Ping advice required

Folks,

Just want to pick a few brains here to see if this can be explained.

I am on a fibre connection 1.3 miles from the cab. On the 17th June I noticed my online gaming lagging and decided to have a look at the quality monitor that runs.

Quality Monitor

I felt this was strange and since then and to date has remained at the higher level.

I have a few stats from the BTO modem. The first one was taken 01/12/11

# xdslcmd info --pbParams
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Max: Upstream rate = 1228 Kbps, Downstream rate = 18156 Kbps
Path: 0, Upstream rate = 797 Kbps, Downstream rate = 15641 Kbps

Discovery Phase (Initial) Band Plan
US: (0,95) (696,1183)
DS: (32,687) (1192,1627)
Medley Phase (Final) Band Plan
US: (0,95)
DS: (32,687)
VDSL Port Details Upstream Downstream
Attainable Net Data Rate: 1228 kbps 18156 kbps
Actual Aggregate Tx Power: 10.5 dBm 9.2 dBm


This one was taken earlier this week

# xdslcmd info --pbParams
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Max: Upstream rate = 1204 Kbps, Downstream rate = 21504 Kbps
Path: 0, Upstream rate = 1204 Kbps, Downstream rate = 14999 Kbps

Discovery Phase (Initial) Band Plan
US: (0,95) (868,1207) (1972,2783)
DS: (32,859) (1216,1963) (2792,3959)
Medley Phase (Final) Band Plan
US: (0,95)
DS: (32,859) (1216,1963) (2792,3959)
VDSL Port Details Upstream Downstream
Attainable Net Data Rate: 1204 kbps 21504 kbps
Actual Aggregate Tx Power: 10.4 dBm 11.4 dBm
============================================================================
VDSL Band Status U0 U1 U2 U3 D1 D2 D3
Line Attenuation(dB): 13.1 66.6 69.1 N/A 29.0 0.1 0.1
Signal Attenuation(dB): 14.8 N/A N/A N/A 29.0 0.1 0.1
SNR Margin(dB): 6.8 N/A N/A N/A 6.2 0.0 0.0
TX Power(dBm): 10.5 N/A N/A N/A 11.4 -128.0 -128.0


I have rebooted everything a few times and my ip profile has dropped from 18.5 to 14.52Mb but it has not increased back up gradually with me not resetting which makes me think the profile is stuck?

On Wednesday I obtained these stats from the modem

# xdslcmd info --stats
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Max: Upstream rate = 1200 Kbps, Downstream rate = 21904 Kbps
Path: 0, Upstream rate = 1204 Kbps, Downstream rate = 14999 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): 6.6 6.8
Attn(dB): 0.0 0.0
Pwr(dBm): 11.4 10.4
VDSL2 framing
Path 0
B: 29 31
M: 1 1
T: 62 53
R: 16 0
S: 0.0635 0.8312
L: 5797 308
D: 1027 1
I: 46 32
N: 46 32
Counters
Path 0
OHF: 19315782 1046078
OHFErr: 3376 7
RS: 1693003480 3823289
RSCorr: 2519078 0
RSUnCorr: 615926 0

Path 0
HEC: 53579 0
OCD: 0 0
LCD: 0 0
Total Cells: 2750037011 0
Data Cells: 12673573 0
Drop Cells: 0
Bit Errors: 0 0

ES: 108 7
SES: 21 0
UAS: 18 18
AS: 95406

Path 0
INP: 11.00 0.00
PER: 4.91 11.01
delay: 16.00 0.00
OR: 65.04 23.24

Bitswap: 18705 1

Total time = 1 days 2 hours 30 min 26 sec
FEC: 2519078 0
CRC: 3376 7
ES: 108 7
SES: 21 0
UAS: 18 18
LOS: 0 0
LOF: 0 0
Latest 15 minutes time = 26 sec
FEC: 775 0
CRC: 0 0
ES: 0 0
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
Previous 15 minutes time = 15 min 0 sec
FEC: 292046 0
CRC: 222 0
ES: 19 0
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
Latest 1 day time = 2 hours 30 min 26 sec
FEC: 1037808 0
CRC: 1847 1
ES: 69 1
SES: 10 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
Previous 1 day time = 24 hours 0 sec
FEC: 1481270 0
CRC: 1529 6
ES: 39 6
SES: 11 0
UAS: 18 18
LOS: 0 0
LOF: 0 0
Since Link time = 1 days 2 hours 30 min 5 sec
FEC: 2519078 0
CRC: 3376 7
ES: 108 7
SES: 21 0
UAS: 0 0
LOS: 0 0
LOF: 0 0

Is there anything obvious in these figures. I am not too sure why the Tx power is showing -128

Any help would be most welcome. The BT checker has my line at 14.3Mb however it has always been over 18Mb since 17a became active on the line last November.

As the line is still above BT's fault threshold there is no complaint to be accepted

At a guess, it could be that your line (2km long) is too long to use the D2 and D3 bands go nothing is being transmitted and the power is effectively nil ... -128 dBm is about 160 attoWatts or 0.16 zeptoWatts or 160x10^-18 Watts or 0.16x10^-21 Watts

The step up in the BQM graph is almost certainly interleaving being turned on, or significantly increased in depth. Now 1207, but you haven't given us an earlier figure for comparison.

It could be that a connection has recently been made to your cabinet that is causing significant cross-talk with your line. What was/is the BT Wholesale estimate?

Either that, or an engineer installing FTTC for someone else has moved your wiring in the PCP a little in the process, giving a similar effect.

I'm assuming you didn't acquire or replace, or even re-site anything electrical or electronic immediately before the problem started?

I have rebooted everything a few times

Not a good idea if you did them close together.

... my ip profile has dropped from 18.5 to 14.52Mb

which is correct for your downstream rate. The rate determines the profile, not the other way round. It is possible that your attempts to improve things have however resulted in banding being applied, to stabilise the line. 14999kbps is a suspicious number.

Hi,

Thanks for the replies. Here are a couple of snapshots prior and after. The rise occurred 17/06/12 at approx 0600hrs so I doubt an engineer was at the cab or it was a delayed reaction.

16th

17th crunch day

18th

The dropped packets on the 18th is me rebooting and leaving off for a few minutes.

the checker shows this;

For Telephone Number 028xxxxxxx on Exchange BELFAST ORMEAU

Your exchange is ADSL enabled, and our initial test on your line indicates that it is VERY UNLIKELY you will be able to receive fixed 512Kbps or 256Kbps broadband service due to the very long length of your telephone line. However, your order will be accepted if you still wish to order. An engineer may need to visit who will, where possible, supply the broadband service.

Additionally, your line may be able to support an estimated ADSL speed between 1 to 2 Mbps using Broadband Enabling Technology. A solution created specifically for communities who have very long telephone lines. If you decide to place an order, an appointment might be required where an engineer may need to visit your premises who will, where possible, supply the service.

Our test also indicates that your line currently supports an estimated ADSL Max broadband line speed of 1Mbps; typically the line speed would range between 750Kbps and 2.5Mbps.

Our test also indicates that your line currently supports an estimated ADSL2+ broadband line speed of 1Mbps; typically the line speed would range between 1Mbps and 3.5Mbps.

Our test also indicates that your line currently supports a fibre technology with an estimated WBC FTTC Broadband where consumers have received downstream line speed of 14.3Mbps and upstream line speed of 1Mbps.


Originally it started of at 8Mb for FTTC so it has nearly doubled since going live.

The idea of an engineer working at the cabinet sounds plausible however would there be a delay with increase in the ping or would it start immediately? It is just the time it started is too early for an engineer if instant.

There have been no changes and as previously posted the ping has always shown low 30's since installed last August. This did happen once before last November but it fixed itself within a couple of days and unfortunately the graphs are archived and I cant seem to lift them from thinkbroadbands server.

The modem has not been rebooted since Tuesday so hopefully my profile might start increasing

I was meaning we didn't have earlier full stats, where the interleaving depth is shown (The D: line).

What was the huge burst of high latency on the 16th? Just you downloading something, which is fine, or some external cause?

If something got disturbed so the DLM increased the interleaving depth that would be after a period assessing the error rates. So it could have been some time on the 16th that it noticed something start.

The modem has not been rebooted since Tuesday so hopefully my profile might start increasing

You seem still confused about (IP?) profiles. And banding removal requires an engineer visit.

I suggest a single reboot of the modem tomorrow or at the weekend, well inside daylight hours. Say 10am-5pm. Then post the --stats and --pbParams data taken immediately afterwards.

Thanks for all your help. A reboot on Saturday and I will post the stats

Hi Bob

Here are the stats from pbParams and stats. Hopefully you might be able to point me in the right direction as to a possible cause

These were obtained straight after a reboot of modem and router


BusyBox v1.9.1 (2010-10-15 17:59:06 CST) built-in shell (ash)
Enter 'help' for a list of built-in commands.

# ls
var tmp proc linuxrc etc bin
usr sbin mnt lib dev BTAgent
# xdslcmd info --stats
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Max: Upstream rate = 1208 Kbps, Downstream rate = 21472 Kbps
Path: 0, Upstream rate = 1208 Kbps, Downstream rate = 11399 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): 11.5 6.6
Attn(dB): 0.0 0.0
Pwr(dBm): 11.4 10.4
VDSL2 framing
Path 0
B: 29 31
M: 1 1
T: 40 53
R: 16 0
S: 0.0833 0.8285
L: 4416 309
D: 783 1
I: 46 32
N: 46 32
Counters
Path 0
OHF: 18072 12671
OHFErr: 0 0
RS: 6596712 671502
RSCorr: 440 0
RSUnCorr: 0 0

Path 0
HEC: 0 0
OCD: 0 0
LCD: 0 0
Total Cells: 3016314 0
Data Cells: 793 0
Drop Cells: 0
Bit Errors: 0 0

ES: 0 0
SES: 0 0
UAS: 19 19
AS: 140

Path 0
INP: 11.00 0.00
PER: 7.50 10.97
delay: 16.00 0.00
OR: 76.80 23.32

Bitswap: 0 1

Total time = 2 min 41 sec
FEC: 440 0
CRC: 0 0
ES: 0 0
SES: 0 0
UAS: 19 19
LOS: 0 0
LOF: 0 0
Latest 15 minutes time = 2 min 41 sec
FEC: 440 0
CRC: 0 0
ES: 0 0
SES: 0 0
UAS: 19 19
LOS: 0 0
LOF: 0 0
Previous 15 minutes time = 0 sec
FEC: 0 0
CRC: 0 0
ES: 0 0
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
Latest 1 day time = 2 min 41 sec
FEC: 440 0
CRC: 0 0
ES: 0 0
SES: 0 0
UAS: 19 19
LOS: 0 0
LOF: 0 0
Previous 1 day time = 0 sec
FEC: 0 0
CRC: 0 0
ES: 0 0
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
Since Link time = 2 min 19 sec
FEC: 440 0
CRC: 0 0
ES: 0 0
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0

# xdslcmd info --pbParams
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Max: Upstream rate = 1212 Kbps, Downstream rate = 21472 Kbps
Path: 0, Upstream rate = 1208 Kbps, Downstream rate = 11399 Kbps

Discovery Phase (Initial) Band Plan
US: (0,95) (868,1207) (1972,2783)
DS: (32,859) (1216,1963) (2792,3959)
Medley Phase (Final) Band Plan
US: (0,95)
DS: (32,859) (1216,1963) (2792,3959)
VDSL Port Details Upstream Downstream
Attainable Net Data Rate: 1212 kbps 21472 kbps
Actual Aggregate Tx Power: 10.4 dBm 11.4 dBm
============================================================================
VDSL Band Status U0 U1 U2 U3 D1 D2 D3
Line Attenuation(dB): 13.1 66.6 69.4 N/A 29.0 0.1 0.1
Signal Attenuation(dB): 14.8 N/A N/A N/A 29.0 0.1 0.1
SNR Margin(dB): 6.8 N/A N/A N/A 11.5 0.0 0.0
TX Power(dBm): 10.5 N/A N/A N/A 11.4 -128.0 -128.0
#

Discovery Phase (Initial) Band Plan
US: (0,95) (868,1207) (1972,2783)
DS: (32,859) (1216,1963) (2792,3959)
Medley Phase (Final) Band Plan
US: (0,95)
DS: (32,859) (1216,1963) (2792,3959)


That doesn't look at all right.

Usually the Band Plans at Medley Phase only display what your connection is actually capable of.

Your attainable rate, sync speed, attenuation, SNRM values all confirm you would not get anything at all from tones (2792,3959) & quite unlikely to get anything from tones (1216,1963).

Also, 11399 current sync speed does look very much like an intentional DLM banded speed.

I wonder if your modem could be going faulty?
Which version is it?

Are you aware of anyone else connected to the same cabinet that is also currently experiencing problems?


EDIT:

Just found this.
I think it's from your own 8c profile connection last September:-

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

& the whole thing:-

Text

1 23 45 67 89 1011 1213 1415 1617 1819 2021

xdslcmd: ADSL driver and PHY status Status: ShowtimeRetrain Reason: 0 Max:    Upstream rate = 1232 Kbps, Downstream rate = 18252 KbpsPath:   0, Upstream rate = 797 Kbps, Downstream rate = 15641 Kbps  Discovery Phase (Initial) Band Plan US: (0,95) (696,1183) DS: (32,687) (1192,1627) Medley Phase (Final) Band PlanUS: (0,95) DS: (32,687)        VDSL Port Details       Upstream        Downstream Attainable Net Data Rate:       1232 kbps         18252 kbpsActual Aggregate Tx Power:       10.5 dBm           9.3 dBm ============================================================================  VDSL Band Status        U0      U1      U2      U3      D1      D2      D3   Line Attenuation(dB):  13.3    63.1     N/A     N/A    28.2    0.1      N/A   Signal Attenuation(dB):  17.1     N/A     N/A     N/A    28.2     N/A     N/A           SNR Margin(dB):  19.1     N/A     N/A     N/A    6.4      N/A     N/A            TX Power(dBm):  10.5     N/A     N/A     N/A    9.3      N/A     N/A

Edited by Bald_Eagle1 (Sat 30-Jun-12 13:17:55)

Hi,

You found some of the stats I was looking for. I formatted the laptop a few months ago and I must not have backed the stats up.

The modem is a 3B

Just found some from APRIL (Modified date)

# xdslcmd info --stats
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Max: Upstream rate = 1216 Kbps, Downstream rate = 21800 Kbps
Path: 0, Upstream rate = 1220 Kbps, Downstream rate = 18438 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): 6.3 6.9
Attn(dB): 0.0 0.0
Pwr(dBm): 10.8 10.4
VDSL2 framing
Path 0
B: 63 31
M: 1 1
T: 50 53
R: 16 0
S: 0.1104 0.8205
L: 5799 312
D: 293 1
I: 80 32
N: 80 32
Counters
Path 0
OHF: 372144 189796
OHFErr: 16 0
RS: 74479203 1468628
RSCorr: 72286 0
RSUnCorr: 549 0

Path 0
HEC: 120 0
OCD: 0 0
LCD: 0 0
Total Cells: 73026070 0
Data Cells: 20189 0
Drop Cells: 0
Bit Errors: 0 0

ES: 9 0
SES: 0 0
UAS: 17 17
AS: 2065

Path 0
INP: 3.00 0.00
PER: 5.51 10.87
delay: 8.00 0.00
OR: 46.39 23.54

Bitswap: 440 1

Total time = 34 min 44 sec
FEC: 72286 0
CRC: 16 0
ES: 9 0
SES: 0 0
UAS: 17 17
LOS: 0 0
LOF: 0 0
Latest 15 minutes time = 4 min 44 sec
FEC: 2056 0
CRC: 0 0
ES: 0 0
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
Previous 15 minutes time = 15 min 0 sec
FEC: 38477 0
CRC: 13 0
ES: 7 0
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
Latest 1 day time = 34 min 44 sec
FEC: 72286 0
CRC: 16 0
ES: 9 0
SES: 0 0
UAS: 17 17
LOS: 0 0
LOF: 0 0
Previous 1 day time = 0 sec
FEC: 0 0
CRC: 0 0
ES: 0 0
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
Since Link time = 34 min 23 sec
FEC: 72286 0
CRC: 16 0
ES: 9 0
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
#

Edited by NuttyMucker (Sat 30-Jun-12 13:25:16)

Everything appears to have worsened since April.

Using the 96.79% calculation, I imagine your IP Profile for your sync speed of 11399 will be 11.03Mbps as per the BT speed tester.

I believe the reportable fault threshold rate for FTTC connections is 12Mb, so it looks like you may now have a decent reason for requesting an engineer's visit (unless they fob you off with claims that you are rebooting the modem too often).

If you have enabled the inbuilt modem logs (ideally setting the clock to the correct date/time) you will be able to see every reboot & uninitiated modem resync.

Quite often ISPs & BT do not see all the "on the fly" resyncs, so they could/would argue that your connection is actually stable & "performing within acceptable limits".

Not much to work with there I'm afraid, especially as any modem stats are supposed to be a secret that us users who pay for our connections are not allowed to see (officially).