O2 Telefónica, Ericsson renew core network partnership

Believing it is now ready for the next step in commercialising differentiated connectivity to launch advanced 5G standalone (SA) network slicing services relying on assured quality of service, rather than a “best effort” connection, and offer network programmability through exposure of network application programming interfaces (APIs), O2 Telefónica in Germany has signed an extension to its core network partnership with Ericsson to launch the next stage in its drive to capture 5G value in the country.

Ericsson’s dual-mode 5G Core and cloud infrastructure offerings already support mobile connectivity for O2 Telefónica’s 45 million 5G SA, 5G non-standalone, 4G and 2G subscribers. The companies said that going forward, they will continue innovating and building functionality in the core network to further future-proof the network. This ambition is said to be seen most clearly with what is claimed to be the implementation of the world’s first in-service software upgrade in the containerised dual-mode 5G core user plane.

“We always want to offer our customers an outstanding network experience by delivering the full value of cloud-native and 5G standalone to them,” said O2 Telefónica chief technology and information officer Mallik Rao. “The core network is the heartbeat for this. With Ericsson, we have embarked on a cloud-native transformation journey, and are now going to develop it further by expanding our portfolio and capabilities towards network slicing, automation, and API access.

The deal is also said to underscore O2 Telefónica’s plans to build on the capabilities delivered through its recent cloud-native transformation with Ericsson, which modernised its packet core network to be running on Ericsson cloud infrastructure, facilitated the roll-out of 5G SA and enhanced its infrastructure so it can evolve at scale.

The collaboration covers Ericsson’s dual-mode 5G core, cloud-native infrastructure (bare metal containers-as-a-service infrastructure), network functions virtualisation infrastructure offerings and associated capabilities to deliver advanced 5G core automation and orchestration to allow O2 Telefónica to take advantage of the benefits of its cloud-native ecosystem.

Using Ericsson’s full-stack core network – including applications, infrastructure and automation tools – the partners completed in May 2025 what is claimed to be a world-first in-service software upgrade (ISSU) of network functions in the core network’s user plane in O2 Telefónica’s production network under load, at scale and without service disruption. A feature of cloud-native architecture, ISSU is designed to give high-performance mobile networks the ability to upgrade software without any service downtime.

ISSU is also intended to increase the automation level of the network and greatly reduces the need for manual interventions. Delivered through a continuous integration and continuous delivery pipeline, this improves flexibility and time to market for new services introduction and enhances operational efficiency.

The result is that customers can benefit from an improved network that is always provided with the latest updates in terms of mobile offerings and security.

“For the first time worldwide, we have jointly implemented in-service software upgrades in the containerised user plane at scale,” said Rao. “This allows us to roll out new features faster and without temporary maintenance breaks – an important step towards the network of the future.”

Daniel Leimbach, head of customer unit for Western Europe at Ericsson, said: “Our deep partnership with O2 Telefónica in Germany has been a significantly rewarding one from the start. Meeting its challenge to deliver a cloud-native core network for its 45 million subscribers while ensuring it was flexible enough to evolve in line with its strategy meant breaking new ground across a range of disciplines.”