSS and operational model needs to be resolved first.”

Bye also said he’s hesitant to virtualize the network, because currently, if there’s a problem with a certain piece of hardware, like a switch, C Spire can go to the switch vendor and get it to resolve the issue. “When you start getting into a virtualized environment, whose throat do you choke? Now the burden goes back to the carrier.”

Jay Bluhm, vice president of network planning at Sprint, says his company is also taking a wait-and-see approach to SDN. Bluhm says Sprint will likely deploy NFV for some applications but isn’t ready to deploy it throughout the whole network. “The issue is scaling it throughout the network,” he says. “It’s a big change to the network.”

Bluhm’s sentiments about SDN are not going unnoticed by vendors. Volker Held, head of 5G marketing at Nokia, told SDxCentral earlier this month that many service providers are starting small by deploying NFV in the core or tackling the cloud then seeing how that develops before expanding throughout the network.

Not all operators are convinced that virtualization of the network will result in any cost savings. C Spire’s Bye noted that much of the investment in the wireless network is in the radio access network (RAN). “If you virtualize a switch, it’s not a huge savings,” he said.

Nevertheless, some vendors like Ericsson and Nokia argue that eventually, all wireless operators will have to migrate to SDN and NFV if they want to offer new 5G services that require low latency at the edge of the network. And some even argue that eventually it will be difficult to purchase non-virtualized products, because so many of the bigger operators are shifting away from buying end-to-end hardware stacks.