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Specere
Posts: 1
Registered: ‎11-11-2012

Frequent modem reboots due to T4 timout

For the last several weeks we have been getting frequent cable modem reboots. The model logs say these are due to T4 timeouts. In the last 1.5 weeks we have called support and they had us disconnect from the router to discount it as this issue. While disconnected from the router we still had the timeouts. Just recently I move the modem off the splitter and connected it directly to the incoming line. Still having timeout issues.

 

Here are the logs from right after the most recent reboot without a splitter involved.

 

Nov 11 2012 18:16:47

3-Critical

R02.0

No Ranging Response received - T3 time-out;CM-MAC=7c:bf:b1:61:43:c7;CMTS-MAC=00:01:5c:32:da:cf;CM-QOS=1.1;CM-VER=3.0;

 

Nov 11 2012 18:16:38

6-Notice

I401.0

TLV-11 - unrecognized OID;CM-MAC=7c:bf:b1:61:43:c7;CMTS-MAC=00:01:5c:32:da:cf;CM-QOS=1.1;CM-VER=3.0;

 

Nov 11 2012 18:16:38

5-Warning

Z00.0

MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1;CM-MAC=7c:bf:b1:61:43:c7;CMTS-MAC=00:01:5c:32:da:cf;CM-QOS=1.1;CM-VER=3.0;

 

Jan 01 1970 00:00:22

3-Critical

R02.0

No Ranging Response received - T3 time-out;CM-MAC=7c:bf:b1:61:43:c7;CMTS-MAC=00:01:5c:32:da:cf;CM-QOS=1.1;CM-VER=3.0;

 

Jan 01 1970 00:00:13

6-Notice

N/A

Cable Modem Reboot due to T4 timeout ;CM-MAC=7c:bf:b1:61:43:c7;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.0;

 

Nov 11 2012 18:15:47

3-Critical

R06.0

Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=7c:bf:b1:61:43:c7;CMTS-MAC=00:01:5c:32:da:cf;CM-QOS=1.1;CM-VER=3.0;

 

Nov 11 2012 18:15:47

3-Critical

R03.0

Ranging Request Retries exhausted;CM-MAC=7c:bf:b1:61:43:c7;CMTS-MAC=00:01:5c:32:da:cf;CM-QOS=1.1;CM-VER=3.0;

 

Nov 11 2012 18:15:47

3-Critical

R06.0

Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=7c:bf:b1:61:43:c7;CMTS-MAC=00:01:5c:32:da:cf;CM-QOS=1.1;CM-VER=3.0;

 

Nov 11 2012 18:15:47

3-Critical

R03.0

Ranging Request Retries exhausted;CM-MAC=7c:bf:b1:61:43:c7;CMTS-MAC=00:01:5c:32:da:cf;CM-QOS=1.1;CM-VER=3.0;

 

Nov 11 2012 18:15:47

3-Critical

R06.0

Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=7c:bf:b1:61:43:c7;CMTS-MAC=00:01:5c:32:da:cf;CM-QOS=1.1;CM-VER=3.0;

 

Nov 11 2012 18:15:47

3-Critical

R03.0

Ranging Request Retries exhausted;CM-MAC=7c:bf:b1:61:43:c7;CMTS-MAC=00:01:5c:32:da:cf;CM-QOS=1.1;CM-VER=3.0;

 

Nov 11 2012 18:15:45

3-Critical

R02.0

No Ranging Response received - T3 time-out;CM-MAC=7c:bf:b1:61:43:c7;CMTS-MAC=00:01:5c:32:da:cf;CM-QOS=1.1;CM-VER=3.0;

 

Nov 11 2012 17:51:30

6-Notice

I401.0

TLV-11 - unrecognized OID;CM-MAC=7c:bf:b1:61:43:c7;CMTS-MAC=00:01:5c:32:da:cf;CM-QOS=1.1;CM-VER=3.0;

 

Nov 11 2012 17:51:29

5-Warning

Z00.0

MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1;CM-MAC=7c:bf:b1:61:43:c7;CMTS-MAC=00:01:5c:32:da:cf;CM-QOS=1.1;CM-VER=3.0;

 

Jan 01 1970 00:00:13

6-Notice

N/A

Cable Modem Reboot due to power reset ;CM-MAC=7c:bf:b1:61:43:c7;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.0;

 

Nov 11 2012 17:49:52

3-Critical

T05.0

SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=7c:bf:b1:61:43:c7;CMTS-MAC=00:01:5c:32:da:cf;CM-QOS=1.1;CM-VER=3.0;

 

Nov 11 2012 17:49:50

3-Critical

R02.0

No Ranging Response received - T3 time-out;CM-MAC=7c:bf:b1:61:43:c7;CMTS-MAC=00:01:5c:32:da:cf;CM-QOS=1.1;CM-VER=3.0;

 

Nov 11 2012 17:49:18

6-Notice

I401.0

TLV-11 - unrecognized OID;CM-MAC=7c:bf:b1:61:43:c7;CMTS-MAC=00:01:5c:32:da:cf;CM-QOS=1.1;CM-VER=3.0;

 

Nov 11 2012 17:49:18

5-Warning

Z00.0

MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1;CM-MAC=7c:bf:b1:61:43:c7;CMTS-MAC=00:01:5c:32:da:cf;CM-QOS=1.1;CM-VER=3.0;

 

Jan 01 1970 00:00:18

3-Critical

R02.0

No Ranging Response received - T3 time-out;CM-MAC=7c:bf:b1:61:43:c7;CMTS-MAC=00:01:5c:32:da:cf;CM-QOS=1.1;CM-VER=3.0;

 

Here is the signal page from the same time:

 

 

Downstream

Bonding Channel Value

Channel ID

 

Frequency

717000000 Hz 

723000000 Hz 

729000000 Hz 

735000000 Hz 

 

Signal to Noise Ratio

37 dB 

37 dB 

37 dB 

37 dB 

 

Downstream Modulation

QAM256 

QAM256 

QAM256 

QAM256 

 

Power Level

The Downstream Power Level reading is a snapshot taken at the time this page was requested. Please Reload/Refresh this Page for a new reading

-3 dBmV  

-2 dBmV  

-1 dBmV  

-2 dBmV  

 

Upstream

Bonding Channel Value

Channel ID

 

Frequency

35000000 Hz 

22000000 Hz 

28200000 Hz 

 

Ranging Service ID

4598 

4598 

4598 

 

Symbol Rate

5.120 Msym/sec 

2.560 Msym/sec 

5.120 Msym/sec 

 

Power Level

41 dBmV 

40 dBmV 

41 dBmV 

 

Upstream Modulation

[3] QPSK
[3] 64QAM
 

[3] QPSK
[2] 16QAM
 

[3] QPSK
[3] 64QAM
 

Ranging Status

Success 

Success 

Other 

 

Signal Stats (Codewords)

Bonding Channel Value

Channel ID

 

Total Unerrored Codewords

2932382 

2932503 

2932385 

2932476 

 

Total Correctable Codewords

16 

11 

16 

 

Total Uncorrectable Codewords

702 

578 

706 

611 

 

We also have logs and signal pages from right after reboots with the splitter attached... and there goes my internet once more.

 

Hopefully someone can shed some light onto what is happening and give us a solution.

Cable Expert
i-am-nerdburg
Posts: 11,146
Registered: ‎06-27-2009
Cable Expert
i-am-nerdburg
Posts: 11,146
Registered: ‎06-27-2009
Cable Expert
i-am-nerdburg
Posts: 11,146
Registered: ‎06-27-2009

Re: Frequent modem reboots due to T4 timout

Specere,

T4 errors indicate that your modem was unable to contact the headend for a long time. It usually indicates an intermittent signal problem. Your power levels/SNR are fine. Next time it happens, grab another set of signal levels and post pls. Also call Comcast and request:

 

• Upstream Signal to Noise Ratio (SNR): Above 30 is acceptable. Higher is better. 
• Upstream Receive Power: Ideally this number should fall within the -7dBmV and +7dBmV range.