Verizon has reached another milestone on its path toward selecting its source or sources of NG-PON2 optical line terminals (OLTs). The service provider says it has successfully demonstrated interoperability between the OLTs of its two RFP finalists, ADTRAN and an Ericsson/Calix team (see "Verizon narrows NG-PON2 choices to Ericsson/Calix and ADTRAN"). The competing OLTs showed interoperability with a pair of reference design optical network terminals (ONTs) as well as with each other.
Ensuring interoperability among potentially multi-sourced OLTs at first deployment represents one of Verizon's key goals of the NG-PON2 program, according to Dr. Denis Khotimsky, Distinguished Member of the Technical Staff and Verizon's lead engineer for the trial. Full interoperability would provide maximum flexibility in rolling out NG-PON2, Dr. Khotimsky pointed out. Interoperability would enable the service provider to more easily roll out new capabilities, support ONTs from multiple vendors, and replace one vendor's OLT with another's if problems arose.
In the trial, conducted at the Verizon Labs facility in Waltham, MA, the OLTs worked with a pair of ONTs – reference designs from chipmakers Broadcom and Cortina Access. The reference ONTs included tunable transceivers, which implies development of this key technology piece has shown progress (see "ADTRAN describes NG-PON2 tunable ONT transceivers (sort of)"). The transceivers in this interop showed the tuning time Verizon seeks, Dr. Khotimsky said.
The test plan followed Verizon's Open OMCI specifications that define the OLT-to-ONT interface. Verizon plans to release the specifications "in the next few months," according to the press release that announced the trial.
Dr. Khotimsky reported that the trial also demonstrated interoperability at a number of layers, from PMD to upper management. The trial also demonstrated interoperability between the competing OLTs. Both systems performed equally well, he said.
NG-PON2 evaluation progresses
Both ADTRAN and the Ericsson/Calix team have offered pizza box style platforms that leverage software-defined networking (SDN) capabilities to promote rapid service creation and interoperability (see "Ericsson/Calix, ADTRAN prep for Verizon NG-PON2 finals" and "Calix unveils Verizon NG-PON2 platform, the AXOS E9-2 Intelligent Edge System"). Verizon's evaluators are pleased with what they've seen from the two OLTs so far, Dr. Khotimsky said. While challenges have arisen with both systems, finding shortcomings and fixing them are part of the evaluation process, he explained.
As far as when Verizon will decide whether to go with one vendor or both, Dr. Khotimsky would only report that the choice has not yet been made. Verizon will move forward when it is satisfied that NG-PON2 technology is sufficiently mature and cost-effective and that market demands require it, he added.
He also declined to describe additional milestones or demonstrations that might need to occur during the evaluation process.
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