Breaking down barriers between network operators and ONU vendors with vOMCI

Breaking down barriers between network operators and ONU vendors with vOMCI

By Lincoln Lavoie, Technical Chair at Broadband Forum

As the migration towards disaggregation of Access Nodes, specifically Optical Line Terminal (OLT) devices, continues to gather pace, operators are on the lookout for new ways to achieve greater flexibility and interoperability. That is why Broadband Forum recently published TR-451 ‘vOMCI Specification’ and MR-451 ‘ONU Management using Virtualized OMCI’, which is a new specification that enables operators to de-couple the Optical Network Unit (ONU) and OLT, and the OMCI software stack.

An ONU is the end-user device or piece of equipment for Fiber-To-The-Premises (FTTP) deployments that converts an optical fiber signal into a more conventional electrical signal that customers’ routers understand. An OLT is the operator’s equipment that connects with the ONUs to build out a network. It connects into the operator’s core network and helps to manage the end-user connections as part of the wider Passive Optical Network (PON). The OLT manages the configuration of the ONU via OMCI, where the OMCI software stack was historically embedded within the OLT. The new TR-451 ‘vOMCI Specification’ defines how one or more OMCI stacks can be operated outside of the OLT’s software, potentially hosted in cloud infrastructure.

These latest documents have armed operators with more choice in how they can create, activate and maintain services associated with ONUs.

Vendor lock-in avoided

Operators may opt to partner with the same vendor for both the ONU and OLT packages for convenience and to ensure no compatibility problems. However, Virtualized ONU Management (vOMCI) can lead to increased flexibility for PON deployments and decrease time to market for multi-vendor ONU interoperability. The new standard de-couples the ONU, OLT, and OMCI stacks, avoiding OLT vendor lock-in and the management cycle of optical modems being tied to a specific vendor’s OLT or their software release cycles. This encourages competition between vendors with operators having increased freedom to choose from other ONU vendors and introduce more end-user devices into their network.

Operators can choose a best of breed solution for the OLT, OMCI stack(s), and the ONU devices. In some cases, those might be provided by one vendor, or in another case, the OMCI stack could be provided by the OLT vendor, or even a third party. vOMCI also allows for multiple OMCI stacks to be in use by a single OLT.

When previously, the management cycle of the ONU was tied to a specific vendor’s OLT, now operators are afforded more choice. TR-451 increases the number of potential ONU vendors, allowing operators to better negotiate the best prices for ONUs.

Complementing existing offerings

The latest specification can be used in the evolution of the management of ONUs, not as a replacement for the management processes and data models already in use by operators but to complement their existing offerings. Operators can future-proof their infrastructure while maintaining their investment in existing ONU device catalogs.

The specification enables easier interoperability testing and on-boarding of ONUs within an operator’s ecosystem and cloud-based network. It supports various deployment models where virtualized functions can be deployed to the cloud or within existing management system solutions.

vOMCI brings tangible benefits

The OMCI functionality that is traditionally embedded within OLT network elements has been moved into an operator’s network. vOMCI has been introduced as a solution to centralize operations without relying on each OLT to act as a management entity. This means operators’ OLT vendors no longer need to be intimately involved in the roll-out of the management services and features provided by the ONU. Ultimately, ONU management will be more adaptive to changes in operators’ business processes and services, and less costly to maintain.

The vOMCI stack will be hosted in cloud infrastructure, continuing the efforts to disaggregate the Access Node. The recent specification work provides operators with a migration path from one of their largest network investments, existing Access Nodes such as OLTs and Multi-Service Access Nodes (MSANs) to a new disaggregated software-driven model approach. This approach enables clear separation of the control and management planes, decoupling the hardware and centralizing the software investment inside a CloudCO architecture.

By extending the flexibility to the OMCI stack, increased and easier interoperability between the OLT (including the vOMCI stack) and ONU devices is anticipated. Notably, operators can now reduce the time, cost and complexity associated with onboarding new ONU vendors, roll-out future upgrades and services quickly, and seamlessly evolve their networks by applying new innovations and flexibility.

Download the latest documents here: TR-451 and MR-451.