AT&T Virtualizes XGS-PON OLTs with VOLTHA 1.0

The virtualization of telecommunications networks offers great rewards but, at the same time, requires massive amounts of research and development. Much of this is new.

Late last week, AT&T took a significant step by providing the Optical Networking Foundation (ONF) with version 1.0 of its Virtual Optical Line Termination Hardware Abstraction (VOLTHA 1.0) specification.

Optical line termination (OLT) devices are the transition points between passive optical networks (PONs) that serve subscribers and the active elements of the carrier network. They also multiplex, or consolidate, data coming from individual subscribers. RCR Wireless’ Martha DeGrasse provides a very clear description of the role of the OLT:

Passive optical networks use fiber optic cables to connect an optical line terminal to dozens of endpoints. The optical line terminal converts electrical signals into optical signals, and splitters are used to distribute those signals to the endpoints. Because the splitters do not require any power, the network is called a passive network.

VOLTHA is the transitioning of these tasks from hardware to software for cloud-based use in XGS-PON, which is a symmetrical (equal capacity in both directions) 10 Gigabit per second (Gbps) passive network.

VOLTHA will be part of a field XGS-PON field trial that AT&T announced in June. The story at SDxCentral on the VOLTHA 1.0 release says that it “supports” the Central Office Re-Architected as a Data Center (CORD) initiative. The idea, which is a central theme of virtualization in general, is to enable generic hardware platforms to support the software where most of the heavy lifting now will be done. The story says that “VOLTHA provides isolation between a vendor agnostic PON management system and vendor-specific PON hardware devices.”

VOLTHA version 1.1 is expected soon and “a more robust” version 2.0 next year, according to SDxCentral.

XGS-PON may take more of the spotlight as time passes because the economics are trending in its direction. In a July story at Light Reading, Eddy Baker, the assistant vice president of Access Architecture and Design at AT&T, told Carol Wilson that the key is that XGS-PON, which can carry business, residential and mobile backhaul function, is declining in costs faster than anticipated and has reached equity with Gigabit PON (GPON).

Virtualization is an extremely complex undertaking. The work that AT&T is doing in its labs, in collaboration with its partners and in bodies such as the ONF is vital. In this case, it is bringing virtualization to a high-capacity passive networking architecture that is designed to enable it to run smoothly with the functionality, applications and services they must support.

Carl Weinschenk covers telecom for IT Business Edge. He writes about wireless technology, disaster recovery/business continuity, cellular services, the Internet of Things, machine-to-machine communications and other emerging technologies and platforms. He also covers net neutrality and related regulatory issues. Weinschenk has written about the phone companies, cable operators and related companies for decades and is senior editor of Broadband Technology Report. He can be reached at cweinsch@optonline.net and via twitter at @DailyMusicBrk.