Non forced router resets.

[#1]

I have PN's TG582n wireless(sort of) router and curious as to why, it disconnects and then reconnects for no apparent reason.
It is permanently powered on and except for a local power cut some time ago has never been switched off and on by myself. I have noticed it will stay connected for some time, usually around 2-3 weeks, seems perfectly stable with a good connection. Then, as last evening, it just reset. The "bandwidth" indicated on the router has increased from 5.1Mb/s to 5.3Mb/s contrary to the previous time when it reduced from 5.6 to 4 point something.
Is this the exchange equipment automatically changing things in an attempt to achieve the best connection, or something else?
However, as far as I could determine the 5.6 setting was perfectly alright for a good two weeks then there was the sudden reduction for whatever reason. 

[#2]

Are you seeing the same symptoms as me? http://community.plus.net/forum/index.php/topic,109919.msg941686.html#msg941686
If the router is losing sync for a few seconds without losing the PPPoA session the DLM at the exchange may raise your target noise margin to try to stabilise the line. In my case it resulted in interleaving being put on when my previous Netgear had been running for nearly a year with it off.

[#3]

Thanks for the reply jelv. I'm not sure if this is the same. I did look at your link but was lost after a couple of the posts!
I managed to find the router connection log and it only shows last evenings event.
Dec 14 18:42:33 PPP link up (Internet) [87.113.231.131]

Info Dec 14 18:42:32 PPP CHAP Chap receive success : authentication ok

Info Dec 14 18:42:32 PPP CHAP Receive challenge (rhost = pcl-ag07)

Info Dec 14 18:42:31 PPP CHAP Receive challenge (rhost = bras-red5.wv)

Info Dec 14 18:42:26 xDSL linestate up (ITU-T G.992.5; downstream: 5302 kbit/s, upstream: 1062 kbit/s; output Power Down: 19.7 dBm, Up: 12.7 dBm; line Attenuation Down: 46.0 dB, Up: 24.6 dB; snr Margin Down: 9.2 dB, Up: 6.3 dB)

Info Dec 14 18:42:00 xDSL linestate down

Warning Dec 14 18:41:53 PPP link down (Internet) [87.113.121.50]
I was just browsing at the time, Firefox shutdown and when I tried to re-opened it the router log in screen appeared. After two or three further attempts, without entering log in details, Firefox restarted normally. I presume that coincided with the re-connection.
It think this must have happened a few times but yesterday was the only time I actually witnessed the event. 

[#4]

That is different because you are seeing the PPP link going down. I wasn't getting that.

[#5]

I had that with my old router[Buffalo] and the TG582n after my old one died.  It always happened when I had an increase in my BT IP profile.  I get the feeling there is now a auto system that will force a dropped sync to force a new IP profile.

[#6]

" I get the feeling there is now a auto system that will force a dropped sync to force a new IP profile."
I did wonder about something like that Gus.
It just seemed odd that it would happen with what appeared to be a perfectly good and stable connection which had been fine for a reasonable length of time. 
Maybe someone from PN would know if there is some kind of "auto system" at the exchange. Oh, I'm on ADSL2+ too.

[#7]

Hi,
I've posted a log of your recent connection;
<img src="http://ccgi.psmith12.plus.com/visradius/generated/image13557392772431.png"/>
Your disconnection on the 15th was caused by a change to your speed profile, this was due to your sycn rate increasing on the 14th when you lost sync on your line.
Prior to that it has been very stable.

[#8]

With regard to your question, the DLM (dynamic line management) system is exactly that - it changes your line profile to adapt to the current line conditions and sync rate. It's not ideal but does do what it's meant to (eventually).

[#9]

Thanks for that, it's definitely not a concern to me because, as seen, the line/connection is quite stable.
I was just curious about the reason(s) for this happening.
It would seem I answered my own question, more or less, towards the end of my opening post.  
Thanks again.