Downstream light keeps blinking

[GEO714]

I have C6300 cable modem router with internet service through TimeWarner Cable aka Spectrum in Anaheim CA. My DS light keeps blinking I have reset router several times called cable company they refreshed signal still light keeps blinking anyone have any idea why this is happening???

[DarrenM · Accepted solution]

Hello GEO714

I see you are getting T3 timeouts which may be a issues with noise on the cable lines they may need to send a tech out to check your lines.

T3 Timeout ( Ranging Request Retries Exhausted )

Explanation: The cable modem has sent 16 Ranging Request (RNG-REQ) messages without receiving a Ranging Response (RNG-RSP) message in reply from the CMTS. The cable modem is therefore resetting its cable interface and restarting the registration process. This typically is caused by 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. This error message is DOCSIS event message is R03.0, Ranging Request

DarrenM

[DarrenM]

Solid amber. One downstream channel is locked.

• Solid green. Two or more downstream channels are locked.

• Blinking green. The modem router is scanning for a downstream channel.

• Off. No downstream channel is locked.

DarrenM

[GEO714]

What happens if it won't stop blinking

[DarrenM]

Are you having any issues with the modem or slow speeds?

DarrenM

[GEO714]

There was lagging going on yesterday today seems ok so far bunch of critical errors in event log

[DarrenM]

I would say keep a eye on the modem if it starts acting up more post your logs and power levels of the modem may help us figure out if its a issue with the modem or the ISP.

DarrenM

[GEO714]

Where can I post logs

[DarrenM]

should be able to post them here in the thread.

DarrenM

[GEO714]

Here is my event log showing errors

[DarrenM · Accepted solution]

Hello GEO714

I see you are getting T3 timeouts which may be a issues with noise on the cable lines they may need to send a tech out to check your lines.

T3 Timeout ( Ranging Request Retries Exhausted )

Explanation: The cable modem has sent 16 Ranging Request (RNG-REQ) messages without receiving a Ranging Response (RNG-RSP) message in reply from the CMTS. The cable modem is therefore resetting its cable interface and restarting the registration process. This typically is caused by 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. This error message is DOCSIS event message is R03.0, Ranging Request

DarrenM

[MTWOODLAND]

I'm having simular problems with power levels on the downstream channels. specially channel 5 " not locked" status. power levels " according to Comcast +10 to -10 dBmv. when I see a level of -16dBmv I have terrible Mbps speeds. ( 50Mbps-ish) .. now after doing 1 or 2 or 3 " modem reboots, internally ) channel 5 may or may not change to Comcast dBmv comfort level, and I then get steady downstream light on front panel and My Promised speeds of 200-230Mbps. my question is Who /Where / What does this dBmv come from, ? my box or comcast feed ?

[GEO714]

Give Comcast a call tell them to test line on all channels to make sure it’s not on their end. That will help expose where issue is with Router or Lines? My issue ended up being Spectrum Lines up on pole squirrels had bitten into lines they had to replace who section of lines. Have not had a blinking light issue since

[MTWOODLAND]

sending a *jpg in hope a Netgear Guru / Tech could confirm that captured channels and the levels that my c3700-100nas have locked onto are the signal strenght sent from ISP. Or am I having problems with modem capturing the signal. Was charged a fee last week, yet not positive they troubleshot problem, just swapped out a splitter and left.

[GEO714]

What does your error log show

[MTWOODLAND]

is there another log file other than Advanced>Admin>Logs ?  only showing Dos attacks from Ping of Death. and DHCP issuing IP's to my wifi devices.

[MTWOODLAND]

hold on, SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=a0:63:91:51:20:78;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;    ......    Unicast Ranging Received Abort Response - Re-initializing MAC;CM-MAC=a0:63:91:51:20:78;CMTS-MAC=e8:65:49:b9:19:d0;CM-QOS=1.1;CM-VER=3.0;

[MTWOODLAND]

this was captured when internet failure last week. Am I looking at Downstreaming channels signal strenght / captured from ISP ...Upstream was extremely high and unlocked.  Downstream unlocked channels and dBmv -15, -14,  ... my understanding is if Upstream dBmv is above 45-50 this causes Downstream and connection failures.

[GEO714]

I’m not 100% but this looks like a line issue from your provider when they tested line what did they say it looked like? How long have you had your router? Is it new or been using it awhile now

[MTWOODLAND]

Couple yrs. i have faith in my router, more than Comcast .. also possible related or not, issues with frozen TV , pixelated screens, frozen controls

[MTWOODLAND]

Of course they initially tested, probably, maybe.. now tested individual channels, or performed load tests. Who knows

[MTWOODLAND]

update to downstream channels that will not lock due to dBmv and SNR problems.

I found if I setup manually the Starting Frequency for the 8 channels on the Basic page/ during initialization and registration I get awesome results. now for some reason my ISP changes them after a few minutes. Does anyone know how to lock the startup freq permanently ?