intermittent loss of connectivity T3 timeouts all throughout the day

[greggel]

Similar to this case, I am also experiencing this problem:

https://forums.xfinity.com/t5/Your-Home-Network/Intermittent-quot-No-Ranging-Response-received-T3-ti...

At least a handful of times a day we experience downtime from the modem and it is difficult to troubleshoot why.   I have a router behind the modem and also experienced intermittent connectivity loss without the router in the mix.

What should I do next?

Thanks.

event log timeouts:

Thu Jun 25 17:10:45 2020	Notice (6)	TLV-11 - unrecognized OID;CM-MAC=b0:77:ac:92:55:df;CMTS-MAC=00:01:5c:6b:86:4a;CM-QOS=1.1;CM-VER=3.0;
Time Not Established	Notice (6)	Honoring MDD; IP provisioning mode = IPv6
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Notice (6)	WiFi Interface [wl0] set to Channel 40 (Side-Band Channel:36) - Reason:INIT
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Tue Jun 23 12:43:18 2020	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=b0:77:ac:92:55:df;CMTS-MAC=00:01:5c:6b:86:4a;CM-QOS=1.1;CM-VER=3.0;
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Mon Apr 27 17:43:47 2020	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=b0:77:ac:92:55:df;CMTS-MAC=00:01:5c:6b:86:4a;CM-QOS=1.1;CM-VER=3.0;
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out

Status - Connection

The statuses listed show the connection state of the cable modem contained within the SBG6580. They are used by your service provider to evaluate the operation of the cable modem.

Startup Procedure
Procedure	Status	Comment
Acquire Downstream Channel		Locked
Connectivity State	OK	Operational
Boot State	OK	Operational
Configuration File	OK
Security	Enabled	BPI+

Downstream Bonded Channels
Channel	Lock Status	Modulation	Channel ID	Frequency	Power	SNR	Corrected	Uncorrectables
1	Locked	QAM256	34	645000000 Hz	-3.7 dBmV	39.5 dB	0	0
2	Locked	QAM256	35	651000000 Hz	-4.6 dBmV	39.0 dB	0	0
3	Locked	QAM256	36	657000000 Hz	-5.2 dBmV	38.3 dB	0	0
4	Locked	QAM256	37	663000000 Hz	-6.6 dBmV	38.2 dB	0	0
5	Locked	QAM256	38	669000000 Hz	-5.4 dBmV	38.9 dB	0	0
6	Locked	QAM256	39	675000000 Hz	-3.4 dBmV	38.9 dB	0	0
7	Locked	QAM256	40	681000000 Hz	-3.4 dBmV	39.0 dB	0	0
8	Locked	QAM256	41	687000000 Hz	-3.0 dBmV	38.9 dB	0	0

Upstream and downstream activity:

Upstream Bonded Channels
Channel	Lock Status	US Channel Type	Channel ID	Symbol Rate	Frequency	Power
1	Locked	ATDMA	34	5120 Ksym/sec	30100000 Hz	51.0 dBmV
2	Locked	ATDMA	33	5120 Ksym/sec	36500000 Hz	52.5 dBmV
3	Locked	ATDMA	35	5120 Ksym/sec	23700000 Hz	50.0 dBmV
4	Locked	ATDMA	36	5120 Ksym/sec	17300000 Hz	49.2 dBmV

[EG]

The upstream power is on the high side and it may be intermittently fluctuating even higher to out of spec levels. That can cause random disconnects, spontaneous re-booting of the modem, speed, packet loss, and latency problems.

In a self troubleshooting effort to try to obtain better connectivity / more wiggle room, check to see if there are there any excess/unneeded coax cable splitters in the line leading to the modem that can be eliminated/re-configured. Any splitters that remain should be high quality and cable rated for 5-1002 MHz, bi-directional, and no gold colored garbage types like GE, RadioShack, RCA, Philips, Leviton, Magnavox, and Rocketfish from big box stores like Home Depot, Lowes, Target, Wal-Mart etc. Splitters should be swapped with known to be good / new ones to test

If there aren't any unneeded splitters that can be eliminated and if your coax wiring setup can't be reconfigured so that there is a single two way splitter connected directly off of the drop from the street/pole with one port feeding the modem and the other port feeding the rest of the house/equipment with additional splits as needed, and you've checked all the wiring and fittings for integrity and tightness and refresh them by taking them apart then check for and clean off any corrosion / oxidation on the center wire and put them back together again, then perhaps it's best to book a tech visit to investigate and correct.

[greggel]

thanks for this comment it is super helpful as I am very inexperienced here in troubleshooting anything from the street.

I found a single splitter inside the house, in my basement, which is an antronix 2-way splitter, with 2 jacks for -3.5db out.  Is this splitter any good?  Any opinion on it?

I feel like at this point I have reached my limit in what I can troubleshoot, other than replacing that splitter and may reach out to support to come out.  Unless you think I should just buy a new splitter in replacement of this one.  I am not sure I can go without this splitter as its bringing connectivity into my basement as well as my home.

Thanks though, for the thorough response.

[EG]

It's a good quality brand splitter but it may be malfunctioning. Who knows. YMMV. You could certainly try swapping it out.