View Full Version : ADSL Experts in here please!
Just moved into a new (shared) place and am getting fairly shoddy results on my line here...
Here are the stats that my router has given me, what hope do I have of improving this with better filters / test sockets and things?
show dsl interface atm0
ATU-R (DS) ATU-C (US)
Modem Status: Showtime (DMTDSL_SHOWTIME)
DSL Mode: ITU G.992.1 (G.DMT)
ITU STD NUM: 0x01 0x01
Vendor ID: 'ALCB' 'IFTN'
Vendor Specific: 0x0000 0x7153
Vendor Country: 0x00 0xB5
Capacity Used: 96% 96%
Noise Margin: 13.5 dB 14.0 dB
Output Power: 20.0 dBm 11.0 dBm
Attenuation: 44.0 dB 26.5 dB
Defect Status: None None
Last Fail Code: None
Selftest Result: 0x00
Subfunction: 0x15
Interrupts: 650 (1 spurious)
Activations: 2
Init FW: embedded
Operartion FW: embedded
SW Version: 3.919
FW Version: 0x1A04
Interleave Fast Interleave Fast
Speed (kbps): 3840 0 128 0
Reed-Solomon EC: 48019 0 16 18
CRC Errors: 1015 0 82 2
Header Errors: 992 0 27 12
Bit Errors: 0 0
BER Valid sec: 0 0
BER Invalid sec: 0 0
LOM Monitoring : Disabled
DMT Bits Per Bin
00: 0 0 0 0 0 0 0 3 4 4 4 4 4 3 3 3
10: 3 3 2 2 2 2 2 2 2 0 2 0 0 0 0 0
20: 0 0 0 0 0 0 5 5 6 7 7 7 8 8 8 8
30: 8 8 8 8 9 9 9 8 8 8 8 8 8 8 8 2
40: 9 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8
50: 8 8 8 8 7 8 8 8 8 8 8 8 8 8 8 8
60: 8 8 8 7 7 7 7 7 7 7 7 7 7 7 7 7
70: 7 7 7 7 7 7 7 7 7 7 7 7 7 6 6 7
80: 7 7 7 7 7 6 6 6 6 6 6 6 6 6 6 6
90: 6 6 6 6 6 6 6 6 5 6 6 6 6 6 6 6
A0: 6 5 5 5 5 5 5 4 5 5 5 5 5 5 5 5
B0: 2 5 4 4 4 4 4 4 4 4 4 4 4 5 5 5
C0: 5 4 4 4 4 4 2 4 4 4 3 3 3 3 3 3
D0: 2 0 0 0 0 0 2 2 2 2 2 2 3 3 3 2
E0: 2 3 3 3 3 3 2 2 0 2 2 2 2 2 2 2
F0: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Training log buffer capability is not enabled yet.
Thanks!
44dB attenuation is pretty bad and will most likely be down to line length/condition - you can try better filters etc. but I don't think it will help much.
For comparison:
Link Information
Uptime: 9 days, 17:29:30
DSL Type: G.992.5 annex A
Bandwidth (Up/Down) [kbps/kbps]: 1,230 / 3,826
Output Power (Up/Down) [dBm]: 12.0 / 17.0
Line Attenuation (Up/Down) [dB]: 25.5 / 46.5
SN Margin (Up/Down) [dB]: 6.5 / 8.0
Have you tried the usual trick - master socket faceplate off and plugged straight into the test socket with no filters? That'll tell you for sure.
Line stats don't look spectacularly bad, but they are certainly plenty bad enough. If you've got cheapo crap filters (which I would doubt given your background) then by all means change them. Otherwise, probably not a huge amount to be gained.
PS - the high Noise Margin may indicate there is either still some more line training to be done, or that you have sporadic noise on the line, or it may simply be down to the high attenuation. The default target is typically 6.
Lucky sod... they're not bad, here are mine... ;)
ADSL Link Downstream
Connection Speed 3008 kbp
Line Attenuation 63.0 db
Noise Margin 6.9 db
Lucky sod... they're not bad, here are mine... ;)
ADSL Link Downstream
Connection Speed 3008 kbp
Line Attenuation 63.0 db
Noise Margin 6.9 db
Lucky? In the last three years I have gone from a 100Mbps synchronous connection to a 20Mbps async and now down to about 4Mbps?
4Mbps feels utterly dreadful to use in comparison!
You aren't the only one, though I never had the 20Mb intermediate stage :p
Damn students! Think of us lot that have never had 100Mbps*
* OK, so I had it at work for a while. Think they might be rate-limiting for higher priority stuff now though as I never see that sort of speed.
Does ADSL learn? I've moved to the master socket and am getting no difference at all.
Leave it a week, should have found its limit by then - try not to keep killing the connection as it may get interpreted as instability and the speed reduced.
Does ADSL learn? I've moved to the master socket and am getting no difference at all.
What has your sync rate changed to? Have a read up on BRAS profiles and you'll see why a small increase in sync rate could give you bugger all extra throughput.
If you're finding the link stable ask your ISP to disable interleaving, you should notice lower ping times thanks to the lack of packet chopping, sorting and re-assembling.
What was the uptime of the ATM interface when you took the stats? Quite a few CRC's there.
I don't really understand phone lines and all that, but we moved into this house (new build) last October, and for a long time our line connection was only 2mb when BT said it was capable of 8mb
Only recently we've started to connect at the 8mb that the line is capable of, I've not changed anything for this to happen and i doubt anyone else has - maybe just patience will improve your connect :D
I wonder if 21CN enablement had anything to do with that. No idea why it should, but it's a change that might have happened. BRAS should settle out within 10 days (and usually much quicker) providing the line is stable, so I doubt it's that.
I didn't know about 21CN, but I've just looked into that and Chester is on the list of enabled exchanges.
Theres a PDF of enabled exchanges accurate as of March;
http://www.btplc.com/21CN/Theroadto21CN/Keymilestones/Documents/WBC_Enabled_Exchanges_as_at_March09_Issue1.pdf
Cheers Mark :)
It's just the WBC portion of 21CN at this point, which I really wouldn't expect to have an effect, but again, you never know. The full 21CN switchover (which will move voice lines over to a digital network) happens over the next year or so.
What has your sync rate changed to? Have a read up on BRAS profiles and you'll see why a small increase in sync rate could give you bugger all extra throughput.
If you're finding the link stable ask your ISP to disable interleaving, you should notice lower ping times thanks to the lack of packet chopping, sorting and re-assembling.
What was the uptime of the ATM interface when you took the stats? Quite a few CRC's there.
0 bits per second different. :(
0 bits per second different. :(
Ah. The sync rate change should happen pretty much straight away of it's going to happen.
That said, the stats you posted had an SNR of 13.5dB which is in itself a bit odd. RADSL has an SNR target of around 6dB so your sync rate would go up as your SNR goes down to that target.
The theory behind using the test socket is that eliminating any extensions would result in less noise on the line and therefore a more favourable signal:noise ratio and a higher sync rate.
The fact that your sync rate hasn't changed at all and you have a relatively high SNR would almost imply that your connection is a fixed rate rather than adaptive rate ADSL but the sync rate you posted is indicative of it being an adaptive rate.
Most strange.
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