Re: My Network
 

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).

I'm not disagreeing with anything you're saying, however all I can tell you is what VM staff were actually trained to look at. I'm not saying it's correct, just that's what the training told agents to look for. Modulation never came into it (it was very briefly glossed over).

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. They have (or had) a tool that gave a lovely colourful view on the errors in that area and a lovely arbitrary %. If the % was above a certain number, it was raised as an outage. If not, it was left to it (Ironically, the threshold was something like 30% but when a line was completely down, the tool only ever reported a static 25% - NFF!). For individual customers, it was T3 and T4 timeouts that mattered in this case (As well as power/SNR).

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



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.

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.

Re: My Network
 

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.



The flap list etc for area outages.

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

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


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.

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

Re: My Network
 

Again, you're not really listening to what I'm saying. Internally at Virgin, they have shifted the SNR and power level targets over the years. Again, it seems TW and NTL had different targets as well for whatever reason (Either different equipment in use, different standards, or whatever). The guidelines used to be a lot looser than they are now, so it may well have even been a cost-cutting measure, who knows.

Also, when Virgin first released 50Mbit, not all agents were trained to deal with it. There was a special "50Meg" team of agents and only those agents would handle 50meg calls (as a customer you had a special number, or if you phoned through to regular BB support, you'd get transferred into the "50meg queue"). Part of this training involved understanding different power levels and SNR targets (As well as the channel bonding). If the only difference was that channels were bonded, then the "training" wouldn't have taken a week and been done by all agents.

And it doesn't matter. From the agent's perspective, they don't care if it's upstream or downstream, just that they're either going to send a tech to the customer or raise an outage for the area - so that's how faults are diagnosed, either it affects the customer or it affects the area. Beyond that, the responsibility ends for the agent so they were never trained to understand what was really going on or what those errors truly meant. That was the job of either the fault tech or the outage teams to determine.


Once more, and I really must stress this, that's not how the agents were trained. The agents were not trained to check modulation and then assess power levels, they were simply told "If this customer is ex-TW, the levels are x and if they are ex-NTL, the levels are y". Again, I'm not saying this was correct (In fact I know later this was very very wrong as new equipment was installed in both areas) and I'm not disagreeing with your statements, I'm simply telling you that this is how the agents were trained to identify the "correct" power levels. There were 3 sets - TW, NTL and DOCSIS3. Also, not all agents were remotely kept up to date with this either, not all of them got retraining as the targets were adjusted.

Once more, I'm telling you how agents were trained to identify it, not what the actual reasoning is. And this is probably why different agents gave out different information over the years.


I was not present pre-merge so I cannot comment.