Skip to main content
GH1's profile

GH1

New Contributor

 • 

5 Messages

Closed

Modem resetting for no apparent reason

My modem is always on, but over the last month or so it does a complete reset, on its own, once or twice a day, which of course knocks me offline, usually at the worst possible time. By complete reset, I mean the power light is on and the Receive, Send and Online lights successively flash, then turn solid. So it's a total re-sync with the head end, just like when it's power cycled. But it's defintely not a power problem. I've tried using a backup brick, but that didn't help, and in any case the brick runs from a UPS along with an Ooma Telo, my router, and a desktop computer, and none of them are resetting. When it occurs, the reset completes at normal speed - there's no indication of any trouble on the line. And of course I've taken apart and reconnected ALL of the cable connections in my house, including the one behind the wall plate, but that didn't help. The modem is an SB5120, which of course is DOCSIS 2. I can tell from the modem log that there's a lot of downstream channel changing going on (although I've never seen an upstream channel change - always 27.5 MHz), but those happen very quickly, and haven't caused a problem. It's the resets, which last a minute or two, that do get in the way. In the log these show up with a lot of DHCP entries. My S/N is usually 35, sometimes 34, downstream power is -1, and upstream power is 42. When I take the splitter out, S/N doesn't change, downstream power changes from -1 to 1, and upstream from 42 to 38. I called customer service, and of course they said everything looks fine. But they also said their records showed my modem had been continuously online for six days, which isn't correct. I mean, the splitter test alone defintely took it offline even if the resets don't show up as going offline. The modem is only 10 years old, so barely broken in. Also, my Essential service level, my modem, my G router and G computer are all pretty well matched right now, so buying a new modem doesn't get me anything except a fix for the reset problem. But what I don't want to do is buy a new modem still have the reset problem because it's really some Cox amplifier or whatever that's going flaky and causing the resets, and my existing modem is actually working perfectly. It seems to me if it's a modem problem, I would sometimes see resets happening in quick succession, or in some kind of random pattern, but that's not the case. It always seems to be between 8 and 24 hours between resets. And so far as I can tell, lease renewal is working ok - appears to be 12 hours. Well, I'm posting in the hope that there's some other explanation - maybe I'm missing a firmware update, or there really is a problem at Cox that's causing this. Below are some log copies from a couple days ago. Thanks for any help.

Software Version: SB5120-2.19.0.16-SCM00-NOSH Hardware Version: 4 MIB Version: II GUI Version: 1.0 VxWorks Version: 5.4

2015-12-29 08:14:29 5-Warning D103.0 DHCP RENEW WARNING - Field invalid in response

2015-12-29 08:14:29 5-Warning DHCP: Renew: Another TFTP server IP address

2015-12-29 07:06:13 7-Information Channel Change Complete - Enabling Bridge

2015-12-29 07:06:13 7-Information C203.0 DCC arrive new

2015-12-29 07:06:08 7-Information Starting Ranging On Channel 2

2015-12-29 07:06:08 7-Information Dynamic Channel Change of Downstream Requested - Disabling Bridge

2015-12-29 07:06:08 7-Information Dynamic Channel Change of Downstream Requested - Setting tuner to 837.0MHz

2015-12-29 07:06:08 7-Information C202.0 DCC depart old

2015-12-28 20:14:35 7-Information SNMP: Working in SNMP V1/2c Only NmAccess mode

2015-12-28 20:14:33 7-Information INITIALIZATION COMPLETE - MODEM IS OPERATIONAL

2015-12-28 20:14:33 7-Information B401.0 Authorized

2015-12-28 20:14:33 6-Notice I401.0 TLV-11 - unrecognized OID

2015-12-28 20:14:33 7-Information SEC: Co-Signer CVC from configuration file was verified

2015-12-28 20:14:32 7-Information REGISTRATION COMPLETE - Waiting for Operational status

2015-12-28 20:14:32 7-Information REG: Capability type isn't supported by CMTS

2015-12-28 20:14:32 7-Information Registration file - downloaded

2015-12-28 20:14:30 7-Information Trying to download Configuration file ...

2015-12-28 20:14:30 7-Information Time of day - retrieved

2015-12-28 20:14:29 7-Information DHCP - parameters acquired

2015-12-28 20:14:29 7-Information DHCP: ACK: Setting (*) CM TFTP Boot file: ^1/E27143A5/138001

2015-12-28 20:14:29 7-Information DHCP: Setting CM IP address to: 10.35.68.105

2015-12-28 20:14:29 7-Information DHCP: Setting (*) CM Syslog Server address to: 10.254.254.254

2015-12-28 20:14:29 7-Information DHCP: Setting (*) CM Time Server address to: 172.19.57.118

2015-12-28 20:14:29 7-Information DHCP: Setting (*) CM Subnet mask to: 255.255.240.0

2015-12-28 20:14:29 7-Information DHCP: Setting (*) CM Gateway address to: 10.35.64.1

2015-12-28 20:14:29 7-Information DHCP: OFFER: Setting (*) CM TFTP Boot file: ^1/E27143A5/138001

2015-12-28 20:14:29 7-Information DHCP select: Setting (*) CM TFTP Server address to: 172.26.54.5

2015-12-28 20:14:29 7-Information DHCP: Offered (*) CM IP address to: 10.35.68.105 -unknown number of missing log entries here - the log doesn't hold many entries-

2015-12-28 11:20:08 7-Information Channel Change Complete - Enabling Bridge

2015-12-28 11:20:08 7-Information C203.0 DCC arrive new

2015-12-28 11:20:04 7-Information Starting Ranging On Channel 2

2015-12-28 11:20:03 7-Information Dynamic Channel Change of Downstream Requested - Disabling Bridge

2015-12-28 11:20:03 7-Information Dynamic Channel Change of Downstream Requested - Setting tuner to 819.0MHz

2015-12-28 11:20:03 7-Information C202.0 DCC depart old

2015-12-28 09:22:46 5-Warning D103.0 DHCP RENEW WARNING - Field invalid in response

2015-12-28 09:22:46 5-Warning DHCP: Renew: Another TFTP server IP address

2015-12-27 21:22:51 7-Information SNMP: Working in SNMP V1/2c Only NmAccess mode

2015-12-27 21:22:50 7-Information INITIALIZATION COMPLETE - MODEM IS OPERATIONAL

2015-12-27 21:22:50 7-Information B401.0 Authorized

2015-12-27 21:22:49 6-Notice I401.0 TLV-11 - unrecognized OID

2015-12-27 21:22:49 7-Information SEC: Co-Signer CVC from configuration file was verified

2015-12-27 21:22:48 7-Information REGISTRATION COMPLETE - Waiting for Operational status

2015-12-27 21:22:48 7-Information REG: Capability type isn't supported by CMTS

2015-12-27 21:22:48 7-Information Registration file - downloaded

2015-12-27 21:22:47 7-Information Trying to download Configuration file ...

2015-12-27 21:22:47 7-Information Time of day - retrieved

2015-12-27 21:22:46 7-Information DHCP - parameters acquired

2015-12-27 21:22:46 7-Information DHCP: ACK: Setting (*) CM TFTP Boot file: ^1/E27143A5/138001

2015-12-27 21:22:46 7-Information DHCP: Setting CM IP address to: 10.35.68.105

2015-12-27 21:22:46 7-Information DHCP: Setting (*) CM Syslog Server address to: 10.254.254.254

2015-12-27 21:22:46 7-Information DHCP: Setting (*) CM Time Server address to: 172.19.57.118

2015-12-27 21:22:46 7-Information DHCP: Setting (*) CM Subnet mask to: 255.255.240.0

2015-12-27 21:22:46 7-Information DHCP: Setting (*) CM Gateway address to: 10.35.64.1

2015-12-27 21:22:46 7-Information DHCP: OFFER: Setting (*) CM TFTP Boot file: ^1/E27143A5/138001

2015-12-27 21:22:46 7-Information DHCP select: Setting (*) CM TFTP Server address to: 172.26.54.5

2015-12-27 21:22:46 7-Information DHCP: Offered (*) CM IP address to: 10.35.68.105

Discussions

 • 

Updated 

4K

9

0

0

G

GH1

New Contributor

 • 

5 Messages

It looks like none of the CRLFs in my post were saved. Not my fault. I typed in the text, and even edited it to add more CRs, and everything looked fine before posting, but they were ignored too. Sorry. Maybe Cox can fix this? Edit: I have a copy of the post with all the line ends restored. Should I try to post again? Edit2: In Compose and Preview, everything looks fine. But after posting, when I read the post, none of the line ends show up. Why is this happening? Does everyone else see it formatted properly?

0

0

E

EdwardH

Valued Contributor

 • 

755 Messages

Fixed the log portion so its easier to read but the forums did not see any of the formatting when previewing it on our end before that.

As far as the modem it is not showing issues at least in its logs for the signal dropping on any of the channels, however with a single channel modem if something does effect one channel it does reset to pick another one. When you notice the resets are you able to see what the real time downstream signal is showing to see if it is matching what we have or if there a issue with the logs it is reporting to us?

---

0

0

G

GH1

New Contributor

 • 

5 Messages

EdwardH said:
Fixed the log portion so its easier to read but the forums did not see any of the formatting when previewing it on our end before that.

As far as the modem it is not showing issues at least in its logs for the signal dropping on any of the channels, however with a single channel modem if something does effect one channel it does reset to pick another one. When you notice the resets are you able to see what the real time downstream signal is showing to see if it is matching what we have or if there a issue with the logs it is reporting to us?

---
I'm confused about the formatting issue here in the forum. When I typed the text of my post, there were a number of paragraphs, all of which showed up correctly in the Compose and Preview windows. But after posting, all of the EOLs were converted to spaces. Is this because I'm using IE 11, or do I have something set wrong? When I read others' posts, some are formatted in paragraphs, but others are all run together like mine.

With respect to the modem, the log entries involving just downstream channel changes don't cause any problem. But the sequences showing DHCP renegotiation do dump me offline and screw things up. Since the log space is so limited, whatever may have caused the reset has scrolled off the log when the DHCP reset is finished. So I'm never able to tell what may have happened immediatately before. But the downstream stats are always the same - 34 or 35 on S/N, and -1 on power. The frequency of course varies a good bit.


Edit: I had the same loss of EOL characters on this post, but found that I can correct that in editing by using as an EOL the characters "br /" within a "<>" pair. I would suggest that I shouldn't have to do that.

0

0

E

EdwardH

Valued Contributor

 • 

755 Messages

I am aware of the hard returns in formatting for the forums but not aware if there are issues specific to IE 11 or a recent update for it.

As far as the modem goes, the DHCP lease should renew every 24 hours it is unlikely to change unless something with the direct connection changes but that should not cause any noticeable change when doing so. To see if it is a issue with how it loaded the current firmware though we can resend the last update for it again to check there were no errors. Is there a time that works best for us to send it? As it will reset the connection for about 10 minutes.

---

0

0

G

GH1

New Contributor

 • 

5 Messages

EdwardH said:
I am aware of the hard returns in formatting for the forums but not aware if there are issues specific to IE 11 or a recent update for it.

As far as the modem goes, the DHCP lease should renew every 24 hours it is unlikely to change unless something with the direct connection changes but that should not cause any noticeable change when doing so. To see if it is a issue with how it loaded the current firmware though we can resend the last update for it again to check there were no errors. Is there a time that works best for us to send it? As it will reset the connection for about 10 minutes.

---

The DHCP lease is renewing every 12 hours:

2015-12-31 06:24:30 5-Warning D103.0 DHCP RENEW WARNING - Field invalid in response
2015-12-31 06:24:30 5-Warning DHCP: Renew: Another TFTP server IP address
2015-12-30 18:24:29 5-Warning D103.0 DHCP RENEW WARNING - Field invalid in response
2015-12-30 18:24:29 5-Warning DHCP: Renew: Another TFTP server IP address

Those don't cause any problem. Also, simple downstream dynamic channel changes like these don't cause problems:

2015-12-29 23:36:05 7-Information Channel Change Complete - Enabling Bridge
2015-12-29 23:36:05 7-Information C203.0 DCC arrive new
2015-12-29 23:36:01 7-Information Starting Ranging On Channel 2
2015-12-29 23:36:00 7-Information Dynamic Channel Change of Downstream Requested - Disabling Bridge
2015-12-29 23:36:00 7-Information Dynamic Channel Change of Downstream Requested - Setting tuner to 819.0MHz
2015-12-29 23:36:00 7-Information C202.0 DCC depart old
2015-12-29 22:56:03 7-Information Channel Change Complete - Enabling Bridge
2015-12-29 22:56:02 7-Information C203.0 DCC arrive new
2015-12-29 22:55:58 7-Information Starting Ranging On Channel 2
2015-12-29 22:55:57 7-Information Dynamic Channel Change of Downstream Requested - Disabling Bridge
2015-12-29 22:55:57 7-Information Dynamic Channel Change of Downstream Requested - Setting tuner to 849.0MHz
2015-12-29 22:55:57 7-Information C202.0 DCC depart old
2015-12-29 18:40:52 7-Information Channel Change Complete - Enabling Bridge
2015-12-29 18:40:52 7-Information C203.0 DCC arrive new
2015-12-29 18:40:47 7-Information Starting Ranging On Channel 2
2015-12-29 18:40:47 7-Information Dynamic Channel Change of Downstream Requested - Disabling Bridge
2015-12-29 18:40:47 7-Information Dynamic Channel Change of Downstream Requested - Setting tuner to 819.0MHz
2015-12-29 18:40:47 7-Information C202.0 DCC depart old

Neither of those types of events cause the modem to do a complete re-sync like this:

2015-12-28 20:14:35 7-Information SNMP: Working in SNMP V1/2c Only NmAccess mode
2015-12-28 20:14:33 7-Information INITIALIZATION COMPLETE - MODEM IS OPERATIONAL
2015-12-28 20:14:33 7-Information B401.0 Authorized
2015-12-28 20:14:33 6-Notice I401.0 TLV-11 - unrecognized OID
2015-12-28 20:14:33 7-Information SEC: Co-Signer CVC from configuration file was verified
2015-12-28 20:14:32 7-Information REGISTRATION COMPLETE - Waiting for Operational status
2015-12-28 20:14:32 7-Information REG: Capability type isn't supported by CMTS
2015-12-28 20:14:32 7-Information Registration file - downloaded
2015-12-28 20:14:30 7-Information Trying to download Configuration file ....
2015-12-28 20:14:30 7-Information Time of day - retrieved
2015-12-28 20:14:29 7-Information DHCP - parameters acquired
2015-12-28 20:14:29 7-Information DHCP: ACK: Setting (*) CM TFTP Boot file: ^1/E27143A5/138001
2015-12-28 20:14:29 7-Information DHCP: Setting CM IP address to: 10.35.68.105
2015-12-28 20:14:29 7-Information DHCP: Setting (*) CM Syslog Server address to: 10.254.254.254
2015-12-28 20:14:29 7-Information DHCP: Setting (*) CM Time Server address to: 172.19.57.118
2015-12-28 20:14:29 7-Information DHCP: Setting (*) CM Subnet mask to: 255.255.240.0
2015-12-28 20:14:29 7-Information DHCP: Setting (*) CM Gateway address to: 10.35.64.1
2015-12-28 20:14:29 7-Information DHCP: OFFER: Setting (*) CM TFTP Boot file: ^1/E27143A5/138001
2015-12-28 20:14:29 7-Information DHCP select: Setting (*) CM TFTP Server address to: 172.26.54.5
2015-12-28 20:14:29 7-Information DHCP: Offered (*) CM IP address to: 10.35.68.105

The best time for a firmware re-do would be in the afternoon between 1:00 and 3:00 pm Central time. But this only started happening a few weeks ago, so if there hasn't been a recent update, and I have the latest version, I think that's unlikely to be the problem.

0

0

T

Tecknowhelp

Valued Contributor II

 • 

2.8K Messages

"My S/N is usually 35, sometimes 34,"

I think this is your main issue. That modem is very old, have you tried another? Or had your coaxial looked at?

0

0

G

GH1

New Contributor

 • 

5 Messages

Tecknowhelp said:

"My S/N is usually 35, sometimes 34,"

I think this is your main issue. That modem is very old, have you tried another? Or had your coaxial looked at?

I don't have another modem to try. I know it's old, but that doesn't mean it's gone bad. Of course if I can't find any other solution, the only thing left will be to buy a new modem. But I do worry about shelling out the cash for that only to find that the problem still exists. I really hate it when that happens. As for the cable, well, customer service says everything is fine, and they see no reason to roll a truck. S/N of 34 or 35 is ok with them. I mean, I'm sure if I insisted they would send a tech out, but I doubt he'd find a problem with the line, and I don't want to have to pay for that trip. The drop is actually pretty new, and in conduit out to the pedestal in the neighbor's yard. And it would be an amazing coincidence if a reset happened while the tech was here. Nobody has that kind of luck. My guess is if it's not my modem it's some piece of Cox equipment somewhere up the line that's flaky. But that's just a guess.

It just seems to me that if the modem is going bad, I would be seeing a more random pattern in the resets. But I don't. They are never less than about 8 hours apart, and usually more like 15 to 20 hours apart. Once or twice a day, but never more than that. The only thing I see that's curious is that while I see multiple downstream channel changes (not resets) every day, I never see an upstream channel change. Maybe the modem is being asked to change the upstream channel, but can't do that for some reason, so it resets, only to end up back on the same channel anyway.

0

0

T

Tecknowhelp

Valued Contributor II

 • 

2.8K Messages

GH1 said:
S/N of 34 or 35 is ok with them

I disagree with them. Should be above 36 but depends on the QAM. 

What makes you think it's a upstream issue? That wouldn't effect downstream speed that much.

If you were thinking it's a maintenance issue, posting here won't do much good IMO. This forum is for ideas, not actual solutions if it's something out on the pole that needs to be fixed. Only a technician can diagnose that. If you trust the technician's competence that is.

0

0

B

Becky

+2 more

Moderator

 • 

4.3K Messages

Hi GH1,

I doubt the issue is the firmware. Have you considered the age of the modem? You've definitely gotten your money's worth out of that Motorola modem!  I believe all of the issues you have reported may indicate the modem is approaching the end of its lifespan. It may be time to replace the SB5120 with a DOCSIS 3.0 modem. You can get a new modem from Cox or from any other retailer, as long as it is on the list of Cox-approved modems, found at http://bit.ly/CoxCMs.

0

0