Slow ADSL Speed

[jamie2497]

Hey guys,

Been having massive problems with my ADSL recently as it seems to be degrading in speed over time. I reset the router about 2 hours ago. My router stats are as follows:

Up Stream

1103 (Kbps.)

Down Stream

3815 (Kbps.)

Noise Margin

Upstream - 5db
Downstream - 7db

Attenuation

Upstream - 49db
Downstream - ---db (no reading?)

Fast Path FEC Correction

Near End indicator - 0 Far End indicator - 0

Interleaved Path FEC Correction

Near end - 0 Far End - 0

Fast Path CRC Error

Near end - 121395 Far End - 0

Interleaved Path CRC Error

Near end - 121395 Far End - 0

Loss of Signal defect

Near End - 0 Far End - 0

Fast Path HEC Error

Near end - 64684 Far End - 0

Interleaved HEC Error

Near end - 64684 Far End - 0

Now obviously the lack of attenuation readings, the CRC and HEC errors seem to be problems but i don't really have the knowledge of what it could be.
The connection says 3mb downstream but im seeing a max of 2mb which degrades slowly down to about 0.2mb

My ISP is Zen internet and i've contacted BT and asked them to do a check on the line and they say it seems to be fine. I've also tried the Test line which still doesn't give an Attenuation reading, states its connected at 6mb but is actually again only giving around 2mb.

Any help would be much appreciated guys.

 

[Tealc]

HEC Errors - Header Error Check/Correction

Count of HEC Errors. HEC is a type of CRC error check which has been performed on the header of an ATM cell, but 1 bit errors can be corrected. This count is usually where HECs have been uncorrected and have been discarded.

If these errors are too high within a short period of time it will slow throughput... and could even lead to connection instability - See Out Of Cell Delineation.

Sounds bad to me.

CRC Errors - Cyclic Redundancy Check

Count of CRC errors. CRC is an error detection code used to verify packet transmission between the sender and receiving end. A CRC error indicates that part of the data packet is corrupt and requires retransmission. - see Cyclic Redundancy Check (CRC) for a more in depth explanation.

Many CRC errors in a short period of time will show a noticeable reduction in throughput speed. This can be an early indication that there is too much noise on the line and in extreme situations can lead to loss of sync (disconnection with the exchange).

That sounds even worse. 121395 in 120 minutes means you are getting 17 unrecoverable CRC errors every second, which is a lot. Also notice the errors are all on your end, suggesting that

Now you have a noise margin which suggests your modem can hear the signal over the line noise but it's possible it just can't work out the downstream attenuation for some reason. I'm not sure if that's critical or whether it's just a number it works out based on signal attenuation.

Your upstream attenuation is also massively high. Typically you'd see this at around half of your downstream attenuation, and this is mainly because the signal in the lower frequencies used for upload travel differently to the higher frequencies. You'd expect on a 3Mbit line to get a upload attenuation of sub 30 dB. I'm not sure what way around the errors show up and whether they are reported at the local end or at the remote end so can't be sure which of the up or down directions is causing you an issue. I expect it's probably the down as you can't read attenuation but you never know.

What I'd do first is plug into the master socket or even better test socket (as it removes any extensions from the line) and have a look and see if the numbers resolve and whether the errors settle down.

Any noise on the line? What sync speed and attenuations have you historically had?

 

[jamie2497]

So do you reckon it could be my end, say either the router/filter/cable to the phone line?

Basically ive only been living here for 3 months. When i got here they didnt have a filter on the phone line which made it unstable but for some reason the internet just would not work when a filter was used. Today that problem was fixed and now everything has a filter on so i figured the problem had been solved but the speed is just getting slower and slower.

Before it was fixed the router would connect at about 1.5mb but would obviously get disconnected when the phone rang, zen eventually banded the line which solved the filter issue, the banded profile got removed today. The upload has always been around 1mb and shows this when doing a speedtest however the router connected downstream and download speed have never been correct.

There also doesn't seem to be any noise on the line.