How can BT zero-rate just one bit of the BBC?

Answer: it probably can't, 100%. But it can get pretty close.

BT has said that it will zero rate access to BBC Bitesize, which is a resource of educational content and videos.

The operator is doing this to make the content available to students and children who might otherwise not be able to afford to access it. (The operator assesses there may be 400,000 households that rely solely on mobile phones for internet access. These households also tend to be from lower income bands. Zero-rating access to Bitesize might enable users that otherwise face data caps or per-Mb pricing on data to keep accessing educational content.)

Another education content provider, Oak Academy, has moved its videos away from YouTube to its own domain to enable BT to zero-rate it. That’s because if its video lessons had stayed on YouTube, BT would have had no way of identifying Oak Academy’s YouTube videos from all the other billions of YouTube videos its customers watch.

The situation at BBC Bitesize is different. Bitesize sits under the overall BBC domain,, and like all BBC content is https/SSL encrypted. That gives BT a head-scratcher – how to separate out Bitesize content from all the other BBC streams and content, zero-rate the former and send the rest to its charging engines. It’s not simply case of just looking at the source of the traffic or the packet headers and rating them accordingly.

The issue raised its head publicly when the BBC itself ran an article questioning why Vodafone was not joining in with BT to zero-rate educationally useful material. Three and Vodafone both told the BBC’s reporter that they cannot see a way to zero-rate just a part of the BBC’s website, and that if they followed BT’s lead they would have to wave through all of the BBC’s content. BT gave the impression that it is doing something very clever that the others perhaps don’t the skills or capability to do.

If you follow the logic of what Vodafone and Three are saying it would seem that during the duration of the scheme, scheduled to begin from the end of January, BT customers will be able to watch all of the BBC’s content zero-rated against their bundles and pricing packages. That would seem to be a pretty big story.

BT has confirmed to TMN that it is indeed probably going to have some non-Bitesize BBC content being zero-rated. But it is also confident that it can catch most of it through a mixture of means. It may also take steps after a user session, analysing and re-routing some zero-rated streams back to the charging path.

A BT spokesperson told TMN: “For Bitesize we’re using a variety of different tools to zero rate, from basic config at URL level to signature detection in streams. However, we do acknowledge that with the speed we’ve taken to make it happen, it’s not a perfect system, and that there may be some additional traffic that passes through in the early stages. That’s why we’re in daily contact with the BBC technical teams, to work on how we can better identify and reroute any traffic that gets through outside of Bitesize. Given the scale of the digital learning issue, our view was that we’d rather go more quickly with this route, than go slow or do nothing at all.”

For industry watchers, the technical aspects are interesting. It is possible to carry out some heuristic analysis on content types to classify them as a specific application, even where encryption means you cannot inspect the packets themselves. We spoke to traffic management specialist Enea Openwave to ask it what it thinks could be possible here. Enea Openwave has a lot of experience in identifying traffic flows in order to help operators make decisions around network optimisation, charging and security. It has seen increasing use of SSL and other codecs for traffic on its carrier customers’ networks, which has necessitated other means of traffic and application classification beyond packet inspection.

Enea’s view is that it is indeed possible to zero-rate just the Bitesize content hitting a network from the BBC domain, and in fact it says it has done so itself.

Santiago Bouzas, Director of Product Management at Enea, said, “Yes – it is technically possible. In fact we have analysed BBC Bitesize’s traffic and implemented a mechanism that can identify subscriber sessions that are accessing Bitesize. We use a heuristics-based signature analysis to identify these. While there is a potential for limited amount of leakage in certain edge case scenarios where the user is simultaneously accessing additional BBC content, such leakage is minimal. It would not prevent an operator from launching such a use case.”

So there is support for BT’s claim here – in most cases it does indeed stand a chance of identifying Bitesize from other BBC content. Perhaps the other operators could get on the phone to Enea (and the BBC) and find out how it could be done.

For BT’s part, it is prepared to take a bit of a hit to achieve a greater good, but it does seem that it is not zero rating the whole of the BBC’s output. BT is aware that the very concept of zero rating starts raising net neutrality concerns, and it certainly wouldn’t want to be seen to be prioritising BBC content over other broadcast and content providers such as, say, BT Sport.