Since AS6453 is the official connectivity/technology sponsor for FOM, I suspect they will be leasing some dark fiber to COTA for the F1 race. Some of the F1 teams have their own telecom sponsors (Vodafone McLaren, etc) which will be doing the same. Don't know who would be pulling the actual fiber though...
From what I was told from talking to the on-site IT guy for Caterham, all teams are provide an MPLS connection back to their respective factory. I seem to recall was an insanely small connection for what is the "pinnacle of motorsports"... something like 4mbit or so.
Admittedly this was input from only one team, and a "lower tier" team at that. This was also last year (2011). I remember being distinctly surprised at the relatively low amount of bandwidth they were provided at the track. Tom Walsh