Cable Modem Down-Time

[Mike Elphick]

Hi,

We've had an NTL internet cable connection since June 2006, but it is frequently down. We've put up with this for months, but I am now working more from home where an internet connection is essential. I think we pay for the 1Mb option £13 per month. The system goes up and down, more frequently on Sundays and weekends when it can be down for one or even two days, but more usually for about 6 to 12 hours (occasionally it goes down for just 10 minutes). If it goes off during the week it will most likely be evening night and early morning.

My wife and I are very frustrated by this and the point has come to complain, but we have been fobbed off with a new cable modem and calls to India where the engineer sometimes tells us there is nothing wrong with our system and we are charged for a premium rate call. The engineer is due to come again tomorrow morning (Tuesday 13th November) - what can he do to resolve the situation? I've posted below the status levels during a period when the system was down (this morning).

Cable Modem Status
Acquire a Downstream Channel 690000000 Hz In Progress
Connectivity State In Progress Not Synchronized
Boot State In Progress Unknown

Cable Modem Downstream
Downstream Lock : Locked
Downstream Channel Id : 3
Downstream Frequency : 402750000 Hz
Downstream Modulation : QAM256
Downstream Symbol Rate : 5360.537 Ksym/sec
Downstream Interleave Depth : taps32Increment4
Downstream Receive Power Level : 4.9 dBmV
Downstream SNR : 41.0 dB

Cable Modem Upstream
Upstream Lock : Not Locked
Upstream Channel ID : 1
Upstream Frequency : 25800000 Hz
Upstream Modulation : QPSK
Upstream Symbol Rate : 2560 Ksym/sec
Upstream transmit Power Level : 61.0 dBmV
Upstream Mini-Slot Size : 2

We don't have cable TV, but we do use a router. When the system is not operational, either the Sync or Ready lights will flash continuously or the Ready light will be permanently off. We frequently (hundreds of times!!!!) reboot, by removing power from both modem and router, first restoring power to the modem followed by the router sometime after the modem has rebooted. It will be obvious when the modem is actually working because one can see the Tx and Rx lights both pulse. We use Windows XP, but the problem has obviously nothing to do with our PCs or Network

What do you guys think the problem is?

Thanks

Mike

[Peil]

Slightly O.T. but if you really need the line for work then it might be worthwhile looking at getting a business broadband connection.

If it's used for work purposes it should (YMMV) be reclaimable on expenses or offset against tax if your self employed.

At least that way you get an SLA.

[Axegrinder]

Your upstream is at its limit, thats the reason your connection is dropping, me thinks you need an attenuator.

[Mike Elphick]

Your upstream is at its limit, thats the reason your connection is dropping, me thinks you need an attenuator.Yes, thanks. After Googling about a bit, I understand a little bit more.

The dBmV had me thrown for a bit until I discovered the log range is multiplied by 20. The upstream seems to get stuck on 61dBmV, which must be the modem's maximum output limit, but why do you recommend an attenuator when this reflects power the modem has to put out to reach the UBR - doesn't that imply there's too much attenuation in the upward connection?

Mike

[jaycee]

Attenuators are used to quieten down noisy forward paths. The reverse path being at 61.0dBmV can only be fixed by an engineer - usually by adjusting gain in the line amp in the cabinet, although it could also mean bad cabling. Your forward path SNR is high, so it probably means the cabinet gear needs adjustment.

If India are being dumb, just tell them your SYNC/RDY lights have gone out and you can't get service. Unscrew the coax from the modem if neccesary. Once they book an engineer out, show him the readings and he'll do the neccesary work!

[homealone]

Attenuators are used to quieten down noisy forward paths. The reverse path being at 61.0dBmV can only be fixed by an engineer - usually by adjusting gain in the line amp in the cabinet, although it could also mean bad cabling. Your forward path SNR is high, so it probably means the cabinet gear needs adjustment.

If India are being dumb, just tell them your SYNC/RDY lights have gone out and you can't get service. Unscrew the coax from the modem if neccesary. Once they book an engineer out, show him the readings and he'll do the neccesary work!

sounds like a plan - remember to get them to credit back the call charges ;)

[Mike Elphick]

Attenuators are used to quieten down noisy forward paths. The reverse path being at 61.0dBmV can only be fixed by an engineer - usually by adjusting gain in the line amp in the cabinet, although it could also mean bad cabling. Your forward path SNR is high, so it probably means the cabinet gear needs adjustment.

If India are being dumb, just tell them your SYNC/RDY lights have gone out and you can't get service. Unscrew the coax from the modem if neccesary. Once they book an engineer out, show him the readings and he'll do the neccesary work!Thanks for the advice. The engineer came and agreed that there was something wrong with their network (someone else in our street, he told us, was having the same problems). He adjusted the amplifier and told me he would talk to his network team. I'll give them a couple of weeks and report back...

Mike

[Mike Elphick]

Thank you for the advice. My system is up and running and I now have no 'down-time'.

However, I think being pre-armed with the modem status levels was most important in getting a resolution.

I put up with the poor service from NTL because that is what I expected having had previous negative experience with them, particularly relationships with their customer service where it was difficult to tell who was the customer and who was the service provider :shocked:. Well done Virgin Media!