Noise problem causing low profile

[Rik]

Login to the router. On the first page displayed, there is a 'show statistics' button. In the window that opens, you will see your line stats in the bottom half of the screen.

[Kheldar]

bt speed tester thingy...


Test1 comprises of Best Effort Test:  -provides background information.
    IP profile for your line is - 1000 kbps
    DSL connection rate: 448 kbps(UP-STREAM)  2752 kbps(DOWN-STREAM)
    Actual IP throughput achieved during the test was - 923 kbps


ahha u mean this Rik...


ADSL Link Downstream Upstream
Connection Speed 2752 kbps 448 kbps
Line Attenuation 52 db 15.5 db
Noise Margin 6 db 24 db


polls it every 5 seconds it appears as standard

[Rik]

That's what I expected, your profile is at 1meg. Keep an eye on the router log (possibly set it to email you daily) and watch for disconnections. Manually, or using Routerstats, check the noise margin to see if it's dropping away and forcing re-syncs. If you can maintain your connection for 3 days, then your profile will rise. If you haven't already, then check your wiring, following the sticky on the subject.

[Kheldar]

That's what I expected, your profile is at 1meg. Keep an eye on the router log (possibly set it to email you daily) and watch for disconnections. Manually, or using Routerstats, check the noise margin to see if it's dropping away and forcing re-syncs. If you can maintain your connection for 3 days, then your profile will rise. If you haven't already, then check your wiring, following the sticky on the subject.

ok configured it to mail me logs.

what am i looking for - just it saying connection lost ?

also whats with the  noise margin thingy ? and the attenuation?

[Rik]

You're looking for entries which go like this:

Sun, 2007-05-27 21:01:54 - LCP down.
Sun, 2007-05-27 21:01:55 - Loss of synchronization :1
Sun, 2007-05-27 21:01:56 - Initialize LCP.
Sun, 2007-05-27 21:01:56 - LCP is allowed to come up.
Sun, 2007-05-27 21:02:15 - CHAP authentication success

The LOS number will increment until you re-boot the router.

Noise margin is the amount of 'headroom' which the router has to distinguish your ADSL signal from the background noise. In the days of vanilla ADSL, the higher the better. Max, however, starts off with a target margin of 6db, and tries to get your line running as fast as it can with this margin. If it can't get the line stable, though, it will increase the margin if necessary, and potentially turn on interleaving and error correction. This will improve reliability, but it's no good if you want to play games.

Attenuation is a measure of how far you are from the exchange (though it is also affected by the quality of your line). In this case, low figures are best. My d/s attenuation is 56db, which limits me to a 2.5Mbps connection.

[Kheldar]

ok cheers rik

so whats my line noise / atten looking like then from above figures ?

umm just copied these....wtf is it with that noise figure  


ADSL Link Downstream Upstream
Connection Speed 2720 kbps 448 kbps
Line Attenuation 52 db 15.5 db
Noise Margin 2147483647 db 23 db

[Rik]

For that attenuation, I'd expect you to sync at 3200-3300kbps. However, it isn't going to happen while you have a noise figure like that, which is the router's way of telling you it doesn't like your line. That's not a large positive number, but rather a negative number, -2db I think. The Netgear will generally hold the line down to about -3db and then re-sync. Given the figure you quote, I'd guess it's been doing that quite a lot, hence your low profile.

If you have a test socket (check the sticky), try plugging into that. If things improve, your internal wiring is the issue and needs to be sorted, if not, you need to contact support and get them to have BT take a look at the line. They will want a BT speed test result, so keep the figures handy. My guess is, though, that your internal wiring is an issue.

You may also want to try Routerstats, which is linked in the same sticky. That will graph your noise margin and give you a very accurate picture of what is happening.

Edit: It's worth noting that the browser interface mis-reports u/s attenuation, which is double the figure shown, ie 31db.

[Kheldar]

this morning i've got....

ADSL Link Downstream Upstream
Connection Speed 1952 kbps 448 kbps
Line Attenuation 50 db 15.5 db
Noise Margin 6 db 25 db

[Rik]

Classic overnight re-sync. Check your wiring thoroughly, if you can't improve things, talk to support about getting a BT engineer out.

[Kheldar]

Test1 comprises of Best Effort Test:  -provides background information.
    IP profile for your line is - 1500 kbps
    DSL connection rate: 448 kbps(UP-STREAM)  2496 kbps(DOWN-STREAM)
    Actual IP throughput achieved during the test was - 1382 kbps

today i have the above and.....

ADSL Link Downstream Upstream
Connection Speed 2496 kbps 448 kbps
Line Attenuation 52 db 15.5 db
Noise Margin 7 db 25 db

[Rik]

You should be on a profile of 2000 for that sync speed, throughput around 1900kbps. I suspect your line is still dropping sync frequently?

[Kheldar]

how do i check if its dropping sync ?

router log ?

[Rik]

Yup. The easiest way is to have it send you an email every morning. Then you can see if the connection dropped overnight, which is when it's most likely to.