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Capped Line?

jamiek
Newbie
Posts: 7
Registered: 05-06-2014

Capped Line?

Hi,
I've just moved over from BT and was wondering if the router stats below indicate a capped line?  There didn't appear to be any training period when I shifted ISP.
As far as I'm aware my target SNR Margin is 6dB but immediately after any re-syncs 3776 Kbps is the max sync rate I can achieve, with, as you can see, a noise margin of  around 7dB.
The line is stable and I can hold sync for a couple of weeks.
I realise that with such a relatively high attenuation this isn't bad but those extra few Kbps may be enough to push my IP profile up to the next banding...
The tech support team weren't able to shed any light- only that my speed was working within estimates (which was 0.75Mbps!!)
Any help appreciated!
ADSL Line Status
Connection information
Line state: Connected
Connection time: 0 day, 02:42:59
Downstream: 3,776 Kbps
Upstream: 448 Kbps

  ADSL settings
VPI/VCI: 0/38
Type: PPPoA
Modulation: G.992.1 Annex A
Latency type: Interleaved
Noise margin (Down/Up): 7.0 dB / 17.0 dB
Line attenuation (Down/Up): 54.5 dB / 30.0 dB
Output power (Down/Up): 19.5 dBm / 12.3 dBm
FEC Events (Down/Up): 76677 / 137
CRC Events (Down/Up): 9 / 0
Loss of Framing (Local/Remote): 0 / 0
Loss of Signal (Local/Remote): 0 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): 0
HEC Errors (Down/Up): 48 / 0
Error Seconds (Local/Remote): 0 / 0
13 REPLIES
Community Veteran
Posts: 38,423
Thanks: 1,008
Fixes: 58
Registered: 15-06-2007

Re: Capped Line?

when you moved from BT did you change routers
also you seem to have either been provisioned on ADSL1 or your exchange isn't 21CN enabled and you are on 20CN
jamiek
Newbie
Posts: 7
Registered: 05-06-2014

Re: Capped Line?

Hi,
No I'm still using the HomeHub 3 from BT, although I've got a HH5 sitting here (but it has issues holding on to sync, losing connection a couple of times an hour, I think because of REIN interference...)
No date for 21CN provisioning out here in the sticks I'm afraid...
Community Veteran
Posts: 38,423
Thanks: 1,008
Fixes: 58
Registered: 15-06-2007

Re: Capped Line?

I doubt that it has been capped but my experience - from memory - is that the 20CN sync moves in steps and 3776kbps is one of them
Moving up to 3968kbps for the next profile could be difficult
jamiek
Newbie
Posts: 7
Registered: 05-06-2014

Re: Capped Line?

Thanks Jim,
I was under the impression that the router would sync at the fastest speed possible while still allowing for the target SNR margin to be maintained.  The IP profile moves in steps according to the sync rate - so for me to move up to a 3.5Mbps IP profile I would need to get my sync rate beyond 3968kbps (which is tantalisingly close) and would, I think, be possible if I could use the extra 1dB noise margin "overhead" that I currently have.
What difference would using another router make?
Community Veteran
Posts: 38,423
Thanks: 1,008
Fixes: 58
Registered: 15-06-2007

Re: Capped Line?

it could make it better or worse - not much help there I am afraid
It does sync at the fastest rate possible but seems to move in steps which I think are  32kbps
jamiek
Newbie
Posts: 7
Registered: 05-06-2014

Re: Capped Line?

I see.
So what could it be that's stopping me syncing at the full potential that the target noise margin allows? I now have a noise margin of 7.2 dB but re-syncing will only allow a max downstream of 3776kbps...
Community Veteran
Posts: 38,423
Thanks: 1,008
Fixes: 58
Registered: 15-06-2007

Re: Capped Line?

I have no idea sorry
This will need some staff input so I will duck out
Plusnet Staff
Plusnet Staff
Posts: 6,346
Thanks: 31
Fixes: 5
Registered: 26-11-2011

Re: Capped Line?

Hi jamiek,
I've just taken a look at your line. Your SNR is sat at 6db at the moment, which is the lowest target we can set for a 20CN circuit. Other than this the lien is looking clear. There isn't any banding/restrictions on your line. From what I can see, 3776K is the maximum speed your line is comfortable at syncing at whilst keeping the line stable.
Chris Pettitt
Cloud Environments Engineer
jamiek
Newbie
Posts: 7
Registered: 05-06-2014

Re: Capped Line?

Thanks for that Chris,
My query is really why my line isn't then syncing upon restart with a noise margin of 6dB? It re-syncs at 3776kbps even if that leaves the margin (at the moment) at around 7dB.  This would imply that there is extra speed available (and my connection is steady for weeks on end) but it just isn't being allowed to sync at the higher rate.
(I take it you mean SNR Margin rather than SBR by the way?)
Plusnet Staff
Plusnet Staff
Posts: 6,346
Thanks: 31
Fixes: 5
Registered: 26-11-2011

Re: Capped Line?

Sorry, yes, I was referring to the SNR Target.
Your line probably does but there could, potentially be something that's causing the SNR to rise a little to 7db. You'd see very little variation in speeds between 6db-7db though.
Chris Pettitt
Cloud Environments Engineer
jamiek
Newbie
Posts: 7
Registered: 05-06-2014

Re: Capped Line?

No, looking at the router event log it usually resyncs with a SNR margin of around 7 dB (7.2 last time). I realise that there would not be a massive difference in speed but I only need less than 200kbps to get to the next IP profile banding of 3.5 Mbps.
Not a major problem I know but I am curious as to why this should be happening!
Superuser
Superuser
Posts: 10,411
Thanks: 1,903
Fixes: 19
Registered: 22-08-2007

Re: Capped Line?

Hi, Jamie,
Welcome to the forums.  I take it that your exchange does not support 21CN WBC services?  In that case I can understand your desire to squeeze as much as possible out of the line.  Is there any noise on the line?  Dial 17070 option 2.
Is the router in the master socket?  Do you have any extension sockets?  Do you know if the bell circuit is connected on extension wiring?
If your line has been banded, then you will see the SNRM applicable to the best speed attainable within the band.  If that were the case though, I'm sure Chris would have considered that.
jamiek
Newbie
Posts: 7
Registered: 05-06-2014

Re: Capped Line?

Hi Townman,
No- 20CN only unfortunately although with my attenuation I'm not sure ADSL 2+ would help... master socket, no bell wire, no extensions, no noise.
I had considered banding but I think that's only applicable to 21CN services isn't it?
I had been having problems a few months ago with frequent drop-outs caused by a few factors (including the afore mentioned HH5). This caused DLM to kick in and my target SNR margin was stuck at 9 dB until a manual reset.  I don't think that that is connected however, unless DLM has capped my max sync rate.