• Vodafone UK has been revamping its national network for the past three years
• The Redstream evolution programme has collapsed multiple networks into one greener and more distributed architecture
• The move has given the telco a virtualised, programmable, edge-based network that is fit for purpose, explained Vodafone UK’s head of infrastructure and energy, Francesca Serravalle, during the recent DSP Leaders World Forum 

WINDSOR, UK – DSP Leaders World Forum 2024 – Network operators have long been talking about and planning single, distributed, greener network architectures that are essential for the cloud-oriented, digital services era. Delivering against that vision is tough and resource intensive, but Vodafone UK believes its Redstream programme has met the brief and shown how telcos can revamp their networks to meet internal as well as external demands, explained the operator’s head of infrastructure and energy, Francesca Serravalle, during the recent DSP Leaders World Forum. 

Serravalle was the co-host for the session titled Building digital infrastructure from core to edge, and to start the discussion she gave an opening address that provided an update on how Vodafone UK has spent the past three years executing its Redstream evolution strategy to build a single core-to-edge network that will replace multiple service-specific networks and enable the operator to deal with the demands of its consumer, enterprise and wholesale customers. “We have created a unique and single converged backbone, which is serving the consumer, the broadband and the enterprise customers,” she noted. “That backbone comprises more than 200 sites connected by more than 55,000km of fibre… we have created an edge-based architecture because we want to decentralise the services. Those edge sites host the service platform, transport platform, IP and optical platform, internet platform and content platform, enabling us to deliver low-latency services but also enabling local breakout” to other platforms, she noted. 

The development of the distributed edge sites is still a work in progress, of course. In response to questions from her fellow session speakers – Darrell Jordan-Smith, chief revenue officer at Wind River, Vivek Chadha, senior VP and global head of telco cloud at Rakuten Symphony, and Dean Dennis, managing director of global solutions at Verizon Business –  Serravalle noted that the network intelligence is currently centralised and there are multiple domain orchestration systems being used to manage the programmable network. 

But “in the future the intelligence will be distributed [to] the edge… if we want to monetise our network, we will need a service orchestrator that will be able to dynamically provision and manage the entire network. We will need distributed intelligence as we are moving towards a more interconnected world… there will be interconnection with lots of internet platforms and content providers [and] we also need a more seamless experience between network providers as well… we will need distributed intelligence” to manage the complexity. “We are not there yet but that will be the future,” noted the Vodafone UK executive. 

As you’d expect, Redstream is a programmable, software-defined network (SDN). ”We have invested heavily on SDN through a hierarchical architecture – we have an optical controller, an IP controller, and a TDO [transport domain orchestrator] that will automate the service provisioning and service assurance… and, in the future, we want to leverage open APIs to make the transport network even more programmable. We have also chosen a number of sites to deliver our telco cloud, our virtualised core,” she added. 

Key to the Redstream design is that it should have plenty of capacity and be scalable for future data transport demands. “In terms of the design principle of the architecture, there were three criteria. One, it is future-proofed. So we have built a 10Gbit/s access [network], 100Gbit/s aggregation [links] and an 800Gbit/s core [transport backbone]. Scalability is important so that we can maximise our investments – adding on top rather than replacing.”

Equally as important, but perhaps the toughest challenge of all, Vodafone UK wants to keep its operating expenditure (opex) costs flat and it is attempting to do so by simplifying the network as much as possible, relying on passive rather than active optical systems, generating some of its own power by using solar panels at its sites and datacentres and switching off old platforms: Vodafone UK has already turned off its 3G mobile network, for example.    

“Normally there is a clear linear relation between data growth, 5G rollout and energy consumption, but we gave ourselves a challenge that even if we are rolling out 5G and have major data growth, we want to keep energy consumption flat,” noted Serravalle during the session discussion. “We had to do quite a few things in the radio access network, in the transport, in the core. The first thing we did was really try to simplify the network as much as we could and move from legacy to a fully cloudified network” as quickly as possible. “We’re trying to accelerate that so we don’t have a double stack of IT [systems],” she explained. 

“And we leverage big data. We’re building use cases using big data… one of these is to… ingest energy data from passive infrastructure and active infrastructure and then create a heat map” that will allow us to “take targeted actions…  we’re also delivering intelligence in the radio to change the radio resource dynamically, based on user distribution and the traffic. So we are doing a lot, but it’s a really big challenge,” she noted. 

And one of the challenges, according to Wind River’s Jordan-Smith, is the array and types of data sources that telcos have to deal with when trying to make sense of what is happening in their networks. “There’s a lot of opportunity for improvement” in terms of observability. “The problem is that each one of these systems still pumps out data in a different context and there’s no way of actually collating that efficiently at this moment in time without also doing other silos, which then actually layers even more complexity across everything that’s going on,” he stated. 

Serravalle and her fellow speakers went on to discuss a number of network infrastructure innovation topics, including the complexity associated with cloud-oriented networks and the potential use of graphics processing units (GPUs) in telecom networks. You can watch the full session on demand here. 

- Ray Le Maistre, Editorial Director, TelecomTV