Why 15 Mbps?

According to the Superfast Surrey FAQ:

Our Programme Contract states that we will be providing 94% of homes and businesses in our programme deployment area with download speeds of 15 mbps or above. 15 mbps is the minimum speed that will be received at the busiest times in and is guaranteed at a wholesale level, in other words, it is the speed at which Internet Service Providers will offer a service.

This revelation, first published by us in February, has sparked angry commentary in the media and on forums, since it appears to be a significant climb down on the much publicised “ambition” for “100% superfast” coverage (“superfast” meaning at least 24 Mbps). So I was very interested to read this explanation in section 2.2 of the BDUK guidelines:

In assessing projects for State aid approval, the NCC requires that NGA technologies that are used in NGA white intervention areas must provide the same outputs as those defined for other established NGA network deployments. Specifically, the NCC will expect to see that the technical solution:

  •  is capable of providing access speeds in excess of 30Mbps download, not only by reference to theory and technical standards, but also by evidence of calibrated performance measurements of an existing deployment within the area of interest or an demonstrably equivalent deployment in a similar geographical environment;
  •  typically provides at least a doubling of average access speeds in the target NGA intervention area;
  • must be designed in anticipation of providing at least ~15Mbps download speed to end-users for 90% of the time during peak times in the target intervention area, as demonstrated by industry-standardised or reliable independent measurements;
  •  must show how the solution would adapt to maintain capability and end-user experience in changes to key parameters such as increased take-up and increased demand for capacity, and be able to show using clear calculations that this is both technically and commercially viable;
  •  must have characteristics (e.g. latency, jitter) that enable advanced services to be delivered e.g. video-conferencing and High Definition video streaming to be provided to end users as evidenced by trials results not necessary obtained within the area of interest; and
  •  have longevity such that one might reasonably expect increases in performance within the next 7 years.

Section 2.1 is perhaps more puzzling:

Requirement 1: The subsidised solution must deliver a ‘step change’ in network capability and service availability and consistently provide a high quality experience to end users

2.1 This requirement ensures that where a basic broadband infrastructure already exists, State aid must only be used to deploy infrastructure that genuinely offers a significant new capability to end users.

This appears to contradict the reasons given to me by Superfast Surrey for not being able to help Ewhurst residents, or other outliers in completed commercial areas, who are currently unable to order a “fibre” service. Naturally I will take this up again with the team.

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4 Responses to Why 15 Mbps?

  1. PhilT says:

    I don’t really see the 15 as a climbdown, it’s a different measure to the “over 24″ or “over 30″ speed capability which is still required in the first point listed above.

    The 15 is effectively the Committed Information Rate or guaranteed throughput that may occur at times of peak load. A 48 port card in an FTTC cab connected with a 1 G fibre has about 20M per user of peak shared capacity to the exchange and this has always been the case.

    The general public don’t understand that there are several speeds associated with a broadband connection (or any data connection) and this is just a manifestation of that – I’m pleased they have defined a minimum throughput for peak load as 4G LTE Wannabes will struggle to deliver that for more than a handful of people on a sector antenna.

  2. David Nye says:

    Yes indeed Phil T; and this public misunderstanding is entirely the fault of BT Group who consistently present the figures in headlines designed to give this false impression. Not helped by SCC joining in, without understanding exactly what they were announcing.

  3. David Nye says:

    BT have finally admitted that they are in fact blocking the publication of contract details, which previously they have claimed to be available from the Councils. It appears that we are lucky in Surrey to have access to proposed coverage at postcode level.

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