5G Cloud

5G cloud, let’s demystify it

What do we mean by the cloud? What are the different types of cloud environments? What parts of a telco business and network can be moved to the cloud today, and what are the possibilities for the future? VIAVI demystifies the cloud…

In part I of our two-part blog, we looked at the rise of the hyperscalers and notable telco/cloud partnerships, as well as giving a brief overview of the different types of cloud model available. In part II we take a deeper dive into which elements of the network telcos are moving to the cloud – and those that they hope to migrate further down the line.

What elements are telcos moving to the 5G cloud?

The 5G core

The 5G core has been specifically designed as a cloud native architecture, and is designed to use cloud technologies and a Service Based Architecture (SBA). The 5G core is designed to be distributed rather than centralized, meaning some parts of it can be placed in a centralized data center and some at the network’s edge, enabling applications and services such as machine-to-machine (M2M) and ultra-reliable low latency communications (URLLC).

A number of telco providers are testing and running the 5G core in the public cloud. DISH recently announced that it plans to build its entire 5G core on AWS with Nokia; Swisscom also recently announced that it is building its 5G core with AWS, and many others are likely to follow suite. Other telcos, however, will opt to build the 5G core in their own private cloud, working with vendors such as Ericsson, Nokia and Metaswitch.


In the future, different cloud environments will support different parts of the RAN, which include the centralized unit (CU), the distributed unit (DU) and the remote unit (RU). Today, only the centralized unit (CU) can be hosted in the cloud – enabled by public cloud providers. However, most telcos have not yet made this move, as rigorous testing of the cloud environment – whether that’s AWS, Google Cloud or Azure – needs to be conducted first. Let’s look at this in some more detail.

The CU

Tests must be carried out to ensure that the CU works according to 3GPP specs and O-RAN C-plane and U-plane profiles. Telcos need to be sure that the CU interoperates with other 5G network functions and components, and that the network is capable of performing under loaded conditions, such as those we’ll see in edge computing applications.

VIAVI announced recently our support for this, by enabling O-CU testing AWS Outposts. This is the industry’s first O-RAN O-CU test solution deployed on AWS Managed Services (AMS) at the network edge.

The DU

Hosting the distributed unit (DU) in the cloud is in trial stage at the moment, with hopes that we’ll see this part of the 5G radio network hosted in the cloud as part of the commercial networks of the future. Today, Open RAN is making it possible to host the DU away from the base station in a private cloud. In the next year or two we will see it hosted in public cloud edge locations, such as AWS Outposts.

The RU

The RU is still an integrated part of the base station and resides close to the antenna. The RU involves delivering extremely latency sensitive data in real time, which requires massive amounts of processing power. Cloud servers hosted away from the base stations don’t currently have the processing power to achieve this; an issue that might be overcome by adding hardware accelerators to the system.

No software-only component can achieve this today, yet despite this – and compounding the cloud confusion of many telcos – some parties are claiming otherwise. It will be at least five years until we see the see the RU hosted in a public cloud infrastructure. Until then, the software will be managed as part of a telecom provider’s private infrastructure. VIAVI constantly works to support telcos to optimize and develop their networks, so watch this space!


Both business support systems (BSS) and operations support systems (OSS) are ripe for public cloud migration, and can be hosted in public, private or hybrid cloud environments. This offers a number of benefits for telcos and signals a dramatic shift away from the traditional approach of hosting BSS and OSS on hardware on-premise.

Moving BSS (which could include things like subscriber charging, customer management and customer services) to the cloud brings greater scalability and flexibility without the costs involved in buying new hardware and scaling up and down as new subscribers are added or leave. The flexibility of the cloud environment also means that telco developers can create new services and launch them to market faster – a real commercial imperative for telcos.

In December last year, a number of telcos partnered to launch an industry organization to accelerate the use of cloud-native software for IT systems. TM Forum’s new open digital architecture (ODA) is designed to support telcos to deploy cloud native software-based networks and ensure BSS and OSS can interoperate.

Many telcos have already moved BSS and OSS to the cloud environment: according to ACG Research,  30% of newly deployed OSS and BSS solutions are cloud based, with that figure predicted to increase to 90% by 2025.


The RAN Intelligent Controller (RIC) is cloud native, and a central component of an open and virtualized RAN network. The RIC can be hosted in a public or private cloud at the edge of the network. It aligns with 3GPP release 15 and beyond and supports network slicing, eMBMS, MCx etc. It helps operators to optimize and launch new services by allowing them to make the most of network resources, and helps operators to ease network congestion.

The RIC also provides an open platform which can host xApps. These can be developed by third parties and will open the door to innovation in Open RAN networks, allowing telcos to more easily deploy intelligent, cloud-native RAN applications.

All of the above moves will be gradual and will require specialist skills and expertise. The decision of whether to utilize public cloud, private cloud, or a hybrid approach involving the two, will depend on the specific needs of the telco and its customers. Moving any element of a telco business – and any component of network infrastructure – will ultimately, though, enable the digitalization and transformation of the telco sector and will mean a better experience for end-users.

The only thing holding many telcos back? A lack of knowledge – and confusing messaging from some in the industry – about the cloud. Hopefully some of these issues have been addressed in this two-part blog and, as developments in cloud and cloud-based network testing continue, we’ll work to ensure that we continue to demystify the cloud.

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TeraVM Marketing

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