A couple of clarifications:
1. Upstream DOES use QPSK. (At least in systems using the Motorola CyberSufr). That's why the upstream is slower. QPSK is less susceptable to interference, but is slower than the downstream. Downstream doesn't have the interference problem, since you don't have all those connections adding their noise together.
2. @Home uses optional proxy servers. You can configure your web browser to use the proxy, or not. My previous ISP (still have web sites there) tells me that they get about 30% hits on the proxy. (That is, 30% of pages come from the proxy - 70% have to go out to the net.) It's not specific web sites, but simply according to popularity. Quite importantly, this also caches FTP, so that when you download a popular piece of software, it most likely is being served-up locally. My understanding is that Roadrunner forces you to use the proxy.
3. RoadRunner requires that you run a "login" program. They have a 20-minute timeout on inactivity. @Home doesn't have a login of any kind, and you actually don't have to install their software at all.
4. I've been told that upstream nodes actually handle fewer users than downstream nodes, but I don't have an exact figure. If this is correct, then this partially mitigates the lower upstream bandwidth. |
