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Brownie2k
15-04-2010, 23:52
Hi everyone,

I could do with a little bit of help on my connection, since i've had my Virgin Media connection, it's been totally fine, no problems, full advertised speeds (50mb), it's been totally fine. To an extent all that remains, although lately i've noticed that the number of correctable and uncorrectable codewords have started to rise.

I'm finding that i have to restart the modem every 24 - 48 hours too, it just pretty much stops working. Although MSN, AIM etc work fine, i can't access ANY webpages untill i restart the modem. My router is fine too and is set up correctly, so i'm at a loss as to why this is happening.

I contacted Virgin about it, and they said i have fluctuating power levels, but they dont fluctuate very much to be honest, they vary from about 1.2 - 3.0. Virgin have said that this is due to a problem with a card in the green box near my house which will be sorted.... someday. Could this be affecting the codewords too? I seem to be getting a few T3 time outs too. Or is it more likely that i'll need to contact Virgin Media for a new Cable Modem?

I'll post my stats if needed, but i've just restarted the modem again, so all appears normal.

Thanks everyone, i hope someone can advise me here.

Paul

Brownie2k
22-04-2010, 18:24
I'm actually rather confused now to be honest... I've continued to get the random internet droppages, and i've noticed a big increase on T3 timeouts when the problems occour. Plus i get a lot of ToD errors, but i've read thats not really a problem. I've also noticed that my Upload Power has dropped from 54.50dBmV and it's now around 41 - 43.50dBmV.

I've contacted Virgin and he agreed that the power level and amount of T3's i'm getting is definitely a problem and has arranged a tech for Saturday. I'm pretty certain that it's not an oversubscribed UBR, i'm getting a constant 49 - 50Mb speed on speedtests, and gamefiles.virginmedia.com is giving me 5.78MB/s (wireless N) which is exactly what i'd normally get.

Does anyone have any idea why this is happening? Do i have a problem at the Cab, or could it be a Modem problem? Here's my current stats:

Cable Modem Status
Item Status Comments
Acquired Downstream Channel 298.751221 MHz Primary Downstream Locked
Ranged Upstream Channel 42.799732 MHz Success
Provisioning State OK Operational
Ethernet Link Status Up 100 Mbps/Full duplex

Cable Modem Downstream
DS-1 DS-2 DS-3 DS-4
Frequency 298750000 306750000 314750000 322750000
Lock Status
(QAM Lock/FEC Sync/MPEG Lock) Y/Y/Y Y/Y/Y Y/Y/Y Y/Y/Y
Channel Id 13 14 15 16
Modulation 256QAM 256QAM 256QAM 256QAM
Symbol Rate
(Msym/sec) 6.952 6.952 6.952 6.952
Interleave Depth I=12
J=17 I=12
J=17 I=12
J=17 I=12
J=17
Power Level
(dBmV) 0.71 0.45 0.12 0.24
RxMER
(dB) 37.09 37.36 37.36 37.36
Correctable
Codewords 1170 704 875 1446
Uncorrectable
Codewords 289 265 256 278

Cable Modem Upstream
US-1 US-2 US-3 US-4
Channel Type 1.0 N/A N/A N/A
Channel ID 5 N/A N/A N/A
Frequency
(Hz) 42800000 N/A N/A N/A
Ranging Status Success N/A N/A N/A
Modulation 16QAM N/A N/A N/A
Symbol Rate
(KSym/sec) 2560 N/A N/A N/A
Mini-Slot Size 2 N/A N/A N/A
Power Level
(dBmV) 43.50 N/A N/A N/A
T1 Timeouts 0
T2 Timeouts 0 0 0 0
T3 Timeouts 2 0 0 0
T4 Timeouts 0 0 0 0

Cable Modem Upstream Burst
US-1
Req
Init Maint
Per Maint
Short Data
Long Data

(1)
(3)
(4)
(5)
(6)



Modulation Type QPSK QPSK QPSK 16QAM 16QAM

Differential Encoding OFF OFF OFF OFF OFF
Preamble Length 64 128 128 144 160
Preamble Value Offset 140 6 6 216 216
FEC Error Correction (T) 0 5 5 5 10
FEC Codeword Information Bytes (k) 16 34 34 78 235
Maximum Burst Size 2 0 0 8 0
Guard Time Size 8 48 48 8 8
Last Codeword Length FIX FIX FIX SHORT SHORT
Scrambler on/off ON ON ON ON ON

Cable Modem Operation Configuration
General Configuration
Network Access : Allowed
Maximum Number of CPEs : 1
Baseline Privacy : Enabled
DOCSIS Mode : DOCSIS 3.0
Config File : Pcaa1a92007a50b13.cm
Primary Downstream Service Flow
SFID : 28926
Max Traffic Rate : 53000000 bps
Max Traffic Burst : 10000 bytes
Min Traffic Rate : 0 bps
Primary Upstream Service Flow
SFID : 28925
Max Traffic Rate : 1750000 bps
Max Traffic Burst : 3044 bytes
Min Traffic Rate : 0 bps
Max Concatenated Burst : 0 bytes
Scheduling Type : Best Effort

As i've wrote this, my power has jumped back to 51.00dBmV, but around 9pm ish, it'll drop to 41 - 43 again? It's getting very confusing to be totally honest!

Brownie2k
24-04-2010, 16:17
Well i've just had the engineer here, and he's took the 6db Attenuator off my modem, saying the power levels are better at the higher end of the 0 - 6 range. I was also told the lower the upload power level the better.
So my new stats look like this:


Cable Modem Downstream
DS-1 DS-2 DS-3 DS-4
Frequency 298750000 306750000 314750000 322750000
Lock Status
(QAM Lock/FEC Sync/MPEG Lock) Y/Y/Y Y/Y/Y Y/Y/Y Y/Y/Y
Channel Id 13 14 15 16
Modulation 256QAM 256QAM 256QAM 256QAM
Symbol Rate
(Msym/sec) 6.952 6.952 6.952 6.952
Interleave Depth I=12
J=17 I=12
J=17 I=12
J=17 I=12
J=17
Power Level
(dBmV) 5.72 5.50 5.25 5.72
RxMER
(dB) 37.36 37.94 37.94 37.94
Correctable
Codewords 10 12 11 8
Uncorrectable
Codewords 335 350 317 328


Cable Modem Upstream
US-1 US-2 US-3 US-4
Channel Type 1.0 N/A N/A N/A
Channel ID 5 N/A N/A N/A
Frequency
(Hz) 42800000 N/A N/A N/A
Ranging Status Success N/A N/A N/A
Modulation 16QAM N/A N/A N/A
Symbol Rate
(KSym/sec) 2560 N/A N/A N/A
Mini-Slot Size 2 N/A N/A N/A
Power Level
(dBmV) 41.75 N/A N/A N/A
T1 Timeouts 0
T2 Timeouts 0 0 0 0
T3 Timeouts 5 0 0 0
T4 Timeouts 3 0 0 0


Cable Modem Upstream Burst
US-1
Req
Init Maint
Per Maint
Short Data
Long Data

(1)
(3)
(4)
(5)
(6)



Modulation Type QPSK QPSK QPSK 16QAM 16QAM

Differential Encoding OFF OFF OFF OFF OFF
Preamble Length 64 128 128 144 160
Preamble Value Offset 140 6 6 216 216
FEC Error Correction (T) 0 5 5 5 10
FEC Codeword Information Bytes (k) 16 34 34 78 235
Maximum Burst Size 2 0 0 8 0
Guard Time Size 8 48 48 8 8
Last Codeword Length FIX FIX FIX SHORT SHORT
Scrambler on/off ON ON ON ON ON

Do these look any better than the levels i've posted above? Or do they look somewhat worse then they were? If anyone could comment and help me out, i'd be very much appriciative.