Downstream rate cap and sync speed

[Wingnutz]

Ok - had a problem earlier today with disconnections when recieving or make calls - new filter fixed this.

I've also whilst I had the time removed the bell wire from the mater socket.

Anyway I'm now reconnected and have no more problems with the phones - however...

My 2Wire 2700 is reporting a Downstream Rate Cap of 6656 and a sync of 6654.

Also on the diagnostics page it is also reporting the following

Max1 8309
Max2 8281
Max3 8281

Should I be gettting a sync rate closer to this ? I'm on the upto 24mb ADSL2+ service.

Any help / advice appreciated.

Other modem stats below.

Troubleshooting – DSL Diagnostics
General Information
DSLAM: Country: {0xB5} Vendor: {IFTN} Specific: {0xB971} 
DSL Line (Wire Pair): Line 1 (inner pair)
Downstream Rate Cap: 6656 kbps
Downstream Atten. at 300kHz: 31.9 dB

Uncancelled Echo: -20.7 dB Ok
VCXO Frequency Offset: -5.2 ppm Ok
Final Rx Gain: 21.0 dB Ok
Impulse Noise Comp. Tones: 0 Ok
Excessive Impulse Noise: 0 Ok
Impulse noise protection:  2.54
Delay of latency path:  6.09 ms

Time                                 Rate Max1 Max2 Max3 Mgn1 Mgn2 Attn Pwr
2010/02/16 21:44:36 GMT 1  6654 8309 8281 8281   7.9   7.8    38.7 20.4


Cheers

[Steve]

Where's the downstream margin I think with all the disconnections your target margin will have been elevated at the exchange,hopefully if its now stable it will improve, but it will take several days. BT are very good at taking away and not giving back without a fight.

[Wingnutz]

So the Downstream Rate Cap will have been set by BT (6656) and until my lines hold steady with no disconnects I'm unlikely to see this increase - even though the 2Wire attempted a connection over 8300 three times ??

Sorry not to up on the techy side of this.   

Cheers

[Lance]

On ADSL2+, one of the tools the DLM has is to cap the speed. I think I would drop a quick email to support, explaining that a problem was been resolved and asking if the DLM can be reset.

[Wingnutz]

Lance,

Have e-mailed support - a quick google around has found others mentioning a BT banding / hard cap at the 6656 mark.

Thanks


edit - some info on BT banded profiles and how they 'should' work.. if anyones is interested / not seen / cares .....


http://community.plus.net/forum/index.php/topic,80204.0.html/

[4Way]

Thanks for that

[Steve]

Its interesting that the 2 wire reports the capped profile,We've seen the profile bands before see http://www.idnetters.co.uk/forums/index.php?topic=18201.msg441346#msg441346 but this is the first time I've seen the direct evidence.

[Wingnutz]

Cheers for the link Steve – didn't realise bands had already been posted elsewhere. Hoping that with some amount of stability over the next few days the 'band' will be upped to somewhere near where the modem is trying to sync – 8500ish.

Ran routerstats for most of the evening last night and the reported downstream noise margin never dropped below 8 – so guessing line is now fairly stable

[Steve]

Whats the noise margin variation i.e are you synced at 12 with a 4 drop  or 9 and pretty noise free?

[Wingnutz]

Steve,

this is what the modem was reporting..

Time                                 Rate Max1 Max2 Max3 Mgn1 Mgn2 Attn Pwr
2010/02/16 21:44:36 GMT 1  6654 8309 8281 8281   7.9   7.8    38.7 20.4

I believe it wa trying to sync at around 8300 (the Max1 , 2 and 3 figures) with a margin of 7.9/7.8 (the Mgn1 and 2 figures). But it settled at 6654 due to the BT banding.

The margin remained around the 8 mark all evening.

Cheers

[Steve]

So its pretty stable which is good news.

[PuncH]

Presuming you're on ADSLMax it could take anything up to 14 days of stability before the DLM unbands your connection 

On ADSL2+ it takes about 4 (going from my experience anyway).

[Steve]

Its ADSL2+ Punch so as you say hopefully 4-5 days

[Wingnutz]

From Brian @ support

BT do use banded profiles for ADSL2 services which will limit the
connection rates however these are dynamic profiles so where improvement
to a connection has been made and assuming it is stable and running
error free then the profiles will automatically update.


Hopefully I should see some improvement if (!) the banding in truely dynamic.

One question though - will I have to force a resync at some point or will this be done automatically at the exchange ?

Cheers

[Lance]

I think in the past this has been done automatically by the exchange.

[PuncH]

It was done automatically to mine Lance, when I had connection issues over Christmas/New Year.

[Lance]

I thought I had seen it somewhere!

[Wingnutz]

Thanks Lance / PuncH,

connection has been stable all evening with a noise margin rock steady between 7.5 and 7.9db...

Lets wait and see.  

[PuncH]

 

[Rik]

I can confirm that, with ADSL2+, I've seen the resyncs forced by the exchange.

[Wingnutz]

An update..

Brian in support (top service as usual !!!! ) has got BT to remove the banding - the 2Wire is now reporting a downstream cap of 18004 kbps.

Modem has re-sync'd at 6999 with a 12db noise margin - looks like it's been up'd for some reason was 6db - a new training period

Now hoping for the target margin to reduce over time and see an increase in sync 

[Wingnutz]

Another update...and request for help.

The 2wire has died... after getting sevaral err_dma disconnections and a unknown reboot due to a power failure I have know replaced it with a NetGear DGN1000.

Now this is where I need the advice. Due to the disconnections and attempts to isolate any noise etc my target noise margin has been pushed up to the max 15db. I also suffered with the outtage jsut over a week ago causing disconnects.

Previously before moving to ADSL2+ it was a rock stready 6db.

Moving to ADSL2+ initially put me on a low banded profile - which support got removed - but a 12db margin.

This was reduced in a couple of steps to 6db - with the 2wire at that time - but quickly increased (3db for each disconnection) to the 15db level.

I've now got a 5816 kbps connection, a 33.8db downstream attenuation and the 15db target margin. This remains steady all evening and increase to 16/17db in the day.

This has been steady know for over a week with no 'collisions' report in the router stats - I assume this is 'NetGear Speak' for errors. I've only reset the router once during that period - accidentally !!

How long do you think it will take for the margin to reduce and speed to increase ? Or is it possible the margin is now stuck and will need a kick from someone to get it moving again?

Cheers

[Steve]

Have you spoken to support recently? In theory if your line is relatively noise free now your router should eventually resync at a higher rate.

[Rik]

Though DLM is quite fussy about errors, Steve, so will not reduce the target NM until it's had two weeks of continuous connection with few errors.

Collisions, to me, Wingnutz, would indicate LAN errors, packets across the LAN having to be resent because of clashes.