[MUD_Wizard]

Originally Posted by Kushan

You need to define "A long time". I'm talking about ~5 years ago now and I don't know what the OP's timeframe is, nor if there are agents that still use the "old" guidelines (Wouldn't surprise me).

Virgin introduced Docsis 3 in 2009, with multiple bonded 256 QAM downstreams channels for 50Mb, however 256 QAM would have been available on Docsis 2 before that (but not at launch of Docsis 2).

http://about.virginmedia.com/press-r...test-broadband
http://forums.thinkbroadband.com/vir...fpart=all&vc=1

The number of channels bonded doesn't change the SNR thresholds set by the Docsis specifications. So, sometime after 2003 and well before 2009. Unless VM skipped Docsis 2 for some areas..

Of course most people will have been on Docsis 1 and gradually been moved over to Docsis 3.

Originally Posted by Kushan

Again, agents were taught to look at it slightly differently. They largely ignored post-rs errors for individual customers and instead only looked at the errors on a specific line/cable.

The flap list etc for area outages.

Originally Posted by Kushan

For individual customers, it was T3 and T4 timeouts that mattered in this case (As well as power/SNR).

T3 and T4 timeouts are upstream. It's SYNC errors and MDD's for downstream.

Originally Posted by Kushan

No indeed, they quoted 20dB in some areas as being acceptable (ex-NTL if I recall).

As I said, it's related to modulation. For more info see: http://community.virginmedia.com/t5/...4/td-p/2271297

Originally Posted by Kushan

The power levels these days are definitely more consistent and it was aligned internally with the Docsis 3 rollout, however prior to that the range was much larger (I want to say -10 to +12 but I'm not 100%) and again, did differ by area on occasion.

Power level ranges changed over the years due to aggregate/bonded downstream power and the number of bonded channels changing. See the primer linked above, it has a section devoted to it.

Originally Posted by Kushan

If I had to guess, the guidelines being different for ex-TW and ex-NTL possibly stem from the merging of the two. I would not be surprised if both companies simply had different guidelines for their agents and Virgin simply decided to keep treating them separately until they got their ducks in a row.

Sure there were differences as far as I understand it. Though not on the basics.