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Poor download speeds, and packet loss

New Poster

Poor download speeds, and packet loss

Hi,

 

For the last month or so I've experienced poor download speeds and significant packet loss. (I was away most of the time so could debug it only now).

 

The steps that I have done.

1) Rebooted my modem (waited for a minute before plugging it it)

2) Connected directly to my modem via wire (i.e. without Wifi and without the router).

3) Ran the xfinity speedtest and I am getting download speeds of 10 mbps (while i should be getting ~ 150).

http://speedtest.xfinity.com/results/JQOGQAS1T5Z2CG0
An interesting twist that I noticed that immediately after the reboot of the modem I did get the 170mbps on the speedtest, but on the 2nd or 3rd run I'm getting 10mbps.

4) I checked my modem connection parameters, and as far as I can see everything looks fine.

 

---------------------------

Procedure Status Comment
Acquire Downstream Channel 663000000 Hz Locked
Connectivity State Ok Operational
Boot State -- --
Configuration File -- --
Security Enabled BPI+
IP Provisioning Mode Honor MDD honorMdd(4)

====================
Downstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power SNR Correctables UnCorrectables
1 Locked QAM 256 25 627000000 Hz 1.1 dBmV 37.6 dB 21 1192
2 Locked QAM 256 26 633000000 Hz 0.7 dBmV 37.9 dB 24 2998
3 Locked QAM 256 27 639000000 Hz 0.5 dBmV 37.9 dB 25 3032
4 Locked QAM 256 28 645000000 Hz 0.8 dBmV 37.6 dB 67 2266
5 Locked QAM 256 29 651000000 Hz 1.1 dBmV 38.2 dB 32 2941
6 Locked QAM 256 22 657000000 Hz -1.9 dBmV 36.6 dB 116 3245
7 Locked QAM 256 31 663000000 Hz 1.3 dBmV 38.2 dB 38 3075
8 Locked QAM 256 32 669000000 Hz 0.3 dBmV 38.2 dB 66 2077

===================
Upstream Bonded Channels
Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
1 Locked ATDMA 4 5120 Ksym/sec 17300000 Hz 39.8 dBmV
2 Locked ATDMA 3 5120 Ksym/sec 23700000 Hz 39.8 dBmV
3 Locked ATDMA 2 5120 Ksym/sec 30100000 Hz 39.0 dBmV
4 Locked ATDMA 1 5120 Ksym/sec 36500000 Hz 38.3 dBmV

5) I checked the modem log 

 

Dec 13 01:10:43 2018 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out
Dec 13 01:12:04 2018 Warning (5) MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1
Dec 13 01:13:17 2018 Critical (3) No Ranging Response received - T3 time-out
Dec 13 23:32:53 2018 Warning (5) MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1
Dec 14 06:10:45 2018 Critical (3) No Ranging Response received - T3 time-out
Dec 14 21:35:41 2018 Warning (5) MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1
Time Not Established Critical (3) No Ranging Response received - T3 time-out
Dec 14 21:46:27 2018 Warning (5) MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1
Dec 29 13:08:15 2018 Critical (3) No Ranging Response received - T3 time-out
Dec 31 14:05:10 2018 Warning (5) MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1
Jan 1 00:57:47 2019 Critical (3) No Ranging Response received - T3 time-out
Jan 7 20:45:28 2019 Warning (5) MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1

==========

and it seems benign.

 

6) I checked the traceroute and ping to some public servers (www.google.com)

and I am consistently getting packet loss of 5-15%

Here are ping results:

--- 172.217.15.100 ping statistics ---
87 packets transmitted, 74 received, 14% packet loss, time 85953ms
rtt min/avg/max/mdev = 16.743/21.194/38.712/6.034 ms

Here is the traceroute:
traceroute to 172.217.15.100 (172.217.15.100), 30 hops max, 60 byte packets
1 96.120.62.169 (96.120.62.169) 13.365 ms 13.213 ms 13.169 ms
2 te-0-4-0-11-sur01.pittsburgh.pa.pitt.comcast.net (68.86.102.57) 12.916 ms 14.473 ms 14.459 ms
3 162.151.152.210 (162.151.152.210) 12.773 ms 12.673 ms 12.537 ms
4 162.151.65.5 (162.151.65.5) 14.501 ms 14.136 ms *
5 be-7016-cr02.ashburn.va.ibone.comcast.net (68.86.91.25) 37.356 ms 38.256 ms 38.275 ms
6 be-10189-pe07.ashburn.va.ibone.comcast.net (68.86.83.66) 37.221 ms 26.060 ms 25.989 ms
7 96-87-9-174-static.hfc.comcastbusiness.net (96.87.9.174) 25.922 ms 25.922 ms 50.248.116.190 (50.248.116.190) 17.412 ms
8 * * *
9 iad30s21-in-f4.1e100.net (172.217.15.100) 16.931 ms 216.239.54.104 (216.239.54.104) 16.949 ms 209.85.251.82 (209.85.251.82) 17.747 ms

7) I also checked the wire connection from my modem to the wall and there are no twists or obvious damage to the wire.

8) My modem is netgear cm400

9) While I show the measurements from today, I've seen the same problem (packet loss and slow download speed) before (i.e. yesterday and end of december) 

 

Thanks,  

        Sergey

New Poster

Re: Poor download speeds, and packet loss

Is this standard policy for Comcast to just ignore reports with problems ? I've just got from work, and my internet shows this again --- 8.8.8.8 ping statistics --- 73 packets transmitted, 24 received, 67% packet loss, time 73130ms rtt min/avg/max/mdev = 17.802/27.619/40.660/8.226 ms and speedtest shows download speed of 2mbps...
Official Employee

Re: Poor download speeds, and packet loss

Hello segasai. Welcome to the Xfinity Forums and thank you for creating your first post. I can assist with troubleshooting your internet speed issue and packet loss. To get started, please send me a private message and include your full name so I can assist you. To send me a private, message click my name (ComcastJoeTru) to view my profile. Then click "Send a message" and private message me. 
 


I am an Official Comcast Employee.
Official Employees are from multiple teams within Comcast: CARE, Product, Leadership. We ask that you post publicly so people with similar questions may benefit from the conversation.
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Official Employee

Re: Poor download speeds, and packet loss

Hi segasai. Since we didn't see a response from you on this,  this thread has been locked. Please don't hesitate to send me a private message if you continue to need help with this issue, or create a new post if you need assistance with anything else. Thank you.


I am an Official Comcast Employee.
Official Employees are from multiple teams within Comcast: CARE, Product, Leadership. 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!