BT 'on track' to dump Huawei core but still not sold on cloud RAN

"Burning platform" was how Stephen Elop famously described Nokia when he was CEO in 2011 and Apple had just sailed past it in the smartphone sector. The same expression is today used by Mark Henry, the director of network and spectrum strategy for BT, to describe the Huawei core inherited by the UK telco with its 2016 purchase of EE. Under government orders, BT has just two months left to evacuate that platform and watch it go up in flames. "We are on track, but there are challenges," Henry told Light Reading at last week's Network X show in Paris.

BT should have been off the platform in January but was given an extension that recognized the difficulty of the task. Internal company rules already prohibited the use of the controversial Chinese vendor in the core, which meant BT knew Huawei would have to be removed even before it bought EE. If it meets the latest government deadline, it will have had a Huawei core for about eight years.

The figures make it sound as if BT still has a long way to go, too. "We have migrated millions of customers and over 50% of traffic," said Henry. One issue is the need to maintain parallel cores while systems and customers are transferred. The burning Huawei platform still supports 4G services and "non-standalone" 5G, where a new radio technology is tied to an old 4G core. Alongside that is a more recently introduced Ericsson core designed to handle older services plus "standalone" 5G, the version that severs the 4G tow rope.

This maintenance job means Henry and his team must currently test applications on multiple platforms. "That is a big burden of entirely duplicated effort," he said. If the radio access network (RAN) is included in the mix, BT is today working across three different vendor platforms, according to Henry, given the role Finland's Nokia plays in that RAN domain. BT has until the end of 2027 to remove Huawei from its RAN, but UK rules mean it can no longer buy Huawei's 4G products as replacement parts.

Yet Henry anticipates benefits once the Huawei platform has finally burned and BT is solely reliant on the converged Ericsson core. Unlike the "virtualized" 4G core, the Ericsson one is designed to be "cloud-native." Based on whizzy Internet technologies like containers and Kubernetes, the software it uses is supposed to be less monolithic. This should give BT more freedom and speed when it is deploying new applications. It should also produce savings. "You get elastic scaling for these different software applications and then there is a time-based efficiency," said Henry.

Across various locations in the UK, BT is now testing the software functions it will eventually use with 5G standalone technology. Described as "dual-mode," the same Ericsson core essentially caters to both older 4G and newer 5G systems. This means a single set of software would include the user plane function, a feature of 5G networks, as well as packet gateway technology used in 4G, explains Henry.

Growing pains

What marks BT apart from certain other telcos is its determination to build and operate the network cloud that hosts this converged Ericsson core as well as other telco workloads. Big vendors have previously sold core technology in a package with their own cloud platforms, but those platforms are sometimes good for nothing else. To host other workloads, an operator would need additional platforms. Ultimately, it could be left with numerous vertical cloud silos instead of a single horizontal layer for the whole estate.

Nokia recognized this problem several months ago, deciding to jettison work on its core-hosting platforms and pick Red Hat as its primary cloud partner. It is even transferring 350 employees to Red Hat as part of its arrangement with the IBM subsidiary. While Ericsson has not similarly abandoned its own equivalent cloud-native infrastructure solution (CNIS), BT appears to have little interest in this. Nor has the telco sounded keen on going with Red Hat, VMware or a hyperscaler solution instead.

"We have enough scale to build our own multitenant platform and we need the skills and capabilities to build and operate that inside BT," said Henry. "We want it to be multitenant and in the core we are definitely taking on the responsibility to be a systems integrator. Does it make it more complicated? There are some growing pains, but our core competency is building networks and to unlock the benefits of cloud in telco we have to take on that responsibility and not be paying someone else to do it."

BT is, accordingly, putting the Ericsson core on a network cloud built with the support of Canonical, a privately owned UK software company with headquarters on the Isle of Man. While the division of work responsibilities between BT and Canonical is unclear, the operator clearly prizes control and a degree of technology independence.

"If we do optimization to make things more efficient, the value should go to us," said Henry. "We're always trying to reduce our cost base and if we just buy it as a service then optimization benefits flow to someone else."

The benefits will accrue partly from hosting software written by numerous vendors on this single BT network cloud – what Henry calls "multitenancy." Today, it supports the mobile core, domain name system (which translates Internet domain names into IP addresses) and a couple of other systems that Henry says are "not that big." In time, however, some virtualized "islands" on VMware technology will also be transferred to it, he says. And BT is weighing the future deployment of a cloud RAN on this platform, as well.

Cloud RAN concern

A BT decision about that technology will not be due until 2027, but Henry remains unconvinced. One issue is the need for hardware acceleration at Layer 1, a demanding part of the RAN software stack. Others have argued the more customized silicon used in some accelerators is incompatible with cloudification. And Henry says BT might simply choose to leave its Layer 1 software outside the cloud. "We can still do acceleration in the exchanges but cloudify the other functions," he said.

Disappointingly, he has not seen a vendor solution that would allow BT to pool hardware acceleration and divert network resources from one area to another. But cutting Layer 1 out of cloud RAN might further diminish the attractions of the technology, and those are not obvious to the BT exec.

"I have said to vendors we are not doing cloud RAN unless we get multitenancy benefits and scaling," said Henry. "If it is just putting baseband in a building, we've already paid for infrastructure and cabinets and still have to upgrade the infrastructure and cabinets to do it."

Like some other telcos, Henry also harbors concern about the suitability of Intel and its x86 general-purpose processors in telco operations. Intel's technology currently accounts for nearly all cloud RAN deployments, with x86 dominant in the bigger market for server chips. But several companies, including AWS and Oracle-backed Ampere Computing, are now developing processors based on the architecture of Arm, a UK-headquartered chip designer.

"I am very interested in the energy performance of those different solutions and if I look at the traditional RAN and look inside the box there is a lot of Arm in there for a reason – it is more energy efficient," said Henry. "I think that is a problem for Intel, and I know they are working on it, but we would be driven by the more energy-efficient solution."

Henry's life should at least become a little easier once the Huawei core is gone. Recent reports about service disruption at Sky, blamed partly on the move off Huawei, hold out the prospect of another government extension. But ditching the Huawei core is clearly in BT's long-term business interests. If the original deadline is met, the impact may soon start to show.