ADSL Noise Margin High!

Rik · Mar 15, 2009, 10:44:47

It doesn't seem to be affected by noise in the way that the d/s margin is, Steve, iow it's never varied.

HoriZon · Mar 15, 2009, 11:19:06

Well through the night my sync has changed a few time its currently set at:

Connection Speed 6400 kbps 832 kbps
Line Attenuation 27.0 db 12.5 db
Noise Margin 14.7 db 10.0 db

Up time of 33 hours.

I have asked idnet twice over the phone if this modem is sending errors on the upstream and they said no on both times, they did say they could see these errors when i was synced at about 5400 kpbs on the old modem as well, it has new filters for both sockets as well and its in the master socket all the time.

Not going to start rebooting it all again as i feel this is what has got me here in the 1st place. Well until its fixed that is i know the odd reboot is fine just not what it was doing on the old modem.

Will wait to see what they say tomm and when i have interleaving set back to FAST as it was always on this and i used to sync at 8128 kbps all the time without fail.

Mainly use the connection for gaming as well so i want the best it can be!

Thanks for everyone's help and suggestions so far i know its not a major problem but when its not what i had its stressful

Rik · Mar 15, 2009, 11:30:57

The 9db of extra target margin you've acquired is worth 1500-2100k of sync speed, so almost certainly you'll regain the speed as that margin falls.

Sebby · Mar 15, 2009, 11:53:51

Quote from: stevethegas on Mar 15, 2009, 10:29:32
O.K is there a difference in the upstream noise margin depending on whether your on supermax or normal with the same attenuation.

It will be lower because of the higher upstream sync on SuperMax.

Ted · Mar 15, 2009, 14:56:37

If interleaving is applied to a line running at 8128kbps the maximum line rate will reduced to 7616kbps.

See section 12.1 and 12.2 of the document in Rik's link.

Steve · Mar 15, 2009, 15:39:59

Taken from Kitz "although BT state 7616 is maximum sync speed with interleaving, many instances of higher sync speeds have been reported by users. This is dependent upon your router being able to support S=1/2 mode which effectively combines two RS code words into a larger logical code word of 510 bytes (ANSI T1.413)."

Three routers which have achieved a higher sync than 7616 on my line when interleave was on are the Linksys wag54gs Speedtouch 565v6 (both over 8000) and Netgear DG834N (full sync). Routers syncing at 7616 BT2700HGV and Zyxel P660HW.

Ted · Mar 15, 2009, 16:21:13

I've also heard of people syncing over 7616 with interleaving on. Shouldn't be possible but clearly is

Never heard of anyone syncing at 8128 though. (has anyone?)

I'm more inclined to think its something to do with the exchange equipment rather that routers (or maybe both). I've tried three different routers, Netgear, Linksys and several 2700's. Never went over 7616 until i had interleaving turned off. Got a Thomson 585 v7 but i got that after the change to Fast

, so i can't say with that one.

My point was that, the maximum line speed would be reduced to some degree, on a line where interleaving was turned on.

Sebby · Mar 15, 2009, 16:39:50

Quote from: Ted on Mar 15, 2009, 14:56:37
If interleaving is applied to a line running at 8128kbps the maximum line rate will reduced to 7616kbps.

See section 12.1 and 12.2 of the document in Rik's link.

Though, just to confuse matters, some exchanges will still connect at 8,128k with interleaving enabled.

Ted · Mar 15, 2009, 16:43:07

i'll get my coat!

Sebby · Mar 15, 2009, 16:43:50

HoriZon · Mar 15, 2009, 16:56:51

I'm getting confused now, will having interleaving turned off and it set back to fast improve my connection to what it was or is it a case of time and to wait it out?

The NM is coming down slowly its dropped 2db in the last 24 hours.

Wish idnet worked on a Sunday !!! want to have my line tested as well now

Ted · Mar 15, 2009, 17:04:36

It's confusing for me as well

Basically, You probably won't be able to achieve full sync with interleaving turned on, although you may do (apparently).

However, even if you achieve full sync with interleaving on, it will almost certainly increase your latency (ping) which may be a problem for gamers.

ADSL, don't you love it!

Lance · Mar 15, 2009, 17:20:23

Noise margin targets drop by 3db every 14 days, as long as continuous sync is achieved. Any other changes are purely due to the noise on the line. Interleaving does not affect noise margins but can possibly affect the maximum sync available.

Rik · Mar 15, 2009, 17:22:16

What Lance said, HoriZon. A 2db drop is just a variation in noise margin, ie there's 2db more noise on the line now than earlier.

Ann · Mar 15, 2009, 18:21:20

Quote from: Ted on Mar 15, 2009, 16:21:13
I've also heard of people syncing over 7616 with interleaving on. Shouldn't be possible but clearly is
Never heard of anyone syncing at 8128 though. (has anyone?)

I used to get 8096 with the netgear but only get 7616 with the 2wire. It doesn't make any difference though, because of congestion I only get throughput of 1500 or something if I'm lucky.

HoriZon · Mar 15, 2009, 20:44:54

Was on the phone talking to friend and after i checked my stats they have gone down again:

Connection Speed 5472 kbps 832 kbps
Line Attenuation 27.0 db 12.5 db
Noise Margin 14.6 db 11.0 db

The phone could be the issue here? i will take it out.

LesD · Mar 15, 2009, 21:09:18

Quote from: HoriZon on Mar 15, 2009, 20:44:54
Was on the phone talking to friend and after i checked my stats they have gone down again:

Connection Speed 5472 kbps 832 kbps
Line Attenuation 27.0 db 12.5 db
Noise Margin 14.6 db 11.0 db

The phone could be the issue here? i will take it out.

For your Target Noise Margin to reduce you will need to keep a stable Connection (Sync) Speed for the number of days mentioned in ealier posts. The Noise Margin you see in the 2700 Stats that you have quoted above varies, for me by time of day but the synch speed should not keep changing. This frequent change of sync speed looks like an instability exists and if using the phone causes it the phone could be faulty or not properly filtered. As you say it needs checking out!

Look under Troubleshooting DSL Diagnostics - here in my 2700, to see your target noise margin, Mgn1

Ted · Mar 15, 2009, 21:39:29

Quote from: LesD on Mar 15, 2009, 21:09:18
Look under Troubleshooting DSL Diagnostics - here in my 2700, to see your target noise margin, Mgn1

Les, think you must have misread somewhere, Mark has a Netgear DG834 v4 not a 2wire 2700hgv,

LesD · Mar 15, 2009, 21:59:03

Quote from: Ted on Mar 15, 2009, 21:39:29
Les, think you must have misread somewhere, Mark has a Netgear DG834 v4 not a 2wire 2700hgv,

Ah you are almost right Ted but not misread just failed to remember! A sign of the times.

I must keep eating the blueberries.

That said the point I reiterated about keeping a stable connection is valid but I cannot remember where or if you can see the Target Noise Margin with a Netgear.

Ted · Mar 15, 2009, 22:05:47

Quote from: LesD on Mar 15, 2009, 21:59:03
Ah you are almost right Ted but not misread just failed to remember! A sign of the times.

Failed to remember what?

Steve · Mar 15, 2009, 22:13:50

Probably of some use HoriZon if you start running routerstats you'll find it here it keeps a track of your downstream noise margin and will show you graphically when your connection takes a dive.

LesD · Mar 15, 2009, 22:20:03

Quote from: Ted on Mar 15, 2009, 22:05:47
Failed to remember what?

Sebby · Mar 16, 2009, 00:00:31

Quote from: HoriZon on Mar 15, 2009, 20:44:54
The phone could be the issue here? i will take it out.

It could be the filters. It might be worth replacing them...

HoriZon · Mar 16, 2009, 00:07:06

Quote from: Sebby on Mar 16, 2009, 00:00:31
It could be the filters. It might be worth replacing them...

New ones on them both now, will ring idnet tomm to have the line tested.

HoriZon · Mar 18, 2009, 11:44:00

Just an update:

Had interleaved turned off on Tuesday after phoning them on Monday it made little difference.

I left my modem on for the next day in the master socket and through the night the sync came down while it was connected! lowest was 4700 kbps.

Phoned them today and they have run a few more test and had BT reset my profile whilst i was talking to idnet the sync was 7200 kbps-ish when i came off the phone it is:

Connection Speed 8128 kbps 832 kbps
Line Attenuation 27.0 db 12.5 db
Noise Margin 12.6 db 12.0 db

Going to leave it in the master socket for most of the day just cant leave it there 24/7 as i cant connect my other main PC to the modem or my Xbox 360.

Is resetting the profile putting me on that 10 day thing when you first get ADSL ?