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InTheLight

join:2010-08-15
Phoenix, AZ

DSL modem retraining often

I have 1.5/1.0 DSL service with Qwest, it has been working fine for many years until recently. I have the Actiontec GT701 modem and the WAN stats show that it has retrained 50+ times in the last 37 hours.

SNR is 23/6
Atten is 35/24

As you an see the upstream SNR is on the edge for my provisioning and the modem reports that the upstream connection varies between 1024 and ~860 during all this retraining. The downstream connection rate stays steady at 1.5. As you can imagine, with all this retraining, attempts at streaming media or lengthy downloads from the Net are sketchy.

I disconnected all the phones/filters in the house and ran a new cord from wall outlet to modem and the SNR did not change. Also flashed modem to latest firmware. I called out Qwest and they tell me the line looks OK from the outside of house to CO. The tech told me the SNR on the upstream side was 8 which would mean that I have a 2dB loss in house wiring.

I'm wondering if this is normal loss in the house wiring and if a homerun would be worth trying? Also, why would there be such a disparity in upstream and downstream SNR even from the outside of the house to the CO?

Thanks in advance for any help that you can offer.

Ron


bandit8623

join:2004-09-08
Minneapolis, MN

6 is really low. ur atten is good though.

ADSL Noise Margin and Attenuation Numbers

What do the ADSL Noise Margin and Attenuation Numbers mean? From »mybroadband.co.za/vb/showthread.php?t=46156 :

Noise Margin (AKA Signal to Noise Margin or Signal to Noise Ratio)
Relative strength of the DSL signal to Noise ratio. The higher the number the better for this measurement. In some instances interleaving can help raise the noise margin to an acceptable level.

6dB or below is bad and will experience no synch or intermittent synch problems
7dB-10dB is fair but does not leave much room for variances in conditions
11dB-20dB is good with little or no synch problems* (but see note below)
20dB-28dB is excellent
29dB or above is outstanding

* Note that there may be short term bursts of noise that may drop the margin, but due to the sampling time of the management utility in your modem, will not show up in the figures.

Line Attenuation
Measure of how much the signal has degraded between the DSLAM and the modem. This is largely a function of the distance from the exchange. The lower the dB the better for this measurement.

20dB and below is outstanding
20dB-30dB is excellent
30dB-40dB is very good
40dB-50dB is good
50dB-60dB is poor and may experience connectivity issues
60dB or above is bad and will experience connectivity issues

DSL Rate ***/tx/rx/Rate
The actual service data rate that your ISP has provisioned.

Attainable Line Rate
This is the maximum rate at which your modem can connect to the DSLAM if there was no service provisioning limiting the bandwidth. The higher the number the better.

Occupancy
Occupancy is the percentage of line capacity used. Each DSL line is capable of a certain maximum speed or "capacity" dependant on line distance and other varying factors. The occupancy is an expression of your current sync rate setting over your maximum capacity. There are occupancy rates for both upload and download. The lower the figure, the better. Because of error correction and other factors in the DSL protocols, a margin is required so that a connection can be maintained under varying line conditions. If the occupancy approaches 100%, any interference can cause the ADSL sync to be lost. A useful measurement to monitor when sync problems occur. [AFAIK the billion SNMP utility does not give a direct measurement of occupancy :-( ]


InTheLight

join:2010-08-15
Phoenix, AZ

Thank you for your reply and yes, I am aware of what the numbers mean. However, I'm still unsure about why there would be such a difference between the upstream and downstream SNR and also wondering if 2dB loss in SNR is typical for a home.

Thanks,

Ron


bandit8623

join:2004-09-08
Minneapolis, MN
reply to InTheLight

2 db loss is actually not bad. you should be getting around 15 db at the ont. and around 13 at your jacks (maybe even higher).

since your getting such a low number outside the house i would say its a qwest problem. with the really good attenuation numbers i would say your decently close to the dslam.

try doing an online chat with support. i found it to be way less frustrating. and you can post numbers ect..

hope that helped



trythis1

@qwest.net
reply to InTheLight

Hey, u said it has been working for years.. Nothings changed, eh?
So, tell me, you still have the same modem allt his time?

If nothign has changed, your ol' modem probably just wore out.

Buy a new one.


InTheLight

join:2010-08-15
Phoenix, AZ

I suppose it could be the modem but it is only 3 years old, how long do the Actiontec's normally last?

Ron


bandit8623

join:2004-09-08
Minneapolis, MN
reply to InTheLight

in have the same modem. about 5-6 years old. i also have the latest firmware.