I suffered internet disconnection caused by cable modem reboot or malfunction. It happened every few hour or feww days. I tried contact technical service and on-site check. They all failed to find the root cause. I will post cable model log and hope there is a solution without switching modem. Thanks.
Setting:
1. Sepctrum internet.
2. Motorola MB7420
3. ASUS AC 1300
Cable modem log
1. Connection
[TABLE]
[TABLE]
Startup Sequence

[TABLE]
Startup Step
Status
Comment

Acquire Downstream Channel
531000000 Hz
Locked

Upstream Connection
OK
Operational

Boot State
OK
Operational

Configuration File
OK
?BiABGZgIwAEAAAAAAAAAAHIAQDZHL5MmBGAADAAAUwm4hBMI0Hpj@AAAAAK0i+bpY0Y97anetjk7OqwJSTO96

Security
Enabled
BPI+

[TABLE]
[TABLE]
Connection Status

[TABLE]
System Up Time
0 days 00h:06m:23s

Network Access
Allowed

[TABLE]
[TABLE]
Downstream Bonded Channels


[TABLE]
Channel
Lock Status
Modulation
Channel ID
Freq. (MHz)
Pwr (dBmV)
SNR (dB)
Corrected
Uncorrected
1
Locked
QAM256
2
531.0
-0.3
39.5
0
0
2
Locked
QAM256
1
525.0
-0.6
39.5
0
0
3
Locked
QAM256
3
537.0
-0.5
39.4
0
0
4
Locked
QAM256
4
543.0
-0.3
39.5
0
0
5
Locked
QAM256
5
555.0
-0.2
39.4
0
0
6
Locked
QAM256
6
561.0
0.0
39.4
0
0
7
Locked
QAM256
7
567.0
-0.3
39.4
0
0
8
Locked
QAM256
8
573.0
0.0
39.3
0
0
9
Locked
QAM256
9
579.0
-0.3
39.2
0
0
10
Locked
QAM256
10
585.0
0.0
39.3
0
0
11
Locked
QAM256
11
591.0
-0.1
39.3
0
0
12
Locked
QAM256
12
597.0
-0.1
39.0
0
0
13
Locked
QAM256
13
603.0
0.1
39.3
0
0
14
Locked
QAM256
14
609.0
0.0
39.3
0
0
15
Locked
QAM256
16
621.0
0.2
39.2
0
0
16
Locked
QAM256
24
669.0
0.2
39.1
0
0
Total
0
0
[TABLE]
[TABLE]
Upstream Bonded Channels


[TABLE]
Channel
Lock Status
Channel Type
Channel ID
Symb. Rate (Ksym/sec)
Freq. (MHz)
Pwr (dBmV)
1
Locked
ATDMA
59
5120
30.6
44.3
2
Locked
TDMA
57
2560
19.4
43.8
3
Locked
ATDMA
58
5120
24.2
44.0
4
Locked
ATDMA
60
5120
37.0
44.3
[TABLE]
[TABLE]
Downstream Frequency Setting

[TABLE]
Downstream Frequency Select

2. Event log
Event Log
[TABLE]
[TABLE]
Log


[TABLE]
Time
Priority
Description
Time Not Established
Critical (3)
No Ranging Response received - T3 time-out;CM-MAC=00:40:36:4...
Time Not Established
Critical (3)
No Ranging Response received - T3 time-out;CM-MAC=00:40:36:4...
Time Not Established
Notice (6)
Overriding MDD IP initialization parameters; IP provisioning...
Sun Jul 22 16:17:27 2018
Error (4)
Missing BP Configuration Setting TLV Type: 17.8;CM-MAC=00:40...
Sun Jul 22 16:17:27 2018
Error (4)
Missing BP Configuration Setting TLV Type: 17.9;CM-MAC=00:40...
Cable modem restart every few minutes and cause internet disconnection. Help needed!?