Low sync breach but a problem

I have lost a good chunk of speed over the last week, I was syncing at the 7900kbps mark but I'm now down to 5700kbps.

My problem is that I'm due to move to LLU on Thursday so should I just wait and see what happens or raise a fault with my current ISP?

Post your router stats and exchange.

LCWIN
Att. 32db
SNR 15db
5792kbps

Edited by PiKe (Fri 28-Oct-11 19:37:46)

Your sync is low cuz your NM has risen to 15 dB. You must have noise on your line which will probably remain when you move to LLU (TT is it?) but it is not not the responsibility of the ISP. However you are still likely to get faster on LLU; 12 Meg on a good line but maybe only 9 Meg on your noisy line.

Strange how this has happened since I ordered my migration to TT, I wonder if BT are vindictive at all?

But seriously, It's been getting worse and worse and the SNR hasn't changed, it's been 15db but it's get slower and slower.

Surely its a fault?

Bitloading; is the tone in khz?

Text

1 23 45 67 89 1011 1213 1415 1617 1819 2021 2223 2425 2627

Tone :  # Bits per tone       0 :   0  0  0  0  0  0  7  9  9 10     10 :  11 11 11 11 12 12 11 11 11 11      20 :  11 11 10  9  9  9  8  7  6  4     30 :   2  0  0  3  3  3  4  4  5  5      40 :   6  7  8  8  9  9  8  9 10  9     50 :   9  9 10 10 10 10 10 10 10 10      60 :  10 10 10 10  0 10 10  9 10 10     70 :   9 10  9  9  9  9  9  9  9  9      80 :   9  9  9  9  9  9  9  9  9  9     90 :   9  9  9  9  9  8  8  8  9  8     100 :   9  8  8  9  8  8  8  8  8  8    110 :   9  8  8  8  8  8  8  8  8  8     120 :   8  8  8  8  8  8  8  8  8  8    130 :   7  8  7  8  7  7  7  8  7  7     140 :   7  7  7  7  7  7  7  7  7  7    150 :   7  7  7  7  7  7  7  7  7  7     160 :   7  6  7  7  7  6  7  6  7  7    170 :   7  6  7  6  7  6  6  7  7  6     180 :   6  7  6  7  6  7  6  7  5  6    190 :   7  6  6  6  6  6  6  6  6  6     200 :   6  6  6  6  5  5  6  5  6  6    210 :   5  4  6  6  5  5  6  5  6  6     220 :   6  5  6  5  6  5  5  5  6  5    230 :   5  6  5  5  5  6  5  5  5  6     240 :   5  5  6  6  5  5  5  6  5  5    250 :   5  5  4  5  5  0

Have you rebooted the router?

Yes and I have tried another.

The tone is in units of "bin number"; for almost all DSL products (bar SDSL and VDSL2 profile 30a), you convert bin number to lower frequency by multiplying it by 4.3125 kHz (the width of a bin).

For example, bin 0 covers DC to 4.3125 kHz; bin 32 is 138kHz to 142.3125kHz.

You can fit up to 15 bits in a bin, on a perfect line. In the UK, bins 0 to 5 are never used - bin 0 is voice, and bins 1 to 5 are left empty so that we can filter out interference from voice signals.

If you're on Annex A, bins 5 to 31 inclusive are upload; bins 32 upwards are download. Annex M users will use bins 5 to 63 for upload. ADSL and ADSL2 end at bin 255 (around 1.1MHz); ADSL2+ gets higher speeds by extending the bin range up to bin 511 (at 2.2MHz). Expect to see the two bins next to the switch from download to upload being left empty (bins 31 and 32 on Annex A, bins 63 and 64 on Annex M).

VDSL and VDSL2 get complex, as they alternate bands of upload bins with bands of download bins, and go up much further than ADSL (possibly as far as 30MHz, if you're on profile 30a, which also uses double-width bins of 8.625kHz).

Hi farnz,

In the UK, it also appears there is some US/DS tone "sharing" for VDSL2 connections:-

Old 8c Profile:-
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)

New 17a Profile:-
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) (1972,2783)
DS: (32,859) (1216,1963) (2792,3939)


Paul