West is best

PIA proves its value in project to build a carrier-independent dark fibre route between Bristol and Vantage CWL1 in Wales

Nextgenaccess has recently completed its largest Physical Infrastructure Access (PIA) dark fibre project so far: a circa 58 km route connecting Bradley Stoke in Bristol to the Vantage CWL1 data centre (formerly NGD) – Europe’s largest data centre campus – located near Newport in South Wales.

The carrier neutral route was built quickly and cost-effectively, primarily utilising existing Openreach duct infrastructure. It also required Nextgenaccess to construct both a dedicated 4km fibre section spanning the Severn Bridge – never previously attempted by any other fibre provider – which it now manages with Highways England, as well as a new 3Km section to maintain full diversity from the existing carrier fibre routes.

Project Background

CWL1 is a 750,000 sq ft hyperscale data centre with multiple on-site fibre links supporting tier 1 carrier and service provider networks and has abundant power supplied via direct connection to the 400kV National SuperGrid. The facility provides world-class colocation and cloud hosting services to multinational blue chip enterprises, public sector organisations, government departments, service providers and hyperscalers. Since its opening a decade ago, CWL1 has maintained a 100 per cent uptime record.

NGD Newport South Wales

In line with its future business growth strategy and continued expansion of the data centre campus, CWL1 fully recognised the strategic importance of maintaining diverse and ‘triverse’ fibre routes. Such geo-diversity is seen as mission critical by hyperscalers and global enterprises. It also maximises the choice of providers available at CWL1 for enabling the specific connectivity demands of all customers to be securely fulfilled.      

The end to end 432 Fibre System deployment was subsequently undertaken in a joint initiative with Nextgenaccess, a fibre specialist which uses code powers and duct and pole access agreements to establish carrier neutral fibre routes – without the full capital cost of a new dig.

Project Requirements

In addition to ensuring maximum network geo-diversity for the CWL1 data centre, a key requirement was to deliver a truly carrier-independent fibre route which could be made available by Nextgenaccess to any service provider. Furthermore, it needed to facilitate the future delivery of Full Fibre connectivity to underserved SME businesses located throughout the South West and South Wales. This was a requirement of the company’s major funding partner, Amber Infrastructure Group which supports investment into the UK’s fibre infrastructure for the rollout of 5G and to enhance mobile and Full Fibre connectivity.

  • Deliver a well-engineered, well-managed dark fibre route linking Bristol to CWL1 in South Wales
  • Enable a cost-effective, carrier neutral solution in line with CWL1’s ongoing requirements for maximum network geo-diversity and facilitating the widest possible choice of on-site connections
  • Stimulate carrier and ISP provision of low-cost Full Fibre services to underserved businesses and communities throughout the region
  • Offer mobile operators easy access to direct-to-mast fibre connectivity in support of growing backhaul traffic volumes

The Build

Nextgenaccess engineered the fibre route primarily utilising Openreach duct infrastructure under its PIA/DPA code powers, enabling speedier planning permissions, minimal disruption and therefore faster fibre roll-out at significantly less cost. This method had already been well-proven by Nextgenaccess for building out independent high capacity fibre networks elsewhere in the UK.

As one of the first PIA licensed infrastructure providers, the company has consistently found the widespread coverage of Openreach ducting highly conducive to new dark fibre deployments while also providing longevity due to its design, build quality and trenching depth. On trunk routes this can be 3-4 metres, affording superior protection from accidental damage compared to shallow trenching methods.

openreach fibre ducts

Protection against accidental damage is enhanced further by placing the majority of splice joints in separate, newly constructed, stand-off chambers adjacent to the Openreach estate.  As well as protecting against damage by other contractors this approach also simplifies access to the route for testing and the addition of new customers.

engineers installing fibre

Crossing the Severn

On the 4km section spanning the River Severn, Nextgenaccess deployed 864 fibres in two diverse sub-ducts along the original Severn Bridge (M48). This bridge was chosen instead of the newer Prince of Wales Bridge (M4) or rail tunnel alternatives and had never before been used by any fibre provider. While presenting additional engineering challenges, it was purposely selected bearing in mind CWL1’s requirement for geo-diversity and security. Working closely with Highways England – the Severn Bridge’s operator – entailed complying with the Agency’s specific rules and regulations for fibre containment as well as managing the health and safety implications of working at height over water in confined spaces.

As part of the project Nextgenaccess also used its expertise and code powers to build a new 3Km section of duct to maintain full diversity from the existing carrier fibre routes.

nextgenaccess fibre route bristol wales

Local Full Fibre Connectivity

In order to make low cost Full Fibre more accessible and widespread, the route was designed to pass in close proximity to as many local BT exchanges as viable. Being close to exchanges will make it easier for existing and potential carriers and ISPs to leverage the new dark fibre when provisioning ultrafast broadband services to local businesses and public authorities.

In addition, the route is easily accessible for connection to numerous mobile masts, providing mobile operators with the option of direct fibre-to-mast connectivity – rather than Ethernet – as they strive to manage the exponential growth in backhaul traffic from 5G.

Key Challenges

  • Mitigating risk of damage to Openreach infrastructure
  • Working at height over water in confined spaces
  • Blowing fibre for the first time over the Severn Bridge
  • Maintaining diversity from other routes
  • Meeting Highways England’s specific fibre containment requirements
  • Digging and installing new ducting in areas where older ducting had collapsed due to clay terrain

Design Considerations

PIA was selected as the optimum dark fibre construction solution for the following reasons:

  • Quicker, cheaper, cleaner and much less disruptive than a new dig
  • Environmentally friendly
  • More secure and much less likely to be compromised – Openreach ducts are solid and dug deep
  • Easier to maintain – Openreach records are good and the duct infrastructure is well managed
  • Easier to extend further – Openreach ducts are widespread

For added resilience all fibre cables were deployed within a dedicated, clearly marked orange/white sub-duct. For added security 80 percent of splice joints are within dedicated Nextgenaccess stand-off chambers, newly constructed adjacent to the Openreach ducts. This makes joints easy to access and removes all risk of them being damaged by other contractors.

To facilitate a simple connection within CWL1, Nextgenaccess installed a cabinet containing a large optical distribution frame (ODF). The incoming fibres are presented on one side of the ODF, the other side of which is spliced onto several internal fibre cables. These are run into the various data halls making it quick and simple to patch through new connections for new customers.


As it expands rapidly, the new dark fibre route helps ensure CWL1 continues to offer enterprise, HPC and hyperscaler customers the highest levels of availability and security. These now benefit from an additional, diverse/triverse high capacity fibre route enabling dedicated low latency, high speed fibre network services between CWL1 and locations throughout the UK and internationally.

The Nextgenaccess 432 Fibre System also supports CWL1’s growing role as a major communications hub and Internet peering centre for the South West of England and Wales. For example, the London Internet Exchange (LINX) has recently extended its LINX Wales exchange operation to CWL1 – including a direct PoP – as it looks to expand low latency, non-London transit services throughout Wales. 

In addition, the route makes CWL1 an attractive PoP destination for more carriers and ISPs. SSE Enterprise Telecoms, for example, has recently committed to taking multiple fibre pairs on the new route in order to connect its 12,000km UK-wide network to the CWL1 data centre. This has followed an increase in demand for high capacity services to CWL1 and the rest of the UK. At the same time, alternate carriers, telecom operators, service providers and resellers now have a cost-effective carrier independent solution for delivering ultrafast broadband to thousands of currently underserved SME businesses across the region.

Mark Weller, Managing Director, Nextgenaccess, said, “We are delighted our new dark fibre route is now connected to CWL1 and fully operational. Our DPA / PIA license enables us to deploy fibre far more quickly with minimum disruption. If we had followed the traditional road dig approach it would have taken over five times as long and cost more than ten times as much. The successful completion of this project demonstrates how we can help address the UK’s full fibre deficit in strategic areas very cost-effectively, ultimately enabling significantly lower cost full fibre services for end users.”

Simon Bearne, Commercial Director, Next Generation Data, added: “As a major European colocation, Internet peering and cloud hosting hub, the new independent dark fibre route is a key addition to CWL1’s expanding list of connectivity options. It allows our major customers to have even more choice, flexibility and control over how and with whom their ultrafast or custom fibre services are provided.”

Future Potential

The route and its carrier neutral approach is creating growing demand from carriers and service providers, a number of which are also interested in the potential of using a similar approach and even rail for extending dark fibre westwards into the Cardiff Capital Region and beyond.

About Nextgenaccess

Nextgenaccess is a carrier neutral, managed fibre infrastructure service provider. We design, plan, install and maintain new dark fibre routes that become integral to our customers’ core and access networks.

We operate in a sustainable way and always look to re-use existing infrastructure assets in preference to building new ones. Our Openreach PIA licence gives us the right to deploy fibre and sub-duct anywhere within the UK’s most extensive network of ducts and poles and chambers. This re-use approach is not only environmentally friendly, it is also far less, disruptive, costly and time consuming when compared to a new dig.

We aren’t restricted to Openreach infrastructure however, and where necessary we use our code powers to build out from it to create lead-ins, overcome congestion and maintain route diversity. This blended approach enables to undertake Special Engineering Designs (SED) to meet the increasingly demanding requirements of our carrier, Data Centre, service provider and hyperscaler customers. For example, we have also just completed a new 65Km fibre route into the Next Generation Data Centre in Newport (CWL1), this now enables carriers to provide the high level of diversity demanded by the new generation of hyperscalers wishing to establish a presence there.

Unlike others that also hold a PIA licence, we have many years, and hundreds of kilometres of, practical experience working with Openreach. We know how to make PIA work and how to get the most out of the UK’s largest telecoms infrastructure provider. We have also been granted national Path to Collaborate status which enables us to resolve issues with Openreach infrastructure without having to go through a lengthy approvals process. We welcome the opportunity of working with you to provide better connectivity from our portfolio of managed fibre infrastructure services.

  • Access Connect – point to point dark fibre connections to service provider’s customers’ premises
  • Carrier Connect – Dark fibre connections between existing carrier network nodes
  • Data Centre Connect – Dark fibre connections between data centres and/or carrier network nodes
  • Small Cell Connect – Dark fibre connection from a mobile operator’s baseband unit to Small Cells
  • Public Sector Connect – dark fibre networks that support the local community

Nextgenaccess is a privately-owned company with investment from the National Digital Infrastructure Fund, a commercial fund established in 2017 by Amber Infrastructure Group which has over £8 billion of assets under management with interests in digital and other public infrastructure, sustainable energy and real estate.