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The Road to Five Nines

What is Five Nines

When used to describe the availability of any system, Five Nines means 99.999%, which is equivalent to no more than about 5 minutes’ worth of unplanned or planned downtime in a rolling 12-month period.

A system with Four Nines availability (99.99%) has no more than about 53 minutes’ downtime over the same period, so Five Nines is about 47 minutes a year better.

2. How to Get Five Nines

High-availability services (with Five Nines) typically have the following attributes.

No single point of failure

In terms of infrastructure, this means for example that service continuity does not depend on any single site, platform, device or connection. In terms of people – in the case for example of managed IT services – there is no dependence on any individual at any time.

Geographic diversity

This means that service is delivered from different places. For example, using data centres located (as a rule of thumb) at least 30 miles (or 50km) apart and providing local access from different telephone exchange buildings, each connected to geographically-diverse core network nodes.

Network resilience

Use of core connectivity provided by different network operators protects against an outage (fault, planned maintenance) in any single operator’s network. Local connectivity provided by different operators or using the same operator’s resilience product avoids disruption arising from any single fault with an operator’s line plant – cabinets or masts, ducts, cables etc.

3. Why Five Nines Costs More

Five Nines reliability is designed into any reputable service, but what is outside of the control of the service provider is any local connectivity between the service and its users on the corporate network or whilst roaming.

Any purchaser of services needs therefore to strike a balance between service performance (user experience, availability) and purchasing cost. The operational importance of any applications running over-connectivity is a decisive factor. For example, if email access is interrupted it’s a nuisance, but if (say) hosted telephony in a contact centre goes down, it is extremely disruptive and frustrating for the affected organisation’s users, customers or constituents.

Matching connectivity to the applications it carries is, therefore, an important risk-based decision. Consider for example the various types of fixed-line connectivity that we provide and their respective monthly availability service levels as set out in Table 3‑1 below.

Type of Connectivity

Monthly Availability Service Level

Broadband, Fibre Broadband


Fibre Ethernet, EoFTTC, EFM – without Broadband backup


Fibre Ethernet, EoFTTC, EFM – with Broadband backup


Fibre Ethernet with EoFTTC or EFM backup


Dual Fibre Ethernet with different tail providers


Dual Fibre Ethernet with same tail provider using their resilience product


Table 3‑1 – Managed Data Availability

The key difference between a Four Nines service (Fibre Ethernet with copper-based backup) and the highest-availability services is that the latter use dual fibres. In the UK market, at least for now, fibre is priced at a premium over copper, so to get from Four Nines to Five Nines using fixed-line connectivity, the additional cost of the spare fibre is unavoidable.

One alternative is to take the Four Nines service and put in place a business continuity plan which factors in the reduced service performance available when there is an incident with the fibre. Another alternative is to use our 4G Direct Internet Access (4G DIA) as a back-up, providing a fast mobile data connection (subject to the quality of mobile coverage at the served site).

4. Intercity – Our Five Nines Capability

Our network has no single point of failure, is geographically diverse and is resilient, as illustrated in Figure 4‑1 below.

Figure 4.1 -Intercity Network

In the UK, the main hub of the Internet is Telehouse North (THN) which is the primary home of The London Internet Exchange connecting over 850 autonomous systems from over 80 countries. Our network includes connectivity between this site and our new data centre in Birmingham. In addition, our Bolton data centre is connected to Equinix MA1 in Manchester, which is the most important network node outside of London, providing geographic resilience which is not dependent on London Docklands. A layer 2 private transit connection also connects between THN and MA1.

Data centres

Our data centres are built to Tier 3 specification, each supporting 99.98% uptime, a target which has never been breached, with no outages in the last 3 years.

Multiple carriers

We deliver services using connectivity from a number of different carriers and this includes the external connectivity and interconnects used within our network. Our Birmingham data centre is served by fibre from a Tier 1 carrier, whilst at Bolton our connectivity partner is a different Tier 1 carrier. This multi-carrier approach, using separate networks, guards against an incident affecting any single carrier.

Our network is configured to fail-over automatically via its internal interconnects, provided by three different Tier 1 carriers, each with their own network.

Services delivery from active/standby platforms monitored 24/7

Our Touch portfolio of cloud services, providing telephony, computing and firewall are delivered from dual platforms hosted in Birmingham and Bolton.

For example, a customer’s firewall (Touch Secure) service can be delivered primarily from Birmingham, with Bolton on standby or vice versa. This means there is no reliance on a single data centre for continuous security service availability.

We monitor our service delivery platforms and network connectivity from our Intercity Secure Operations Centre (ISOC) which is based in the same buildings as our data centres and manned round the clock.

The ISOC also provides our managed IT services, maintaining, monitoring and managing our customers’ networks, providing a managed service desk and remote support.

Advice on how many nines you need

You are best placed to understand the importance of any applications used within your organisation and the financial impact of any service interruption. We can help by advising on the various means of service delivery and setting realistic expectations about their respective availabilities.

You are then best placed to decide on the number of nines you need.

Up next

Intercity cements commitment to closing regional skills gap with Ahead Partnership

Birmingham-headquartered IT specialist, Intercity Technology, has collaborated with social enterprise, Ahead Partnership, to improve the pipeline and diversity of talent in Birmingham’s tech sector.

With Ahead Partnership, the IT specialist will work to enhance the employability skills of local young people through a range of initiatives, including a volunteering programme and work experience scheme.

Initially, up to 6 students aged between 16 and 18 will take part in a pilot of the scheme, which will involve training, shadowing employees in the Intercity Technology Birmingham office, and gaining hands-on experience of roles across the business.

Following this pilot, Intercity will roll out a fully-structured programme where students will learn new skills and gain insight into what it’s like to work in the tech industry.

Intercity cements commitment to closing regional skills gap with Ahead PartnershipThis is just one of many collaborations facilitated by Ahead Partnership as it works to connect employers across the public and private sector with education partners to promote social and economic change.

Andrew Jackson, CEO at Intercity Technology commented: “We’re always looking for new ways to invest in future talent in the region, especially in the tech sector, and we’re immensely proud to be working in collaboration with Ahead Partnership to push this even further.

“Giving young people first-hand experience of the tech sector is a great way to get them excited about the opportunities the industry has to offer. It’s only through this engagement and investment in talent that we will be able to further reinforce Birmingham’s position as a leading tech hub, and draw even more attention to the exciting work happening in the region.”

Stephanie Burras CBE, chief executive of Ahead Partnership said: “We are delighted to have Intercity’s support to help raise the profile of careers in digital across the West Midlands.

“Given the region’s aspiration to become a global digital hub, it is crucial that we act now to develop a pipeline of talent. The programme of activity that Intercity has put in place will show young people what is on offer through a set of really engaging activities focused around the workplace.”

Andy Street, Mayor of the West Midlands added: “Bridging the skills gap is an ongoing challenge for the region, but through collaboration between businesses, social enterprises, and educational institutions, we can make significant progress.

“This is particularly important when it comes to the future of our city’s rapidly growing tech industry, so it’s great to see Intercity Technology and Ahead Partnership joining forces to give aspirational young people the chance to gain valuable work experience and develop their technical skills.”