Quote:
Originally Posted by Ignitionnet
Your current phone line connects to a single point of failure line card via a single point of failure piece of copper, and from there goes on a fibre link whose resilience to JCB action may or may not be especially strong.
Resilience is supplied by using battery back up power supply for the amplifiers.
That is adequate, alongside ensuring that you've Pre-EQ and the UGS service flows that VoIP will use run at a very conservative modulation or aggressive dynamic upstream modulation profile if it's possible. Given each call requires just 64kbps running them at QPSK is fine.
QPSK with Pre-EQ, etc, etc, means upstream SNRs right down to ~12dB are feasible.
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That's all well and good, but historically the broadband has been much less reliable than the phone line (Not a slant on the infrastructure, I think it's just the nature of a much more complicated beast). In all the years I've been with Virgin, I think I've had one phone fault but numerous broadband faults.
As for bandwidth, the problem is when congestion hits. It's fine saying you can run it off QPSK but the total bandwidth drops considerably and people are still going to be downloading stuff. QoS is the answer to that but again, historically, Virgin have never been particularly great at that sort of thing and I'm not confident it'll work well in those situations.