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Originally Posted by sollp
Does Telewest use 256 QAM for the modem service, anyone work for Telewest confirm this or know if this is correct, i would have thought it would be 64 QAM. Or is the Telewest network 256 QAM?
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ntl and Telewest both use 256QAM where they can.
Sounds like congestion again. I'd speculate upstream congestion too due to this:
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Symbol Rate: 1.280 Msym/s
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Standard now is 2.56 Msym/s so unless Telewest are using 16QAM which seems unlikely as there's really not much point in a small channel with 16QAM they are going to have a lot of asymettry between upstream and downstream.
I'm actually starting to get an idea that Telewest cut a few corners here and there with their network so that while it gave the appearance of being marvellous once they started to push it and actually were in a position where they had to do big bandwidth upgrades they've found themselves with issues.
I can't say I'm completely amazed by issues in this case, this card has 38Mbit of downstream bandwidth but less than 14Mbit of of upstream available, with only 10Mbit or so of that usable before issues become apparent. With the usage of P2P, servers, etc, that the uncapped service encourages by being 100% uncapped not that much of a surprise that a user on an upstream where only 1.7Mbit or so is available without congestion (5 users of 4M or 10M) is seeing probs.
Making sense too why TW didn't increase the upstreams if the above isn't an uncommon situation. Banging in uBRs is all well and good but if you don't upgrade the RF to allow a higher split (allow more upstream) it's a pointless exercise.