Carrier officials say customers already are benefiting from the project, and that they plan to have 5 percent of the network virtualized this year.
AT&T executives in December 2014 laid out their ambitious plans to virtualize 75 percent of the carrier's massive network by 2020.
The six-year AT&T Domain 2.0 effort
is designed to transform its network from one built on expensive, complex gear and copper wiring to one that is based on software, driven by the principles of software-defined networking (SDN) and network-functions virtualization (NFV).
By the end of 2015, AT&T officials hope to be 5 percent there, and the carrier already is seeing benefits from its growing use of virtual machines.
In a post on the carrier blog, John Donavan, senior executive vice president of technology and operations at AT&T, cautioned people not to overlook what 5 percent will mean for the company and its customers.
"Five percent might not sound like a lot, but it's the critical first step for all the work to come," Donovan wrote. "And it's that 5 percent that ensured that our customers last month were able to browse without ever missing a beat."
He was referring to an outage at one of the carrier's Domain Name System (DNS) facilities in California. Overall, AT&T handles about 190 billion DNS queries a day, with peaks of as many as 3.6 million queries a second, Donovan wrote.
"If that service goes down, people notice," he wrote.
The California facility that sustained the outage processes consumer wireline DNS query traffic. The outage could have meant a serious disruption of service for customers on the Internet. However, as part of the move to a more software-centric network, AT&T now conducts most of its DNS lookups in virtual machines running in the cloud.
"These virtual machines lower costs and improve resiliency by automatically transferring work when needed to other locations," Donovan wrote. "So when that outage occurred, the system automatically redirected incoming queries to another location in California. It ramped up without a hiccup."
In another instance, AT&T also is seeing the benefits of its software efforts in its wireless network. Donovan said the carrier is taking the specialized hardware that traditionally is needed for each function on the mobile packet core and turning them into software.
"We're now running commercial wireless traffic on these virtual machines," he wrote. "The first batch of traffic is on our Mobile Virtual Network Operator service. We got that up and running in less than half the time our traditional methods would have taken."
Donovan noted that "some companies are just starting to grapple with how they'll make this transition. But we're already seeing the first benefits for our customers."
SDN and NFV offer the promise of more scalable, programmable, agile and flexible networks at a time when trends like IT mobility, data analytics, social software and the cloud are putting greater pressure on networks and constantly changing the demands from customers. The technologies are designed to take the control plane and network tasks off of the underlying hardware and putting them into software.
The result is networks that can be programmed in minutes rather than weeks or months, that are more responsive to customer demands and that are more automated and easier to manage. Service providers and enterprises are able to more quickly spin out services to their customers and employees.