Another part of traffic management is planning how much capacity is required. We’ve recently updated how we work out the capacity that is required to work in a far more granular way. Previously we allocated a kilobit per second value to each account type based on three periods of the day - midnight to 8am (night), 8am to 4pm (day) and 4pm to midnight (evening) and calculate the amount of capacity based on the day and evening figures (and the custumer numbers) and the amount of extra bandwidth purchased. Now we are looking on a more hour by and protocol-by-protocol basis which, combined with the extra bandwidth gives a better handle on the forecasting.

With something like iPlayer going from a fraction of 1% to approximately 5% of the total network capacity in only a matter of weeks the forecasting needs to react to changes in usage at the very least on a weekly basis.

And that really best sums up the plans for 2008. We have ideas on some of the things that going to drive usage and what some of the content providers have in store. But ultimately what we are doing is keeping a very close eye on what customers are doing and what’s changing. We knew iPlayer would be big, but we didn’t know exactly how big, we suspect that without the Flash version it wouldn’t have seen as large a take-up as it has, and certainly not as big without the promotion it’s been getting. Same with iTunes movie rentals, if that takes off it could easily account for similar levels of traffic as iPlayer and so could a number of others. We shall just see; it’s one of those interesting rides.