Intermittent routing issue

Intermittently (usually at least 1 time a day), routing is pretty useless.... I don't know if this is from the local hub being overloaded, or the routers just not able to keep up with the traffic .... Here's some pings/traceroutes.

$ date && ping -q -c 10 75.75.75.75
Sun Nov  7 10:27:04 CST 2021
PING 75.75.75.75 (75.75.75.75): 56 data bytes
--- 75.75.75.75 ping statistics ---
10 packets transmitted, 8 packets received, 20.0% packet loss
round-trip min/avg/max/stddev = 14.562/22.326/41.589/8.478 ms

$ date && ping -q -c 10 75.75.75.75
Sun Nov  7 10:32:13 CST 2021
PING 75.75.75.75 (75.75.75.75): 56 data bytes
--- 75.75.75.75 ping statistics ---
10 packets transmitted, 6 packets received, 40.0% packet loss
round-trip min/avg/max/stddev = 17.049/18.944/22.285/1.601 ms

$ date && ping -q -c 10 75.75.75.75
Sun Nov  7 11:09:02 CST 2021
PING 75.75.75.75 (75.75.75.75): 56 data bytes
--- 75.75.75.75 ping statistics ---
10 packets transmitted, 4 packets received, 60.0% packet loss
round-trip min/avg/max/stddev = 15.123/18.059/20.492/1.996 ms

$ date && traceroute -n 75.75.75.75
Sun Nov  7 10:33:53 CST 2021
traceroute to 75.75.75.75 (75.75.75.75), 64 hops max, 52 byte packets
1  192.168.50.1  0.978 ms  0.553 ms  0.557 ms
2  96.120.29.57  15.550 ms * *
3  * 96.110.154.221  12.423 ms  19.911 ms
4  68.85.176.113  15.153 ms  15.993 ms *
5  * 68.87.210.6  18.345 ms  14.798 ms
6  68.86.188.78  14.954 ms *  14.876 ms
7  75.75.75.75  19.804 ms * *

$ date && traceroute -n 1.1.1.1
Sun Nov  7 10:35:37 CST 2021
traceroute to 1.1.1.1 (1.1.1.1), 64 hops max, 52 byte packets
1  192.168.50.1  2.000 ms  0.637 ms  0.598 ms
2  * 96.120.29.57  12.468 ms *
3  96.110.154.221  10.531 ms *  14.464 ms
4  68.85.176.113  15.933 ms  14.887 ms  15.967 ms
5  96.110.40.49  15.195 ms  16.773 ms *
6  96.110.37.22  19.356 ms * *
7  173.167.56.42  35.340 ms  60.182 ms *
8  141.101.73.18  42.832 ms * *
9  1.1.1.1  19.623 ms  23.751 ms  16.074 ms

So, getting between 20%-60% packet loss, and on the traceroutes, the routers in the path aren't responding. Whenever this is going on the Xfinity Phone App shows it can't talk to my Cable modem.

Rebooting the cable modem doesn't do anything except make it so I have no connection at all for an extended time as I can't get a DHCP response until it magically fixes itself (which can be minutes or a couple hours). Plugging into a machine directly doesn't change anything.

This randomly happens. No explicit reason that I can find, we just have very little connectivity. Connections time out, VPN connections drop because it can't pass the keep alive packet, web requests time out or are extremely slow if a connection can be made.

75.75.75.75 _should_ be a Comcast DNS server so that traffic should be on network. 1.1.1.1 is a public DNS server operated by CloudFlare.

*Edit:* Ugh... This code block keeps resetting to HTML/XML anytime you edit the post messing up the formatting *bangs head*

Responses

BruceW

Gold Problem Solver

•

26.3K Messages

3 years ago

Are you connecting via Wifi or Ethernet? If Wifi, it's best to switch to an Ethernet cable connection if possible for testing. That would allow you to determine whether the problem is the Wifi signal or the link between your modem or gateway and Comcast's network. Network connection problems that affect both Ethernet and Wifi devices are often due to poor coax connections or damaged coax cable, usually in or near your home.

If you want to troubleshoot this yourself, please see Internet Troubleshooting Tips. If you still need help, please post your Internet plan speed and the following information from your modem or gateway:

model number
downstream power levels and SNR
upstream power levels
event log, if available (Be sure to remove or blot out any MAC addresses. Forum security processing considers them "personal information" and may prevent the event log from posting if these are present.)

If you can't find the problem or you'd rather have Comcast take care of it, call them at the phone number on your bill or 1-800-Comcast, or use one of the options on https://www.xfinity.com/support/contact-us/. It's not likely they can fix the problem remotely. If not, insist they send a tech out to identify the cause and correct it.

If the tech finds bad coax, splitters, amplifiers, or connections in your home (even if Comcast originally supplied them) you'll probably have to pay for the visit unless you have their Service Protection Plan ( https://www.xfinity.com/support/articles/service-protection-plan, closed to customers that don't already have it). If the trouble is due to a faulty Comcast rental device or anything outside your home you shouldn't be charged.

mitharus

Frequent Visitor

•

19 Messages

@BruceW

> Are you connecting via Wifi or Ethernet?

Both. I have machines that are hard wired in and others that are on WiFi. Both exhibit the same behavior.

> link between your modem or gateway and Comcast's network.

When we moved into the house we got the cabling checked out, when I needed to find out which of the 3 jacks of the 7 ran were actually live.

> due to poor coax connections or damaged coax cable, usually in or near your home.

*Usually* the connection is fine. But suddenly, routers stop responding to ICMP requests (traceeroute) for ... X amount of time and I have packet loss. They're still passing packets to a point, but some sites cannot be reached or sites that can be reached communicate very slowly. Work VPN connection will drop because it cannot pass the keep alive packet. A packet dump shows I'm sending it and it's leaving the router, but it's never getting to the remote side.

> If not, insist they send a tech out to identify the cause and correct it

It's ... intermittent. I cannot guarantee at any point in time the issue will happen. We've had cables checked. I've checked that the jack on modem/wall didn't work loose. If I reboot the Cable modem when it's happening, it takes an extended amount of time to get a DHCP response.

While typing this up, it all came back to normal.

$ date && traceroute -n 75.75.75.75
Sun Nov  7 12:39:42 CST 2021
traceroute to 75.75.75.75 (75.75.75.75), 64 hops max, 52 byte packets
 1  192.168.50.1  1.032 ms  0.588 ms  0.559 ms
 2  96.120.29.57  13.753 ms  12.078 ms  14.159 ms
 3  96.110.154.221  12.478 ms  12.120 ms  19.786 ms
 4  68.85.176.113  23.207 ms  17.866 ms  17.046 ms
 5  68.87.210.6  14.023 ms  23.883 ms  15.063 ms
 6  68.86.188.78  16.880 ms  15.894 ms  16.249 ms
 7  75.75.75.75  19.917 ms  18.875 ms  19.915 ms

So, it'll be perfectly fine for a while here now... until it's not and we go back to the exact same behavior for however long it takes to correct itself.

3 years ago

mitharus

Frequent Visitor

•

19 Messages

3 years ago

And a couple hrs later....

$ date && traceroute -n 75.75.75.75
Sun Nov  7 12:21:38 CST 2021
traceroute to 75.75.75.75 (75.75.75.75), 64 hops max, 52 byte packets
 1  192.168.50.1  1.852 ms  0.617 ms  0.545 ms
 2  96.120.29.57  11.045 ms  22.822 ms  11.105 ms
 3  * 96.110.154.221  20.582 ms  12.039 ms
 4  * * 68.85.176.113  15.702 ms
 5  68.87.210.6  15.346 ms  14.514 ms  15.101 ms
 6  68.86.188.78  15.056 ms * *
 7  75.75.75.75  14.786 ms  16.038 ms  17.796 ms

$ date && ping -q -c 10 75.75.75.75
Sun Nov  7 12:22:28 CST 2021
PING 75.75.75.75 (75.75.75.75): 56 data bytes

--- 75.75.75.75 ping statistics ---
10 packets transmitted, 9 packets received, 10.0% packet loss
round-trip min/avg/max/stddev = 15.186/17.520/24.453/2.673 ms

BruceW

Gold Problem Solver

•

26.3K Messages

3 years ago

Please post the information requested.

mitharus

Frequent Visitor

•

19 Messages

@BruceW

Here's the values ... IIRC these are similar even when the issue is going on:

Model: Arris SB6190
Downstream Power: (Don't know the channel so... ranges) -- 1.00 - 3.90 dBmV
SNR: (Don't know the channel so... ranges) -- 38.61 - 40.37 dB
Upstream Power: (Don't know the channel so... ranges) -- 48.25 - 50.50 dBmB

Event Log:

Sun Nov 07 10:27:12 2021	3	Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.0;
Sun Nov 07 10:27:22 2021	3	No Ranging Response received - T3 time-out;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.0;
Sun Nov 07 10:29:23 2021	3	Ranging Request Retries exhausted;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.0;
Sun Nov 07 10:29:23 2021	3	Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.0;
Sun Nov 07 10:29:47 2021	3	No Ranging Response received - T3 time-out;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.0;
Sun Nov 07 10:35:13 2021	3	Ranging Request Retries exhausted;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.0;
Sun Nov 07 10:35:13 2021	3	Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.0;
Sun Nov 07 10:35:23 2021	3	No Ranging Response received - T3 time-out;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.0;
Sun Nov 07 10:36:11 2021	3	Ranging Request Retries exhausted;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.0;
Sun Nov 07 10:36:11 2021	3	Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.0;
Sun Nov 07 10:36:25 2021	3	No Ranging Response received - T3 time-out;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.0;
Sun Nov 07 12:11:21 2021	3	Ranging Request Retries exhausted;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.0;
Sun Nov 07 12:11:21 2021	3	Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.0;
Sun Nov 07 12:11:45 2021	3	No Ranging Response received - T3 time-out;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.0;
Sun Nov 07 12:24:30 2021	3	Ranging Request Retries exhausted;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.0;
Sun Nov 07 12:24:30 2021	3	Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.0;
Sun Nov 07 12:24:54 2021	3	No Ranging Response received - T3 time-out;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.0;
Sun Nov 07 12:38:50 2021	3	Ranging Request Retries exhausted;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.0;
Sun Nov 07 12:38:50 2021	3	Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.0;
Sun Nov 07 12:39:14 2021	3	No Ranging Response received - T3 time-out;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.0;
Sun Nov 07 13:20:48 2021	5	RCS Partial Service;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.0;
Sun Nov 07 13:20:49 2021	3	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.0;
Sun Nov 07 13:20:49 2021	5	RCS Partial Service;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.0;
Sun Nov 07 13:20:49 2021	3	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.0;
Sun Nov 07 13:20:49 2021	5	RCS Partial Service;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.0;
Sun Nov 07 13:20:53 2021	5	Lost MDD Timeout;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.0;
Sun Nov 07 13:22:27 2021	3	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.1;CM-VER=3.0;

And .... the connection is gone again. Modem was remotely rebooted/cut as I was typing this. I added those log entries there once I could get back on the modem (13:20:48). The Xfinity App is telling me now that: "We've detected performance issues with the network in your area and we're working to make improvements [...]" ... Well see if this is at all relevant once I have internet back and can post this...

3 years ago

BruceW

Gold Problem Solver

•

26.3K Messages

3 years ago

@mitharus wrote: "... Upstream Power: (Don't know the channel so... ranges) -- 48.25 - 50.50 dBmB ..."

The upstream power levels are borderline/too high, which is consistent with the "Ranging" errors in the Event log. Please see the suggestions previously posted to correct.

mitharus

Frequent Visitor

•

19 Messages

@BruceW

https://arris.secure.force.com/consumers/articles/General_FAQs/SB6190-Cable-Signal-Levels/?l=en_US&fs=RelatedArticle

For my modem, it shows that for the Channel Type / Symbol Rate (2560/5120 kSym/s) connected at it should be 45 - 51 dBmV / 45 - 52 dBmV. So while on the upper end it's still well within operating parameters. Current values are: 46.25 - 48.75 dBmV .... These fluctuate on a page reload if they've changed, but they've never been above operating values.

And even with the maintenance being done for "performance issues," shortly after routing is messed up again and I'm having packet loss...

$ date && ping -q -c 10 75.75.75.75
Sun Nov  7 16:12:10 CST 2021
PING 75.75.75.75 (75.75.75.75): 56 data bytes

--- 75.75.75.75 ping statistics ---
10 packets transmitted, 2 packets received, 80.0% packet loss
round-trip min/avg/max/stddev = 17.954/20.334/22.713/2.380 ms

(edited)

3 years ago

mitharus

Frequent Visitor

•

19 Messages

$ date && traceroute -n 75.75.75.75
Sun Nov  7 17:33:15 CST 2021
traceroute to 75.75.75.75 (75.75.75.75), 64 hops max, 52 byte packets
 1  192.168.50.1  1.452 ms  0.553 ms  0.866 ms
 2  * 96.120.29.57  12.782 ms  10.601 ms
 3  * * 96.110.154.221  15.290 ms
 4  * 68.85.176.113  16.740 ms  23.366 ms
 5  * * 68.87.210.6  14.819 ms
 6  * * 68.86.188.78  14.255 ms
 7  * 75.75.75.75  33.376 ms *

$ date && ping -q -c 10 75.75.75.75
Sun Nov  7 17:34:14 CST 2021
PING 75.75.75.75 (75.75.75.75): 56 data bytes

--- 75.75.75.75 ping statistics ---
10 packets transmitted, 6 packets received, 40.0% packet loss
round-trip min/avg/max/stddev = 17.920/20.554/31.256/4.800 ms

3 years ago

mitharus

Frequent Visitor

•

19 Messages

$ date && ping -q -c 10 75.75.75.75
Mon Nov  8 19:18:55 CST 2021
PING 75.75.75.75 (75.75.75.75): 56 data bytes
--- 75.75.75.75 ping statistics ---
10 packets transmitted, 7 packets received, 30.0% packet loss
round-trip min/avg/max/stddev = 14.730/17.101/19.979/2.153 ms

$ date && traceroute -n 75.75.75.75
Mon Nov  8 19:19:18 CST 2021
traceroute to 75.75.75.75 (75.75.75.75), 64 hops max, 52 byte packets 
1  192.168.50.1  1.007 ms  0.550 ms  0.546 ms 
2  * 96.120.29.57  27.495 ms  12.826 ms 
3  96.110.154.221  12.051 ms  9.797 ms  36.053 ms 
4  * 68.85.176.113  16.645 ms  13.731 ms 
5  68.87.210.6  15.148 ms *  14.515 ms 
6  68.86.188.78  14.992 ms  13.962 ms  17.977 ms 
7  * 75.75.75.75  49.286 ms  16.960 ms

$ date && ping -q -c 10 75.75.75.75
Mon Nov  8 19:45:29 CST 2021
PING 75.75.75.75 (75.75.75.75): 56 data bytes

--- 75.75.75.75 ping statistics ---
10 packets transmitted, 4 packets received, 60.0% packet loss
round-trip min/avg/max/stddev = 17.537/24.921/33.522/6.075 ms

Upstream power: 46.75 - 49.25 dBmV

(edited)

3 years ago

BruceW

Gold Problem Solver

•

26.3K Messages

3 years ago

Posting more ping and trace results won't help. You need to correct the signal problems underlying them.

XfinityDilary

Official Employee

•

2.2K Messages

3 years ago

Hello, @mitharus Thanks for reaching out to our Community Forums for assistance with your intermittent connectivity concerns. And for working with @BruceW to reach a resolution. I appreciate your help BruceW! Since it was determined the upstream power levels are borderline/too high, I'd like to take a deeper look. We'll do our best to get this resolved once and for all.

Could you please send our team a private message with your full name and full address? Our team can most definitely take a further look at this issue.

To send a "Peer to peer" ("Private") message:

Click "Sign In" if necessary

• Click the "Peer to peer chat" icon

• Click the "New message" (pencil and paper) icon

• Type "Xfinity Support" in the "To:" line and select "Xfinity Support" from the drop-down list which appears. The "Xfinity Support" graphic replaces the "To:" line

• Type your message in the text area near the bottom of the window

• Press Enter to send it

Your Home Network

mitharus

Intermittent routing issue

BruceW

mitharus

mitharus

BruceW

mitharus

BruceW

mitharus

mitharus

mitharus

BruceW

XfinityDilary

New to the Community?