When it comes to standalone 5G networks, many of the world's largest mobile operators are considering moving to a cloud-native network architecture coupled with containers.

A container is a standard unit of software that combines code and all of its dependencies into one package. The benefits of using containers are that they allow applications to be deployed quickly, efficiently and securely.

Inspired by the openness of the IT industry, many mobile operators believe that a cloud-native architecture coupled with containers will help them develop and deploy telecom networks more quickly and make it possible for them to respond to the explosion in mobile data traffic and the growth in wireless connections.

According to Marisa Viveros, vice president of strategy and offerings, telecommunications, media and entertainment at IBM, containers are key to deploying 5G because a 5G network will deliver ultra-high speeds and low latency. "If you are going to have these super-fast networks you want applications to be equally fast. You want the applications moving and you want workloads to be placed where it makes the most sense," she said, noting that containers will make that possible.

Rakuten's Chief Technology Officer Tareq Amin recently said that the mobile operator's existing architecture is not exactly what he wants because it's still using virtual machines (VMs). His vision is to have a network based on lightweight containers that will break functions down into smaller, configurable components. Rakuten's long-term plan is to have a container-based platform that resides on Rakuten's own cloud.

Amin's statement was unique because wireless operators usually aren't very vocal about their use of containers. Viveros said that telcos don't usually talk about containers when they discuss their network because they focus more on the applications. But she added that operators are definitely aware of the advantages of containers. "Containers have less overhead and require less payloads on the system resources than virtualized machines," she said. Plus, they also provide more portability. "Applications can be running in various containers and you don't have to worry about the operating system or the hardware."

Rakuten isn't alone in its container aspirations. In July 2019, Verizon announced it was working on a proof-of-concept trial in a live network of a container-based wireless evolved packet core. According to Folke Anger, solution line head for packet core at Ericsson, it was important for the vendor to work with an operator that was technically very advanced and had a lot of demands on the network. "We moved some of the evolved packet core applications into a container," Anger said.

Anger added that other operators are also starting to move core network functions into cloud-native network functions. "If you have cloud-native, you need containers."

Verizon talked about its move to a cloud-native network at the recent Red Hat Summit 2020 virtual conference. Srini Kalapala, vice president of technology and supplier strategy at Verizon, said that Verizon is working to bring a truly cloud-native stack to its 5G network. "We are working with you [Red Hat] to bring that capability to our networks. From the RAN to the core it will be built on a cloud-native stack," Kalapala said.

Kalapala added that Verizon has been on this evolutionary path since 2015 and 2016 when it first started virtualizing its network and separating the hardware from the software. "Telcos are following the webscale companies and we are a little behind," he said.

ONAP's Frankfurt release
The Linux Foundation's Open Networking Automation Platform (ONAP) just issued its sixth release, called Frankfurt, which includes a blueprint for operators to scale their 5G networks and includes cloud-native network functions and containerized functions.

ONAP is an open-source software platform that was formed in 2017 after the Linux Foundation combined AT&T's E-COMP platform with OPEN-O, which was a group founded by China Mobile.

The Frankfurt release also introduces end-to-end network slicing with modeling and orchestration of a network slice, including 5G RAN, core and transport network slice elements.

According to the Linux Foundation's Arpit Joshipura, general manager of networking, edge and IoT, the 5G network is a hybrid where VMs will reside with containerized network functions (CNFs). "Containers and VMs have to work together," he said.

Along with the release of Frankfurt, the Linux Foundation also provided details of different operator case studies that involve a cloud-native network architecture. Operators including China Mobile, AT&T, Verizon, Orange and others are in various stages of implementing Frankfurt but have different strategies and different types of deployments.

VMs and containers
Despite the fact that many operators are interested in containers, Viveros said that she believes most operators will have a combination of VMs, containers and physical hardware in their networks. "I think that telcos are going to run networks in the future that use both VMs and containers. They can't decommission what they already have because it will be too expensive," she added. "And some will continue to run the physical network, the virtualized network and the containerized network. They can mix and match depending upon the topology and geographic locations."

That sentiment was echoed by Ericsson's Anger. "There will be a combination of physical, VNFs [virtual network functions], and the cloud native [architecture]."

But Anger also added that although most operators are looking to containers for their 5G deployments, they can be used in a 4G environment. "We have 4G network functions in the evolved packet core."

In addition, Anger said it is possible to have a cloud-native dual-mode network that supports LTE and 5G non-standalone and the 5G core. Anger said that this capability is important for operators that are still seeing a lot of growth in their 4G LTE network.

Although mobile operators may be in the early stages of working with containers, this technology is viewed as being a key component for making 5G networks agile and efficient.

— Sue Marek, special to Light Reading. Follow her @suemarek.