The graphic on the left is from a Vonage test of the connection at a friend’s house near Boston. Comcast cable is her provider. The test was on her computer, which is connected directly to the cable modem. I thought that test result was exceedingly lopsided and Old Skool in respect to upstream performance, so I conducted a different test on the same connection with the same computer. The result: 11958Kbps down and 358Kbps up.
Comcast can do better than that. I suspect the only reason they’re not is because they’d need to “bind” some number of channels that would otherwise carry television. Whatever’s going on, it’s clear that the Net is just gravy on TV. Feh.
Comcast customer here. Vonage shows me with a 10.0Mbps download and a 1.95Mbps upload speed.
7,769Kbps download with Speedtest.net and 939Kbps upload.
11.2Mps down and 2.24Mps up Vonage after I turned utorrent off. Oopsie!
10,014 down and 1,041 up with Speedtest.net.
And I’m going through a router. Still an order of magnitude than your friend is getting on the up side.
Hey Doc, here are the results for my Cox cable connection using Speakeasy.net
13290 kbs (1661.3 KB per sec.) Download
1145 kbps (143.1 KB per sec.) Upload
It’s a question of network engineering. Cable Internet has two channels, one for downloads and the other for uploads. On the download side, there is only one transmitter, so he can jump in the cable immediately each time he wants to transmit, using addresses in the packets he sends to determine who gets the stuff. Every receiver sees every download packet. The cable is running at something like 25 Mb/s (more or less) and that’s pretty close to the utilization.
On the upstream side things are complicated by the fact that you have multiple potential transmitters on the same channel, so they need a control procedure to ensure that they don’t step on each other’s packets. The overhead in this procedure – some sort of time slotted thing overlaid on a polling system – keeps the upload speed down because it drops the cable throughput to something like 25% of the raw signaling rate. It’s kinda like WiFi, where you have systems with signaling rates of 54 Mb/s that can only achieve throughput of 26 Mb/s because of network overhead. If the cable system wanted to offer higher upload speeds, they’d need to set aside more channels or deploy more headends and populate each cable less densely. But their main revenue source is TV, not Internet access, so you’ll have to put up with sharing your cable with lots of other people until that changes.
You’re ahead of the curve, so you get the arrows in the back.
When the cable Internet specs (it’s called DOCSIS, BTW) were written, the expectation of cable providers was that downloads would dominate uploads by at least 100:1, that being the conventional distribution of interactive applications like web browsing. So they were pretty radical to break out as much as a 10:1 ratio. They must have been expecting a lot of e-mail. Now the market has changed and with it the engineering will have to change.
Verizon’s FiOS is by far the coolest thing going in broadband today, and I have lust in my heart for it. I’m on Comcast with not even a DSL option, and the monopoly really stinks. I used to have a sentimental attachment to cable Internet because I wrote the software the @Home installers used, but that was long ago and far away.
Enjoy your Verizon, you lucky dog.
The whole upload process is hampered by the dynamic allocation of IP addresses used. In the days of dial up, the ISP needed fewer IP addressed when they were dynamically allocated, but this is no longer true. I already pay for bandwidth, why should I pay more to allow others to pull data from my system instead of my pushing it?
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