"People always want more bandwidth"

Nomad attended an IET Seminar last week which was presented by Giles Heron who is a Network Architect at BT. Interestingly Giles admitted to not owning a television.

The seminar provided an overview of BTs 21st Century Network project which involves switching the core network entirely over to the use of IP. BT will even be using IP for voice channels (hopefully the quality will be better than Skype). For the local loop BT are currently rolling out ADSL2+ which offers up to 20Mbs (if you live next door to the exchange). For the longer term BT are trialling fibre to the cabinet which will offer 40 Mbs and fibre to the home which will offer up to 100 Mbs.

Nomads reason for turning up however was that the seminar also provided a view of where the networks see demand growth coming from. The ISPs and Telco’s are running scared of the bandwidth implications resulting from the use of video on demand (VOD). Interestingly from a Telco point of view Live TV over internet is not very problematic as the network can cope with point to multipoint streaming; the backhaul bandwidth is not that great. His implication was that BT is considering offering live IPTV as a retail product. Conversely however video on demand creates an enormous backhaul requirement.

Some statistics illustrate the issue: BBC iPlayer currently generates 12Gb of data per second into the BT network. BT already sees peaks in overall network usage due to popular iPlayer demands such as Grand Prix. Looking forwards it is estimated that by 2013 90% of global internet traffic will be video

There was a question from the floor about whether the network operators were expecting a financial return from VOD, particularly given that the lack of return on investment in HD TV made by various broadcasters. Giles admitted that there did not appear to be much return available and the network operators saw themselves running ever faster just to stand still. However the ISPs and Telco’s are committed to provide this bandwidth as this is what the customers want.

Possible mitigation strategies for offloading VOD traffic were discussed. These included Peer to Peer sharing, Local Storage, Network Cache and Download at off peak periods (night time). Nomad did not think of this until he was back home, but the “pull” model of video on demand is obviously flawed and needs replaced with a “push” model. If new editions were streamed to subscribers at set times then point to multi-point streaming could be used to dramatically reduce network load. Obviously the stream needs to be repeated regularly in case subscribers did not have their PC turned on.

The big point that Nomad took away is that the networks have already decided that video on demand is going to happen. The Telco’s planning assumptions are based on people switching to video on demand. A major shift in the way that people watch “television” is under way.