Is my line attenuation good or bad?

iPhone.

Connection Information
DSL
Available eircom broadband
Connected

7168/384 (kbps)
Line Attenuation
29/16 dB

Can anyone tell me if the above stats for sn margin/line attenuation on my 7MB connection are good or bad and if there is any way I can improve or optimise these figures?

eircom: Ant

iPhone. wrote: »

Connection Information
DSL
Available eircom broadband
Connected

7168/384 (kbps)
Line Attenuation
29/16 dB

Can anyone tell me if the above stats for sn margin/line attenuation on my 7MB connection are good or bad and if there is any way I can improve or optimise these figures?

Hi iPhone,

Thanks for your post on the eircom Boards Forum.

The following is a quick guide:

Example

Attenuation: Up: 12.9dB Down: 25.6dB LOWER is better (See below)
Noise margin: Up: 24.1dB Down: 9dB HIGHER is better (See below)

Attenuation is a measure of how much the signal has degraded between the DSLAM and the modem. This is largely attributed to the distance from the exchange. The lower the dB, the better for this measurement. Signal Attenuation is about connection health and is used in these results.
As a rough guide (based on downstream value)...
<20dB and below is excellent
20dB-30dB is very good
30dB-40dB is good
40dB-50dB is not so good
50dB-60dB is poor and may experience connectivity issues
>60dB or above is bad and will experience connectivity issues
Higher speed connections will be more sensitive to attenuation.


Noise margin refers to the difference in strength between the ADSL signal and the background noise on the line. The higher the dB, the better for this measurement.
As a rough guide (based on downstream value)...
<6dB is bad and will experience no sync or intermittent sync problems
7dB-10dB is fair but does not leave much room for variances in conditions
11dB-20dB is good with little or no sync problems
20dB-28dB is excellent
>29dB is outstanding
Low noise margin can be caused by missing, defective or incorrectly connected splitters/filters, faulty telephone equipment in the premises, a defective modem, or noise caused by outside sources such as cheap halogen lamps and stereo equipment, or problems with the telephone company's equipment. If the noise on the line is too high, the modem may lose sync.



The Checklist below should help you with improving your broadband -

http://bit.ly/BBChecks

If you need additional help, call into Broadband Support:

Broadband Technical Support : 1890 260260 (locall); Hours : 08:00 - 22:00 (7 days).

Best wishes,
Ant

iPhone.

Thanks for the information Ant. The following are my stats


Max Allowed Speed (kbps) 7168 384

Down/Up
SN Margin (dB) 6.40 18.00
Line Attenuation (dB) 29.50 16.00
CRC Errors 789 8


Going by what you posted, am I right in saying I have a problem with my noise margin?

eircom: Ant

iPhone. wrote: »

Thanks for the information Ant. The following are my stats


Max Allowed Speed (kbps) 7168 384

Down/Up
SN Margin (dB) 6.40 18.00
Line Attenuation (dB) 29.50 16.00
CRC Errors 789 8


Going by what you posted, am I right in saying I have a problem with my noise margin?

Thanks iPhone,

I've checked your results for attenuation and noise margin with Technical Support and they agree that these are fine.

They are however worried about your CRC errors and have asked that you first do standard troubleshooting before checking your own computer.

They have advised that you call into them if you have any problem doing this. Before you may need to call them, if possible can you temporarily connect just one computer over Ethernet (rj45) cable to your modem. Temporarily shut down other devices and applications currently running. Plug your modem directly on the master phonesocket and remove the Adsl splitter. Disconnect long extension (phone) leads, Sky box(s), fax, etc. from your internal phone wiring. If you have a monitored alarm ensure that the subcontractor has correctly insulated when connecting it to your internal phone wiring:

http://bit.ly/BBChecks


Once you have done this, you may want to check established and listening Tcp/IP and UDP sessions. Take a look at some advice on this on eircom's Forum:

community.eircom.net


Broadband Technical Support : 1890 260260 (locall); Hours : 08:00 - 22:00 (7 days).


Best wishes,
Ant

iPhone.

Thanks for the information Ant. I had a number of old media servers running on my pc from a time when I was trying trying a lot of different ones out before choosing one to use to stream media to my tv.

I forgot to uninstall the old unused media players, these were still using a lot of ports and listening for various mobile devices, netbooks etc which are no longer on my system. Uninstalled all the unused ones and the following is my stats now, the crc errors are greatly reduced so hopefully it is in an acceptable range now?

Downstream Upstream
Max Allowed Speed (kbps) 7168 384
SN Margin (dB) 5.90 20.00
Line Attenuation (dB) 29.50 16.50
CRC Errors 32 0

lucernarian

The CRC thing is just a counter, it's reset to zero every time the connection or router is restarted. So the longer the connection's switched on, the higher that number will be. Basically useless for the purposes of troubleshooting.