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I moved into a home in Gilbert AZ a little over a year ago. I have had internet issues since I moved in. This is a problem since I work from home (like many people do now). The first service by Cox - told to replace my modem (Netgear CM1200), second service visit tech checked all wires and reburied them (I had a new modem: Motorola MB8600), third visit tech checked the connection at the street - found it wasn't as it should have been and fixed it. That seemed to work. Fast forward a couple months and now I lose connection daily. Tech comes out says he can't find any issues, calls his supervisor and the supervisor says it's the modem. Really...when you can't figure out the issue or don't want to take responsibility Cox, you blame the modem.
I checked the error logs for the modem after the tech had left. I received these errors
Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out
SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing
Honoring MDD; IP provisioning mode = IPv4
DHCP WARNING - Non-critical field invalid in response
TLV-11 - unrecognized OID
DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1 2 3.
REG-RSP-MP Mismatch Between Calculated Value for P1.6hi Compared to CCAP Provided Value
RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW
Dynamic Range Window violation
No Ranging Response received - T3 time-out
I waited an hour and rebooted the modem again. My SNR levels are acceptable and within 3 of each other. My pwr levels are acceptable, but not within 3 of each other. No uncorrected packets. A few of my upload channels are below normal.
I received these errors:
SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;
DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1 2 3
So the timeout changed from T4 to T3. I am crossing my fingers that I don't lose internet again tomorrow or Monday or Tuesday... If I call tech support they will tell me to just get their modem.
T4 Timeout - Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities receivedDOCSIS event error message R04.0, Ranging RequestCable modem did not receive a station maintenance opportunity in which to transmit a Ranging Request (RNG-REQ) message within the T4 timeout period (30 to 35 seconds). The cable modem is resetting and restarting the registration process.Typically, this indicates an occasional, temporary loss of service, but if problem persists, check for possible service outages or maintenance activity on this particular headend system.
T3 Timeout - Ranging Request Retries ExhaustedDOCSIS event error message is R03.0, Ranging RequestCable modem has sent 16 Ranging Request messages (RNG-REQ) without receiving a Ranging Response message (RNG-RSP) in reply from the CMTS. The cable modem is therefore resetting its cable interface and restarting the registration process.This typically is caused by too much noise on the upstream that causes the loss of MAC-layer messages. Noise could also raise the signal-to-noise ratio (SNR) on the upstream to a point where the cable modem’s power level is insufficient to transmit any messages. If the cable modem cannot raise its upstream transmit power level to a level that allows successful communication within the maximum timeout period, it resets its cable interface and restarts the registration process. T3 timeouts can also be caused by a bad amplifier on the node, bad tap, coax issues, etc.Some cable modem models/brands may have cleaner upstream signal reducing the number of T3 timeouts (reportedly Zoom 5341-00-00J, for example)
How many T3 errors do you have compared to T4 errors? If you have more T3 then T4, could be a issue with upstream. If not, it could be a issue with the downstream. If you already had multiple techs out I would file a informal FCC complaint.