50M 50mb Broadband Upstream gone down

roger skillin · 26-05-2011, 06:47

I had to restart my modem today, i'm on 50mb and have always had an upstream of 1750000, i'm aware of the upgrades to the upstream levels which i'm still waiting for but after the restart i checked and it's actually gone down, little confused, if anyone can throw any light on the situation it would be a help.

Cable Modem Operation Configuration
General Configuration
Network Access : Allowed
Maximum Number of CPEs : 1
Baseline Privacy : Enabled
DOCSIS Mode : DOCSIS 3.0
Config File : V668732788139190d.cm
Primary Downstream Service Flow
SFID : 8493
Max Traffic Rate : 53000000 bps
Max Traffic Burst : 10000 bytes
Min Traffic Rate : 0 bps
Primary Upstream Service Flow
SFID : 3086
Max Traffic Rate : 1072000 bps
Max Traffic Burst : 8160 bytes
Min Traffic Rate : 0 bps
Max Concatenated Burst : 8160 bytes
Scheduling Type : Best Effort

DOWNSTREAM

Frequency 299000000 307000000 315000000 323000000
Lock Status
(QAM Lock/FEC Sync/MPEG Lock) Y/Y/Y Y/Y/Y Y/Y/Y Y/Y/Y
Channel Id 65 66 67 68
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) -2.63 -2.97 -3.78 -4.15
RxMER
(dB) 36.39 36.17 36.17 36.39
Correctable
Codewords 2460 11734 7453 392
Uncorrectable
Codewords 281 290 292 284

UPSTREAM

Channel Type 2.0 N/A N/A N/A
Channel ID 4 N/A N/A N/A
Frequency
(Hz) 35800000 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) 5120 N/A N/A N/A
Mini-Slot Size 4 N/A N/A N/A
Power Level
(dBmV) 58.21 N/A N/A N/A
T1 Timeouts 0 0 0 0
T2 Timeouts 0 0 0 0
T3 Timeouts 0 0 0 0
T4 Timeouts 0 0 0 0

UPSTREAM BURST

Modulation Type QPSK QPSK QPSK 16QAM 16QAM 16QAM
Differential Encoding OFF OFF OFF OFF OFF OFF
Preamble Length 64 640 384 96 104 104
Preamble Value Offset 652 6 6 1028 1028 1028
FEC Error Correction (T) 0 5 5 6 8 8
FEC Codeword Information Bytes (k) 16 34 34 75 219 219
Maximum Burst Size 0 0 0 6 0 0
Guard Time Size 8 48 48 8 8 8
Last Codeword Length FIX FIX FIX SHORT SHORT SHORT
Scrambler on/off ON ON ON ON ON ON

Sephiroth · 26-05-2011, 07:35

Quote:

Originally Posted by roger skillin

I had to restart my modem today, i'm on 50mb and have always had an upstream of 1750000, i'm aware of the upgrades to the upstream levels which i'm still waiting for but after the restart i checked and it's actually gone down, little confused, if anyone can throw any light on the situation it would be a help.

.....
Primary Upstream Service Flow
SFID : 3086
Max Traffic Rate : 1072000 bpsMax Traffic Burst : 8160 bytes
Min Traffic Rate : 0 bps
Max Concatenated Burst : 8160 bytes
Scheduling Type : Best Effort

......
UPSTREAM

Channel Type 2.0 N/A N/A N/A
Channel ID 4 N/A N/A N/A
Frequency
(Hz) 35800000 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) 5120 N/A N/A N/A
Mini-Slot Size 4 N/A N/A N/A
Power Level
(dBmV) 58.21 N/A N/A N/A
T1 Timeouts 0 0 0 0
T2 Timeouts 0 0 0 0
T3 Timeouts 0 0 0 0
T4 Timeouts 0 0 0 0

Not many people would worry about 1.75 moving down to 1.65! But I do see anomalies in your stats.

1/The modem reports a maximum upstream rate of 1.072 meg. So that can't be right, particularly as your upstream is modulating at the full 16QAM.

2/
At 58.21 dBmv your upstream power is maxing out. Can we see the event log please? This might throw light on what's going o. What other bad experiences occur?

Peter_ · 26-05-2011, 07:59

He needs a technician to resolve his upstream power level so should call in to get one booked.

roger skillin · 26-05-2011, 08:26

Quote:

Originally Posted by Sephiroth

Not many people would worry about 1.75 moving down to 1.65! But I do see anomalies in your stats.

1/The modem reports a maximum upstream rate of 1.072 meg. So that can't be right, particularly as your upstream is modulating at the full 16QAM.

2/
At 58.21 dBmv your upstream power is maxing out. Can we see the event log please? This might throw light on what's going o. What other bad experiences occur?

I didn't complain about the upsteam goind down to 1.65, it has gone down to 1.072 from 1.750.
Thank you i did think the upstream power was a bit off, i will post the event log this evening as i'm at work now.

Sephiroth · 26-05-2011, 09:03

I saw 1.62 on the speed test. If you're referring to the modem stats, then you're right.

Masque says you need a tech to resolve your power level. When it's only the upstream that's playing up, the regular engineers can't do much other than swapping your modem out. If the engineer does attend and puts the Superhub in, don't let him leave until you've refreshed your stats several times to make sure that upstream power is steady and not at 55 dBmv or above. If US power remains high, you will know that your modem wasn't at fault and you should thus elect to keep it rather than move to the hub.

So you know, upstream power is raised under command from the CMTS (the VM end) because it can't make sense of what's coming back upstream. This can be due to noise (but then your modulation would be changed from 16QAM to QPSK) or an impairment anywhere between your modem and the CMTS. If the problem's at the VM end, the local engineer can do nothing about it. Just so you know.

roger skillin · 26-05-2011, 09:25

Quote:

Originally Posted by Sephiroth

I saw 1.62 on the speed test. If you're referring to the modem stats, then you're right.

Masque says you need a tech to resolve your power level. When it's only the upstream that's playing up, the regular engineers can't do much other than swapping your modem out. If the engineer does attend and puts the Superhub in, don't let him leave until you've refreshed your stats several times to make sure that upstream power is steady and not at 55 dBmv or above. If US power remains high, you will know that your modem wasn't at fault and you should thus elect to keep it rather than move to the hub.

So you know, upstream power is raised under command from the CMTS (the VM end) because it can't make sense of what's coming back upstream. This can be due to noise (but then your modulation would be changed from 16QAM to QPSK) or an impairment anywhere between your modem and the CMTS. If the problem's at the VM end, the local engineer can do nothing about it. Just so you know.

My speedtest results is just my signature which i saved when i first had 50mb a while back.

I will have to arrange for an engineer, although i wont be able to test anything as i work 9-5 so it would be one of my parents that would let the engineer in and they don't know anything about computers lol

Sephiroth · 26-05-2011, 09:36

Change your sig!!

Anyway, have a look on the forum. There's another post with 1.07 upstream (http://www.cableforum.co.uk/board/12...ded-today.html).

Looks like a misconfiguration of some sort by VM. You could ask the guy in the other post if he's from your area - as a long shot.

Chrysalis · 26-05-2011, 20:00

could be to mitigate upstream congestion?

when I got put on a 384kbit config last xmas my upstream was very severely congested at the time.

unlike the downstream I dont think VM actively market the upstream speeds so they in affect free to set them lower.

Sephiroth · 26-05-2011, 20:23

Quote:

Originally Posted by Chrysalis

could be to mitigate upstream congestion?

when I got put on a 384kbit config last xmas my upstream was very severely congested at the time.

unlike the downstream I dont think VM actively market the upstream speeds so they in affect free to set them lower.

Chrys

I know what you mean - but VM do actively market their online storage and backup products with the 50 meg BB package. That, of course, requires upstream. And, as you know, downstream can't function without upstream.

So VM mess around with upstream at their peril, IMO. They can in any case rate limit the upstream by policy. It's a lot of trouble to go to to deliberately set a throttled rate unless it was applied only to this user for exceeding one of the policies.

That said, you're right. They are free to mess with the upstream.