As technology evolves, both mobile and fixed networks are constantly changing, becoming faster, more resilient and more streamlined. Light Reading had a chance to visit Virgin Media O2's network management center in Slough to see how these changes play out on site.

Its network was born out of a merger between Liberty Global's cable operator, Virgin Media, and Telefónica's mobile operator, O2, which was announced in 2020 and approved in 2021. The two separate legacies are still visible – the Slough site was historically O2's, focusing primarily on mobile equipment, with a Virgin Media site down the road now set to be phased out.

Still, the company has managed to merge the technology and operational culture into one since the merger, said Daniel Goodenough, VMO2's technical site operations manager for the south. The operator is now splicing its fixed empire with the mobile business into a single meshed network.

VMO2 serves 45.5 million mobile customers and provides 5.8 million premises with a fixed connection. It is also maintaining its pledge – made as part of the merger – to invest £10 billion (US$13.1 billion) over five years to upgrade its networks, having recently started the rollout of its 5G standalone network. 

At the same time, it is upgrading its fixed network from hybrid fiber-coax (HFC) to full fiber and introducing symmetrical XGS PON, a high-speed full-fiber standard. The fixed-line network passes more than 17 million premises, with the full-fiber footprint currently at around 5 million. 

Converged, meshed network

VMO2 is in the process of merging fixed and mobile network elements in what it calls a converged interconnect network (CIN). An important piece of kit, then, is Ciena's 5170 routing and switching product, said Goodenough. So far, VMO2 has around 200 such units in the network, and it plans to grow this to thousands to support future needs.

The network is then organized in what VMO2 calls "intelligent rings," to add redundancies. In the past, networks were built to carry traffic from point to point, with resiliency not among the top priorities, said Goodenough. But it is now becoming more important, and the meshed network, which picks up traffic along its route, allows rerouting in case of a bottleneck or outage.

Outages can, for example, be the result of fiber cuts, which are relatively common. Every week, there are between 10 and 20, according to Goodenough, who said that most are caused by other utilities, whether altnets or gas companies. 

The new network arrangement also means having fewer sites in the long run, because the CIN can cover longer distances and therefore needs fewer large network hubs. This fits into another broad trend of equipment taking up less space. 

Perhaps the most obvious consequence is an eventual reduction in the floorspace used. Currently, the company has around 500 technical sites in total, ranging from large centers like Slough, serving high-capacity, backbone traffic, to smaller facilities such as repeater sites. Eventually, the number of sites will drop to around 10% of the current footprint, Goodenough said.

Freeing up space

But it's not just about shuttering sites, with new uses for freed-up data center space already emerging. In its data center in the Slough facility, VMO2 has brought in content delivery network (CDN) solutions to help deliver a smoother streaming experience. The technology stores content from some of the most popular websites and streaming players, including Netflix and BBC's iPlayer, inside VMO2's data centers to bring it closer to customers.

The operator has also partnered with Akamai, which provides the equipment and then wholesales the storage space to companies.

Apart from the meshed network, the phasing out of 3G and transition to fiber broadband also contribute to an overall reduction in the volume of equipment necessary. With XGS PON – part of the £10 billion investment plan – the reach is much greater than that of the current HFC network. The sunsetting of 3G, with the technology's twilight expected to last until 2025, is also helping VMO2 cut down on equipment.

Tackling peaks

Meanwhile, when it comes to equipment that is being phased out, there are different processes in place. Some is sent back to the vendor for reuse or recycling. According to Goodenough, VMO2's biggest vendors, like Dell, Juniper, Cisco and CommScope, are good at reusing the equipment sent back.

Another important aspect of running a site like the one in Slough is ensuring security and the smooth functioning of the network. The data center environment housing some of the network equipment, as well as the CDN, is broken into two, with one part functioning as a test environment.

This can serve a number of purposes. Apart from being used for training and testing deployment of new equipment, it also connects to faraday cages used to test device prototypes. There are also measures in place to ensure service runs as smoothly as possible during peak traffic hours. Meanwhile, the backbone HFC network – supplied by Juniper Networks – is kept at very low congestion levels to ensure it can shoulder spikes.