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Lurch

1061 posts

Uber Geek
+1 received by user: 71


#16731 25-Oct-2007 11:04
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ADSL

Mode: ADSL2+
Line coding: Trellis On
Status: No Defect
Link power state: L0
 
  Downstream Upstream
SNR margin (dB): 15.8 34.6
Attenuation (dB): 33.5 16.6
Output power (dBm): 18.8 10.7
Attainable rate (Kbps): 9460 796
Rate (Kbps): 5915 164
MSGc (number of bytes in overhead channel message): 59 18
B (number of bytes in Mux Data Frame): 184 4
M (number of Mux Data Frames in FEC Data Frame): 1 1
T (Mux Data Frames over sync bytes): 1 3
R (number of check bytes in FEC Data Frame): 0 0
S (ratio of FEC over PMD Data Frame length): 0.9953 0.9091
L (number of bits in PMD Data Frame): 1487 44
D (interleaver depth): 1 1
Delay (msec): 0 0
 
Super Frames: 46077 46075
Super Frame Errors: 412 3
RS Words: 0 0
RS Correctable Errors: 0 0
RS Uncorrectable Errors: 0 N/A
 
HEC Errors: 275 121
OCD Errors: 36 0
LCD Errors: 0 0
Total Cells: 10392139 122729564
Data Cells: 940614 4309668
Bit Errors: 0 1839
 
Total ES: 109 12
Total SES: 2 9
Total UAS: 32 374595

It states terllis on this is since the line was switched to ADSL2, isnt this suppose to state fast if interleaving is off? Also notice I'm getting alot of errors further down, HEC/OCD... never had these showing under ADSL.. any advice would be much appreciated.

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lonney
85 posts

Master Geek


  #92421 25-Oct-2007 16:06
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"ADSL2 provides better modulation efficiency by mandating four-dimensional, 16-state
trellis-coded and 1-bit quadrature amplitude modulation (QAM) constellations, which
provide higher data rates on long lines where the signal-to-noise ratio (SNR) is low. In
addition, receiver-determined tone reordering enables the receiver to spread out the
non-stationary noise due to AM radio interference to get better coding gain from the
Viterbi decoder."

Best I can find, one website I found suggested that Trellis can degrade performance on short/good lines.

I know of one person that has had issues since being put onto adsl2+, seems it may not be as robust as adsl1?



Lurch

1061 posts

Uber Geek
+1 received by user: 71


  #92510 26-Oct-2007 10:47
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Thanks for the reply, would agree about it not being as robust as ADSL1.... connection speed jumps all over the place. Rather be back on ADSL than ADSL2...

Again, thanks for the reply, have been doing afew googles to try an find out more about it but not that many websites discussing it.

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