Good sync, good IP profile, awful speeds?

Hello,

I recently suffered some problems with my BT Business Broadband line (ADSL2+). After two engineer visits, we have resumed normal service - except, the throughput of the line is awful!

The router is connected at 9863kbps, the IP profile for the line is 6000kbps, but throughput (according to speedtester.bt.com and others) is around 400kbps.

I've tried three different known-good routers, connecting to the master socket, various ethernet cables/WiFi and different computers, all to no avail. As you can understand, this is a confusing situation that both I and the people at the helpdesk can't get their heads around. The situation has gone through to a support team who will ring me tomorrow, but could anybody on here shed some light on the situation?

Edit: Just adding some more details...
ADSL Link Downstream Upstream
Connection Speed 9863 kbps 1183 kbps
Line Attenuation 37.0 db 19.1 db
Noise Margin 6.7 db 5.9 db

Edited by RocketMBA1 (Wed 15-Sep-10 23:52:44)

Others have asked for this information, so I thought I would post it here as well...


Router stats:



/usr/sbin/adslctl: ADSL driver and PHY status
Status: ShowtimeRetrain Reason: 8000
Channel: FAST, Upstream rate = 1183 Kbps, Downstream rate = 9863 Kbps
Link Power State: L0
Mode: ADSL2+
Channel: Fast
Trellis: U:ON /D:ON
Line Status: No Defect
Training Status: Showtime
Down Up
SNR (dB): 6.9 5.9
Attn(dB): 37.0 19.1
Pwr(dBm): 0.0 12.4
Max(Kbps): 12476 1184
Rate (Kbps): 9863 1183
G.dmt framing
K: 176(0) 37
R: 0 0
S: 1 1
D: 1 1
ADSL2 framing
MSGc: 51 12
B: 175 36
M: 1 1
T: 2 4
R: 0 0
S: 0.5693 0.9932
L: 2473 298
D: 1 1
Counters
SF: 3275460 3126419
SFErr(CRCErr): 2024 0
RS: 0 0
RSCorr: 0 0
RSUnCorr: 0 0

HEC: 1325 0
OCD: 216 0
LCD: 0 0
Total Cells: 1236444116 139892
Data Cells: 2021246 790
Drop Cells: 1041
Bit Errors: 0 0

ES: 1603 0
SES: 1 0
UAS: 86 0
AS(Uptime): 53150

INP: 0.00 0.00
PER: 16.22 17.87
delay: 0.14 0.24
OR: 28.10 8.05

Bitswap: 2676 90
Total uptime: 55993

Total time = 15 hours 35 min 39 sec
SF = 3450501
CRC = 2638
LOS = 1
LOF = 9
ES = 1603
Latest 1 day time = 15 hours 35 min 39 sec
SF = 3450501
CRC = 2638
LOS = 1
LOF = 9
ES = 1603
Latest 15 minutes time = 5 min 39 sec
SF = 20892
CRC = 178
LOS = 0
LOF = 0
ES = 102
Previous 15 minutes time = 15 min 0 sec
SF = 55446
CRC = 538
LOS = 0
LOF = 0
ES = 282
Previous 1 day time = 0 sec
SF = 0
CRC = 0
LOS = 0
LOF = 0
ES = 0
15 minutes interval [-30 min to -15 min] time = 15 min 0 sec
SF = 55508
CRC = 70
LOS = 0
LOF = 0
ES = 57
15 minutes interval [-45 min to -30 min] time = 15 min 0 sec
SF = 55446
CRC = 101
LOS = 0
LOF = 0
ES = 55
15 minutes interval [-60 min to -45 min] time = 15 min 0 sec
SF = 55446
CRC = 20
LOS = 0
LOF = 0
ES = 20
Showtime Drop Reason: 8000
Last Retrain Reason: 8000







speedtester results:



Test1 comprises of two tests

1. Best Effort Test: -provides background information.

Download Speed
403 Kbps

0 Kbps 7150 Kbps
Max Achievable Speed
Download speedachieved during the test was - 403 Kbps
For your connection, the acceptable range of speedsis 1000-7150 Kbps.
Additional Information:
Your DSL Connection Rate :9863 Kbps(DOWN-STREAM), 1183 Kbps(UP-STREAM)
IP Profile for your line is - 6000 Kbps
The throughput of Best Efforts (BE) classes achieved during the test is - 17.08:28.15:54.78 (SBE:NBE:PBE)
These figures represent the ratio while sententiously passing Sub BE, Normal BE and Priority BE marked traffic.

The results of this test will vary depending on the way your ISP has decided to use these traffic classes.

2. Upstream Test: -provides background information.

Upload Speed
928 Kbps

0 Kbps 1183 Kbps
Max Achievable Speed
>Upload speed achieved during the test was - 928 Kbps
Additional Information:
Upstream Rate IP profile on your line is - 1183 Kbps


This test was not conclusive and further testing is required.This might be useful for your ISP to investigate the fault.

If you wish to carry out further tests,please click on 'Continue' button.If not, please close the window using 'Exit' button and contact your ISP for further assistance with these results.

I get the impression BT have failed in their implementation of ADSL2+. I suspect any solution is outside your control, and appears to be beyond BT's competence.

Any LLU providers at your exchange? See http://www.samknows.com/broadband/exchange_search

Yeah, there's a couple...

But the original problem has returned! Arrgh! Lost sync a few times today, the latest of which has dropped me back down to 576kbps download.

Do you know what is causing the loss of sync? Is there a burst of line noise from local interference?

I'm unsure - the line was always perfectly stable, staying sync'd for days at a time at 11/12mb. Problems only started at the end of August/beginning of September, when I noticed the speed of connection was dropping and it was losing sync a couple of times a day... The problem compounded and here we are.

I've looked around for sources of interference but I couldn't find anything, unfortunately.

In reply to a post by RocketMBA1:

I've looked around for sources of interference but I couldn't find anything, unfortunately.

Are you in London ? if so what area ?

Down Up
SNR (dB): 6.9 5.9
Attn(dB): 37.0 19.1
Pwr(dBm): 0.0 12.4
Max(Kbps): 12476 1184
Rate (Kbps): 9863 1183

Wonder why the router is reporting that power figure as 0.0 dBm?

In reply to a post by IamQ:

In reply to a post by RocketMBA1:

I've looked around for sources of interference but I couldn't find anything, unfortunately.

Are you in London ? if so what area ?

No sir, Somerset.

In reply to a post by Apprentice:

Down Up
SNR (dB): 6.9 5.9
Attn(dB): 37.0 19.1
Pwr(dBm): 0.0 12.4
Max(Kbps): 12476 1184
Rate (Kbps): 9863 1183

Wonder why the router is reporting that power figure as 0.0 dBm?

I was led to believe that's a bug in the router's software...