Vision of 5G SA core on public cloud fails; replaced by private or hybrid cloud?

For several years, many telecom analysts said it was inevitable that network operators would move telco workloads, especially their 5G SA core network software, into the giant data centers operated by Amazon Web Services (AWS), Google Cloud and Microsoft Azure. For example:

In June 2021, AT&T made an agreement with Microsoft to run its 5G SA core network in the Azure public cloud platform. However, that 5G SA network is still not commercially available!
In July 2023, India’s Tech Mahindra and Microsoft announced they’d collaborate to enable cloud-powered 5G SA core network for telecom operators worldwide. So far we don’t know of any takers?
Dish Network outsourced its entire 5G infrastructure (including 5G SA core network) to run on the AWS public cloud platform which went live in February 2022. See Figure 1. below
In May 2024, O₂ Telefónica in Germany and Nokia announced the deployment of 5G standalone core software on Amazon Web Services (AWS).

Figure 1. DISH 5G Cloud Architecture

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However, the expected big move to telco public cloud did not happen in 2024! “No operators have core applications in the public cloud,” David Hennessy, the chief technology officer of the UK’s Three, told Light Reading earlier this year. 5G networks are spread across the geographies they serve. Hosting all functions in a single place just isn’t possible. Even the core, the domain allowing for the most centralization, is increasingly distributed across multiple facilities at the network “edge.” As a result, network operators are not using public cloud platforms for their 5G SA core or mission critical applications.

T-Mobile-US (the “un carrier”) has deployed its own 5G SA network. Cisco and Nokia are the primary vendors that built T-Mobile’s 5G SA core network. Some European network operators are resistant to use of the public cloud for telco-specific workloads. Those include the UK’s BT, which previously invested time and effort in building its own telco cloud with Canonical, a UK software company. Germany’s Deutsche Telekom has something similar called T-CaaS. Orange also has built a homegrown cloud based 5G SA network. Spain’s Telefónica is still not fully convinced by the other benefits of the public cloud providers. Automation is currently more advanced when both the core network software and infrastructure come from Ericsson than it is when Telefónica takes the core from Nokia and the infrastructure from AWS, according to Cayetano Carbajo, the operator’s director for core networks.

Carbajo is clearly disturbed by the lack of infrastructure standardization in a world of multiple different cloud offerings. Various telcos are working on this through an initiative called Sylva, overseen by the Linux Foundation. The fruit of it should be the ability for Telefónica to move network applications from one cloud to another without having to make big changes. Yet public cloud service providers are not even listed as sponsors on the Sylva website.

The alternative is to keep the 5G core on premises or in a private cloud. The latter might be used by other workloads, but – as the designation implies – it would not be shared with other companies. In general, 5G network operators have distributed their previously centralized workloads around a nationwide network, bringing resources into closer proximity with end-user devices. That results in lower latency as well as other service improvements.

For example, BT hosts its control plane functions at eight UK sites and its user plane software at 16 sites. Replicating this in the traditional public cloud, which relies on a smaller number of giant facilities, would be difficult if not impossible to do. As a result, IBM-owned Red Hat and Broadcom-owned VMware, the best-known cloud-computing players in this area, now propose to bring their software into a telco’s facilities. Microsoft calls it the “hybrid” cloud.

There was a bad omen for public cloud advocates in June when Microsoft revealed it was cutting telecom jobs and abandoning Affirmed Networks and Metaswitch, core network software developers it bought in high-profile deals several years ago. Clearly, Microsoft is retreating from the development of network applications.