Community Forum

Seeing packet loss regularly

Highlighted
New Poster

Seeing packet loss regularly

Hello,

I've been experiencing regular packet loss for the past week.  Typically seeing ~10% loss, but seen up to 60%.


This all began after my neighborhood had an 18hour internet outage.  Prior to that outage, I had no issues.

My troubleshooting so far has been:

  • Hours on the phone + chat support with agents.   Plenty of modem power cycles, reboots, and "signals". 
  • Directly connecting computer to modem (removing wireless router from equation.)

My test is to traceroute google.com.  With that I find the first connection is to a 96.120.4.113.  If I ping that IP, I see 

--- 96.120.4.113 ping statistics ---
131 packets transmitted, 116 packets received, 11.5% packet loss
round-trip min/avg/max/stddev = 9.640/14.861/45.132/5.694 ms

Does anyone have any suggestions on how to further troubleshoot this?  

 

Thanks

Highlighted
Expert

Re: Seeing packet loss regularly

What do the modem's signal stats look like ? Try getting them here http://192.168.100.1 or here http://10.0.0.1

Please post the *Downstream Power Level*, the *Upstream Power Level*, and the *SNR* (Signal to Noise Ratio) numbers.

What is the exact make and model number of the modem ?

Is this with a WiFi connection ?



I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Mark the post as Best Answer!
Highlighted
New Poster

Re: Seeing packet loss regularly

Downstream

Downstream Bonding Channel Value
Channel ID 25  26  27  28 
Frequency 627000000 Hz  633000000 Hz  639000000 Hz  645000000 Hz 
Signal to Noise Ratio 35 dB  35 dB  36 dB  36 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
-8 dBmV   -8 dBmV   -8 dBmV   -7 dBmV  

Upstream

Upstream Bonding Channel Value
Channel ID
Frequency 35600000 Hz  16400000 Hz  22800000 Hz  29200000 Hz 
Ranging Service ID 13949  13949  13949  13949 
Symbol Rate 5.120 Msym/sec  5.120 Msym/sec  5.120 Msym/sec  5.120 Msym/sec 
Power Level 47 dBmV  45 dBmV  46 dBmV  48 dBmV 
Upstream Modulation [2] QPSK
[1] 32QAM
[3] 64QAM
 
[2] QPSK
[1] 32QAM
[3] 64QAM
 
[2] QPSK
[1] 32QAM
[3] 64QAM
 
[2] QPSK
[1] 32QAM
[3] 64QAM
 
Ranging Status Success  Success  Success  Success 

Signal Status

Signal Status (Codewords) Bonding Channel Value
Channel ID 25  26  27  28 
Total Unerrored Codewords 484497309  481561350  481560755  481560923 
Total Correctable Codewords 192  139  125  120 
Total Uncorrectable Codewords 729  727  1457  1436 

Model Name: SB6121
Vendor Name: ARRIS Group, Inc.

Highlighted
New Poster

Re: Seeing packet loss regularly

I also just saw in the modem logs from 1 minute ago
Jul 16 2020 16:01:54 3-Critical R02.0 No Ranging Response received - T3 time-out;

Highlighted
Expert

Re: Seeing packet loss regularly

You didn't answer the questions.. This may not be the direct cause of the problem but it should be addressed regardless.

 

The downstream power is on the low / weak side and it may be intermittently fluctuating even lower to out of spec levels. That can cause random disconnects, spontaneous re-booting of the modem, speed, packet loss, latency problems, and the un-bonding of channels.

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.

 

Good luck !



I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Mark the post as Best Answer!