Vodafone Germany was hoping that network functions virtualization (NFV) would be its ticket to "leave the box business," but the technology has a long way to go, according to Walter Haeffner, a distinguished engineer at the carrier.

At last week's Carrier Network Virtualization conference in Palo Alto, California, Haeffner gave a brief talk about his experiences with NFV, so far. He still has high hopes for the technology but wasn't pleased with the first-pass efforts he saw from vendors.

He is convinced, however, that NFV will have its benefits. His team has drawn up business cases for eight services, such as Internet multimedia subsystem (IMS) work for voice-over-IP, or Domain Name System (DNS) services. Their numbers show potential capex savings of 25 to 45 percent over five years and opex savings of 30 to 60 percent over three years.

Reaching that potential has been the trick.

As a customer of virtualized network functions (VNFs), Haeffner is critical. Seeking to virtualize the mobile packet core, Vodafone tested VNFs from four big vendors and found that all four had done the obvious: port their products directly into virtual machine form.

The result was "monster VMs" and a "monolithic software platform" that doesn't scale any better than the original products would, he said. Moreover, the monster VMs didn't support as many subscribers as expected, and the throughput was troublesome: "several hundred megabits per second. We had expected much more," Haeffner said.

The end goal would be a cloud-native approach — that is, breaking up services into modular microservices that can be upgraded and scaled independently. Realizing this is a "tremendous and very expensive task for our suppliers," Haeffner said. In the near term, he said he would be satisfied with stopgap products.

As part of that, Haeffner is in favor of not moving the data plane (Haeffner called it the "user plane") onto general-purpose servers. The control plane can go there, but keeping the data plane on proprietary hardware would keep Vodafone "on the safe side," he said.

China Mobile has likewise implemented NFV by keeping the data plane on proprietary hardware. Robert Chen, director of cloud infrastructure and applications for China Mobile’s U.S. Research Center, had described the architecture earlier in the conference.

While Haeffner might come across as grumpy about NFV, he's seen some benefits already. "It took us only three or four days to deploy a complete analytics platform on top of this virtualization layer," he said. "When we had to take care of dedicated compute environments, it was a project of half a year or longer."

Vodafone consists of many different organizations spread across many countries, so Haeffner is not the only employee pursuing NFV. David Amzallag, Vodafone's head of network virtualization, SDN, and NFV, spoke at October's SDN World Congress describing a SDN- and NFV-based VPN that he called the Application-Ready Network. The goal is to give Vodafone "one single VPN product worldwide, not many."

Haeffner, though, is among the engineers getting NFV under their fingernails. Vodafone Germany caught the virtualization bug in 2012, hoping to be the first Vodafone organization to launch a major virtualization project.

The team's approach was to recognize that they were newbies to this world and needed help. So, for example, they chose a VMware environment rather that building from open source pieces.

"We had a lot of discussions about open source, but I said that we hadn't the skill in place," Haeffer said. "It's very hard to set up a carrier environment with an open source platform."

Vodafone Germany also started small. Functions that already run on servers, such as DNS, lend themselves to virtualization. Service gateways, such as the broadband remote access server (B-RAS) that China Mobile would like to virtualize, got left alone.

In general, Haeffner said, the biggest and dumbest of appliances make for good virtualization targets. Something big and complex, like a core router, won't get there any time soon, but a route reflector could be a good candidate.

For the medium-sized appliances, it depends on the level of complexity. Vodafone Germany didn't rush to virtualize the systems that are packed with custom silicon, Haeffner said.