ADSL Line keeps desynching

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XennoX

Expert Member
Joined
Nov 15, 2007
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Йоханнесбург (Jhb)
Hey guys, I seem to have a problem with my line.

It keeps desynchronising every day without fail. Today it desynchronised, then synchronised, and could not hold it and the pattern repeated itself for 30 minutes.

Phoned Telkom, guy reset the port and whatnot, and the line behaved itself during the duration of the call. 10 minutes after the call it started its trouble again. Any ideas?

Code: 
Modem Status
	
Connection Status 	  	Connected
Us Rate (Kbps) 	  	128
Ds Rate (Kbps) 	  	384
US Margin 	  	12
DS Margin 	  	27
Trained Modulation 	  	ADSL_G.dmt
LOS Errors 	  	0
DS Line Attenuation 	  	16
US Line Attenuation 	  	14
Peak Cell Rate 	  	301 cells per sec
CRC Rx Fast 	  	0
CRC Tx Fast 	  	2
CRC Rx Interleaved 	  	0
CRC Tx Interleaved 	  	0
Path Mode 	  	Fast Path
DSL Statistics
	
Near End F4 Loop Back Count 	  	0
Near End F5 Loop Back Count 	  	0

Code: 
 Modem Status
	
Connection Status 	  	Connected
Us Rate (Kbps) 	  	128
Ds Rate (Kbps) 	  	384
US Margin 	  	12
DS Margin 	  	12
Trained Modulation 	  	ADSL_G.dmt
LOS Errors 	  	0
DS Line Attenuation 	  	16
US Line Attenuation 	  	14
Peak Cell Rate 	  	301 cells per sec
CRC Rx Fast 	  	0
CRC Tx Fast 	  	35
CRC Rx Interleaved 	  	0
CRC Tx Interleaved 	  	0
Path Mode 	  	Fast Path
DSL Statistics
	
Near End F4 Loop Back Count 	  	0
Near End F5 Loop Back Count 	  	0
 
From my knowledge, your stats seem okay - your line shouldn't be dropping too much if they were stable, but check how at one point your downstream noise margin was 27 (Very good) and the next moment 12, meaning there must be quite a lot of dynamic noise on the line, which obviously gets bad enough at times to desynch your line. Get that routerstats app and graph the noise margins in particular. If you observe that the margins fluctuate wildly and get close to 0, theres probably something wrong on the line. Try the usual diagnostic of unplugging all phones and filters on your line so that it's just the DSL modem using the line, and see if it makes any difference.
 
My line does the exact same thing. I have constant attenuation of ~10 and ~5, and the same thing happens to my neighbour.

Telkom can't help us either. ;/
 
Ditto. Been having this problem on and off for months. If I pick up the phone and start dialling 0800... and then leave the phone off the hook, it comes right almost immediately. If I unplug everything else and just keep the modem on the line it doesn't make any difference.

I've reported it to Telkom about 8 times. Of course by the time I've dialled, the modem behaves beautifully. Each time I have to open a new support ticket, because it is an intermittant problem and they "not allowed" to leave cases open, and of course, after a day or two not desynching they phone me to say they've fixed it. "But what if it starts doing it again?" I ask. "Get a new job number." Hmmm.
 
I've been having loads of desync's too, largely due to the SNR just dropping. It seems to be happening mostly at night, interestingly enough. My SNR graphs are steady during the day, and come 7pm, they just flake all over the place. Some routers handle it better than others.

I've ditched my Cisco, in lieu of an el cheapo Linksys WAG54G that just seems to claw on to the connection no matter what. Sometimes thought, it loses it for a few minutes.

There's definately something up. First, I figured it's the weather, but that didn't relate after a few days of statistics gathering. It's normal for SNR to vary due to noise, or line conditions, but I have a hunch there's a pattern here somewhere.

Make a note of the times you lose synch, or even better, get something like Cacti to graph the SNR if your router supports it.
 
Ditto. Been having this problem on and off for months. If I pick up the phone and start dialling 0800... and then leave the phone off the hook, it comes right almost immediately. If I unplug everything else and just keep the modem on the line it doesn't make any difference.

I've reported it to Telkom about 8 times. Of course by the time I've dialled, the modem behaves beautifully. Each time I have to open a new support ticket, because it is an intermittant problem and they "not allowed" to leave cases open, and of course, after a day or two not desynching they phone me to say they've fixed it. "But what if it starts doing it again?" I ask. "Get a new job number." Hmmm.
Click to expand...

We seem to have the same problem. I phone them, and my router behaves beautifully, it gives me the full 44KB/s I have come to expect from it. As soon as I put the receiver down the line begins to drop again. =/
 
Same here

I'm also having this problem for more than a month now.
 
Same problem here - in JHB. Mine acts up during the peak hours though which lead me to think it was some sort of overload on the exchange.

From 8am-3pm is the worst. At night it never loses sync and on the weekends it holds out all the way through.

I dunno...here I go blaming Telkom again but could it be that the ADSL customer base is growing but the infrastructure isn't?
 
Me in JHB and I have the problem usually between 8pm and 12am.

If the user base is growing and the infrustructure isn't keeping up IMHO that is Telkom's fault through and through.

Thanks for the link fz1.
 
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