Fiber
PON Plugfest Helps Move Industry Closer to New Era of Interoperability
Key Points
- Interoperability standards are fundamental to supporting the development of passive optical network technologies in the broadband industry.
- CableLabs, on behalf of the Broadband Forum, hosted a PON Plugfest for OLT, ONU and test equipment vendors to test interoperability and improve their solutions.
In the broadband industry, network operators and vendors are continually working together to advance interoperability and streamline operations — but the puzzle pieces don't always fall into place easily. Passive optical networks (PONs), for example, face the ongoing challenge of achieving interoperability without stifling innovation. PON standards are intentionally written to be flexible and to encourage innovation. When translated to practical implementation, this approach has led to diverse interpretations, creating interoperability challenges.
PON standards establish functional and behavioral requirements that span a network’s operational layers. These standards alone do not guarantee interoperability among vendors. For network operators, lack of interoperability leads to fragmentation and vendor lock-in. This includes bookended deployments, in which optical network units (ONUs) and optical line terminals (OLTs) must be provided by the same vendor. These limitations and challenges drive up operational costs, increase network complexity and extend time to market as operators grapple with compatibility issues.
Early in the evolution of PON, CableLabs’ DOCSIS®️ Provisioning of EPON (DPoE) specifications and certification program represented a significant advancement in addressing these challenges. By implementing rigorous interoperability testing between ONUs and OLTs, DPoE demonstrated that detailed specifications combined with collaborative industry efforts can achieve multi-vendor PON equipment compatibility. This success provided valuable insights for advancing interoperability across the broader PON ecosystem.
But DPoE's scope was focused on PON based on IEEE standards, so it did not address the interoperability challenges present in PON based on ITU-T standards. This is particularly evident in the deployment of XGS-PON, which is becoming the predominant ITU-T-based PON technology worldwide. As the industry moves toward newer technologies like 25GS-PON and 50G-PON, establishing robust interoperability standards becomes increasingly critical.
BBF has made significant strides in advancing PON interoperability through its comprehensive testing framework. By developing detailed test plans and guidelines, the organization addresses the implementation gaps in ITU-T PON standards. Its cornerstone documents — TR-255 “GPON Interoperability Test Plan,” TR-309 “PON TC Layer Interoperability Test Plan” and TP-247 “G-PON & XG-PON & XGS-PON ONU Conformance Test Plan” — establish rigorous testing protocols for various network scenarios, from traffic management to fault handling.
Advancing Interoperability Together
CableLabs recently hosted a PON Plugfest interoperability event on behalf of the Broadband Forum (BBF). CableLabs, a member of the Broadband Forum, provides the technologies, experts and tools to advance ideas from research to real-world deployment. CableLabs is well equipped to offer testing services for hybrid fiber coax (HFC), fiber to the premises (FTTP) and mobile network equipment — making our state-of-the-art facilities ideal for interoperability testing and an event like this.
This event provided a neutral environment in which vendors could work collaboratively to test their products for interoperability — for both XGS-PON and 25GS-PON implementations — according to test plans created by the Broadband Forum.
Collaborate With Us
It is essential for industry partners like CableLabs and BBF to work together to chart the next phase of specification development and drive interoperability standards for OLTs and ONUs. We invite our members and the vendor community to join us in CableLabs’ Interop·Labs events and in other opportunities for collaboration, such as our working groups, to gain valuable insights into key industry technologies and interoperability challenges and opportunities.