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#36328 by kb7
Tue Dec 08, 2009 9:46 am
Hello. I've been having quite an ordeal.

I did not think this was an install topic, so I documented it in the "Other Topics" forum in the thread named "Ooma takes whole LAN down at least once per day"

But now I think I may actually have an equipment compatibility problem. So although I am well aware of the hazards of starting a second thread, I think I might reach another helpful audience in this forum.

I have COX cable. Using a Surfboard 5100 modem (DOCSIS 2 if memory serves).
Using the Ooma Hub.

The ooma sets up fine but goes down once to three times a day. Loses ooma core. Lights 1 and 2 solid red. Very annoying!
The only way I have found to restore service is to reboot the cable modem! Nothing else works.
The gory details are in the other thread I mentioned.

I see that I am getting a T4 timeout in the cable modem log each (as far as I see) time the ooma goes down.

Does anyone know what this means or have any suggestions?

Thanks!
#36350 by kb7
Tue Dec 08, 2009 11:49 am
Actually, I need to rethink this. Here is a typical sequence of entries in the modem log:

Code: Select all2009-12-08 07:34:53
6-Notice
I401.0
TLV-11 - unrecognized OID

1970-01-01 00:00:56
3-Critical
D003.0
DHCP WARNING - Non-critical field invalid in response.

1970-01-01 00:00:37
3-Critical
R004.0
Received Response to Broadcast Maintenance Request,
But no Unicast Maintenance opportunities received - T4
timeout

2009-12-06
15:29:56
6-NoticeI
401.0
TLV-11 - unrecognized OID


As you see, the T4 timeouts are happening when I reboot the modem. I also see that there are no diagnostics between reboots. In other words, TLV-11 occurs at the end of the reboot (at which point ooma turns BLUE) but there are no more log entries until the next reboot (as evidenced by the reset to 1970).

Since there is no obvious indication of trouble with the modem, I think I need to swap the Ooma under warranty, since this has been the story from day 1.

Any other ideas?
#36375 by ifican
Tue Dec 08, 2009 1:43 pm
before you do that, call cox tech support and have them check and test the modem and see if they show anything on their side. T4 errors are generated on the modem to multiplexer connection i.e. you to cox. My suspicion is the ooma hardware is not retrying the connection after if drops if its wan interface stays connected. Hence the reboot of the modem fixes your problem. I bet you can accomplish the same thing if you unplug the connection on the wan side of the ooma adapter then plug it back in. Give a test and we can work from there.
#36377 by murphy
Tue Dec 08, 2009 1:57 pm
Log into the ooma setup page (http://setup.ooma.com), go to the network page and click the radio button to use the built-in MAC address and then click apply.
Power cycle the cable modem.
#36379 by ifican
Tue Dec 08, 2009 2:12 pm
murphy wrote:Log into the ooma setup page (http://setup.ooma.com), go to the network page and click the radio button to use the built-in MAC address and then click apply.
Power cycle the cable modem.


If this was an ooma to cable modem connection problem this could help, the issue here i believe is his cable modem to isp is resetting because of missed unicast responses thus dropping his connection momentarily, which in turn the ooma adapter looses connection to the core network and retries until it times out. But because the connection from the ooma adapter to the cable modem never stops it doesnt realized that it needs to try again. The downing and uping of the wan link by a reboot of the cable modem causes the ooma adapter to try again and such working because the connection to the core network is once again established.
#36433 by kb7
Tue Dec 08, 2009 8:13 pm
ifican wrote:before you do that, call cox tech support and have them check and test the modem and see if they show anything on their side. T4 errors are generated on the modem to multiplexer connection i.e. you to cox. My suspicion is the ooma hardware is not retrying the connection after if drops if its wan interface stays connected. Hence the reboot of the modem fixes your problem. I bet you can accomplish the same thing if you unplug the connection on the wan side of the ooma adapter then plug it back in. Give a test and we can work from there.


Your suspicion makes a lot of sense. I will try disconnecting and reconnecting the MODEM side of the ooma as you suggest. But... would not cycling power on the ooma have the same net effect? I've done that to no avail.

I plan to put in a call to COX Wedsnesday. They have good people...once I get through to Tier 3 support. :(

I have a worse-than-vague understanding of cable modems. When I ask COX to test the link between them and my modem, is there anything I should tell/ask them besides that I suspect intermittent drops?

Thanks!

P.S. Not to sound like conspiracy theorist, but if I were a cable company offering voice and data solutions, I wonder if I would be ethically challenged to resist the temptation to "deliver" brief dropouts to customers not using my over-priced telephony solution. :) File that under "I have no reason to believe, but it would not surprise me." :)
Last edited by kb7 on Tue Dec 08, 2009 8:30 pm, edited 1 time in total.
#36436 by kb7
Tue Dec 08, 2009 8:23 pm
ifican wrote:
murphy wrote:Log into the ooma setup page (http://setup.ooma.com), go to the network page and click the radio button to use the built-in MAC address and then click apply.
Power cycle the cable modem.


If this was an ooma to cable modem connection problem this could help, the issue here i believe is his cable modem to isp is resetting because of missed unicast responses thus dropping his connection momentarily, which in turn the ooma adapter looses connection to the core network and retries until it times out. But because the connection from the ooma adapter to the cable modem never stops it doesnt realized that it needs to try again. The downing and uping of the wan link by a reboot of the cable modem causes the ooma adapter to try again and such working because the connection to the core network is once again established.


@murphy: Thanks. Based on your advice on the Other Topics forum, I already set the ooma hub to use the built-in MAC for its MODEM port. But I continue to have problems.

@ifican: In my previous post (replying @ you) I mentioned that I though that cycling power to the ooma hub would have the same effect (and more) as pulling the cable from the ooma's MODEM (aka wan) port. Do you think the "state" of the ooma's wan port persists across power cycles? I suppose it could if the ooma draws any power from it's MODEM port, i.e. from the cable between the ooma MODEM port and the router. FYI, I am already planning to try your suggestion the next time it goes down. My reasoning is related but different. I have a hunch that the PCs behind my router will immediately see the cable modem the moment I disconnect the ooma from the router. It's "as is" the ooma seeking for the ooma core network is effectively DoS'ing my lan.
#36444 by ifican
Tue Dec 08, 2009 9:02 pm
I knew you quite imaginative by your conspiracy theory but i have to admit i got a chuckle out of the dos'ing comment. Cox is actually a pretty good network, i got rid of their phone service about 5 years ago and not had any issues. So as far as the call to tech support , up front explain to them whats going on and let them do testing to see if they come up with anything. Let them do basic tests and see what they find, then mention to them that you were looking at the modem logs and noticed the logs are reporting t4 errors everytime you have an interruption. See where they go with that, an off topic side note. The problem could all be on your side but they are usually really good about helping out. Now as to your rebooting the telo, yes in theory it would accomplish the same thing. Knowing this and thinking to myself while typing this all problems are pointing to the modem or the modems connection upstream. This can also easily be tested if you have some spare networking equipment hanging around. Any other routers or switches at your disposal?
#36454 by kb7
Tue Dec 08, 2009 11:00 pm
ifican wrote:I knew you quite imaginative by your conspiracy theory but i have to admit i got a chuckle out of the dos'ing comment. Cox is actually a pretty good network, i got rid of their phone service about 5 years ago and not had any issues. So as far as the call to tech support , up front explain to them whats going on and let them do testing to see if they come up with anything. Let them do basic tests and see what they find, then mention to them that you were looking at the modem logs and noticed the logs are reporting t4 errors everytime you have an interruption. See where they go with that, an off topic side note. The problem could all be on your side but they are usually really good about helping out. Now as to your rebooting the telo, yes in theory it would accomplish the same thing. Knowing this and thinking to myself while typing this all problems are pointing to the modem or the modems connection upstream. This can also easily be tested if you have some spare networking equipment hanging around. Any other routers or switches at your disposal?


Thanks for the advice on approaching the modem testing with COX. I have to say that our experience with COX has actually been very good overall, lest someone think I'm suggesting anything else. Five years ago, when I was getting set up with them, they just happened to be having huge email problems affecting my entire neighborhood for a week. I discovered that their SMTP server was not RFC-compliant and actually talked their network technicians close enough to the problem that they were able to fix it in an hour once they saw what was going on. They have been great.

I don't have a spare cable modem handy, but I am thinking seriously about swapping out the 5-year-old surfboard 5100 just to see if it makes a difference. I was thinking of replacing my router, too, now that .n is catching on. But I think I will have COX see if they can find any obvious faults with the surfboard before I go changing anything. What I really want, of course, is a hardware packet analyzer. :)

Your posts show a lot of insight, and I really appreciate your time.
#36462 by murphy
Wed Dec 09, 2009 4:24 am
Any time you change what is connected to a cable modem it is required that the cable modem be power cycled. A cable modem remembers the first MAC address that connects after it is powered on and will not let anything else connect. That is how the cable company prevents you from pulling more than one IP address from them. This is why it is necessary to lock the ooma to it's built-in MAC address. If left in automatic mode and it decides to spoof the MAC address of your router after having connected using it's built in MAC address, your access to the internet is immediately terminated.

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