AT&T’s 10-gigabit symmetric passive optical network technology (XGS-PON) plans are set to receive some open source brains.

The carrier today released the first version of its Virtual Optical Line Termination Hardware Abstraction (VOLTHA) software into the Open Networking Foundation (ONF). The platform provides a software framework – or “brain” – behind the XGS-PON access network in the cloud.

The VOLTHA software supports the Central Office Re-Architected as a Data Center (CORD) Project plans for multi-vendor, multi-domain service support. VOLTHA provides isolation between a vendor agnostic PON management system and vendor-specific PON hardware devices.

“This software allows us to take white and gray boxes from multiple vendors,” explained Eddy Barker, assistant vice president for technology design and architecture at AT&T. “We have been doing lab evaluations now with four vendors, with their implementation of ONOS and VOLTHA controlling seven different white boxes. The plan is to pick two of them as part of our trial plans this year.”

XGS-PON technology is a fixed wavelength symmetrical 10 Gb/s platform. Compared with traditional gigabit PON (GPON), Barker said, XGS-PON provides up to four-times greater downlink bandwidth and up to eight-times greater uplink bandwidth capacity.

AT&T in June released initial plans for XGS-PON trials later this year. Those trials are part of the carrier’s plans to virtualize access functions within the last-mile network. Barker said the trials will take place in Dallas and Atlanta.

Testing is expected to show support for multi-gigabit per second Internet speeds and allow for merging of services onto a single network. Services to be supported include broadband, and backhaul of wired and 5G wireless services.

AT&T has been working on the VOLTHA project for 18 months, though the initial efforts started off slowly.

“When we first started, it was like any open source project in that it was slow to start,” Barker said. “Part of the process is to recruit service providers, vendors, suppliers, OEMs, and ODMs to join.”

Those efforts eventually landed more than a dozen partners, including ONF and German telecom giant Deutsche Telekom.

Barker said some legacy access vendors were initially hesitant on the plans as they were concerned over the impact on their business models. However, the ongoing push toward greater software-defined network (SDN) control by operators is tipping the scale.

“They have seen the push from AT&T and other international carriers that we are heading in this direction and asking these vendors what they can do to participate,” Barker said. “We convinced them there were still opportunities for integration, hardening, and scaling of these systems into the network. There is still an opportunity to monetize these efforts. It might be different from what they have done in the past, but that’s been something suppliers have been coming around to.”

Details on the companies involved in the efforts are expected to be announced over the coming weeks. “I don’t want to steal any of their thunder,” Barker said.

Barker said the carrier will quickly follow up the initial 1.0 release with a 1.1 version that will include support for Broadcom chipsets. This is expected to allow for increased interaction with white boxes.

That update will be followed next year with a more robust 2.0 update, which is expected to include broader support for AT&T’s other technology initiatives like G.Fast, all versions of PON, and some 5G mobile backhaul.

“The plan is to have all of these operating in some form under the same overarching SDN control,” Barker said. “We might have similar technology using different vendors, but under the hood they are all using ONOS or VOLTHA. Service providers can then substitute not just the hardware platform, but since it’s all open source they will be able to replace the middleware and microservices.”

Barker said the 2.0 update will see VOLTHA exchange its name for something easier to pronounce, hinting at something like “vanilla.”