Solved: No internet, but cable modem is connected

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Larry99

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I have a Motorola SB6121 DOCSIS 3 modem from Charter feeding my own D-Link DIR-655 router. Periodically the Internet is unavailable to my PC that is hard wired to the router. When that happens, it’s only gone for a minute maybe two minutes. Sometimes it will go for days with no problems. Other times it may happen two or three times an hour. I can read the modem status page from my PC when this happens and observe that the four downstream channels are bonded and receiving approximately 0 dBmV (S/N = 37 dB). Upstream is bonded and delivering 47 dBmV. So, I think we can say that the PC is communicating with the modem through the router and the modem is connected to Charter’s head end.


Charter has been out numerous times and says the signal into and out of the modem meets specs. Of course they are never there when the Internet is unavailable. But if they were there they would probably find that the signal carrier meets specs, but there is no Internet. However, Charter repair has told me that this is impossible. If the modem is bonded, it means the Internet is there. Therefore, it is the router that is dropping the Internet (remember I can read the modem status page trough the router when this happens).



Any thoughts?
 

TerryNet

Terry
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Does the modem have Power, Receive, Send and Online LEDs? If so, do they remain a solid green when the problem occurs? Does the Activity LED continue to blink amber? (I have an older Motorola, so don't know if yours has the same indicators.)

Try these tests in a Command Prompt window when you have the problem ...

ping <ISP Gateway>

ping 8.8.4.4

ping yahoo.com


You have to look in your router's WAN (Internet) status to get the IP address of the Default Gateway assigned by the ISP to the router.

I sometimes get a problem that lasts for minutes or hours, can happen several times a day, and can go for months between occurrences. I can ping the ISP's gateway, but can not ping 8.8.4.4 (or any other web address). Means that the ISP is having a problem with their gateway server--it can communicate with me, and probably other customers, but not with anything else.
 

Larry99

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All the modem lights appear as they should and I cannot ping the internet when this happens. I will try pinging the gateway next time. Personally, I think the problem is at their gateway, but Charter service says that is impossible because if my modem is bonded to their streams (as it is) then the Internet must be present. Instead, they say, my router must be filtering out the Internet. Thanks for the thoughts.
 

TerryNet

Terry
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Personally, I think the problem is at their gateway
I do also. If you can ping the gateway but not 8.8.4.4 that is proof in my mind. Of course, I don't work for Charter.
 

Couriant

James
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All the modem lights appear as they should and I cannot ping the internet when this happens. I will try pinging the gateway next time. Personally, I think the problem is at their gateway, but Charter service says that is impossible because if my modem is bonded to their streams (as it is) then the Internet must be present. Instead, they say, my router must be filtering out the Internet. Thanks for the thoughts.
Then that person needs to be fired. Channel Bonding is moot when you are having packet loss or signal issues. Channel Bonding usually affects your speed. If your modem gets only 1 channel, then that is a connection issue between the CMTS (server) and the modem. A reboot to the modem usually fixes it.

Now if the streams show levels out of control, then that's something else. BTW the power level will need to be close to 0 as possible.

Have you tried going direct to the modem? If not, try that and see the issue reoccurs.
 

Larry99

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Direct to modem doesn't make any difference. The last Charter tech that came out on Dec 21 suggested that I replace the 40' RG-59 cable from the drop to the Charter amplifier and he left an RG-6 cable with connectors which I had to snake through the ceiling. He suggested the replacement because of the RG-59 bandwidth and attenuation limitations. I completed that on Dec 27.

Interestingly as I went to connect the new cable at the house drop, the old cable pulled from the connector while the male connector itself remained connected to the female drop connector. Perhaps I had an intermittent connection. Just to see what would happen, I shoved the old RG-59 cable back into the connector without crimping it, but making sure it was shoved in tight. I didn't connect the new RG-6 cable.

I have had no Internet problems since December 27. I also used to have tiling or pixelating on some TV stations and that also cleared up. I am almost ready to say that the problem was due to an improperly installed connector (it wasn't crimped) on the RG-59 cable. I'll wait and see for a few more weeks before I declare the problem solved. This has been going on for some time and after house calls by at least six Charter techs I may have solved it myself. Charter had originally installed the connector on the old in-place cable a few years ago when they replaced the underground cable from the street to my house. I think the tech forgot to crimp it or didn't squeeze hard enough.

I'm not sure why the modem would show that I had four channels bonded yet there was no Internet. Perhaps the security protection information was interrupted by the bad connection while the signal itself was not. Or maybe the four bonded channels dropped out and by the time I looked at the modem they had reestablished themselves, but the Internet was lagging behind by a minute or two. Since I don't know how that works I can only guess.
 

Couriant

James
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Your modem can still show online but the signals may be too low to get you surfing. But it does sound like you found the issue. My concern is that they couldn't do the cable direct to your modem and/or tv. Sounds like bad field technical support there.
 

Larry99

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I would always show a downstream S/N of 37dB or so and a 0 dBmV +/- level even when not receiving Internet, but yet showing four bonded streams. That's what caused the tech to say it was my router which it wasn't because it's been working for the last three weeks, bypassing the router didn't help and I could read the modem through the router when this was happening.

Yes, the tech service is far from the best, but I suppose that is Charter's business model and it works for them. However, I see more and more of my neighbors switching to U-Verse which I am ready to do unless the problem stays fixed.

If Charter had been willing to put a recording line monitor in my house, it would have saved them numerous truck rolls and an almost lost customer. Considering I pay them $5/month for inside wire maintenance that's the least they could do. Incidentally, what I found is that the wire maintenance only applies to wires that are not in the wall/ceiling. Of course the faulty connector was in the open so they just blew it by not checking it out.

The last tech that came out was supposedly just appointed as the supervisor so that's the best they have. The one before that said that when they switched from the current hybrid analog/digital system next month to Switched Digital Video then Charter's problems would clear up and everything would be good. And so on. Each tech had a different explanation and none were correct.
 

Couriant

James
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I would always show a downstream S/N of 37dB or so and a 0 dBmV +/- level even when not receiving Internet, but yet showing four bonded streams. That's what caused the tech to say it was my router which it wasn't because it's been working for the last three weeks, bypassing the router didn't help and I could read the modem through the router when this was happening.
Usually disconnections would be from the upstream SNR being erratic, but something tells me your modem will not show the correct SNR.

Larry99 said:
Yes, the tech service is far from the best, but I suppose that is Charter's business model and it works for them. However, I see more and more of my neighbors switching to U-Verse which I am ready to do unless the problem stays fixed.
Hmm AT&T Support is not much better... hopefully it will work for you.

Larry99 said:
If Charter had been willing to put a recording line monitor in my house, it would have saved them numerous truck rolls and an almost lost customer. Considering I pay them $5/month for inside wire maintenance that's the least they could do. Incidentally, what I found is that the wire maintenance only applies to wires that are not in the wall/ceiling. Of course the faulty connector was in the open so they just blew it by not checking it out. .
Correct. All ISPs will not do wall fishing (too time consuming and can be a pain in the behind), but the $5 is to make sure you don't get charged a service call fee if the issue was the internal wiring.

Larry99 said:
The last tech that came out was supposedly just appointed as the supervisor so that's the best they have. The one before that said that when they switched from the current hybrid analog/digital system next month to Switched Digital Video then Charter's problems would clear up and everything would be good. And so on. Each tech had a different explanation and none were correct.
Not really, it will just free up more frequency to get more TV channels and possibly more speed. Signal issues will happen regardless. If they can get you direct access to the pole that would be better for you as it would not be going through the internal wiring.
 

Larry99

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Not really, it will just free up more frequency to get more TV channels and possibly more speed. Signal issues will happen regardless. If they can get you direct access to the pole that would be better for you as it would not be going through the internal wiring.
Thanks for the info. I think I do have what you refer to as a direct connection. A single coax in a conduit goes from a terminal box on the curb underground to my house. It then goes through a two terminal device that may be a filter or perhaps an attenuator and then into the house where the faulty connector was discovered by me. A 40' coax runs from that connector to the distribution amplifier. Is there any more of a direct connection that I should consider?
 

Couriant

James
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Pole (outside) to modem. Sometimes our techs has to do that. It bypasses all house wiring. If you still having issues then its on the outside.
 

Larry99

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I understand. So far, so good with my connector fix. I'll give it one more week.
 

Larry99

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It's been two months now and no problems. The Internet is always up and tiling on the TV channels disappeared. The problems were all due to a faulty connector on the cable drop. Shame on Charter for not finding the problem. They were very close to loosing a customer. Problem solved.
 
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