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Standard User orly
(fountain of knowledge) Sun 23-Oct-11 17:12:09
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Re: Strange speed increase


[re: Zarjaz] [link to this post]
 
Seems very clearly the 17a profile causing it here looking at the linediag command and seeing the frequencies in use.

---
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BT Infinity 8th July 2010
(NIBA)
600m (approx) to cabinet
29.5Mbit down / 5.5Mbit up
Standard User cmn
(member) Sun 23-Oct-11 21:39:25
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Re: Strange speed increase


[re: orly] [link to this post]
 
Can you post the relevant stats / screenshots for us to examine? thanks.
Standard User Bald_Eagle1
(newbie) Sun 23-Oct-11 21:42:34
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Re: Strange speed increase


[re: orly] [link to this post]
 
Hi Orly,

Have you collected yor stats again, now that profile 17a has been used for a few days on your connection?

Most users seem to be seeing that profile 17a is now being "detected" at Discovery Phase (Initial) Band Plan, but not "fully" used at Medley Phase (Final Band Plan)

My guess is either line/signal attenuation is simply too high (distance from the cabinet), or more likely that the current BT 40Mb cap won't allow any throughput at the higher profile 17a frequencies:-

# xdslcmd info --pbParams
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Max: Upstream rate = 6157 Kbps, Downstream rate = 6352 Kbps
Path: 0, Upstream rate = 6160 Kbps, Downstream rate = 30000 Kbps

Discovery Phase (Initial) Band Plan
US: (0,95) (868,1207) (1972,2783)
DS: (32,859) (1216,1963) (2792,3939)
Medley Phase (Final) Band Plan
US: (0,95) (868,1207)
DS: (32,859) (1216,1963)

VDSL Port Details Upstream Downstream
Attainable Net Data Rate: 6157 kbps 6352 kbps
Actual Aggregate Tx Power: 2.5 dBm 11.6 dBm
============================================================================
VDSL Band Status U0 U1 U2 U3 D1 D2 D3
Line Attenuation(dB): 8.5 47.2 63.8 N/A 20.1 57.6 0.1
Signal Attenuation(dB): 10.6 46.6 N/A N/A 20.1 57.6 N/A
SNR Margin(dB): 6.1 6.3 N/A N/A -7.7 -7.1 N/A
TX Power(dBm): -8.4 2.2 N/A N/A 10.0 6.5 N/A



Paul.

Edited by Bald_Eagle1 (Sun 23-Oct-11 21:49:36)


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Standard User Zarjaz
(knowledge is power) Tue 25-Oct-11 20:30:00
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doubting Thomas


[re: Zarjaz] [link to this post]
 
OK, seen 17A profile on a line myself today. Might just go get the tester from the van and try my own line later ........

Standard User orly
(fountain of knowledge) Tue 25-Oct-11 20:35:29
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Re: Strange speed increase


[re: cmn] [link to this post]
 
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 2
Max: Upstream rate = 6107 Kbps, Downstream rate = 33460 Kbps
Path: 0, Upstream rate = 6104 Kbps, Downstream rate = 30000 Kbps

Link Power State: L0
Mode: VDSL2 Annex B
VDSL2 Profile: Profile 17a
TPS-TC: PTM Mode
Trellis: U:ON /D:ON
Line Status: No Defect
Training Status: Showtime
Down Up
SNR (dB): 7.9 6.2
Attn(dB): 0.0 0.0
Pwr(dBm): 11.7 2.3

---
> Comparison chart of FTTC ISPs
> Got FTTC? Complete the survey

BT Infinity 8th July 2010
(NIBA)
600m (approx) to cabinet
29.5Mbit down / 5.5Mbit up
Standard User Croftie
(regular) Wed 26-Oct-11 00:41:33
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Re: Strange speed increase


[re: orly] [link to this post]
 
What phase of the rollout was your exchange in orly?
Standard User Bald_Eagle1
(newbie) Fri 28-Oct-11 11:48:40
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Re: Strange speed increase


[re: Croftie] [link to this post]
 
Hi All,

My exchange was in Phase 2.

I noticed that my profile had switched from 8c to 17a in the early hours of this morning.

Before the switch :-

# xdslcmd info --pbParams
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Max: Upstream rate = 6454 Kbps, Downstream rate = 23608 Kbps
Path: 0, Upstream rate = 6435 Kbps, Downstream rate = 20345 Kbps

Discovery Phase (Initial) Band Plan
US: (0,95) (696,1183)
DS: (32,687) (1192,1627)
Medley Phase (Final) Band Plan
US: (0,95) (696,1183)
DS: (32,687) (1192,1627)
VDSL Port Details Upstream Downstream
Attainable Net Data Rate: 6454 kbps 23608 kbps
Actual Aggregate Tx Power: 3.2 dBm 9.6 dBm
============================================================================
VDSL Band Status U0 U1 U2 U3 D1 D2 D3
Line Attenuation(dB): 8.6 52.0 N/A N/A 21.5 65.0 N/A
Signal Attenuation(dB): 14.0 51.7 N/A N/A 21.5 65.0 N/A
SNR Margin(dB): 5.9 5.9 N/A N/A 6.2 6.4 N/A
TX Power(dBm): -9.3 2.9 N/A N/A 9.1 -0.1 N/A


After the switch:-

# xdslcmd info --pbParams
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 2
Max: Upstream rate = 4654 Kbps, Downstream rate = 29588 Kbps
Path: 0, Upstream rate = 4647 Kbps, Downstream rate = 25975 Kbps

Discovery Phase (Initial) Band Plan
US: (0,95) (868,1207) (1972,2783)
DS: (32,859) (1216,1963) (2792,3939)
Medley Phase (Final) Band Plan
US: (0,95) (868,1207)
DS: (32,859) (1216,1963)
VDSL Port Details Upstream Downstream
Attainable Net Data Rate: 4654 kbps 29588 kbps
Actual Aggregate Tx Power: 6.3 dBm 12.0 dBm
============================================================================
VDSL Band Status U0 U1 U2 U3 D1 D2 D3
Line Attenuation(dB): 8.4 55.7 64.3 N/A 22.4 65.3 0.1
Signal Attenuation(dB): 14.3 55.0 N/A N/A 22.4 65.3 N/A
SNR Margin(dB): 6.3 6.3 N/A N/A 5.6 5.6 N/A
TX Power(dBm): -4.2 5.8 N/A N/A 10.8 5.3 N/A

A bit of a hit on the Upstream, but an increase on the downstream.

Getting Zilch from the new higher frequency bands though.

Probably due to high attenuation caused by a high resistance fault still present on my line (supposedly fixed ages ago), or that BT still have me capped at a low profile due to all the previous connection issues.

I was manually capped at 25Mb at one point.
Maybe one part of BT hasn't told another part of BT that the faults have been fixed?

My ISP seems too reluctant to even ask BT to try my connection at 40Mb again & I'm not ALLOWED to speak to BT directly myself!!!!!!.

Paul.

Edited by Bald_Eagle1 (Fri 28-Oct-11 11:55:34)

Standard User Croftie
(member) Fri 28-Oct-11 16:42:37
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Re: Strange speed increase


[re: Bald_Eagle1] [link to this post]
 
In reply to a post by Bald_Eagle1:
My exchange was in Phase 2.

Thanks. Me too, hopefully won't be long till it changes here aswell.

In reply to a post by Bald_Eagle1:
I'm not ALLOWED to speak to BT directly myself!!!!!!.

I can sympathise there, ISPs are piggy in the middle, very frustrating

Maybe moving to aaisp (who are apparently very good at getting bt to fix faults) untill it's fixed and then back to your prefered ISP is your only option now.

Edited by Croftie (Fri 28-Oct-11 16:43:12)

Standard User Bald_Eagle1
(newbie) Fri 28-Oct-11 17:05:13
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Re: Strange speed increase


[re: Croftie] [link to this post]
 
In reply to a post by Croftie:
Maybe moving to aaisp (who are apparently very good at getting bt to fix faults) untill it's fixed and then back to your prefered ISP is your only option now.


Hi Croftie,

I am tied in to an 18 month contract, so moving to AAISP would be quite expensive at this stage, especially as AAISP seem to be quite a bit more expensive for my type of internet useage.

I have considered that though, as all the time I have spent trying to get this resolved has some cost attached to it. I still haven't ruled it out.

I actually quite like my current ISP (Plusnet) despite what may have been construed elsewhere.
At least they haven't just given up on me like some others would.
They have got close a couple of times, but are still in there with me (sort of) smile

Good luck when it's your turn for the 17a switch & keep us posted on how it goes.
I don't know whether or not the switch is based on geographical areas but FYI, my exchange is Oldham.


Paul.
Standard User WWWombat
(committed) Wed 02-Nov-11 14:51:00
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Re: Strange speed increase


[re: Bald_Eagle1] [link to this post]
 
In reply to a post by Bald_Eagle1:
Before the switch :-

Discovery Phase (Initial) Band Plan
US: (0,95) (696,1183)
DS: (32,687) (1192,1627)

=============================================

After the switch:-

Discovery Phase (Initial) Band Plan
US: (0,95) (868,1207) (1972,2783)
DS: (32,859) (1216,1963) (2792,3939)

==============================================

A bit of a hit on the Upstream, but an increase on the downstream.

Those numbers in the band plan show another significant change... BT haven't just switched the profile from 8c to 17a, but they've also switched the bandplan from 997 to 998.

As you've noticed, the significant difference (below 7MHz) is to steal 0.6MHz from upstream, and give it to downstream: Downstream gains the bandwidth from 3.0MHz to 3.7MHz, but loses the bit between 5.1MHz and 5.2MHz.

The next significant difference is that the first 1.5MHz of the new bandwidth (up to 8.5MHz) also goes to the downstream in the 998 plan; with 997 it would have gone to upstream.

Seems like BT have chosen to focus *more* onto the downstream deliberately.
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