Line Stats Analysis Results

Expert

Line Stats Analysis Results

This thread will contain the results of the analysis of everyone's line stats that have been posted in the Data/Stats Collection Thread.

 

My initial analysis is not focused so much on distance from the VRAD.  The reason for this is that not too many people have distances that have been told to them by a tech using their specialized meters.  Furthermore, different line conditions can cause inaccuracy in their measured distances.

 

As it turns out, distance from the VRAD isn't the most important thing regarding the type and quality of service that you get anyway.  Instead, the wiring gauge, presence/absence of bridge taps, and the noise margin (signal-to-noise ratio) of the line are much more important.

 

To this end, the data that has been posted in the Data/Stats Collection Thread led to a rock-solid and extremely useful correlation that can be used to immediately judge the quality of your line and the service you can receive.  That correlation is the Downstream Noise Margin and the Max Line Rate.

 

Using only these two parameters, you can tell if A) Your line is working properly (i.e.. no bridge taps), B) What gauge wire is running from the VRAD to your NID, and C) What line profile you should be able to get.

 

Please note that I arrived at the wire gauge conclusions here because there are two distinct groupings of data points.  I am assuming the difference between them is due to wire gauge, because A) It is known that different neighborhoods around the country use two different wire gauges, 22 gauge, and 24 gauge, B) Thinner wire (24 gauge) would have higher attenuation in the high frequencies, which would reduce the max line rate for a given signal-to-noise ratio, which is exactly what the graph shows.  It is possible that the two groupings of data are due to a different cause, but until I either gather more data or have references to other possible conclusions, I'm going to assume the difference is due to wire gauge even though I cannot currently prove that with certainty.

 

There is a 3rd grouping of data that shows some people with a drastically reduced max line rate.  I'm fairly certain these people have a bridge tap on their line that is reducing the max line rate.  If their line was conditioned by I&R to remove the bridge tap, their max line rate would jump up into one of the other two groupings.  I have witnessed this first-hand, as my initial installation was on a line that had a bridge tap.  When the bridge tap was removed, the max line rate shot up by over 15000 Kbps.  I unfortunately cannot compare the numbers that I had at that point to the numbers I have now because those older numbers were using the VDSL1 protocol and at least 2 revisions earlier of the RG firmware.  Those values cannot be reliably compared to today's values obtained with the VDSL2 protocol and the current RG firmware revision (5.29.135.47).

 

Here's the first fully analyzed chart:

 

 

 

 

 

You can plainly see how well the data groups are formed here.  There are two distinct lines of people with properly working service, and a 3rd line of people with service that is probably not running right.  In addition, you can see the very rare people who are so close to the VRAD that they are currently being capped to a maximum line rate of 64000 Kbps.

 

For those of you who have some background in statistics, the linear correlation coefficients (R^2) for each of the 3 trend lines on the chart was > 0.98.  (This means that the computed lines fit the actual data very nicely).

 

The allowable line profile areas were computed by assuming that a line capacity of 80% is required for properly working service.  Line capacity = downstream profile rate / max line rate.  For example, for a properly working 32/5 profile, the downstream profile rate is 32200 Kbps.  FOr a line capacity of 80%, that means that Max Line Rate = Downstream Profile Rate / 80% = 32200 / .8 =  40250 Kbps, which I rounded to 40000.  The other rates separating the profiles were computed similarly.  The exception is the border for No Service, where I upped the allowed line capacity to 85% to allow just a little less max line rate.

 

The people whom I believe have a bridge tap on their line are very interesting.  The bridge tap reduces the max line rate that the line could theoretically carry by nearly 30%.  In the particular case of the person with an 18.5 dBm noise margin and 29000 Kbps max rate, having the line conditioned could conceivably get him a max line rate of 41000 Kbps, which would boost his allowable profile from 19/2 to 32/5 !  He could conceivable go from 1HD/3SD to 3HD/1SD just by having the bridge tap removed.

 

The person with the 10.0 dBm noise margin and a 19200 Kbps max rate is certainly experiencing poor service.  The line capacity in his case is at 100%, with no margin for errors.

 

 

In short, this chart can tell you at a glance whether your service is operating in agreement with everyone else's service.  It can immediately identify what profile you should be on or be able to get.  It can tell you if your line needs conditioning to have a bridge tap removed.  Based on my assumptions, it can also tell you your wire gauge, although that parameter is questionable.

 

When people post their line stats, this chart can be very useful in quickly determining if they are experiencing line problems or if their service is in agreement with normally working service.

 

Message 1 of 283

Re: Line Stats Analysis Results


jjs2132 wrote:

thanks somejoe7777

I have a cat 5e running from my nid to the rg. All my tv connections are running cat 5e.

I have a new nid installed with a new drop wire to the utility pole when they installed my uverse 3 months ago 

What should i do with the noisey line? I been getting some error with picture freezing and internet stalling couple of times a day.

 

                                                                             Thanks John


 

Call tech support and request for a technician to fix your lines.
Message 91 of 283
Mentor

Re: Line Stats Analysis Results

What do they do to fix the line and What should i tell them when i call because i called once about the freezing picture and internet they just told me to reboot the rg and stb and wouldn't send out a tech

 

                                     thanks 

Message 92 of 283
Expert

Re: Line Stats Analysis Results

jjs2132,

 

Your line may also be picking up electrical interference.  If your home run or other inside wiring is running near a ballast, transformer, power supply, etc. it could be creating some of the interference you're seeing on your line.  You might try to find this device and relocate it, or move the line, or both.

 

Message 93 of 283

Re: Line Stats Analysis Results


jjs2132 wrote:

What do they do to fix the line and What should i tell them when i call because i called once about the freezing picture and internet they just told me to reboot the rg and stb and wouldn't send out a tech

 

                                     thanks 


 

Tell them to run their line performance tool, do quality check, check for Code Violations (CV), Severe Error Seconds (SES), Lost of Frequency (LOS), etc... Last time I called, they gave me those figures to let me know how bad my line was. You have to override their troubleshooting script, by telling them you already did all of those with previous reps. Demand for a tech, and refuse any further troubleshooting.

 

I believe any obvious line problem that shows up should be a job for a tech. If its a physical line problem issue, there is nothing they could do over the phone to fix it. Rebooting the equipments may fix it but only temporary.

Message 94 of 283
Mentor

Re: Line Stats Analysis Results

there is a transformer at the end of the block where i live and my rg is in my furnace room would that be a problem too
Message 95 of 283
Teacher

Re: Line Stats Analysis Results

I decided to give this a try since I have been having problems with my service.

 

http://adslm.dohrenburg.net/tools/3800hg-stats.php

 

hope that you can give me some information about this.

thank you for any and all information

 

Message 96 of 283
ACE - Expert

Re: Line Stats Analysis Results

That's not the right link, a good practice is to check each link when your message posts in the thread. :smileywink:

 

Chris


Please NO SD stretch-o-vision or 480 SD HD Channels
1-800-983-2811 to avoid Mr. Voice Recognition
YRMV IMHO Simply a U-verse user, nothing more
*The views and opinions expressed on this forum are purely my own. Any product claim, statistic, quote, or other representation about a product or service should be verified with the manufacturer, provider, or party.
Message 97 of 283
Contributor

Re: Line Stats Analysis Results

First time poster to the Boards. After reading this thread it looks like I should be able to get the 25/2 profile. Called Tech support and was told I am to far from the VRAD 2700' for that profile. Here are my stats.

 

Current Rate:   19192 kbs   2040 kbs Max Rate:   33839 kbs   Not Available Current Connection:   Current Noise Margin:   21.0 dB   Not Available   Current Attenuation:   24.0 dB   Not Available   Current Output Power:   12.3 dBm   6.4 dBm   IP   Bytes   Packets   Drops   Errors   % Transmit:   1662191296   3625467   0   0   0 Receive:   74436012941   57474221   0   0   0

 

Also link to the Graph - http://adslm.dohrenburg.net/tools/db-link.php?link=1549

Thanks in Advance.

Message 98 of 283
Teacher

Re: Line Stats Analysis Results

sorry I did put in the wrong link.

 

http://adslm.dohrenburg.net/tools/db-link.php?link=1559

 

 

Message 99 of 283
Expert

Re: Line Stats Analysis Results

rhuellin,

 

You are quite far from the VRAD, but I don't see any line problems.  With a 33.8 Mbps max rate and a 21.0 dB noise margin, 25/2 should work for you.

 

Call U-Verse sales (not tech support) and tell them you'd like to have the 25/2 profile with 2HD/2SD.  If they complain that you're too far, tell them you'd like to try it anyway and that if you have problems, you'll call back and request to go back to 19/2 and 1HD/3SD.

 

Message 100 of 283
Expert

Re: Line Stats Analysis Results

etrin,

 

You are having tons of line problems.  Your gateway is retraining very often.  You may have a bridge tap or some other problem.

 

Call technical support and request that they dispatch a premises technician to your house. Show him these statistics. He should look for several things that may correct the problem:

- Replace the balun/splitter at the NID.
- Install or replace the home run from the NID to the RG.
- Check for proper grounding at the RG outlet, the NID, and the pedestal.
- If statistics still do not improve, have the premises tech call the Installation and Repair (I&R) group (also known as the line technicians) to have them come look for a bridge tap on your line. If they find one, the bridge tap needs to be removed by rewiring at the pedestals.

 

Message 101 of 283
Scholar

Re: Line Stats Analysis Results

Thanks SomeJoe, but one more question for you. From the stats on the previous post you stated I have a perfect line. Does that mean the 32/5 and possible 3hd will run without problem in the future? I still have not been moved to 32/5 yet.

 

I guess that the answer is yes with perfect line but one never knows for sure.

 

Again thanks for all your time an knowledge with this and all other U-Verse issue's

Message 102 of 283
Expert

Re: Line Stats Analysis Results

camp80, yes, no problem for 32/5 when rolled out for you.

 

Message 103 of 283
Teacher

Re: Line Stats Analysis Results

They first came out and could not find a signal..after about an hour ok it works now. They installed everything.

I started being disconnected every 50 minutes.

They did another dispatch and the guy looks at the box on the side of my house.

man when was this done, he should have replaced this mess when he was here. He tore it down and redid it all. 

OK thats it and left.

Same thing.

talked to a tech 2 agent and he dispatched a lineman.

Well your line does not exist any more and so I build a new one from the vrad(??) to your house. They had a ground in a box on the pole behind your house so I wired around the box...good to go.

well it seemed like it. It was working a lot better then started to disconnect again.

contacted tech 2 again and he did something and I thought they had it fixed.

After a few days it started resetting again (this is the red light on the modem flashing and everything lockes up)

Now its not every 50 minutes but it might go 2 days then reset 2 or 3 times in 1 hour

 

I have cat5 cable from the outside box to the jack the modem is plugged into.

They used coax from this (an old comcast modem) to the utility closet. From there a splitter hits the 3 tv's also with coax.

 

 

 

 

Message Edited by etrin on 02-09-2010 04:24 AM
Message Edited by etrin on 02-09-2010 04:25 AM
Message 104 of 283
Contributor

Re: Line Stats Analysis Results

Hi,  I'm equally as frustrated.  My gateways boots intermittently, and has me wondering if I should switch to cable.  I've been an AT&T customer for a long time.  I'm disappointed in the fact that they can't seem to fix my problem.  I've had my RG replaced, and several techs out the past few months. 

 

Can you make sense of this report for me?  Help!

 

Training History Analysis:
PROBLEM: Due to LOSS OF SIGNAL your 2Wire retrained 3 times since the last reboot. High probablility of noisy or unstable VDSL line.
PROBLEM: In 1 ocasions your modem retrained for UNKNOWN REASONS.

 

Message 105 of 283
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