As a country, we like to think we are reasonably modern in terms of access to technology and connectivity. But let’s not forget it was only a few months ago that headlines were splashed with revelations that a creative firm in London’s Tech City, (the new, world-leading tech cluster), admitted it was quicker to courier a file to a client on a USB stick than to share it over their internet connection. Still think we all have equal access to great connectivity?

As our digital economy continues to grow, network and systems professionals feel it is their responsibility to deliver infrastructure to alleviate the pressure on existing networks and ensure that all businesses have the connectivity and IT infrastructure tools for growth. In the UK today, this means fibre connectivity, provided either other ‘lit’ Ethernet services from your provider, or perhaps by buying ‘dark’ fibre.

What is Dark Fibre?

Essentially, dark fibre is optical fibre infrastructure that is not yet connected to transmission equipment. Data is transported over optical fibre networks by passing light through the cables, these cables are buried in the ground which is an expensive and disruptive process. As such, many providers deploy multiple fibre strands at the same time, and then gradually connect them to the network equipment over time as they are required. Before they are connected, no data is being transported and this is termed dark fibre.

Why might you be interested in it?

With dark fibre, a client has the ability to obtain extremely high levels of performance, superfast speeds and a private highly secure network. The bandwidth potential is enormous, a single port can operate at up to 100Gbps with the correct terminating equipment, if this is combined with DWDM multiplexing equipment it can scale up to 88 ports at that speed, a staggering 8,800Gbps!!

Sounds great – but what are the challenges of dark fibre?

There are of course challenges in choosing dark fibre, you are really leasing unused strands of dark fibre optic cable, which you operate yourself, meaning your private network is separated and not controlled by a network service provider. Buying dark fibre is not like buying a managed telecom service, it’s more like a physical asset than a service, you have to take total responsibility for all of the complex routing equipment.

The fibre itself must be maintained and repaired if there are problems resulting from fibre breaks and these outages can be much longer than other services, so you should be careful to negotiate acceptable SLAs for these repairs. This is the responsibility of the dark fibre provider, but, it does have an impact on the service you deliver. If you need diversity or resilience in your network, you should be especially careful when buying dark fibre. Many carriers use the same rights-of-way when they construct their routes, so you’ll need detailed route maps to validate your diversity. When you buy a leased line or lit service, there is usually some smart technology deployed to deal with failovers, but with dark fibre, you are in full control of the asset, thus considerations have to be made for failover and backup. One of the things that IDE Group work very hard on with our dark fibre circuits, is to ensure that all available paths are resilient and do not cross, where possible.

Dark fibre can be the right solution for many of today’s high-bandwidth enterprise connectivity needs, but make sure you go into it with a full understanding of its advantages and disadvantages. Remember, Dark Fibre is a point to point technology, designed to connect 2 locations such as office to office, or office to Data Centre. It really is simply a cable, albeit a complex and sophisticated cable, as a result there are no internet services automatically supplied on it, it is dark, there is nothing carried on it until you connect it to network equipment and start to route traffic over it yourself. Many customers enquire about a dark fibre link which includes internet access, but this misses the point of dark fibre, it would require a lit service to do this. You will still need to get internet connectivity from your provider and run this as a separate service using your network switch/router to deliver the Internet over the new link.

How do you buy dark fibre?

Ultimately, for many scenarios the positives outweigh the potential negatives both in terms of cost and complexity and dark fibre presents an excellent choice in this case. It used to be that only service providers or data centre operators had access to Dark Fibre, but this is no longer the case. There are a number of dark fibre providers, all with different coverage footprints, different fibre routes, different cost models, different diversity, with different strengths and weaknesses. To ensure you have the right option, you need to compare all of them for diversity, shortest routes, cost comparison, and sometimes splice together multiple networks to get the right solution. Dark Fibre networks can be combined in a variety of ways to deliver point-to-point, point-to-multipoint and even dark fibre ring configurations. You can do this yourself, or you can find specialist aggregators such as IDE Group who do this for you as part of the service and can also usually provide further discounts through bulk buying. We can get the best price as they act as a comparison site with access to those networks, combined with the knowledge that comes from experience of delivering these connections many times already.

Final thought

To conclude there are pros and cons to dark fibre. Whilst it can transform connectivity, and open up new opportunities, the decision to deploy should take all factors into account to ensure that you get the best possible business outcome, the pitfalls and complexity are such that we would always recommend IDE Group guide you through the entire process.