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[Gummby]

Hi

I was advised by Kitz to post this here.

I am having syncing issues with my local exchange. I believe it is the modem. (BT Voyager 210. probably an over heating issue on the modem?

I am currently with Vispa ISP on ADSL 2+.

I was considering a netgear 834 modem to replace my current one.

I have had an engineer round who replaced some part on my BT socket. He states the line was fine.

Anyway. Any thought on the below line info.
Line Mode    ADSL2+         Line State    Show Time    
   Latency Type    Interleave          Line Up Time    00:02:29:06    
   Line Coding    Trellis On         Line Up Count    1    
   Line Power State    L0                   
      
   Statistics    Downstream    Upstream    
   Line Rate    6654 Kbps    444 Kbps    
   Noise Margin    25.0 dB    30.1 dB    
   Line Attenuation    30.5 dB    14.1 dB    
   Output Power    0.0 dBm    12.2 dBm    
   MSGC (number in overhead channel data)    65    10    
   B (number of bytes in Mux Frame)    94    63    
   M (number of Mux Frames in FEC Frame)    1    1    
   T (Mux Frames over sync bytes)    2    1    
   R (number of check bytes in FEC Frame)    16    0    
   S (ratio of FEC over PMD Frame length)    0.4545    4.5310    
   L (number of bits in PMD Frame)    1954    113    
   D (interleaver depth)    64    1    
   Super Frames    554524     554522     
   Super Frame Errors    0     0     
   RS Words    78742476     0     
   RS Correctable Errors    494     0     
   RS Uncorrectable Errors    0     0     
   HEC Errors    0     0     
   OCD Errors    0     0     
   LCD Errors    0     0     
   ES Errors    0     0

[kitz]

Noise Margin    25.0 dB    30.1 dB   

Sync speed obviously very low for the attenuation. 
Can you reboot the router and post another set of stats immediately after the reboot please

[Gummby]

If I reboot it may take me anything from 30 mins to 2 hours to reconnect.  I assume you mean restart the router? I can turn it on and off.

Is that noice margin low??? Is that the issue??

[kitz]

The noise margin is waaaay too high... 
Your line should be syncing at about twice the speed of what it is for your attenuation.

Rebooting the router (turning off/on) and taking some fresh stats immediately after resync should give a clearer indication of what the msan in the exchange is seeing from your line and help see what kind of target profile you are on.

Theres obviously an issue with noise somewhere, not sure from whats posted above so far, whether its the physical line/REIN or the router.

[kitz]

...  and can I ask the other forum members to perhaps come up with some possible suggestions for a good replacement router as Im a bit out of touch with whats the latest available on the market.

Budget £50 max - wireless not essential.

[roseway]

For a replacement router I wouldn't recommend the Netgear DG834(G) unless you can get one of the earlier v4 versions, which has a Broadcom chipset. The current v5 version has rather poor performance due to its Conexant chipset. In general, Broadcom-based routers are reliable performers, and one of the latest ones, the Billion 7700N, is getting good reviews.

For a really cheap option you could get a BT Business hub 2700HGV from Ebay, and these are widely respected for their performance on long and difficult lines, but on your fairly short line they may not be so good, compared to Broadcom types.

[Gummby]

Okay finally back online.


      
   Line Mode    ADSL2+         Line State    Show Time    
   Latency Type    Interleave          Line Up Time    00:00:00:40    
   Line Coding    Trellis On         Line Up Count    1    
   Line Power State    L0                   
      
   Statistics    Downstream    Upstream    
   Line Rate    6654 Kbps    444 Kbps    
   Noise Margin    25.0 dB    28.3 dB    
   Line Attenuation    30.5 dB    14.1 dB    
   Output Power    0.0 dBm    12.0 dBm    
   MSGC (number in overhead channel data)    65    10    
   B (number of bytes in Mux Frame)    94    63    
   M (number of Mux Frames in FEC Frame)    1    1    
   T (Mux Frames over sync bytes)    2    1    
   R (number of check bytes in FEC Frame)    16    0    
   S (ratio of FEC over PMD Frame length)    0.4545    4.5310    
   L (number of bits in PMD Frame)    1954    113    
   D (interleaver depth)    64    1    
   Super Frames    2478     2476     
   Super Frame Errors    0     0     
   RS Words    351936     0     
   RS Correctable Errors    0     0     
   RS Uncorrectable Errors    0     0     
   HEC Errors    0     0     
   OCD Errors    0     0     
   LCD Errors    0     0     
   ES Errors    0     0     

[roseway]

Those stats are essentially identical to the earlier ones, and as Kitz said, you have a very high downstream noise margin. It rather looks as though your speed has been capped at 6654 kbps (although this may just be coincidence), and I think you should ask your ISP to confirm or rule out this possibility.

Otherwise, your suggestion that the modem is the cause of the problem looks quite possible, and really the only way to be certain about this is to replace it.

[Gummby]

Is this high noise margin an issue? Does this mean I am too far away from the exchange? ?? Is this likely to stop me getting FTTC connection in future months??

Could it also be that I am in flats and the flats seem to have wires going from a central cabinet to all the flats? More cable can't be a good thing.

I did wonder about my line speed. I emailed vispa a week or so back and they stated I was on up to 24mb service. Clearly i am only reach a fraction of that speed.


As for the modem. Billion 7700N. if i get a wireless one is there a way to disable the wireless aspect. I certainly don't want free loaders on my broadband. It is also unclear if Modems from retailers automatically enable the best WPA2-psk settings.

[Oranged]

Are you using one of those plug-in telephone extension leads (as sold in DIY outlets) anywhere in your flat ?

Just to explain what everybody has been saying re. noise margin and sync speed, I'm just a little further than you from the exchange and these are my stats on an ADSL2+ connection :

Bandwidth (Up/Down) [kbps/kbps]:   1,313 / 9,411
Data Transferred (Sent/Received) [kB/kB]:   0.00 / 0.00
Output Power (Up/Down) [dBm]:   12.0 / 19.0
Line Attenuation (Up/Down) [dB]:   19.5 / 38.5
SN Margin (Up/Down) [dB]:   7.0 / 6.0

So if your noise margin was similar to mine (which it should be) then your connection speed would be near 15000kbps rather than the 6654kbps that it is currently.

Just a thought re. your comment about the phone cabling within the flats....it is quite possible that this may be a cause. If the flats are relatively new then the cabling was probably installed by the builders/electricians rather than a telecomms engineer.

[roseway]

What Oranged says is right, but bad phone cabling wouldn't explain the very high noise margin. Something else is holding your speed down and your noise margin up, either a cap (or deliberatly high target noise margin) or a disfunctional router.

[HPsauce]

either a cap

That gets my vote. 
The upstream speed of 444 is suspiciously close to 448 that you usually get with ADSL1.
(and I think I've seen on other capped lines)

That said, finding out who has applied it and whether they'll remove it may not be easy.

Trying another router first is a necessary step in diagnosis whatever the cause.

[kitz]

Thanks for posting the 2nd set of stats.   

The reboot at 6654 looks like something is capping your speed.  The additional SNR means that you 'should' be getting much higher speeds.

Your current router the Voyager 210 should support up to 24Mbps and is adsl2+ compatible, but they are a bit old now.

I believe 6656kbps is a common cap that can be set by BTw on the DLM to help stability.  Check with your ISP...  but from your attenuation, your line should be able to support about at least double what you are getting.

Thanks for the recommendation of the Billion Eric, wasnt sure what others would suggest.  I'd already suggested trying to get hold of a v4 netgear with the broadcom chipset via PM, but these seem a bit difficult to source now and most seem to be the v5 with the connexant chipset.

If the BTo engineer has tested the line and says its fine, then the Billion may be the way to go to ensure that its not the router that causing problems.... but I still think that line is capped.

[kitz]

As for the modem. Billion 7700N. if i get a wireless one is there a way to disable the wireless aspect.
I certainly don't want free loaders on my broadband. It is also unclear if Modems from retailers automatically enable the best WPA2-psk settings.

Yes

[kitz]

Bit hard to say from the 1st set of stats since it had only been recording for a couple of hours, but the amount of errors doesnt give me any cause for concern and are all RS corrected.  Theres no CRC/HECs, so it looks as if its been stable up to that point of reboot.

Would be interesting to perhaps monitor over a longer period to say for sure... as it is possible for noise bursts to occur at certain times of the day.

Gummby - did you do the boot at about mid-day... or was that just uptime since the engineer had visited.. or did it resync itself?