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Standard User burakkucat
(committed) Fri 04-Nov-11 23:45:33
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Re: Faults Found by Openreach Engineer


[re: Zarjaz] [link to this post]
 
In reply to a post by Zarjaz:
The Line Rate of 14999 looks suspiciously like it may be BT's default minimum sync rate.

I think that's incorrect.
Are you able to offer any other supporting facts to go with that statement, please?

-----------------------------------------------------

100% Linux and, previously, Unix.
Standard User Bald_Eagle1
(learned) Sat 05-Nov-11 08:25:07
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Re: Faults Found by Openreach Engineer


[re: Zarjaz] [link to this post]
 
In reply to a post by Zarjaz:
The Line Rate of 14999 looks suspiciously like it may be BT's default minimum sync rate.

I think that's incorrect.


Hi Zarjaz,

Would you be able to clarify this a little for us?

Following many connection issues (disconnections, crackly phone line etc.), my FTTC sync rate appeared to be stuck at 14999 k following the repair works.

My ISP told me something like it was the minimum sync rate that BT can set following a period of instability.
They may have said default, rather than minimum - I can't quite recall the exact phrase.

Anyway, it required an engineer's home visit to run a couple of tests & then he phoned BT to reset the profile remotely, while he monitored the result of the reset.

The reset immediately caused the modem to re-sync at around 24Mb or 25Mb.

I have also read other users' forum posts whose connections also appeared to have "stuck" at a 14.999 k sync rate, requiring the same sort of engineer's intervention to reset it.

Paul.
Standard User Zarjaz
(knowledge is power) Sun 06-Nov-11 11:00:50
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Re: Faults Found by Openreach Engineer


[re: Bald_Eagle1] [link to this post]
 
I said 'I think', as it would be strange that I hadn't come across this 14999 sync rate myself ( I do dabble a bit with this sort of thing). Were your ISP basing this on the 15 meg or above that is the default product ?

The engineers phone call is no magic, they just ring the FTTC SMC repair team and ask for the sync rate to be reset/recalculated. I suspect that the line would regain it's full speed it's self, if left to it's own devices, if and when the original fault has been cleared. Te phone call just speeds things up.


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Standard User Cyberoonie
(newbie) Sun 06-Nov-11 19:41:13
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Re: Faults Found by Openreach Engineer


[re: Bald_Eagle1] [link to this post]
 
In reply to a post by Bald_Eagle1:
Following many connection issues (disconnections, crackly phone line etc.), my FTTC sync rate appeared to be stuck at 14999 k following the repair works.

The reset immediately caused the modem to re-sync at around 24Mb or 25Mb.


Did you happen to notice any different in the attainable rate when you had this problem or did that remain the same throughout?

I was meant to receive a phone call today with regards to the issue - nothing as of yet but they did ring at 9pm last time.

In terms of current stats they are:

Uptime: 202822
Attainable Rate: 16564 / 3260
SNR: 2.9 / 7.3
Output Power: 8.8 / 1.1

Line Rate: 14999 / 2538
CRC Errors: 56571 / 0
FEC Errors: 1004 / 2
HEC Errors: 15700 / 0

No signs of any increased speed or error reduction - well at least not according to the modem.
Standard User Bald_Eagle1
(learned) Mon 07-Nov-11 08:47:40
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Re: Faults Found by Openreach Engineer


[re: Zarjaz] [link to this post]
 
In reply to a post by Zarjaz:
I said 'I think', as it would be strange that I hadn't come across this 14999 sync rate myself ( I do dabble a bit with this sort of thing). Were your ISP basing this on the 15 meg or above that is the default product ?

The engineers phone call is no magic, they just ring the FTTC SMC repair team and ask for the sync rate to be reset/recalculated. I suspect that the line would regain it's full speed it's self, if left to it's own devices, if and when the original fault has been cleared. Te phone call just speeds things up.


Hi Zarjaz,

TBH, I'm not sure what they based it on.

One problem with FTTC technology is that it is still new enough, that not many (If any) fully understand it yet. So the information filtering back to end users is rather vague, with a lot of it probably based on assumptions & comparisons to known ADSL technology rather than fact.

This is not at all helped by the BT modem being locked down (as installed) & many/most users can't even see their connection stats.

At the time my sync speed was stuck at 14999 K, I had no access to my own stats & had to just rely on the BT Performace/Speed tester, along with rather limited ISP reports to find my stats etc.

I was told to wait for 10 days or so at a time to allow DLM to settle, which made no difference.
It appears to be reasonably common for DLM, or BT's database, or something else to cause stuck profiles / sync rates that can only be "unstuck" via an engineer's visit.

Maybe when/if FTTC becomes a self-install process, end users/ISPs will be able to request profile resets directly (or maybe ISPs will be given access to reset it directly).

In my case, my original 30+ Mb actual downloads speeds (for a full month) have never returned (sync speed must have been up to 35Mb back then).
Even with the slight improvement following the profile switch to 17a, the best I have achieved for a few months is 24Mb actual downloads. They are usually around 20Mb to 22Mb.

I am not 100% convinced that my line's "faults" were ever fully fixed, or possibly BT is currently restricting my profile due to the history of disconnections etc. in their database?

Nobody seems prepared/able to confirm why I achieved really quite good speeds right through & beyond the initial 10 day training period, yet now I achieve nowhere near those speeds.

I don't suppose you have any suggestions as to how I could get factual confirmation of the current position do you?

One engineer, who is sadly no longer an active member of a different public forum (Kitz), suspected my D-side may be suffering from a continued (possibly intermittent) HR fault, not now severe enough to cause a complete loss of connection following SOME repair works, but severe enough to be restricting my profile / sync & therefore download speeds.

My stats do now show high attenuation values, but the physical line length has never been actually confirmed, so I don't know if they are too high for its length.
Unfortunately, I have no idea what the attenuation values were when I solidly obtained decent speeds, with no noticed disconnections.

So, back to the original thread, it MAY be possible that Cyberoonie is experiencing similar issues now that his line has been "fixed".


Paul.
Standard User Bald_Eagle1
(learned) Mon 07-Nov-11 08:59:06
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Re: Faults Found by Openreach Engineer


[re: Cyberoonie] [link to this post]
 
In reply to a post by Cyberoonie:
Did you happen to notice any different in the attainable rate when you had this problem or did that remain the same throughout?

I was meant to receive a phone call today with regards to the issue - nothing as of yet but they did ring at 9pm last time.

In terms of current stats they are:

Uptime: 202822
Attainable Rate: 16564 / 3260
SNR: 2.9 / 7.3
Output Power: 8.8 / 1.1

Line Rate: 14999 / 2538
CRC Errors: 56571 / 0
FEC Errors: 1004 / 2
HEC Errors: 15700 / 0

No signs of any increased speed or error reduction - well at least not according to the modem.


Hi Cyberoonie,

I didn't have access to my stats back then so I'm unable to answer your question, & now that I do, nobody takes a blind bit of notice as my connection is supposedly performing within specification for its BT estimated speeds.

My pre-install estimated speed was 14.6MB & following the recent profile switch to 17a the estimated speed has increased to 24Mb.

The fact that I achieved much higher speeds solidly for the first month (months before the profile switch) appears to be conveniently overlooked as a possible "fluctuation".

For curiosity, have you had chance to discuss the possibility of BT resetting your profile yet?


Paul.

Edited by Bald_Eagle1 (Mon 07-Nov-11 11:49:13)

Standard User Cyberoonie
(newbie) Mon 07-Nov-11 19:31:28
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Re: Faults Found by Openreach Engineer


[re: Bald_Eagle1] [link to this post]
 
Hi Bald Eagle,

Nothing from BT as of yet - work has taken a priority over the past few days so I'll be calling them tomorrow.

I did send a message to the BT Care team as suggested, I'll wait and see what comes back from that.

Whilst the connection has resynced since my last post, it wasn't for the better. The current stats are:

Uptime: 64927
Attainable Rate: 16269 / 2828
SNR: 5.1 / 5
Output Power: 8.8 / 1.4

Line Rate: 14644 / 2682
CRC Errors: 29530 / 0
FEC Errors: 1046 / 0
HEC Errors: 7255 / 0

Ill let you know how I get on with BT tomorrow
Standard User Bald_Eagle1
(learned) Thu 10-Nov-11 21:54:57
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Re: Faults Found by Openreach Engineer


[re: Cyberoonie] [link to this post]
 
In reply to a post by Cyberoonie:
Ill let you know how I get on with BT tomorrow


Hi Cyberoonie,

Any good news for us?

Paul.
Standard User Cyberoonie
(newbie) Fri 11-Nov-11 09:54:16
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Re: Faults Found by Openreach Engineer


[re: Bald_Eagle1] [link to this post]
 
In reply to a post by Bald_Eagle1:
Hi Cyberoonie,

Any good news for us?

Paul.


Hi Paul,

After an hour and a half arguing on the phone with BT India I finally had an engineer ring randomly (nice of it when BT let you know they have passed it on to Openreach!) to say he'll be over in the morning.

He turned up, had the profile reset, checked the cab and now have the following stats:

Uptime: 4273
Attainable: 22224 / 1897
SNR: 6.9 / 6.1
Attenuation (according to the engineer) 32.1 / ?
Output Power: 10.6 / 4.5

Line rate: 21318 / 1936
CRC Errors: 0 / 0
FEC Errors: 6228 / 7
HEC Errors: 37391 / 0

The only bit I have noticed is that the HEC errors are sky rocketing again.

Also, he came, plugged the gear in and said your attainable is 23000 (and therefore is fixed).. it was already 23000 after the 17a profile change yesterday (increasing from 18000). I'm not really sure now whether he's reset my profile and now has the best speed with a fault remaining on the line, or whether that's as good as it gets even on 17a.

Edited by Cyberoonie (Fri 11-Nov-11 09:55:13)

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