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Dropped packets and T3 Timeouts reported in modem logs

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heimdal
Occasional Visitor

Dropped packets and T3 Timeouts reported in modem logs

I'm seeing packet loss on my Business cable internet connection. I think it may only be outbound packets.

 

I actually work at a location with Comcast fibre. Atttempting continuous pings from that location to the home system shows packet loss at varying rates.

 

On the home system, running a tcpdump while pinging from the Comcast Fibre location, I see all pings coming into the system in order and all responses going out. There are no indications that inbound packets are lost.

 

On the other end, I see some dropped response packets and those that make it through are not in order. It's as if something on the upstream side of my connection is the issue, not the downstream side.

 

This is happening even when bandwidth is minimal (less than 2kbps).

 

I have powecycled the Comcast modem and the network equipment behind it.

 

From my Modem, all the stats I can see look good.

 

Downstream power level ranges between -4.4 and -0.6 dBmV

Downstream SNR 38.605 and 40.366 dB

Upstream Power level 51.250 and 51.750 dBmV

Cannot find my Upstream SNR.


However, the event logs show frequent T3 timeouts:

 

2019/3/18 13:16:00 Critical [Docsis][563]: No Ranging Response received - T3 time-out
2019/3/18 13:14:05 Critical [Docsis][563]: No Ranging Response received - T3 time-out
2019/3/18 13:14:03 Critical [Docsis][563]: No Ranging Response received - T3 time-out
2019/3/18 13:14:02 Critical [Docsis][563]: No Ranging Response received - T3 time-out
2019/3/18 13:00:43 Critical [Docsis][563]: No Ranging Response received - T3 time-out
2019/3/18 13:00:41 Critical [Docsis][563]: No Ranging Response received - T3 time-out
2019/3/18 13:00:40 Critical [Docsis][563]: No Ranging Response received - T3 time-out
2019/3/18 12:54:57 Critical [Docsis][563]: No Ranging Response received - T3 time-out
2019/3/18 12:49:13 Critical [Docsis][563]: No Ranging Response received - T3 time-out
2019/3/18 12:45:48 Critical [Docsis][563]: No Ranging Response received - T3 time-out
2019/3/18 12:43:30 Critical [Docsis][563]: No Ranging Response received - T3 time-out
2019/3/18 12:32:05 Critical [Docsis][563]: No Ranging Response received - T3 time-out
2019/3/18 12:18:45 Critical [Docsis][563]: No Ranging Response received - T3 time-out
2019/3/18 12:18:44 Critical [Docsis][563]: No Ranging Response received - T3 time-out
2019/3/18 12:16:49 Critical [Docsis][563]: No Ranging Response received - T3 time-out
2019/3/18 12:16:48 Critical [Docsis][563]: No Ranging Response received - T3 time-out
2019/3/18 12:16:46 Critical [Docsis][563]: No Ranging Response received - T3 time-out
2019/3/18 12:16:45 Critical [Docsis][563]: No Ranging Response received - T3 time-out
2019/3/18 12:16:44 Critical [Docsis][563]: No Ranging Response received - T3 time-out
2019/3/18 12:09:07 Critical [Docsis][563]: No Ranging Response received - T3 time-out
2019/3/18 12:09:05 Critical [Docsis][563]: No Ranging Response received - T3 time-out

 

From my home system:
>mtr -r -c 1000 <comcast fibre connection>
HOST: <my home system> Loss% Snt Last Avg Best Wrst StDev
1. <router IP> 0.0% 1000 7.2 6.0 1.2 69.4 5.4
2. 96.120.28.<hidden> 3.8% 1000 10.8 18.9 9.4 426.7 17.5
3. po53-rur01.griffith.in.chica 3.0% 1000 16.4 18.2 9.4 100.6 8.7
4. be-173-ar01.area4.il.chicago 2.4% 1000 22.7 24.1 10.7 117.2 9.5
5. be-123-rur02.homewood.il.chi 3.9% 1000 24.5 24.5 12.1 111.3 9.2
6. te-0-0-0-0-sur04.homewood.il 3.6% 1000 21.7 24.7 11.9 110.3 9.5
7. 50-206-170-62-static.hfc.com 3.8% 1000 15.9 25.8 12.5 141.2 10.4
8. <comcast fibre IP> 3.4% 1000 20.6 26.0 13.7 108.6 8.7

 

I can see varying rates of loss at different times.  This one is actually pretty good, but it was soon after a modem cycle if that might actually matter.

Accepted Solution

Re: Dropped packets and T3 Timeouts reported in modem logs

My issue is gone.  I've been working with reps via PMs.  The latest update was

 

  • I just checked the area and it looks like we started working with an issue on the main node your line is connected to yesterday.

 

My problems had started a day before that, but fixing that issue also fixed my issue.

View solution in context
Official Employee

Re: Dropped packets and T3 Timeouts reported in modem logs

Good afternoon, thanks for taking the time to reach out to us and I would love to help. Can you please send a private message with the phone number, full address of the account, and your name? 

heimdal
Occasional Visitor

Re: Dropped packets and T3 Timeouts reported in modem logs

Thanks!

 

PM Sent.

Highlighted
heimdal
Occasional Visitor

Re: Dropped packets and T3 Timeouts reported in modem logs

My issue is gone.  I've been working with reps via PMs.  The latest update was

 

  • I just checked the area and it looks like we started working with an issue on the main node your line is connected to yesterday.

 

My problems had started a day before that, but fixing that issue also fixed my issue.