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BT moves to converged networks, but no date for cloud-native core yet

While operators score quick points by deploying 5G base stations alongside their existing 4G cores, the really tough migration challenges will come when they move to a full 5G Standalone solution, with a cloud-native 5G core. For many fixed/mobile operators, this will also be the trigger to start implementing a converged core to improve flexibility and resource efficiency across all their networks, but that will add another layer of complexity to the migration effort. But others will put the convergence elements in place first, including the cloud infrastructure, and then deploy a single cloud-native core on top.

This is the approach taken by UK incumbent BT, which has turned to Juniper to help deliver its Network Cloud infrastructure plan to enable converged services that can combine 4G, 5G, WiFi and fixed lines. On the mobile side, its MNO arm, EE, is already deploying some virtualized elements of the core in readiness for 5G, and that activity may be accelerated by the migration away from Huawei equipment in the mobile core, in line with BT corporate policy (though the operator is a major proponent of Huawei in its 5G RAN trials). But there is no firm timescale for a cloud-native 5G and converged core as yet, and for now BT’s immediate goal is to implement flexible, virtualized network infrastructure that can support different lines of business and applications, current and future, from one platform.

It has already deployed a common platform for all its fixed broadband technologies, but now needs to add its wireless connections too. This will involve the integration of its substantial WiFi investments as well as EE’s cellular networks.

Using Juniper’s platform, BT will be able to create converged services as well as combining a range of currently separate network functions and sharing them across the organization worldwide. The common services will span voice, mobile core and RAN, global services, as well as BT’s ISP, TV and IT services, and many internal functions.

BT has been moving towards converged services with its BT Plus bundles and various options to combine WiFi with mobile or fixed broadband, or use cellular small cells as back-up when wireline connections fail. However, an automated, programmable network will allow far more radical ways of harnessing the combined networks, allowing BT to integrate partners in a simple, uniform way and adjust the platform in software to support new services.

BT’s chief architect, Neil McRae, said the processing of choosing a supplier prioritized a solution that would enable BT to “hit the ground running”, and that “being able to integrate seamlessly with other partners and solutions, and aligning with our roadmap to an automated and programmable network” were also key criteria.

The telco will also use other Juniper offerings to help build out the network, including

dynamic end-to-end networking policy and control; AppFormix for cloud operations management; and the QFX Series for a flexible spine and leaf underlay fabric. It has previously said it hopes to have its fully converged network in wide-scale commercial usage by 2022.

Juniper CTO Bikash Koley was effusive about his customer, saying BT was “leveraging the ‘beach-front property’ it has in central offices around the globe, to optimize the business value that 5G’s bandwidth and connectivity brings”.

While BT has revealed few details about its 5G core yet, it has said that it has drawn up blueprints for the sort of core it would require to support the next generation of 5G standards, Release 16, including enablement of network slicing, in which BT has been a significant triallist. The telco has kicked off its procurement process for the 5G core, which will be fully cloud-native (decomposing the core into microservices, specifically designed for the cloud, rather than reworking conventional functions to run in virtual machines).

Dave Salam, EE director of mobility and analytics, told LightReading earlier this year that timing is all when it comes to the emerging cloud-native core technologies. “AT&T has done this quite early but I’m not sure anyone has saved money out of that approach,” he said. “We chose to delay for Release 16 to get the right functionality and maturity and have the technology in the right way to stitch elements together.”

His aim is to make greater use of open source tools like Kubernetes to make its cloud even more open and programmable than its existing platform, which relies on first generation virtualized technology (from VMware), rather than cloud-native elements like containers, and builds on OpenStack (which BT has pushed heavily for open cloud infrastructure, but has also acknowledged it has cost a significant amount to customize to get it to full carrier-grade functionality).

The cloud-native core will help BT to deploy new network functions quickly, and anywhere in the network, depending on the requirement at any one time, which is an important step to slicing. However, the telco is clear that many new services will not run on 5G alone, but will need additional investments in elements such as edge computing nodes – of which BT would need about 1,000 to cover the UK, it says. The operator is now trialing mobile edge technology and use cases with Nokia and Mavenir but has not identified strong business models yet.

Some operators are moving more quickly towards choosing their cloud-native 5G core platform and suppliers. Middle Eastern MNO Ooredoo Qatar recently selected Nokia to build a 5G cloud-native core to support the enhanced services it is planning when 5G goes live, initially in capital Doha this year, in which drones feature heavily. Like several other Gulf countries, Qatar is very interested in autonomous aerial taxis and Ooredoo has trialled a 5G-connected drone which can transport two people at 130 kilometers an hour for up to 20 minutes.

Nokia will deploy its cloud-based architecture in Ooredoo’s data centers alongside the operator’s existing core, rolling out Nokia AirFrame, CloudBand, NetAct and a software-defined network from the Nuage Networks subsidiary. The main virtual network functions to be deployed on the cloud are Mobile Core for Voice, Cloud Packet Core, Subscriber Management Registers and Policy Control.

The operator’s COO, Yousuf Abdulla Al Kubaisi, commented: “The modernization of our core network will enhance our capabilities to innovate with new services. It will also help us to meet additional demands for high speed data services in general as well as bursts in demand, particularly in upcoming mega sporting events [Qatar is hosting the next soccer World Cup]. Our 5G network will open the floodgates for machine learning, automation and microservices use cases for consumer and business customers in the country.”

AirFrame is Nokia’s data center solution which underpins a scalable and distributed cloud-based architecture, with support for open specifications like Facebook’s Open Compute Project. CloudBand supports management of virtual infrastructure and of the  lifecycles of VNFs. NetAct provides a consolidated view of multi-domain, multi-technology networks. And the Nuage SDN enables data center network automation.

A smaller provider of cloud-native cores is Affirmed Networks, which recently announced UnityCloud, for 5G Standalone (SA) roll-outs. The architecture enables MNOs to bring multiple generations of wireless technology into a single network, and microservices allow them to deploy niche or unproven services quickly and at low cost, to reduce the risk and drive a wider variety of services.

Scott Heinlein, senior director of marketing, said in an interview: “When you think about virtualization and what’s been done, so far it’s helped a lot around the capex side. It’s helped mobile operators scale their networks so that they’re able to absorb the increase in bandwidth.” But that has done little to reduce opex or support services agility, which will be the next goals, and cloud-native can help by driving automation and flexibility into the network.

Affirmed Networks released a 5G mobile core for the Non-Standalone (NSA) technology last year – NSA can work with the 4G core, but some MNOs want to migrate to a virtualized 5G core while still in NSA mode in the RAN. However, many of the full benefits of future 5G releases, like slicing, will depend on full SA implementation.

The vendor says it is in multiple trials with unnamed operators. UnityCloud can be deployed on-premise or in public, private or hybrid cloud environments.

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