An Unusual Capacity Problem on Openreach’s UK FTTP Poles

Network capacity problems come in all sorts of different shapes and sizes, but the case of one street in London shows that those looking to order Openreach’s swanky new gigabit-capable Fibre-to-the-Premises (FTTP) broadband service may sometimes also run into an issue with there being no space for new lines on local poles.

At this stage the issue that we cover in this article is still somewhat of a rarity, but engineers inform us that it’s becoming more common as Openreach’s network expands. The operator’s full fibre network is currently available to around 4 million premises, but it could reach as many as 20 million homes and business by around 2025-30 (at a cost of c.£12bn).

In this case the problem occurred when we were informed that somebody living on a street in London, which had been covered by the new FTTP network a while ago, had found themselves being unable to get the service installed and activated – even though their neighbours had already been connected.

A relative of the individual concerned informed us that they had subsequently faced an 18-month battle with their ISP (BT) to get the problem resolved. Similarly, a quick check of local addresses revealed that FTTP was not listed as being available to the street (i.e. you couldn’t order it from an ISP), even though it had definitely been deployed before and was already live at several properties.

The cause of this long running drama? “Too many wires” on the local poles, said the ISP (note: telegraph poles do have to obey some limits for safety and weight etc.).

A Spokesperson for Openreach said:

“It transpires that FTTP is available to this customer. However it appears there is currently a waiting list which could point towards there being a possible capacity issue at the CBT [Connectorised Block Terminal]. Our Fibre Availability team have a case for this customer. It seems we’re just waiting for some build to increase capacity.”

The CBT is one of those odd looking rectangular black boxes (with various nodules sticking out), which you’ll often see affixed to the top of poles in Openreach’s overhead FTTP deployments (see here). So if there’s a capacity problem then it means that the CBT can’t handle additional customer connections to the network (i.e. ports all consumed or some other issue with the local poles). You can see what a similar underground CBT looks like below (this is a 12 port model but they do come in smaller sizes):

Openreach will normally plan and build FTTP in a way that ensures there will be enough lines to cater for demand, but there are always cases where demand (or some other factor) can upset that model. We don’t know for certain why this particular street ran into problems, but it does have a lot of houses that have been divided into flats (i.e. possibly more than the usual demand per property for new lines).

Tackling Pole Load

Whether due to an issue with load on the poles or merely port capacity at the CBT, resolving pole loading issues can still be a complex problem (depending on the type of pole and arc of dropwires etc.). Engineers have informed us that you can sometimes get around this by removing one copper wire as a new fibre is added, but that isn’t always possible (e.g. one copper cable may feed two subscribers). Hybrid copper and fibre drop cables can also be used.

In short, rationalising copper dropwires to reduce the number of wires in the canopy, or a pole swap in order to increase the total number of dropwires permitted, is generally preferable to adding completely new poles into an area and thus having to reroute all drops accordingly (lots of extra cost and complexity). Plus, there’s always the possibility of an underground extension, but that too has time and cost considerations.

Openreach are currently understood to be reviewing how they manage pole loading issues and we’re expected to hear more about that in the near future. As such we’ll come back to this issue in the Spring, once we know what approach is to be adopted (ISPs will be informed about this shortly).

We should add that this sort of issue may crop up on other overhead fibre networks too, including those ISPs that may be harnessing existing poles via Openreach’s Physical Infrastructure Access (PIA) product to run their own fibre. Suffice to say that this sort of problem isn’t unique to one operator and as FTTP expands then it may become a bigger issue.

As for the customer in this specific case. The length of time involved suggests that there wasn’t a simple fix (normally a fix might take many weeks, but 18-months seems excessive). The good news is that Openreach plan to solve the problem by installing additional drop cables from the pole to connect the customer, which has already begun and will take about two weeks to complete.