Verizon has completed NG-PON2 interoperability with five vendors for its OpenOMCI (ONT Management and Control Interface) specification, bringing it one step closer toward achieving interoperable PON network systems.
After conducting an initial NG-PON2 trial in December 2016, the telco plans to offer OpenOMCI specifications, which define the optical line terminal (OLT)-to-optical network terminal (ONT) interface, to the larger telecom industry.
Besides ONT management and provisioning, the trial focused on transmission convergence layer features that allow support of not only business and residential traffic but also wireless transport services. These features are unique to NG-PON2 compared to GPON and BPON systems.
OpenOMCI is aligned with the ITU-T Recommendation G.989.3.
Verizon, along with ADTRAN, Broadcom, Cortina Access, Ericsson/Calix and Intel, worked together to develop the OpenOMCI specification that led to what the telco said was a successful trial at its Technology Center in Waltham, Massachusetts, in May.
Vincent O’Byrne, Ph.D., director of technology at Verizon, told FierceTelecom that the OpenOMCI specification will help to ensure they can deploy an array of OLTs and ONTs in its network.
“Since October 2016 we have been working with the vendors on enabling interoperability to mix and match one vendor’s OLT with another vendor’s ONTs, which is an object we have had since we started deploying BPON in 2004,” O’Byrne said. “We have been working with these vendors and have developed OpenOMCI communications between the OLT and the ONT and how that issue is handled for NG-PON2.”
Driving openness, stability
By creating tools to craft a multiwavelength PON system, Verizon said its OpenOMCI specification will achieve a few key benefits: optimize the number of managed entities and methods that can be used to implement a particular service function while disallowing vendor-proprietary objects and features that have proven to be a major obstacle for PON interoperability efforts.
O’Byrne said that it would be able to more effectively choose various PON vendors to satisfy specific network needs.
“This defines specifications that ensure a vendor has no proprietary managed entities (MEs),” O’Byrne said. “A vendor who is compliant with this has to support various MEs if they are supporting services like data or voice.”
Having delivered PON-based FTTH systems for over 10 years, Verizon said the OpenOMCI also includes specific managed entities that can improve PON system stability.
Verizon has support for developing the specification not only from two of its key platform vendors, Adtran and Calix/Ericsson, but also from a number of silicon vendors, including Cortina, Broadcom and Intel. Specifically, Verizon will be able to continue with a deployment if a vendor’s product is discontinued, for example.
“We have cases before where one vendor’s platform has gone end of life,” O’Byrne said. “This allows us, if something goes wrong with one vendor, … to continue to a deployment of NG-PON2 irrespective of whatever the issue the vendor is having.”
Specifically, if Verizon deployed an OLT and there’s a delay in ONTs or one vendor goes end of life, the telco can optimize the use of the outside plant because it would have one fiber and one splitter. As a result, Verizon would be able to achieve efficiencies by deploying one type of OLT. It also means that it can be flexible with the vendors it works with in cases where a vendor does not support POTS services, for example.
“If we have specialized ONTs we have to deploy such as DS-1 or others that need to support a certain number of POTS lines, we could go to one vendor and get their ONT and they have sufficient volume and deploy it on the OLT of both vendors,” O’Byrne said. “You don’t keep on splitting the volume associated with an ONT type so it allows development at volume, and it should make it easier to establish business cases for the OLT and the ONT vendors.”
Additionally, OpenOMCI can support Verizon if it decided to develop its own type of ONT.
Similar to what Verizon has done on GPON, O’Byrne said that “it allows us to deploy that ONT against both of these vendor’s OLTs so it increases the flexibility and reducing the risk of anything happening from a vendor’s performance.”
Provider interest growing
Verizon-led NG-PON2 interoperability effort is important not only for Verizon but also to drive industry-wide acceptance of NG-PON2 technology. The effort is based on lessons learned over the last 13 years of PON deployment.
Interest in the OpenOMCI specification is strong with a number of Tier-1 providers, including Deutsche Telekom, SK Telecom and Vodafone, participating in the trial as virtual observers. This enabled these providers to get access to the specification, test plans and readouts. After successfully completing the trial, Verizon shared its OpenOMCI specification with the industry for possible inclusion within the appropriate standards bodies.
“Our intent is not to have a proprietary standard for Verizon,” O’Byrne said. “Part of what we did is we shared it with these operators and shared it within the standards community and offer it as one path forward.”
O’Byrne added that the service provider wants to show other service providers how to solve a specific problem of interoperability between OLTs and ONTs.
“Standards will typically define a lot of options, so in theory you could have an infinite number of permutations of all the options so we defined it as a series of options that Verizon will go forward with and making that open to other operators and chip vendors,” O’Byrne said. “They could make the choice to use that because it solves a particular problem one way, but it’s giving people a solution to a problem if they want to ensure interoperability for NG-PON2.”