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Trouble Isolating Connection Issue

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Official Employee

Re: Trouble Isolating Connection Issue

Great! I'm happy to know things seem to be working for you. Please don't hesitate to reach out if you have any other questions or concerns. 

I am an Official Comcast Employee.
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Frequent Visitor

Re: Trouble Isolating Connection Issue

Just wanted to give everyone an update, and happily say that my issue seems to be solved. It is 24hrs now, with a stellar connection and zero event logs. The tech came out last night 7pm and worked on it. He couldn't find any issues with the tap and confirmed with the local station that the connection looked good. He even checked my neighbors history and it was running 9 days. He simply changed my cable line to a new terminal on the tap and voila! Issue resolved Smiley Happy 

 

*** Just a heads up for people struggling with intermittent connection and comcast techs say everything should be working. Have them test a different terminal on the tap if one is available becuase the current one may just barely be functioning. ****

Frequent Visitor

Re: Trouble Isolating Connection Issue

So about 6 or 7 houses down from mine is this mess. Not sure if it causing the issues but it sure doesn't look safe. I'll be notifying the tech about this once he comes.

 

20180220_170915 (2).jpg
Diamond Problem Solver

Re: Trouble Isolating Connection Issue

They are o/k. You could try asking for a tier 2 rep.

Frequent Visitor

Re: Trouble Isolating Connection Issue

Alright so I just got off the phone with comcast. Here is what they were able to provide me:

 

Upstream Rx Power .-4

 

Upstream SNR          31.3

 

Upstream ICFR        N/A

 

Tier 1 support said they did not have access to ICFR, transferred to advanced tech support.. The guy seemed really annoyed and said they don't have the upstream ICFR and only a technician can validate it. Hopefully, the other two numbers can help!

Frequent Visitor

Re: Trouble Isolating Connection Issue

Okay, I will do that and see what they say and report back.

Diamond Problem Solver

Re: Trouble Isolating Connection Issue

The stats as read at the modem level at that moment in time were o/k but there are three additional signal stats that can cause the issue which can't be read by the modem. They can only be read from their end by them polling the CMTS (Cable Modem Termination System) at the local headend facility.

They are the "Upstream Rx Power" (Upstream Receive Power Level), the "Upstream SNR Ch." (Upstream Signal To Noise Ratio), and the "Upstream ICFR" (In Channel Frequency Response). These are as equally important in diagnosing connectivity issues as are the modem's stats.

You can call in and ask what these figures are. The Upstream Receive Power Level should fall within the range of -2dB to +2dB with 0dB being in the middle and perfect.

The Upstream SNR should be least 31dB, and the higher it is the better.

The ICFR should be no higher than 2 dB.

You could have an intermittent noise ingress issue in only the upstream channel(s) / return path only somewhere.

They will be able to see whether or not everything is in the green zone and also see a history plot for the modem.


Frequent Visitor

Trouble Isolating Connection Issue

I've been dealing with horrible connection issues since I've started using Xfinity for internet (2months). Both the wifi and ethernet will drop numerous times throughout the day, and my event logs are always flooded with T3's and some T4's. This issue has persisted over two different modems TP Link Archer CR500 and my current Netgear C7100v. By now I have spent hours on the phone with both comcast and netgear support, but of course they just reset the modem and call the problem solved. This weekend I did have a comcast tech come to the house he said the signal looked okay and updated the firmware. I really hope that someone on here can help solve this issue because it is driving me crazy!

 

Stats:

Show Statistics

 
System Up Time      14:08:28
Port Status TxPkts RxPkts Collisions Tx B/s Rx B/s Up Time
WAN Link Up 284174 1147529 5126 100238720 1475604758 0:04:20
LAN1 100M/Full 25021 23072 0 18860496 13987712 14:08:28
LAN2 Link Down 14:08:28
LAN3 Link Down 14:08:28
LAN4 Link Down 14:08:28
WLAN 289 M 9064 103472 0 23047450 23978632 14:08:28
WLAN 1300 M 85894 175063 0 53945944 35945770 14:08:28

 

*****The WAN seems to always drop but the others stay connected*****

 

 

 

 

Frequency start Value
This field below allows you to modify the frequency the cable modem start with its scan during initialization and registration. Enter the new start frequency and restart the cable modem for it to take effect.
Starting Frequency

<tabindex=-1>Startup Procedure
Procedure Status Comment
Acquire Downstream Channel 615000000 Hz Locked
Connectivity State OK Operational
Boot State OK Operational
Configuration File OK ------------
Security Enable BPI+

<tabindex=-1>Downstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power SNR Correctables Uncorrectables
1 Locked QAM256 17 615000000 Hz 3.3 dBmV 39.8 dB 352 513
2 Locked QAM256 1 513000000 Hz 3.6 dBmV 40.3 dB 456 396
3 Locked QAM256 2 519000000 Hz 3.8 dBmV 40.4 dB 365 369
4 Locked QAM256 3 525000000 Hz 3.6 dBmV 40.2 dB 452 298
5 Locked QAM256 4 531000000 Hz 3.3 dBmV 40.2 dB 374 431
6 Locked QAM256 5 537000000 Hz 3.2 dBmV 40.1 dB 418 304
7 Locked QAM256 6 543000000 Hz 3.2 dBmV 40.1 dB 449 511
8 Locked QAM256 7 555000000 Hz 3.4 dBmV 40.1 dB 358 328
9 Locked QAM256 8 561000000 Hz 3.3 dBmV 39.8 dB 396 398
10 Locked QAM256 9 567000000 Hz 3.0 dBmV 39.8 dB 419 421
11 Locked QAM256 10 573000000 Hz 3.0 dBmV 39.9 dB 403 405
12 Locked QAM256 11 579000000 Hz 3.4 dBmV 40.0 dB 383 390
13 Locked QAM256 12 585000000 Hz 3.4 dBmV 40.0 dB 332 365
14 Locked QAM256 13 591000000 Hz 3.4 dBmV 39.9 dB 375 351
15 Locked QAM256 14 597000000 Hz 3.1 dBmV 39.8 dB 373 452
16 Locked QAM256 15 603000000 Hz 3.2 dBmV 39.8 dB 314 338
17 Locked QAM256 16 609000000 Hz 3.2 dBmV 40.8 dB 0 0
18 Locked QAM256 18 621000000 Hz 2.9 dBmV 40.3 dB 0 0
19 Locked QAM256 19 627000000 Hz 2.5 dBmV 39.9 dB 0 0
20 Locked QAM256 20 633000000 Hz 2.3 dBmV 39.9 dB 0 0
21 Locked QAM256 21 639000000 Hz 2.7 dBmV 40.0 dB 0 0
22 Locked QAM256 22 645000000 Hz 2.4 dBmV 39.9 dB 0 0
23 Locked QAM256 23 651000000 Hz 2.4 dBmV 39.9 dB 0 0
24 Locked QAM256 24 657000000 Hz 1.9 dBmV 39.4 dB 0 0

<tabindex=-1>Upstream Bonded Channels
Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
1 Locked ATDMA 69 5120 Ksym/sec 35800000 Hz 40.8 dBmV
2 Locked ATDMA 70 5120 Ksym/sec 29400000 Hz 42.0 dBmV
3 Locked ATDMA 71 5120 Ksym/sec 23000000 Hz 43.0 dBmV
4 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
5 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
6 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
7 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
8 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV

Current System Time: Mon Feb 19 13:26:55 2018 

 

Time Priority Description
2018-02-19, 13:19:53.0 Notice (6) Honoring MDD; IP provisioning mode = IPv6
2018-02-19, 13:19:40.0 Critical (3) No Ranging Response received - T3 time-out;CM-MAC=b0:b9:8a:d7:19:b0;CMTS-MAC=00:01:5c:82:e2:62;CM-QOS=1.0;CM-VER=3.0;
2018-02-19, 13:19:22.0 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=b0:b9:8a:d7:19:b0;CMTS-MAC=00:01:5c:82:e2:62;CM-QOS=1.1;CM-VER=3.0;
2018-02-19, 13:15:02.0 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=b0:b9:8a:d7:19:b0;CMTS-MAC=00:01:5c:82:e2:62;CM-QOS=1.1;CM-VER=3.0;
2018-02-19, 13:12:07.0 Notice (6) Honoring MDD; IP provisioning mode = IPv6
2018-02-19, 13:11:55.0 Critical (3) No Ranging Response received - T3 time-out;CM-MAC=b0:b9:8a:d7:19:b0;CMTS-MAC=00:01:5c:82:e2:62;CM-QOS=1.0;CM-VER=3.0;
2018-02-19, 13:11:36.0 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=b0:b9:8a:d7:19:b0;CMTS-MAC=00:01:5c:82:e2:62;CM-QOS=1.1;CM-VER=3.0;
2018-02-19, 13:07:16.0 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=b0:b9:8a:d7:19:b0;CMTS-MAC=00:01:5c:82:e2:62;CM-QOS=1.1;CM-VER=3.0;
2018-02-19, 13:00:27.0 Critical (3) SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=b0:b9:8a:d7:19:b0;CMTS-MAC=00:01:5c:82:e2:62;CM-QOS=1.1;CM-VER=3.0;
2018-02-19, 13:00:11.0 Notice (6) Honoring MDD; IP provisioning mode = IPv6
2018-02-19, 13:00:02.0 Critical (3) No Ranging Response received - T3 time-out;CM-MAC=b0:b9:8a:d7:19:b0;CMTS-MAC=00:01:5c:82:e2:62;CM-QOS=1.0;CM-VER=3.0;
2018-02-19, 12:59:43.0 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=b0:b9:8a:d7:19:b0;CMTS-MAC=00:01:5c:82:e2:62;CM-QOS=1.1;CM-VER=3.0;
2018-02-19, 12:55:23.0 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=b0:b9:8a:d7:19:b0;CMTS-MAC=00:01:5c:82:e2:62;CM-QOS=1.1;CM-VER=3.0;
2018-02-19, 12:54:52.0 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=b0:b9:8a:d7:19:b0;CMTS-MAC=00:01:5c:82:e2:62;CM-QOS=1.1;CM-VER=3.0;
2018-02-19, 12:54:52.0 Critical (3) Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=b0:b9:8a:d7:19:b0;CMTS-MAC=00:01:5c:82:e2:62;CM-QOS=1.1;CM-VER=3.0;
2018-02-19, 12:54:52.0 Critical (3) 16 consecutive T3 timeouts while trying to range on upstream channel 2;CM-MAC=b0:b9:8a:d7:19:b0;CMTS-MAC=00:01:5c:82:e2:62;CM-QOS=1.1;CM-VER=3.0;
2018-02-19, 12:23:01.0 Notice (6) Honoring MDD; IP provisioning mode = IPv6
2018-02-19, 12:22:37.0 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=b0:b9:8a:d7:19:b0;CMTS-MAC=00:01:5c:82:e2:62;CM-QOS=1.1;CM-VER=3.0;
2018-02-19, 12:18:17.0 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=b0:b9:8a:d7:19:b0;CMTS-MAC=00:01:5c:82:e2:62;CM-QOS=1.1;CM-VER=3.0;
2018-02-19, 11:23:29.0 Notice (6) Honoring MDD; IP provisioning mode = IPv6
2018-02-19, 11:22:59.0 Critical (3) No Ranging Response received - T3 time-out;CM-MAC=b0:b9:8a:d7:19:b0;CMTS-MAC=00:01:5c:82:e2:62;CM-QOS=1.0;CM-VER=3.0;
2018-02-19, 11:22:32.0 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=b0:b9:8a:d7:19:b0;CMTS-MAC=00:01:5c:82:e2:62;CM-QOS=1.1;CM-VER=3.0;
2018-02-19, 11:18:12.0 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=b0:b9:8a:d7:19:b0;CMTS-MAC=00:01:5c:82:e2:62;CM-QOS=1.1;CM-VER=3.0;
2018-02-19, 11:02:13.0 Notice (6) Honoring MDD; IP provisioning mode = IPv6
2018-02-19, 11:02:05.0 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=b0:b9:8a:d7:19:b0;CMTS-MAC=00:01:5c:82:e2:62;CM-QOS=1.0;CM-VER=3.0;
2018-02-19, 11:01:59.0 Critical (3) No Ranging Response received - T3 time-out;CM-MAC=b0:b9:8a:d7:19:b0;CMTS-MAC=00:01:5c:82:e2:62;CM-QOS=1.0;CM-VER=3.0;
2018-02-19, 11:01:43.0 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=b0:b9:8a:d7:19:b0;CMTS-MAC=00:01:5c:82:e2:62;CM-QOS=1.1;CM-VER=3.0;
2018-02-19, 10:57:23.0 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=b0:b9:8a:d7:19:b0;CMTS-MAC=00:01:5c:82:e2:62;CM-QOS=1.1;CM-VER=3.0;
2018-02-19, 10:57:06.0 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=b0:b9:8a:d7:19:b0;CMTS-MAC=00:01:5c:82:e2:62;CM-QOS=1.1;CM-VER=3.0;
2018-02-19, 10:57:06.0 Critical (3) Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=b0:b9:8a:d7:19:b0;CMTS-MAC=00:01:5c:82:e2:62;CM-QOS=1.1;CM-VER=3.0;
2018-02-19, 10:57:06.0 Critical (3) 16 consecutive T3 timeouts while trying to range on upstream channel 0;CM-MAC=b0:b9:8a:d7:19:b0;CMTS-MAC=00:01:5c:82:e2:62;CM-QOS=1.1;CM-VER=3.0;
2018-02-19, 10:11:25.0 Notice (6) Honoring MDD; IP provisioning mode = IPv6
2018-02-19, 10:11:21.0 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=b0:b9:8a:d7:19:b0;CMTS-MAC=00:01:5c:82:e2:62;CM-QOS=1.0;CM-VER=3.0;
2018-02-19, 10:11:04.0 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=b0:b9:8a:d7:19:b0;CMTS-MAC=00:01:5c:82:e2:62;CM-QOS=1.1;CM-VER=3.0;
2018-02-19, 10:06:44.0 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=b0:b9:8a:d7:19:b0;CMTS-MAC=00:01:5c:82:e2:62;CM-QOS=1.1;CM-VER=3.0;
2018-02-19, 08:50:47.0 Notice (6) Honoring MDD; IP provisioning mode = IPv6
2018-02-19, 08:50:37.0 Critical (3) No Ranging Response received - T3 time-out;CM-MAC=b0:b9:8a:d7:19:b0;CMTS-MAC=00:01:5c:82:e2:62;CM-QOS=1.0;CM-VER=3.0;
2018-02-19, 08:50:22.0 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=b0:b9:8a:d7:19:b0;CMTS-MAC=00:01:5c:82:e2:62;CM-QOS=1.1;CM-VER=3.0;
2018-02-19, 08:46:02.0 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=b0:b9:8a:d7:19:b0;CMTS-MAC=00:01:5c:82:e2:62;CM-QOS=1.1;CM-VER=3.0;
2018-02-19, 08:41:46.0 Notice (6) Honoring MDD; IP provisioning mode = IPv6

 

I really can't wrap my head around why both modems are having issues. As far as I can tell my levels look fairly good. Let me know if you have any ideas to remedy this. Thank you!