Other VoIP providers have had to do deals with internet providers to get them to improve from "best endeavours" to "advanced services" to prioritise streaming traffic. And some ISPs simply don't allow new P2P connections after the number reaches a set level. You try to set up a BitTorrent and it fails to connect.
The good news about 21CN is that, as Samknows summarises, there are more options for quality of service:
The QoS (Quality of Service) options are where the WBC products really stand out against [the ADSL option of] IPStream. QoS allows you to prioritise certain types of internet traffic; so you could prioritise a VoIP phone call (which is sensitive to latency) above a large peer-to-peer download (which is far less sensitive).
The new services are "best effort", "assured rate" and "real time", with the last being the highest quality with the least latency or interruption.
Will that solve the problem? Initially, I'll bet it does. But, at first, there will be no need for real time and its associated higher costs, because with a higher-speed pipe a simple best effort service will work fine. So people who are offering real time based services will be undercut by those who use best effort and get away with it - at first.
And the problem of upload remains. In a sensible world, the need for fast uploads could have been predicted. Telecoms has always been half upload and half download - I dial your number and we spend our time sharing the load in each direction. The reason it was decided to make DSL asymmetric was partly technology - it goes MUCH faster down if you restrict the upload - but also expectation, because many of the people buying DSLAM equipment wanted to compete in the cable TV market.
In short, they wanted to be broadcasters.
The mobile world is suffering from the same delusion right now, with operators clinging desperately to the idea that they can sell video clips to 3G phone users. In reality, they could generate far more traffic just by making it easier for users to upload more. The reason they don't go that way is that they simply don't have the spare capacity. Oh, OK, they have the spare capacity today, but if the video traffic started to become popular (that is to say, if more than five per cent of us started uploading video clips and sharing them over the air) the network would collapse.
It's a rule: code expands to fill available memory; data expands to fill available disk, and transmissions increase until congestion becomes a problem. Providing unlimited "dark fibre" and completely free switchgear at zero power drain would be the only way to avoid that basic truth. ®