Throttling

A while ago, I blogged about the NBN Australia and how much benefits that city folks like myself will (not) receive. There is another little quirk that NBN Co. never mentions – throttling.

Throttling refers to the traffic control measure applied by all ISPs and telcos to limit the speed/bandwidth available to the end users – squeezing the pipe, if you like.

Have you ever wondered why your Limewire/Frostwire bandwidth is so low (as low as a few Kbps – lower than dial-up speed) although you have allowed the highest settings in the software? That is because ISPs throttle many P2P traffic including Limewire/Frostwire. Such traffic policy control has been standardised by the telco industry body 3GPP under the topics of PCRF and PCEF (TS 23.203), where DPI is usually used to detect the type of traffic (e.g. Limewire, IMAP, FTP, Skype, etc.) and apply the service policies and charging to the individual traffic sessions. These standards are implemented by all the major network equipment vendors.

Throttling is applied because such P2P traffic can amount to more than 80% of the total traffic of an ISP, which is not surprising considering a HD movie can be as big as 10s of Gigabytes. So it is pretty certain that even if you have an unlimited internet plan with 1Gbps burst rate, it can still take days/weeks to download that movie you are dying to see.