3 ms·

Thank you for saying, succinctly and clearly, what I've always figured was the case. However. If the majority of traffic came p2p, then the asymmetry of uploa

Thank you for saying, succinctly and clearly, what I've always figured was the case. However. If the majority of traffic came p2p, then the asymmetry of upload/download bandwidth on shared media like cable modems would start to be a significant issue, wouldn't it? Only on the local segment, but on _every_ such segment. In that case, the seedbox-as-CDN-node route would be a no-brainer for ISPs to install. Are we reinventing the topology of Usenet?

AnthonyMouse 5y ago
Cable connections are typically asymmetric, but the average user doesn't max out their connection 100% of the time. Even if you have a 100 Mbps down 10 Mbps up connection, your average transfer rate might be 5 Mbps because most of the time your connection is idle. Which means you can feed it from peers with an upload cap of 5 Mbps, in theory, if they kept their uplinks saturated all the time. Or an upload cap of 10 Mbps if they all kept their uplinks half saturated all the time. And you can still get 100 Mbps downloads that way by downloading from multiple peers at once, which doesn't change the average transfer rate required from each peer because then twenty people upload at 5 Mbps for 10 seconds instead of one peer having to upload at 5 Mbps for 200 seconds to transfer the same amount of data. But the asymmetric link speed is artificial anyway. There is no technical reason they couldn't make fully symmetric cable modems -- in fact they did so in DOCSIS 4.0, though it's not widely deployed yet. The main reason they're hesitant to offer it is, ironically, that P2P isn't sufficiently widely used. Because then hosting is scarce and people will have the incentive to do high volume hosting on their own connections. Which is bad for the ISP who offers a fast uplink, because they rely on over-subscribing their connections to offer the prices they do. If you give someone a fast uplink, it's quite easy to saturate it 24/7 by serving files to millions of users. So the ISPs don't want to do that. But if P2P distribution was the default then that wouldn't be a problem because nobody would need to do that. You'd upload your thing once or some small number of times and then the users could get it from each other instead of millions of people all trying to get it from the one host. Everyone could have a 100 Mbps uplink and the average upload speed would still equal the average download speed, e.g. 5 Mbps, because that's all you need when the load is evenly distributed.

AnthonyMouse 5y ago

Cable connections are typically asymmetric, but the average user doesn't max out their connection 100% of the time. Even if you have a 100 Mbps down 10 Mbps up connection, your average transfer rate might be 5 Mbps because most of the time your connection is idle. Which means you can feed it from peers with an upload cap of 5 Mbps, in theory, if they kept their uplinks saturated all the time. Or an upload cap of 10 Mbps if they all kept their uplinks half saturated all the time. And you can still get 100 Mbps downloads that way by downloading from multiple peers at once, which doesn't change the average transfer rate required from each peer because then twenty people upload at 5 Mbps for 10 seconds instead of one peer having to upload at 5 Mbps for 200 seconds to transfer the same amount of data. But the asymmetric link speed is artificial anyway. There is no technical reason they couldn't make fully symmetric cable modems -- in fact they did so in DOCSIS 4.0, though it's not widely deployed yet. The main reason they're hesitant to offer it is, ironically, that P2P isn't sufficiently widely used. Because then hosting is scarce and people will have the incentive to do high volume hosting on their own connections. Which is bad for the ISP who offers a fast uplink, because they rely on over-subscribing their connections to offer the prices they do. If you give someone a fast uplink, it's quite easy to saturate it 24/7 by serving files to millions of users. So the ISPs don't want to do that. But if P2P distribution was the default then that wouldn't be a problem because nobody would need to do that. You'd upload your thing once or some small number of times and then the users could get it from each other instead of millions of people all trying to get it from the one host. Everyone could have a 100 Mbps uplink and the average upload speed would still equal the average download speed, e.g. 5 Mbps, because that's all you need when the load is evenly distributed.