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Intermittent lag spikes - what do?

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Intermittent lag spikes - what do?

edit: Logs from modem attached at the bottom.

 

Here you can see pingplotter against www.comcast.net, 8.8.8.8 and 1.1.1.1. An incredible amount of packet loss.

  • 37ms aveage latency to the closest Comcast gateway (the hop after the modem). About 1% packet loss.
  • po-109-rur101.bellevue.wa.seattle.comcast.net / 68.87.206.121 is the second hop in all traces, and here we see an average of 30-37ms and 1.5% packet loss.
  • The problem seems to start with be-103-ar01.seattle.wa.seattle.comcast.net / 69.139.164.77 which brings the packet loss up to around 15%, 

ping-1.1.1.1.PNGping-8.8.8.8.PNGpingplotter-comcast.PNGping-comcast.net.PNG

 

Hi,

 

I'm experiencing consistent lag spikes making it pretty much impossible to play any online games, as they kick you out when they see 250ms+ ping. Sometimes it works fine for 15 minutes, others just a couple of minutes. The spikes happen regardless of the target, even pinging a DNS server (see below) sees the spikes.

 

Is there anything that can be done? I have restarted Google WiFi, and power cycled the modem twice. Also made sure no one else is doing anything else on the network while testing.

 

Equipment:

Modem - MOTOROLA SB6183

WiFi router - Google Wifi (2x, mesh)

Internet service - "Performance Pro Tier"

 

From the traceroute results below, I find it really strange that a) the latency between my modem and the gateway is so high, and b) that the 3rd Comcast gateway spikes so high.

 

2 12 ms 18 ms 11 ms 96.120.101.157 <------ first gateway, almost 20ms!
3 130 ms 10 ms 119 ms po-109-rur101.bellevue.wa.seattle.comcast.net [68.87.206.121] <------ 3rd gateway, spikes seen here

 

 

 

ping -t 8.8.8.8

Pinging 8.8.8.8 with 32 bytes of data:
Reply from 8.8.8.8: bytes=32 time=14ms TTL=121
Reply from 8.8.8.8: bytes=32 time=20ms TTL=121
Reply from 8.8.8.8: bytes=32 time=12ms TTL=121
Reply from 8.8.8.8: bytes=32 time=30ms TTL=121
Reply from 8.8.8.8: bytes=32 time=99ms TTL=121
Reply from 8.8.8.8: bytes=32 time=18ms TTL=121
Reply from 8.8.8.8: bytes=32 time=12ms TTL=121
Reply from 8.8.8.8: bytes=32 time=22ms TTL=121
Reply from 8.8.8.8: bytes=32 time=14ms TTL=121
Reply from 8.8.8.8: bytes=32 time=12ms TTL=121
Reply from 8.8.8.8: bytes=32 time=14ms TTL=121
Reply from 8.8.8.8: bytes=32 time=12ms TTL=121
Reply from 8.8.8.8: bytes=32 time=13ms TTL=121
Reply from 8.8.8.8: bytes=32 time=139ms TTL=121
Reply from 8.8.8.8: bytes=32 time=56ms TTL=121
Reply from 8.8.8.8: bytes=32 time=110ms TTL=121
Reply from 8.8.8.8: bytes=32 time=13ms TTL=121
Reply from 8.8.8.8: bytes=32 time=12ms TTL=121
Reply from 8.8.8.8: bytes=32 time=14ms TTL=121
Reply from 8.8.8.8: bytes=32 time=17ms TTL=121
Reply from 8.8.8.8: bytes=32 time=16ms TTL=121
Reply from 8.8.8.8: bytes=32 time=14ms TTL=121
Reply from 8.8.8.8: bytes=32 time=13ms TTL=121
Reply from 8.8.8.8: bytes=32 time=12ms TTL=121
Reply from 8.8.8.8: bytes=32 time=16ms TTL=121
Reply from 8.8.8.8: bytes=32 time=91ms TTL=121
Reply from 8.8.8.8: bytes=32 time=13ms TTL=121
Reply from 8.8.8.8: bytes=32 time=14ms TTL=121
Reply from 8.8.8.8: bytes=32 time=14ms TTL=121
Reply from 8.8.8.8: bytes=32 time=18ms TTL=121
Reply from 8.8.8.8: bytes=32 time=24ms TTL=121
Reply from 8.8.8.8: bytes=32 time=16ms TTL=121
Reply from 8.8.8.8: bytes=32 time=17ms TTL=121
Reply from 8.8.8.8: bytes=32 time=56ms TTL=121
Reply from 8.8.8.8: bytes=32 time=109ms TTL=121
Reply from 8.8.8.8: bytes=32 time=30ms TTL=121
Reply from 8.8.8.8: bytes=32 time=13ms TTL=121
Reply from 8.8.8.8: bytes=32 time=14ms TTL=121
Reply from 8.8.8.8: bytes=32 time=12ms TTL=121
Reply from 8.8.8.8: bytes=32 time=20ms TTL=121
Reply from 8.8.8.8: bytes=32 time=17ms TTL=121
Reply from 8.8.8.8: bytes=32 time=16ms TTL=121
Reply from 8.8.8.8: bytes=32 time=13ms TTL=121

Ping statistics for 8.8.8.8:
Packets: Sent = 43, Received = 43, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 12ms, Maximum = 139ms, Average = 28ms
Control-C
^C

tracert 8.8.8.8 Tracing route to google-public-dns-a.google.com [8.8.8.8] over a maximum of 30 hops: 1 121 ms 1 ms 2 ms 192.168.1.1 2 12 ms 18 ms 11 ms 96.120.101.157 3 130 ms 10 ms 119 ms po-109-rur101.bellevue.wa.seattle.comcast.net [68.87.206.121] 4 11 ms 10 ms 11 ms po-2-rur102.bellevue.wa.seattle.comcast.net [69.139.160.26] 5 16 ms 21 ms 15 ms be-103-ar01.seattle.wa.seattle.comcast.net [69.139.164.77] 6 14 ms 14 ms 16 ms be-33650-cr01.seattle.wa.ibone.comcast.net [68.86.93.165] 7 13 ms 13 ms 13 ms be-10846-pe01.seattle.wa.ibone.comcast.net [68.86.86.90] 8 13 ms 20 ms 15 ms 50.242.150.242 9 183 ms 20 ms 15 ms 108.170.245.97 10 13 ms 18 ms 17 ms 108.170.237.201 11 15 ms 12 ms 14 ms google-public-dns-a.google.com [8.8.8.8]

 

Modem logs:

 

Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Sun Jan 06 12:40:11 2019	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=d4:04:cd:98:36:64;CMTS-MAC=00:59:dc:79:a5:5d;CM-QOS=1.1;CM-VER=3.0;
Sun Jan 06 12:42:21 2019	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=d4:04:cd:98:36:64;CMTS-MAC=00:59:dc:79:a5:5d;CM-QOS=1.1;CM-VER=3.0;
Sun Jan 06 12:44:34 2019	Critical (3)	No Ranging Response received - T3 time-out
Sun Jan 06 12:59:53 2019	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=d4:04:cd:98:36:64;CMTS-MAC=00:59:dc:79:a5:5d;CM-QOS=1.1;CM-VER=3.0;
Sun Jan 06 13:02:03 2019	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=d4:04:cd:98:36:64;CMTS-MAC=00:59:dc:79:a5:5d;CM-QOS=1.1;CM-VER=3.0;
Sun Jan 06 13:03:06 2019	Critical (3)	No Ranging Response received - T3 time-out
Sun Jan 06 16:29:08 2019	Critical (3)	No Ranging Response received - T3 time-out
Sun Jan 06 16:37:30 2019	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=d4:04:cd:98:36:64;CMTS-MAC=00:59:dc:79:a5:5d;CM-QOS=1.1;CM-VER=3.0;
Sun Jan 06 16:39:40 2019	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=d4:04:cd:98:36:64;CMTS-MAC=00:59:dc:79:a5:5d;CM-QOS=1.1;CM-VER=3.0;
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Notice (6)	Honoring MDD; IP provisioning mode = IPv6
Tue Feb 26 14:12:02 2019	Warning (5)	Unicast DSID PSN startup error

Modem information:

 

Information
Standard Specification Compliant	DOCSIS 3.0
Hardware Version	1
Software Version	D30CM-OSPREY-2.4.0.0-GA-03-NOSH
Cable Modem MAC Address	d4:04:cd:98:36:64
Serial Number	393383730401174210172333
Status
Up Time	0 days 08h:50m:27s

Modem startup procedure

 

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

Modem download/upload channels

 

Downstream Bonded Channels
Channel	Lock Status	Modulation	Channel ID	Frequency	Power	SNR	Corrected	Uncorrectables
1	Locked	QAM256	21	615000000 Hz	-2.8 dBmV	36.9 dB	8	0
2	Locked	QAM256	16	585000000 Hz	-2.8 dBmV	37.0 dB	0	0
3	Locked	QAM256	17	591000000 Hz	-2.0 dBmV	37.2 dB	1	0
4	Locked	QAM256	18	597000000 Hz	-1.7 dBmV	37.2 dB	3	0
5	Locked	QAM256	19	603000000 Hz	-1.8 dBmV	37.1 dB	2	0
6	Locked	QAM256	20	609000000 Hz	-2.3 dBmV	37.0 dB	7	0
7	Locked	QAM256	22	621000000 Hz	-3.2 dBmV	36.9 dB	4	0
8	Locked	QAM256	23	627000000 Hz	-3.6 dBmV	36.8 dB	4	0
9	Locked	QAM256	24	633000000 Hz	-4.1 dBmV	36.6 dB	13	0
10	Locked	QAM256	25	639000000 Hz	-4.8 dBmV	36.4 dB	19	0
11	Locked	QAM256	26	645000000 Hz	-5.1 dBmV	36.3 dB	17	0
12	Locked	QAM256	27	651000000 Hz	-5.1 dBmV	36.4 dB	29	0
13	Locked	QAM256	28	657000000 Hz	-4.8 dBmV	36.5 dB	19	0
14	Locked	QAM256	29	663000000 Hz	-4.5 dBmV	36.5 dB	27	0
15	Locked	QAM256	30	669000000 Hz	-3.8 dBmV	36.6 dB	10	0
16	Locked	QAM256	31	675000000 Hz	-3.3 dBmV	36.5 dB	21	0

Upstream Bonded Channels
Channel	Lock Status	US Channel Type	Channel ID	Symbol Rate	Frequency	Power
1	Locked	ATDMA	4	5120 Ksym/sec	23700000 Hz	43.3 dBmV
2	Locked	ATDMA	1	5120 Ksym/sec	30100000 Hz	43.3 dBmV
3	Locked	ATDMA	2	5120 Ksym/sec	36500000 Hz	43.3 dBmV
4	Locked	ATDMA	3	5120 Ksym/sec	17300000 Hz	43.3 dBmV

 

Frequent Visitor

Re: Intermittent lag spikes - what do?

I can't answer your question about the latency issue, but I feel your pain as I had to delve into the world of DOCSIS specifications when I expereienced a signal quality issue due to an unterminated port on a splitter. Your zero number of "uncorrectable" errors over what appears to be a month or so, along with your acceptable signal and SNR levels indicate that this is not a problem with the cable modem or it's connection to the system. It's likely an issue on your home network.

Frequent Visitor

Re: Intermittent lag spikes - what do?

I just went back and looked at your stats again, and it appears the uptime was actually only about eight hours. You're getting a few more "correctables" in that period of time than I'm seeing, so if you start seeing "uncorrectables" (which is a condition that will throw you out of sync when gaming) than it could be some corrosion beginning to form at a connection.

 

"Correctables" are OK. If you continue to see them coming in at a consistent rate, than thats what error correction is for, and the rate at which they accumulate is going to vary with the SNR of the system; in fact they are a certainty and their probability of occuring within a certain time is mathmatically proportional to the SNR.

 

 

Highlighted
Expert

Re: Intermittent lag spikes - what do?


@milwire3 wrote:

 Your zero number of "uncorrectable" errors over what appears to be a month or so, along with your acceptable signal and SNR levels indicate that this is not a problem with the cable modem or it's connection to the system. It's likely an issue on your home network.


FWIW, there are three additional signal stats which can't be read by the modem. These are equally important to troubleshooting. 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.

There could be 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.




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