Here we go again; cablemodem service falling apart...

[ChrisJenkins]

I'm posting here hoping for some real assistance with a recurring probelm that NTL/VirginMedia seem unable to address. I have Broadband XL curently running at (theoretically) 20 Mbit/s.

First, my setup. I have a home LAN (GigaBit) with multiple PCs and two servers. My router/firewall is a server running Windows 2003 Server Standard Edition with Service Pack 2 and is fully up to date on updates. This server has 2 NICS; one is connected to the private local LAN and the other to the NTL/VM cable modem.

Second, some background. I have had this problem, numerous times since first taking up the (then) NTL cable modem service in 2000. Each time NTL/VM first deny there is any issue, then eventually they grudgingly send an engineer who either finds nothing or says my signal levels are a little off normal. Sometimes he changes the cable modem , sometimes he fits (or removes) the attenuator on the back of the CM and sometimes he fiddles with stuff in the junction box at the end of the street. Sometimes this improves things for a while, sometimes not.

Okay, here is a description of what is observed when the problem occurs.

All the lights on the CM look normal and transmit/receive lights are flickering but there is no IP traffic in our out via the CM. The server shows that IP address, gateway address etc. are valid but any attempt to ping the gateway, the VM DNS servers or other well known addresses (specified by IP address to avoid name resolution being involved) fails with no reply.

Similarly, attempts to ping the IP address assigned to the server by the CM fail (I have called friends and asked them to do this while the problem is occurring).

Sometimes this persists for a long time (10s of minutes) in which case if I restart the CM everything returns to normal. Much more commonly, after a few minutes of this alive-but-dead situation the modem restarts itself and all is well again.

Basically, I suffer this problem all the time but there are periods, such as the past few weeks, when instead of this hapnning just a few times a day it starts happening 10, 20 or 30 times a day.

On 27th May, I installed a monitoring tool on my server that pings several IP addresses every minute (the local CM gateway and both NTL DNS servers plus 2 other 'highly available' addresses at my external DNS provider). If any of the pings fail, it logs it. There have been 196 failures logged since then. Of course, some of these problems could be due to issues further out in the network but 34 of them were failures to ping the local gateway (82.3.208.1).

I am reluctant to call VM support since every previous time it has taken numerous calls and a lot of 'assertiveness' on my part to get them to even acknowledge there is some problem.

Clearly, there is some persistent problem affecting my connection which sometimes worsens for reasons unknown. This is very frustrating, not just because of the problem itself but also due to the seeming lack of interest from VM support in resolving it.

Anyone got any suggestions at all?

Thanks, Chris Jenkins

[trilly]

I can't offer any assitance other than I have similar issues as well, Camberley based, Called VM 2nd June who advised everything working OK and to prove it run a test fan speedtest from VM HQ to speedtest.net and they also had a problem. Put it down to one off but problem keeps coming back.

Only thing I have noticed is that the power levels on the cable modem tend to fall but neverthless remain constent, around : -

Downstream Receive Power Level : -3.9 dBmV
Downstream SNR : 26.8 dB

When well approx: -
Downstream Receive Power Level : 1.5 dBmV
Downstream SNR : 38.0 dB

When called VM about this advised this was within limits.

At the moment 15th June very poor speeds on everything , sometimes not working at all.

Restarting the CM sorts it out sometimes for a 1 minute , sometimes 5, sometimes not at all.

At a loss what to do now.

Config, Netgear WN834BV2 draft N router connected to cable modem, then Netgear ProSafe GS105 1GB Switch, 1PC running wired connection at 100MB then server running at 1GB.

[ChrisJenkins]

I should have mentioned that I am located in Bracknell. Not sure if I am running of the same broadband infrastructure as you in Camberley or not...

I am assembling a spreadsheet of the outages based on my automatic monitoring process. If nothing else it will provide good evidence for Ofcom! If VM don't take this problem seriously and take some real action to diagnose and resolve it I am going to contact them...

[Axegrinder]

Downstream Receive Power Level : -3.9 dBmV
Downstream SNR : 26.8 dB

When well approx: -
Downstream Receive Power Level : 1.5 dBmV
Downstream SNR : 38.0 dB



Your downstream SNR is too low, any lower than that you will lose your service, also keep an eye on the downstream power level make sure it doesnt go much lower than that. Other than that there fine.

[penfolder]

my downstream power level has been down to -11 and still rock solid.

---------- Post added at 21:57 ---------- Previous post was at 21:56 ----------

sorry - just read again. SNR not power level. please ignore!

[whydoIneedatech]

my downstream power level has been down to -11 and still rock solid.

---------- Post added at 21:57 ---------- Previous post was at 21:56 ----------

sorry - just read again. SNR not power level. please ignore!

Post your power levels here.

[penfolder]

Downstream Lock : LockedDownstream Channel Id : 6Downstream Frequency : 402750000 HzDownstream Modulation : QAM256Downstream Symbol Rate : 5360.537 Ksym/secDownstream Interleave Depth : taps32Increment4Downstream Receive Power Level : -4.3 dBmVDownstream SNR : 39.8 dB

[whydoIneedatech]

Downstream Lock : LockedDownstream Channel Id : 6Downstream Frequency : 402750000 HzDownstream Modulation : QAM256Downstream Symbol Rate : 5360.537 Ksym/secDownstream Interleave Depth : taps32Increment4Downstream Receive Power Level : -4.3 dBmVDownstream SNR : 39.8 dB

They are fine but what about your upstream power level?

[penfolder]

Cable Modem UpstreamUpstream Lock : LockedUpstream Channel ID : 2Upstream Frequency : 29200000 HzUpstream Modulation : QPSKUpstream Symbol Rate : 2560 Ksym/secUpstream transmit Power Level : 52.0 dBmVUpstream Mini-Slot Size : 2

[whydoIneedatech]

Cable Modem UpstreamUpstream Lock : LockedUpstream Channel ID : 2Upstream Frequency : 29200000 HzUpstream Modulation : QPSKUpstream Symbol Rate : 2560 Ksym/secUpstream transmit Power Level : 52.0 dBmVUpstream Mini-Slot Size : 2

No problem there either your modem is behaving as it should:)

[ChrisJenkins]

My power levels as of this moment are:

Downstream Receive Power Level: -1.2 dBmV
Downstream SNR: 39.2 dB

Upstream transmit Power Level: 41.0 dBmV

It's hard to say what the power levels are when the problem occurs because usually when the problem occurs the cable modem web interface is unresponsive and i cannot connect to it...

The situation is getting really bad now and I'm going to have to face the pain of calling Virgin Media support. Yesterday we experienced 61 occurrences of the connection dropping due to this issue!

[whydoIneedatech]

My power levels as of this moment are:

Downstream Receive Power Level: -1.2 dBmV
Downstream SNR: 39.2 dB

Upstream transmit Power Level: 41.0 dBmV

It's hard to say what the power levels are when the problem occurs because usually when the problem occurs the cable modem web interface is unresponsive and i cannot connect to it...

The situation is getting really bad now and I'm going to have to face the pain of calling Virgin Media support. Yesterday we experienced 61 occurrences of the connection dropping due to this issue!



What modem do you have Chris?

At least the call is free on 151

[ChrisJenkins]

It's a small black modem labelled 'ntl: 250'. It's not the cost of the call that bothers me, it''s:

1. The lack of knowledge of the people who answer the phones
2. The fact that they don't listen carefully when I explain the problem
3. They insist on going through a pointelss troubleshooting script even though I've already been through those steps a hundred times
4. They always make me reboot my server (which takes 15 minutes and takes a bunch of stuff on my internal network offline)
5. After all that they say they can't see any problem (since typically the problem is not occurring at the time I manage to get through to them)
6. I then have a big argument to try and get them to do some kind of more detailed investigation which always ends up in them sending an engineer and telling me they will charge me if no fault is found.
7. An engineer calls, check signal levels. Usually they are okay. He swaps the modem. Sometimes this fixes things for a while, sometimes not. Then the whole process repeats itself.

That is why I dread calling them. The whole process is a very frustrating and negative experience, usually without a satisfactory outcome. As someone with 25 years IT and networking experience it frankly drives me up the wall. If there was a viable alternative to Virgin Media in my area I would switch but (a) there isn't and (b) I suspect the experience with other providers is no better.

Chris

[whydoIneedatech]

It's a small black modem labelled 'ntl: 250'. It's not the cost of the call that bothers me, it''s:

1. The lack of knowledge of the people who answer the phones
2. The fact that they don't listen carefully when I explain the problem
3. They insist on going through a pointelss troubleshooting script even though I've already been through those steps a hundred times
4. They always make me reboot my server (which takes 15 minutes and takes a bunch of stuff on my internal network offline)
5. After all that they say they can't see any problem (since typically the problem is not occurring at the time I manage to get through to them)
6. I then have a big argument to try and get them to do some kind of more detailed investigation which always ends up in them sending an engineer and telling me they will charge me if no fault is found.
7. An engineer calls, check signal levels. Usually they are okay. He swaps the modem. Sometimes this fixes things for a while, sometimes not. Then the whole process repeats itself.

That is why I dread calling them. The whole process is a very frustrating and negative experience, usually without a satisfactory outcome. As someone with 25 years IT and networking experience it frankly drives me up the wall. If there was a viable alternative to Virgin Media in my area I would switch but (a) there isn't and (b) I suspect the experience with other providers is no better.

Chris

Why do they ask you to reboot your server? as all you need connected to your modem when you call is a single machine via an Ethernet cable, if you call again just have one machine connected and do not mention your server.

If you spoke to me, all I would ask is you to connect as above, asking you to reboot the modem and other basic steps is to cover our backs in case we are being recorded for quality or training purposes.

[jaycee]

Yes - lie to them and do not tell them you have a server or router. When they ask you to reboot, simply disable the NIC, twiddle your thumbs for a minute, then re enable it.

This is what I always do whenever I call VM with this kind of problem, except in my case its "ifconfig xl0 down" ;)

[whydoIneedatech]

Yes - lie to them and do not tell them you have a server or router. When they ask you to reboot, simply disable the NIC, twiddle your thumbs for a minute, then re enable it.

This is what I always do whenever I call VM with this kind of problem, except in my case its "ifconfig xl0 down" ;)

We do have Tools that can see into the Modem and read the MAC address of the Device connected to it, we then put the MAC address into another Tool which tells us what that device is, so no point saying " No I have disconnected the Router" because we can see you have not!

[jaycee]

Except in my case, all you would see is a network card made by 3COM, and you cant tell if thats my server, my desktop, or whatever.

Not to mention the stupidity behind being asked to reboot your system *when the SYNC/RDY lights have gone out* - really, who on earth put that in the script?

edit: I guess i should clarify that what I really mean here is the Indian support team - on the rare occasion that I have gotten through to UK based support, I have found them to be pretty clued up and able to recognise when the customer knows about networking etc...

[whydoIneedatech]

Except in my case, all you would see is a network card made by 3COM, and you cant tell if thats my server, my desktop, or whatever.

Not to mention the stupidity behind being asked to reboot your system *when the SYNC/RDY lights have gone out* - really, who on earth put that in the script?

edit: I guess i should clarify that what I really mean here is the Indian support team - on the rare occasion that I have gotten through to UK based support, I have found them to be pretty clued up and able to recognise when the customer knows about networking etc...

So you have a cloned MAC address on your router which just gives false and unreliable information both to us and yourself slowing down any diagnosis because you are trying to be clever. Do not be annoyed at that because you are obviously PC literate which is good.

It is actually surprising how many times you get a modem back online by just simply rebooting it, and we have to ask in case we are being recorded for quality purposes, if we do not ask we are marked down, even though when talking to someone like you we can tell that you have already done this.

I know what you mean about India and I am sorry you have to deal with them.

[jaycee]

I should point out my "router" is a Pentium 3 machine running FreeBSD 7, so there is no cloning going on :) but i cant help feeling that often, the "its your router" line is pulled out because VM arent willing to admit to a fault.

Rebooting the modem is fair enough, and usually the first thing I try.. but rebooting the PC? Fair enough that some people have stupid firewalls (cough Norton Internet Security cough) but rebooting a PC because the RDY light has gone out is dumb. I always grind my teeth with annoyance when India asks me to do this.

[whydoIneedatech]

I should point out my "router" is a Pentium 3 machine running FreeBSD 7, so there is no cloning going on :) but i cant help feeling that often, the "its your router" line is pulled out because VM arent willing to admit to a fault.

Rebooting the modem is fair enough, and usually the first thing I try.. but rebooting the PC? Fair enough that some people have stupid firewalls (cough Norton Internet Security cough) but rebooting a PC because the RDY light has gone out is dumb. I always grind my teeth with annoyance when India asks me to do this.

Sorry from the line of your previous posts it sounded like you had a router.;)

I would not ask you to reboot a PC unless we had changed a setting in the PC that warranted it, and the is not many that would require that.

As for the fault being with the router, I have had many calls with no connection through the router but as soon as you connect direct to the PC and in some cases re enable the NIC they have a connection and they still think its the modem.:dozey:

Plus as previously stated if the modem can see your MAC address I can tell you what you are connected to.

If I spoke to you it would be pretty obvious that you know how a computer works.:)

[mmm]

I hope I get through to you whydoIneedatech when I next phone up to report a network fault - if the "cable" light is out on a Terayon modem (which used to be a regular occurence) rebooting my router or PC is really not going to help a lot...

[jaycee]

Yep I also hope that I have the fortune to get through to you and your colleagues in future - it is always nice to speak with a tech who is *actually* a tech who knows whats going on, and not someone whose been trained to read a script and use a few diagnostic tools!

whydoIneedatech - Do you do support on the newsgroups ? I often go there if I have a fault that hasn't caused complete loss of service... I was really glad when I learned that VM had kept on Blueyonder's old newsgroup support service!

[whydoIneedatech]

I hope I get through to you whydoIneedatech when I next phone up to report a network fault - if the "cable" light is out on a Terayon modem (which used to be a regular occurence) rebooting my router or PC is really not going to help a lot...

If you have a Terayon then you really need to get it upgraded, call Tech Support say its dropping out and they should replace it.

---------- Post added at 20:38 ---------- Previous post was at 20:35 ----------

Yep I also hope that I have the fortune to get through to you and your colleagues in future - it is always nice to speak with a tech who is *actually* a tech who knows whats going on, and not someone whose been trained to read a script and use a few diagnostic tools!

whydoIneedatech - Do you do support on the newsgroups ? I often go there if I have a fault that hasn't caused complete loss of service... I was really glad when I learned that VM had kept on Blueyonder's old newsgroup support service!

If you have a Virgin phone line then its free on 151.

I do not do Newsgroups or E-contact I prefer being on the phones.;)

[jaycee]

whenever i ring 151 and select broadband faults it tells me to ring the 0906 number, which is always staffed by India!

[whydoIneedatech]

whenever i ring 151 and select broadband faults it tells me to ring the 0906 number, which is always staffed by India!

The 0906 number no longer works, you should only ring 151 option 3.

[bunter]

I am having exactly the same problem. An engineer was out today to check but its not fixed. I have no idea what causes this and its is intensely frustrating.