Who needs MPLS? A dark fibre network saves York Council

City of York Council (CYC) set out to rethink its patchwork of network service contracts for voice and broadband and ended up building a city-wide dark fibre network that delivers fixed and wireless free public Internet access to all York libraries. Those services will be expanded into public parks later this year.

Next up, the network will be extended to York residents and businesses, and the council is in the early stages of considering city-wide free WiFi.

Previously, CYC had a number of different managed and unmanaged service contracts around voice, data, connectivity and ISP services, which it was looking to restrategise in order to achieve economies of scale, flexibility and better manageability. Yet simply switching them all over to another supplier was a high profile, high risk project that could have negatively affected not just council employees but also residents and the year-round tourist trade.

The council had two main contracts nearing termination. One was school and library broadband provision that came from the now-defunct UK government funded National Grid for Learning (NGFL), and another provided voice and data to the rest of the council’s buildings. There were also unmanaged and managed support agreements for its traffic management control systems.

“We thought we could pull those three requirements together and go out to the markets with a very open tender, not being specific about any solutions,” said Roy Grant, head of ICT at CYC.

Most of the suppliers tendered traditional MPLS offerings, but Pinacl Solutions came back with a dark fibre option, supported by City Fibre Holdings. “This made the rest of the designs look very inadequate; a fibre network next to a traditional MPLS network is like chalk and cheese,” said Grant. The contract with Pinacl is worth £13.7 m over eight years. The dark fibre network build came in at just under £4.2m while the rest of the money pays for ongoing maintenance and support of all the managed voice and data services. The lure of the deal was the extra capacity, scalability of the network and the fact that costs were fixed.

“The dark fibre option is future proof and far exceeded any known vector guidelines. It also put us on a completely different roadmap for delivering converged networks. This offering came at a fixed price for the eight-year duration of the contract and the only thing we would have to change would be the devices,” said Grant.

York Council's dark fibre network design

The city-wide network is a metro Ethernet design with a single mode fibre backbone. There are two core 10Gb fibre rings, one for schools and one for the council. Both rings are linked via five POP sites, with OSPF as the backbone routing protocol.

“The fibre ring is effectively a ‘dark fibre’ install which means that potentially any kit can be attached in the future such as WDM (wavelength division multiplexing), which can, in effect, give you almost unlimited bandwidth,” said Grant.

So far there are 104 sites connected to the network all on 1Gb uplinks and City Fibre has laid around 100km of fibre.

The single mode fibre is driven using SNMP managed transition media convertors located in two chassis at the five POPs and at remote sites. The transition units convert the fibre into cat 6 copper, which then plugs into two HP 5406 chassis (one for council and one for education) in the POPs and HP 2610 switches at the edge. Both pieces of kit are managed for alarms and the links are monitored and measured for traffic utilisation.

Makings of a dark fibre network rollout

The deployment team selected a few sites to roll out a staged cutover, and when that went well, it accelerated the rate of deployment. The issues that faced the council were not at all technical network problems: “If I had to do the same work again I would ask more environmental questions. We were struggling to get access over one of the railway bridges because [the owners] were slow to respond. If there were lessons learned it was around where you need access to areas or buildings that you don’t own. Five or six sites were delayed a little bit due to access over just one railway bridge.”

CYC has ended up with a single unified IP network across the city, “an outcome that we never thought we would get anywhere near when we started the tender process” said Grant. “We have a footprint in York now that puts us in the top five or ten councils in the UK in terms of being future proof. Most importantly it has exceeded any upcoming guidelines for school connectivity and will support around 24,000 pupils,” he says.

Looking to the future the council also plans to move CCTV, video conferencing, and a variety of traffic management services over to the network.