Bridging the GPON Gap

After showering some technology love on EPON in recent years, CableLabs has since begun to apply some affection toward GPON, another fiber-to-thepremises standard that has also begun to take a limited hold in the cable industry.

Essentially looking to replicate the work that’s well underway with Ether net passive optical networks (EPON), CableLabs confirmed that it has sparked a new interoperability initiative that will enable cable operators to use DOCSIS-style provisioning on fiber-fed Gigabit passive optical networks (GPON).

Those specs, to be called DOCSIS Provisioning of GPON, or DPoG, are currently in the draft and review phase, CableLabs said, noting that it anticipates releasing the first public version of the DPoG specs later this year.

Much of that effort is expected to capitalize on the work CableLabs has completed with the current DOCSIS Provisioning of EPON (DPoE) specifications, which have already produced a set of interoperable products from multiple vendors (see table).

As a chief operational benefit, the new specs enable operators to purchase interoperable gear from multiple sources and reuse their DOCSIS provisioning and back-office systems for fiber-to-the-premises deployments.

Cable operators have been using both EPON and GPON technologies on a limited basis, generally relegating that activity to greenfield residential network buildouts and fiber-based services tailored for business customers.

CableLabs’ recent work around GPON came to light on July 8, when Calix said its Open Link Cable system, already in use by Grande Communications, is designed to align with the emerging DPoG specs and is “based on concepts” introduced by the current DPoE platform.

The CableLabs focus on both GPON and EPON appears to dovetail with a larger effort focused on FTTP technology.

CableLabs is also seeking to bring unity to the PON standards governed by the Institute of Electrical and Electronics Engineers (IEEE) and the International Telecommunications Union (ITU). That CableLabs initiative, called “OnePON,” aims to bridge some of the technical differences separating EPON and GPON as the standards bodies move ahead on new generations of those platforms.