By the end of 2016, AT&T expects to have 105 data centers in its integrated cloud, which serves as the basis for its virtualization strategy.

The AT&T Integrated Cloud (AIC) is a data center design that includes top-of-rack switches, storage, servers, and software at the hypervisor.

“It’s a compilation of elements that creates data centers in different sizes that we can deploy anywhere,” says Ken Duell, AT&T’s assistant vice president of development and engineering.

The carrier seems to interchange the words “data centers,” “nodes,” and “zones” for its AIC. Earlier this year, John Donovan, AT&T’s chief strategy officer of technology and operations, said the telco had already deployed 74 AIC nodes by the end of 2015. Now an AT&T spokesperson has verified to SDxCentral that “we’ll get to 105 AIC zones by the end of 2016, from 74 at the end of 2015."

AT&T uses Juniper’s Contrail Networking to manage its AIC infrastructure. Contrail orchestrates across heterogeneous environments with both physical and virtual elements.

Duell says it’s necessary to glue all these data centers together along with existing network elements, and AT&T engineers think Ethernet VPN (EVPN) may be the best protocol to do that. “EVPN helps glue the old to the new in a clean, coherent way,” he says.

EVPN is an Internet Engineering Task Force (IETF) standard that just got approved in October.

“It’s a tool that has a lot of promise,” says Duell. "We want to surface this to other players to see if they think it has the same promise — just open up conversation.”

“EVPN is a technology that can interconnect clouds; it’s effectively the protocol layer,” says Scott Miles, senior director of cloud marketing with Juniper. “Juniper was part of the early EVPN development of the standard.”

Miles says large providers such as AT&T need to connect different clouds in far-flung geographic locations. “EVPN allows you to stitch together at an overlay level. We can provision this from our switches, or Contrail can orchestrate it.”

On top of this cloud infrastructure, AT&T is already running virtual network functions (VNFs) in live production. These are being deployed and managed with its in-house Enhanced Control, Orchestration, Management & Policy (Ecomp) platform, which was publicly revealed earlier this month.