The convergence of wireless and wireline networks will provide a consistent 5G experience no matter how consumers are connected, delivering on the technology’s many promises – from better and differentiated Quality of Experience (QoE) to advances in the IoT and AI fields. In 2023, fixed and mobile networks are continuing to converge and with operators investing heavily into network upgrades, there is a crucial need for a common, converged core infrastructure. Comprehensive standards are the foundation for the industry to fully capitalize on the benefits offered by 5G Convergence.
Broadband Forum’s Wireless-Wireline Convergence (WWC) Work Area, in a fruitful collaboration with 3GPP, has done the groundwork specifying the connection points between wireline broadband and 5G core networks. Addressing the needs of operators so they could leverage their assets with combined subscriber offerings with a converged core, Broadband Forum’s specifications released with 3GPP Rel.16 have advanced this mission significantly. Good news for the industry is that Broadband Forum continues its specification work in partnership with 3GPP to unlock the full potential of 5G convergence.
More options and value for operators
WWC standards have brought more options and value to integrated, fixed and mobile operators so they can deploy 5G technology confidently. The work has provided the opportunity to make more effective and efficient use of wireless and wireline network assets, while creating the potential for new, improved, and converged services. It allows operators to provide a uniform experience to their customers irrespective of the access or appliance they are using, supported by a common and streamlined back office and control plane.
Building on the foundations of Broadband Forum’s WWC Phase 1, the specifications released by Broadband Forum in Phase 2 have expanded the deployment options, enhanced functionalities, and unlocked more value from the 5G system. Specifically, in 2022, three new specifications were released: TR-456 Issue 2 ‘Access Gateway Function Functional Requirements’, TR-470 Issue 2 ‘5G Wireless Wireline Convergence Architecture’, and TR-124 Issue 7 ‘Functional Requirements for Broadband Residential Gateway Devices’. Together they have provided operators with new 5G deployment options, including 5G hybrid access using wireline and LTE or NR, enhanced service capabilities, and an easier transition from a legacy to the 5G network.
TR-456 Issue 2 ensures that operators have the capacity to multiplex multiple sessions between the 5G-Residental Gateway (5G-RG) and the Access Gateway Function (AGF) on top of the customer VLAN. Multi-session enables the same user to connect to multiple service networks, while previously the user was limited to a single data network. This enables each session to be unique in terms of User Plane Function selection, and operators can place video traffic, business traffic or community Wi-Fi all on their own wireline connection with different policies for each. The specification also expands support for legacy CPE (Residential Gateways that do not have any 5G capability) in the form of multi-session support and expanded legacy authentication models. It also addresses other operational aspects of relevance for production networks such as Maximum Transmission Unit handling, improved Non-Access-Stratum (NAS) transport reliability and Quality of Service enhancements.
The WWC architecture specification TR-470 Issue 2 delivers Hybrid Access with the functionality of Access Traffic Steering, Switching, Splitting (ATSSS), supporting multiple traffic distribution mechanisms and policies. This is for Residential Gateways with dual access: wireline (PON or DSL) side and wireless (5G or LTE). The LTE support is critical as operators can create and manage logical sessions that leverage existing network coverage, and therefore offer services with seamless availability for connectivity.
TR-124 Issue 7 adds Multi-Access support and specifies requirements for the Residential Gateways connected to the 5G System which allow operators to maximize throughput, redundancy, and reliability. This provides the ability to not only run isolated sessions on each access, but to run multiple sessions that use multiple access either as active-standby or simultaneously.
Furthermore, during phase 2, Broadband Forum interacted and collaborated with 3GPP to fine-tune some aspects of WWC in 3GPP Release 16 specifications. As part of the maturing of the specs an open source software reference implementation for 5G-RG was launched, named Broadband Forum’s Open Broadband 5G-RG project (OB-5WWC).
Extending the toolkit for operators while ensuring a smooth evolution path
While Phase 2 was successfully completed with the specifications published in 2022, the WWC Work Area now progresses with Phase 3 specifications addressing value-added services beyond connectivity. These enhancements are for Hybrid Access using the 5G-RG supporting the split of non-IP traffic on multi-access and multipath sessions. Leveraging other features from the 5G Toolkit, this phase of work ties into our ongoing collaboration with 3GPP directed towards its 3GPP Release 18 specification work and delivery.
Phase 3 is also going to deliver key specifications including WT-457 (FMIF Functional Requirements) and WT-458 (Wireless and Wireline Convergence with Control and User Plane Separation. Reference Architecture, Interface, and Protocol Specification), both of which expand the deployment options for 5G WWC. The Work Area is also working on enabling IMS-based Voice support for 5G-RGs, with work on the architecture (WT-493, IMS for 5G-RG Architecture) and a profile for residential voice (WT-494, IMS for 5G-RG Residential Voice Requirements), converging legacy voice services onto the 5G system.
The Broadband Forum is also unlocking the full potential of the 5G-RG as we expand the capabilities of the network to achieve an end-to-end integration with devices located behind 5G-RGs. Phase 3 will better bridge the world between the home and the network, allowing for more advanced service offerings with differentiated QoE end-to-end. This important phase of work has opened up the next chapter of network convergence for players across the broadband ecosystem and highlights the crucial role that standards will continue to play in 2023 and beyond. The industry can leverage innovation and common procedures specified by Broadband Forum that result in enhanced customer experience across available network assets and this specification development ensures a smooth and standardized evolution path.
