Hi Mike, re: "if the MSO gives us a current cable channel of 6mhz, and uses it to allow us to go out and choose content from the 500 million or so websites out there in WWW land, would that cause a huge downstream contention issue?"
The answer to what you ask is no, but you may want to rephrase your question after reading this. A 6MHz channel is assigned for downstream data, and provides roughly 30Mbps to however many customers the CMTS (really, the MSO, since the CMTS is configured by them) wants on the channel. Contention (by my definition)doesn't apply to the downstream channel because the CMTS is the only one accessing it. I think what Frank was referring to is "above" the actual channel, in the CMTS's queues [just before the data is sent downstream], where it could potentially (if the channel is overprovisioned)have more data to send than it has bandwidth to send it on.
If that is the case, the CMTS is supposed to (or should anyway--there is no requirement on how the MSO configures its CMTS) load balance by shifting users to less-utilized channels.
The other issue is downstream per-connection bandwidth caps. If a connection is trying to pull greater than its bandwidth cap, either the flow is shaped to spread out the bandwidth (assuming the excess was in bursts rather than continuous) and still meet the cap over some time interval, or packets are just plain dropped until space is available in that connection's queue.
In general you'd be hard pressed to hit the cap (mine is capped about 2.8Mbps w/ cox@home. they test this when installing or servicing the modem) if pulling data from the greater internet, but from within their intrAnet it could be hit, but rarely. A couple hundred kilobits per second is probably the average I get from the greater internet.
There is no requirement on how or what gets done here, if downstream-cap-exceeding or overprovisioning or poor balancing becomes an issue. But in general you can expect that it won't be anticipatory on the MSO's part. Probably only after weeks of complaints would they address any problems with overprovisioning (especially if they need to spend money to fix it).
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