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Standard User maggiej
(learned) Wed 13-Mar-13 11:48:55
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ADSL2+ Speed Drop


[link to this post]
 
Some advice please.

My BB speed (BT line - non LLU) has been steadily dropping since the middle of February. It has gone from over 18 MBS - SNR 3.1 to 11 MBS - SNR 13.8. I do understand that the increased SNR is reason for the speed drop. I have been monitoring my connection with Routerstats to try and see what is going on. There was one day during Feb when my router kept disconnecting and presume this is the reason for the current speed. According to my ISP it is the router which is losing the connection and nothing wrong with the line?? I have subsequently completely reset the router and my connection has remained stable for over 6 days (12 SNR) until yesterday when it disconnected again and yet another drop in the SNR margin to the present 13.8. During this time, the Upstream rate has also been fluctuating from 1265 down to 598 with interleaving being applied and then removed. I have been waiting for the DSLAM?? to kick-in but it does not appear to have done so - except to knock the speed down and not up. Am I being impatient?

Any suggestions/advice would be most appreciated before I go back to my ISP again.

Thanks

Edited by maggiej (Wed 13-Mar-13 11:53:07)

Administrator MrSaffron
(staff) Wed 13-Mar-13 12:06:41
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Re: ADSL2+ Speed Drop


[re: maggiej] [link to this post]
 
The router is most likely reacting to bursts of noise, the provider cannot really tell where these are coming from.

It could be a joint on the line, a solder joint in the router, or a bit of damp in the home causing corroded connections, or as unlinked as your heating boiler now sparking more and the radio interference from this causing problems for the ADSL.

For the DLM to reduce target noise margin you are looking at the system wanting to see you as stable for two weeks.

Andrew Ferguson, andrew@thinkbroadband.com
www.thinkbroadband.com - formerly known as ADSLguide.org.uk
The author of the above post is a thinkbroadband staff member. It may not constitute an official statement on behalf of thinkbroadband.
Standard User 4M2
(fountain of knowledge) Wed 13-Mar-13 12:10:09
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Re: ADSL2+ Speed Drop


[re: maggiej] [link to this post]
 
Before you contact your ISP again can you connect the router to the test socket behind the master NTE5 (if you have a master NTE5?) faceplate (or filtered faceplate?) using a different dangle micro filter (?) and post your full current router stats?


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Standard User maggiej
(learned) Wed 13-Mar-13 12:40:37
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Re: ADSL2+ Speed Drop


[re: 4M2] [link to this post]
 
Thanks for the quick response. Unfortunately I do not have a master NTE socket in my property. However, I did replace the filter connecting the router when I reset it and below are my current stats:

Statistics -- xDSL

Mode: ADSL_2plus
Traffic Type: ATM
Status: Up
Link Power State: L0

Downstream Upstream
Line Coding(Trellis): On On
SNR Margin (0.1 dB): 138 88
Attenuation (0.1 dB): 200 104
Output Power (0.1 dBm): 0 128
Attainable Rate (Kbps): 15932 984

Path 0 Path 1
Downstream Upstream Downstream Upstream
Rate (Kbps): 11767 891 0 0

MSGc (# of bytes in overhead channel message): 51 67 0 0
B (# of bytes in Mux Data Frame): 209 27 0 0
M (# of Mux Data Frames in FEC Data Frame): 1 1 0 0
T (Mux Data Frames over sync bytes): 2 1 0 0
R (# of check bytes in FEC Data Frame): 0 0 0 0
S (ratio of FEC over PMD Data Frame length): 0.5696 0.9696 0.0 0.0
L (# of bits in PMD Data Frame): 2949 231 0 0
D (interleaver depth): 1 1 0 0
Delay (msec): 0.14 0.24 0.0 0.0
INP (DMT symbol): 0.0 0.0 0.0 0.0

Super Frames: 6787851 539117 0 0
Super Frame Errors: 0 0 0 0
RS Words: 0 0 0 0
RS Correctable Errors: 0 0 0 0
RS Uncorrectable Errors: 0 0 0 0

HEC Errors: 4294967243 423 0 0
OCD Errors: 52 0 0 0
LCD Errors: 0 0 0 0
Total Cells: 3058772039 1690069 0 0
Data Cells: 5146314 18210 0 0
Bit Errors: 0 0 0 0

Total ES: 689 11
Total SES: 38 0
Total UAS: 159 4294967259
Standard User maggiej
(learned) Wed 13-Mar-13 12:53:21
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Re: ADSL2+ Speed Drop


[re: MrSaffron] [link to this post]
 
Thanks for yr advice. So really could be anything?? If it is a suspect joint on the line (we're in a rural location here - overhead wires etc) would it not show up as a fault on the line? Central heating boiler - as it's on most of the day wouldn't it keep affecting the router? If it is something to do with the router innards, can try an old Netgear and see what happens but will wait on that in line with the two weeks to see if the DLM does kick in..
Administrator MrSaffron
(staff) Wed 13-Mar-13 12:58:34
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Re: ADSL2+ Speed Drop


[re: maggiej] [link to this post]
 
It may be the cold weather has allowed some water ingress to a joint outside and resulting in a High Resistance fault.

In theory there are tests for this CIDT is its name, and often is not run and it can detect faults that the traditional tests miss.

For background
http://www.openreach.co.uk/orpg/home/products/llu/ci...

Andrew Ferguson, andrew@thinkbroadband.com
www.thinkbroadband.com - formerly known as ADSLguide.org.uk
The author of the above post is a thinkbroadband staff member. It may not constitute an official statement on behalf of thinkbroadband.
Standard User 4M2
(fountain of knowledge) Wed 13-Mar-13 13:03:36
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Re: ADSL2+ Speed Drop


[re: maggiej] [link to this post]
 
Yes noise affecting the line some where - downstream sync with a 6dB SNRM on a 20dB attenuation should be ~20000Kbps

Your current downstream sync time SNRM may even be 15dB which is, as you suggested, really holding back the sync speed.

As your ISP mentioned, it might possibly be the router causing the problem so can you perhaps try another router?
Standard User maggiej
(regular) Wed 13-Mar-13 16:35:57
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Re: ADSL2+ Speed Drop


[re: 4M2] [link to this post]
 
Well I've taken the plunge and swapped over the router. Back to my old Netgear 834G v5. It is immediately reporting slightly better figures:


System Up Time 00:51:33

Port Status TxPkts RxPkts Collisions Tx B/s Rx B/s Up Time
WAN PPPoA 4409 4229 0 358 886 00:50:55
LAN 100M/Full 9756 10381 0 1422 599 00:51:13
WLAN 11M/54M 9828 7469 0 880 514 00:51:33

ADSL Link Downstream Upstream
Connection Speed 12503 kbps 1279 kbps
Line Attenuation 20.0 db 9.5 db
Noise Margin 12.00 db 5.5 db

I guess time will tell now. Will be interesting to see if it was the other router playing up (TP Link) or problems on the line. Shame really as I am not too keen on the Netgear as I know v5 is not one of the better versions as it does not seem to give as much info as other routers can..

Thanks for the input
Standard User RobertoS
(sensei) Wed 13-Mar-13 17:11:25
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Re: ADSL2+ Speed Drop


[re: maggiej] [link to this post]
 
That's an amazing upstream sync change.

My broadband basic info/help site - www.robertos.me.uk | Domains,website and mail hosting - Tsohost.
Connection - Plusnet UnLim Fibre (FTTC). Sync ~ 54.2/15.2Mbps @ 600m. - BQM

"Where talent is a dwarf, self-esteem is a giant." - Jean-Antoine Petit-Senn.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Allergy information: This post was manufactured in an environment where nuts are present. It may include traces of understatement, litotes and humour.
Standard User 4M2
(fountain of knowledge) Wed 13-Mar-13 17:21:24
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Re: ADSL2+ Speed Drop


[re: maggiej] [link to this post]
 
Give it a day or two with the Netgear and if there is no improvement with the downstream SNRM, ideally down to 6dB, and a sync speed of 20000Kbps then give your ISP a shout. Tell them that you have tried an alternative router, the line is still not performing as it should and insist that you have some tests done on the line.

Good luck smile

P.S. probably best not to mention that you don't have a NTE5/test socket at this stage unless specifically asked. Also have you tried a quiet line test (dial 17070 with a corded phone.)
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