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CMTS Ranging Issues

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CMTS Ranging Issues

Hi there,

 

I'm having an issue where my cable modem is re-booting frequently, but intermittently. The problem seems to be most prevalent in the evening hours. I have called Comcast about it multiple times, and spoken with the cable modem manufacturer as well. I have swapped cable modems (different model altogether) and the problem still persists. I polled the modem, and all the signal and SNR information is showing that it's in-range, but those readings are only available when the modem is active, not when the problem is occuring. I've tried to poll the modem during the issue, but the modem is always in the process of rebooting by the time the issue happens, so there's nothing useful there.

 

What I did notice, and tried to communicate to the Comcast service rep on the phone was that the event log is showing a series of ranging errors in the log that correspond with these outages. There are four entries in the event log that seem to repeat around the same time the modem self-reboots:

 

No Ranging Response received - T3 time-out;CM-MAC=3c:04:61:3d:8f:5b;CMTS-MAC=80:e0:1d:02:78:ee;CM-QOS=1.1;CM-VER=3.0;

 

Unicast Ranging Received Abort Response - initializing MAC;CM-MAC=3c:04:61:3d:8f:5b;CMTS-MAC=80:e0:1d:02:78:ee;CM-QOS=1.1;CM-VER=3.0;

 

SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=3c:04:61:3d:8f:5b;CMTS-MAC=80:e0:1d:02:78:ee;CM-QOS=1.1;CM-VER=3.0;

 

TLV-11 - unrecognized OID;CM-MAC=3c:04:61:3d:8f:5b;CMTS-MAC=80:e0:1d:02:78:ee;CM-QOS=1.1;CM-VER=3.0;

 

The two "Ranging" errors are the ones that are occuring most frequently.

 

Comcast is sending a service technician on Wednesday, but I'm not sure that's going to accomplish anything if the issue is not occuring in the moment. The middle of the day is when the issue is least likely to happen. I have read other posts in this forum suggesting that the CMTS needs to be polled, and a true resolution requires the assistance of the staff at my local headend/hub facility. However, I haven't found anything about the successful resolution of this issue in the forum. Does anyone monitoring this thread have any experience with this issue, and any advice to help expedite resolution?

Expert

Re: CMTS Ranging Issues


@tcabral81 wrote:

Hi there,

 

I'm having an issue where my cable modem is re-booting frequently, but intermittently. The problem seems to be most prevalent in the evening hours. I have called Comcast about it multiple times, and spoken with the cable modem manufacturer as well. I have swapped cable modems (different model altogether) and the problem still persists. I polled the modem, and all the signal and SNR information is showing that it's in-range, but those readings are only available when the modem is active, not when the problem is occuring. I've tried to poll the modem during the issue, but the modem is always in the process of rebooting by the time the issue happens, so there's nothing useful there.

 


I used to have a lot of ranging errors until I moved my modem to a different connector on my splitter, bypassing a problematic stretch of interior wiring. 

Since you have a tech coming over, for the time being, please post the information requested on this thread, and not just what the event log messages show. 

 


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New Poster

Re: CMTS Ranging Issues

Thanks for the guidance. I was away from home and only had the error messages with me. I was about to pull and attach the modem info, when Comcast called to let me know there was an outage in the area and it is now resolved. I asked what the nature of the error is, but they couldn't tell me.

 

Just wanted to close off. Thanks again for the help.