AT&T and the Open Networking Foundation (ONF) are looking to integrate ONF’s efforts behind passive optical networks (PON) and the open source – and AT&T-initiated – Open Networking Automation Platform (ONAP).

Consider this the ultimate acronym mash-up.

The actual work will integrate Virtual Optical Line Termination Hardware Abstraction (VOLTHA) software with ONAP. VOLTHA provides a software framework – or “brain” – behind AT&T’s 10-gigabit symmetric passive optical network technology (XGS-PON) access network in the cloud. It also allows AT&T to take white and gray boxes from multiple vendors.

The integration work builds on AT&T’s ongoing XGS-PON field trials. XGS-PON is designed to provide up to four-times greater downlink bandwidth and up to eight-times greater uplink bandwidth capacity compared with gigabit-PON (GPON).

Tom Anschutz, distinguished member of AT&T’s technical staff, said the integration work will "allow greater automation of the existing field trials, and support expanding them."

"We expect to integrate in an agile method, with more capabilities added over several months," Anschutz said.

AT&T has been working on VOLTHA since early 2016. The carrier eventually managed to attract interest from more than a dozen partners, including German telecom giant Deutsche Telekom. VOLTHA was migrated into the ONF last October.

Timon Sloane, VP of marketing with the ONF, explained that combining VOLTHA and ONAP allows PON devices to be software-defined networking (SDN) programmable and plugged into a Central Office Re-architected as a Data Center (CORD) framework.

“This makes a PON device look like an OpenFlow switch,” Sloane said. “It’s a natural extension of the CORD work and allows operators to bring in PON from multiple vendors.”

Anschutz added that the work will broaden the application of ONAP to access networks and make ONAP more appealing to carriers who "support access networks and want a common large scale automation system."

The latest partnership with ONF also builds on AT&T’s previous GPON and CORD work. GPON is part of AT&T’s network backhaul strategy, while CORD is about re-architecting network operations at the edge.

For PON, Anschutz explained ONF's work has helped create a driver stack that can hide differences in access types and silicon providers of the access technology.

"This will improve AT&T’s agility in supporting additional technologies and suppliers, and break the classic access vendor lock-in achieved through the complex integration of their EMS (element management systems) systems into classic OSS and BSS," Anschutz said.

AT&T has been a long-time supporter of the CORD project and views it as central to its 5G efforts. VOLTHA also supports CORD and provides isolation between a vendor-agnostic PON management system and vendor-specific PON hardware devices.

ONAP is the open source version of ECOMP that was merged with Open-O inside the Linux Foundation last year. ONAP is being used by carriers to help automate control over network operations. Carriers using the platform include AT&T, Bell Canada, and Verizon.

Sloane linked the two by stating ONAP acts as an orchestrator that operators can use to tell CORD to turn on 5G services and then support those services at the edge.

AT&T recently announced it had completed XGS-PON tests in Atlanta and Dallas, both of which are headquarter locations for AT&T. The trials used a virtualized broadband network gateway (vBNG) to manage subscribers testing multi-gigabit internet traffic of AT&T’s DirectTV Now video service.

At the end of the trial, Eddy Barker, assistant vice president for access architecture and design at AT&T, noted the carrier had replaced VOLTHA with a new platform dubbed Open Source Access Manager Hardware Abstraction (OSAM-HA). OSAM is a vendor agnostic platform for managing broadband access network elements and services. It’s separate from vendor-specific access EMS.

Barker said OSAM-HA allowed for abstraction of the virtual network functions (VNFs). It also acts as an interface between the abstracted infrastructure at the lower level and ONAP that AT&T uses higher in the stack.

“It’s a pipeline between orchestration and ONAP down into these software-defined access functions,” Barker explained. “We sort of have an end-to-end control plane that goes between ONAP and the access portion of the network.”

Barker noted that due to the interlinking, the carrier could avoid duplicating actions at different operational layers.

“I don’t have to go and control or spin up VNFs down in the access control mechanism,” Barker said. “I can go up and can interlink up with ONAP, have it spin up the VNFs, have it turn up vLANs (virtual location area networks) to establish end-to-end infrastructure or provision Layer 3 gateways.”

Barker explained that the carrier’s VOLTHA efforts were being pushed into OSAM-HA. He added that the name change is requiring some work within ONF to include the latest updates into the open source community workflow.

"VOLTHA or equivalent hardware abstractions will all integrate with ONAP using the same OSAM software," Anschutz said of the latest partnership.