Random Net Dropouts

[neoapple]

This is an ongoing issue now and it's one that I really want sorted. Every time I phone up Virgin it's like sorry sir we can't find an issue here etc. Been going on for a few months now.

But yet every so often my internet just freezes, literally! Sometimes the cable modem just locks up and wont respond to it's 192.168.100.1 address, yet the router I have Netgear WRT54GL Running Tomato works fine.

The only way I found to get the internet back is to reset the VM Cable Modem, either by power cycle it or through the restore default settings if it aint locked it's self up.

Cable Modem Downstream
Downstream Lock : Locked
Downstream Channel Id : 52
Downstream Frequency : 306750000 Hz
Downstream Modulation : QAM256
Downstream Symbol Rate : 6952 Ksym/sec
Downstream Interleave Depth : taps12Increment17
Downstream Receive Power Level : 4.0 dBmV
Downstream SNR : 39.8 dB

Cable Modem Upstream
Upstream Lock : Locked
Upstream Channel ID : 3
Upstream Frequency : 42800000 Hz
Upstream Modulation : QAM16
Upstream Symbol Rate : 2560 Ksym/sec
Upstream transmit Power Level : 53.0 dBmV
Upstream Mini-Slot Size : 2

Boot Code Version : 3.1.6d
Software Version : 2.94.1015
Hardware Version : 1.19

It's one of those NTL 250 Modems and I currently have the 20mb service

Before anyone asks, it's NOT my router as I have tried it with and without the router, even linked it upto a Cisco router.
I have cable tested all my network cables, even tried running STP cable from router to cable modem in case it was some strange interference.
I have checked all cables going from the cable modem, they appear to be screwed in tightly. Even resorted to using factory made Patch cable in case my hand made cables where the cause.
Incase anyone asks it's not a PC issue as I have tried and tested other PC's and they all can't access the internet when it goes.

My location is Bromley.

[Mick Fisher]

I have the same sort of problem although my modem loses it's upsteam, although India can see a problem, for some reason they won't book an engineer so I have had to resort to using the"Thinking of Leaving Us" option to get an engineer booked.

Looks like you might have to do the same.

Incidentally when you cannot access the cable modem try resetting the DHCP if it is an available option in your router.

Your signal levels look OK to me.

[Sephiroth]

@ neo

Is your upstream power steady at 53 dBmv or does it move up past 55 dBmv (which is bad)? Refresh the upstream screen to see if it moves.

If it does, post your eventlog in the middle of doing stuff (not immediately after a reboot).

[TommyTomTom]

Mine does the same occasionally although it's done it twice tonight, think it's the same model modem, it seems to be getting very hot.

// 3 times tonight :(

[neoapple]

Well currently now since I last posted it's now sitting at 55.0

Sometimes i see this in the event log

Thu Aug 19 07:16:43 2010 Thu Aug 19 07:16:43 2010 Information (7) New UCD in effect
Thu Aug 19 07:16:43 2010 Thu Aug 19 07:16:43 2010 Information (7) Starting on-the-fly UCD change.

As of 19:00 (21/08/10) it's dropped to 46.0

[Sephiroth]

Like I said, please post the full event log in the middle of doing stuff (not immediately after a re-boot).

[neoapple]

This is all i currently have in my event log.

I have noticed that my upstream keeps fluctuating between 46 - 55

Jumped to 52.5 then to 47 then 45 and all in the space of 5 mins!

Then sometimes it can take a few seconds for webpages to be requested.

Thu Aug 19 07:53:42 2010 Thu Aug 19 07:53:42 2010 Information (7) New UCD in effect
Thu Aug 19 07:53:42 2010 Thu Aug 19 07:53:42 2010 Information (7) Starting on-the-fly UCD change.
Thu Aug 19 07:16:43 2010 Thu Aug 19 07:16:43 2010 Information (7) New UCD in effect
Thu Aug 19 07:16:43 2010 Thu Aug 19 07:16:43 2010 Information (7) Starting on-the-fly UCD change.
Thu Aug 19 07:15:49 2010 Thu Aug 19 07:15:49 2010 Information (7) New UCD in effect
Thu Aug 19 07:15:49 2010 Thu Aug 19 07:15:49 2010 Information (7) Starting on-the-fly UCD change.
Thu Aug 19 07:14:52 2010 Thu Aug 19 07:14:52 2010 Information (7) New UCD in effect
Thu Aug 19 07:14:52 2010 Thu Aug 19 07:14:52 2010 Information (7) Starting on-the-fly UCD change.
Thu Aug 19 07:13:53 2010 Thu Aug 19 07:13:53 2010 Information (7) New UCD in effect
Thu Aug 19 07:13:53 2010 Thu Aug 19 07:13:53 2010 Information (7) Starting on-the-fly UCD change.
Thu Aug 19 07:13:25 2010 Thu Aug 19 07:13:25 2010 Information (7) New UCD in effect
Thu Aug 19 07:13:25 2010 Thu Aug 19 07:13:25 2010 Information (7) Starting on-the-fly UCD change.

Below Here is reboot

Wed Aug 18 19:21:48 2010 Wed Aug 18 19:21:48 2010 Information (7) The s/w filename specified in the config file is the same as ...
Wed Aug 18 19:21:48 2010 Wed Aug 18 19:21:48 2010 Information (7) A software upgrade filename was specified in the config file.
Wed Aug 18 19:21:47 2010 Wed Aug 18 19:21:47 2010 Information (7) Authorized
Wed Aug 18 19:21:47 2010 Wed Aug 18 19:21:47 2010 Information (7) Registration complete!
Wed Aug 18 19:21:47 2010 Wed Aug 18 19:21:47 2010 Information (7) We registered with a DOCSIS 1.1 config file!
Wed Aug 18 19:21:47 2010 Wed Aug 18 19:21:47 2010 Information (7) Received a REG-RSP message from the CMTS...
Wed Aug 18 19:21:47 2010 Wed Aug 18 19:21:47 2010 Information (7) Sending a REG-REQ to the CMTS...
Wed Aug 18 19:21:47 2010 Wed Aug 18 19:21:47 2010 Information (7) CableModem SNMP configure complete
Wed Aug 18 19:21:47 2010 Wed Aug 18 19:21:47 2010 Information (7) IP init completed ok
Wed Aug 18 19:21:47 2010 Wed Aug 18 19:21:47 2010 Information (7) CableModem TFTP init ok
Time Not Established Time Not Established Information (7) CableModem DHCP client init ok
Time Not Established Time Not Established Critical (3) DHCP WARNING - Non-critical field invalid in response.
Time Not Established Time Not Established Information (7) MAP w/initial maintenance region received
Time Not Established Time Not Established Information (7) Downstream sync ok
Time Not Established Time Not Established Information (7) MAP w/initial maintenance region received
Time Not Established Time Not Established Information (7) Beginning initial ranging...
Time Not Established Time Not Established Information (7) downstream time sync acquired...
Time Not Established Time Not Established Information (7) Downstream sync ok
Time Not Established Time Not Established Information (7) starting ds time sync acquisition...
Time Not Established Time Not Established Information (7) MAP w/initial maintenance region received

[Sephiroth]

The event list suggests that you have an upstream problem. There is instability and the incrementing power levels confirm this.

if the modem is struggling to communicate with the CMTS, then the power output is stepped up until the CMTS can read a sensible signal. If it can't, you'll get timed out or switched to another upstream channel.

VM's tech support could ascertain what's happenig by examining the CMTS "flap list". You can Google the terms I've used if you don't fully understand all this weird stand. A good definition of the flap list is at: http://www.juniper.net/techpubs/software/cable/junosg30/g10-hwguide/html/troubleshooting3.html

[neoapple]

Since i last posted what was in my event log there has been more added.

I have copied everything that happened this morning

Sun Aug 22 06:39:50 2010 Sun Aug 22 06:39:50 2010 Information (7) The s/w filename specified in the config file is the same as ...
Sun Aug 22 06:39:50 2010 Sun Aug 22 06:39:50 2010 Information (7) A software upgrade filename was specified in the config file.
Sun Aug 22 06:39:50 2010 Sun Aug 22 06:39:50 2010 Information (7) Authorized
Sun Aug 22 06:39:50 2010 Sun Aug 22 06:39:50 2010 Information (7) Registration complete!
Sun Aug 22 06:39:50 2010 Sun Aug 22 06:39:50 2010 Information (7) We registered with a DOCSIS 1.1 config file!
Sun Aug 22 06:39:50 2010 Sun Aug 22 06:39:50 2010 Information (7) Received a REG-RSP message from the CMTS...
Sun Aug 22 06:39:49 2010 Sun Aug 22 06:39:49 2010 Information (7) Sending a REG-REQ to the CMTS...
Sun Aug 22 06:39:49 2010 Sun Aug 22 06:39:49 2010 Information (7) CableModem SNMP configure complete
Sun Aug 22 06:39:49 2010 Sun Aug 22 06:39:49 2010 Information (7) IP init completed ok
Sun Aug 22 06:39:49 2010 Sun Aug 22 06:39:49 2010 Information (7) CableModem TFTP init ok
Sun Aug 22 06:39:16 2010 Sun Aug 22 06:39:16 2010 Information (7) CableModem DHCP client init ok
Sun Aug 22 06:39:16 2010 Sun Aug 22 06:39:16 2010 Critical (3) DHCP WARNING - Non-critical field invalid in response.
Sun Aug 22 06:39:09 2010 Sun Aug 22 06:39:09 2010 Information (7) MAP w/initial maintenance region received
Sun Aug 22 06:39:09 2010 Sun Aug 22 06:39:09 2010 Information (7) Downstream sync ok
Sun Aug 22 06:39:09 2010 Sun Aug 22 06:39:09 2010 Information (7) Beginning initial ranging...
Sun Aug 22 06:39:09 2010 Sun Aug 22 06:39:09 2010 Information (7) downstream time sync acquired...
Sun Aug 22 06:39:09 2010 Sun Aug 22 06:39:09 2010 Information (7) Downstream sync ok
Sun Aug 22 06:39:08 2010 Sun Aug 22 06:39:08 2010 Information (7) starting ds time sync acquisition...
Sun Aug 22 06:39:06 2010 Sun Aug 22 06:39:06 2010 Information (7) Locked on the downstream. Waiting for UCDs...
Sun Aug 22 06:39:06 2010 Sun Aug 22 06:39:06 2010 Information (7) Downstream lock ok
Sun Aug 22 06:39:05 2010 Sun Aug 22 06:39:05 2010 Information (7) Sync Start
Sun Aug 22 06:39:05 2010 Sun Aug 22 06:39:05 2010 Critical (3) Received Response to Broadcast Maintenance Request, But no Un...
Sun Aug 22 06:39:05 2010 Sun Aug 22 06:39:05 2010 Information (7) Reset downstream scanning state!
Sun Aug 22 06:38:32 2010 Sun Aug 22 06:38:32 2010 Critical (3) Started Unicast Maintenance Ranging - No Response received - ...
Sun Aug 22 00:03:28 2010 Sun Aug 22 00:03:28 2010 Warning (5) DHCP RENEW WARNING - Field invalid in response

[Sephiroth]

Thing is, posting partial event logs doesn't tell us what happened between Aug-19 and Aug-22. If the log was blank, nothing was going wrong but we can't be sure o that at this distance.

Also, what happened this morning? Did you reboot the modem? Or were you still asleep? The log you just posted is a perfect restart. There's nothing in the log to show a reset initated from the other end. Was there a power glitch? Did your clocks go off or something?

[neoapple]

Everything posted is whats in my logs. I have no idea why there is a gap but there is.
There was no power surge as far as i know as my router has the correct uptime.

I was still asleep. But one thing I do know is, I can't seem to keep a constant upstream signal.

[Sephiroth]

I'm wondering whether you have a duff modem. The T3 errors that one normally associates with upstream problems simply aren't recorded/there.

Upstream is absolutely key to everything. It must be working in some way - after all the reset was impeccable.

You could report this on the Virgin forum where 2nd line support can have a look.