9 Messages
XB8 - Downstream, upstream, & codewords tables missing stats 📉
Summary
The XB8's status page under under Gateway > Connection > XFINITY Network is missing stats for Downstream, Upstream, & Codewords tables, it displays zeros or blank columns. These were displaying correctly, up until 2024/09/24 after it rebooted itself.
* Internet performance did not change after this, but noticed the firmware version did change.
Example of the issue
Just one example, missing data changes when the page is refreshed.
Page from http://10.0.0.1/network_setup.jst
|
Downstream
|
Channel Bonding Value | ||||||||||||||||||||||||||||||||
| Channel ID |
9
|
1
|
2
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
37
|
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Lock Status |
Locked
|
Locked
|
Locked
|
Locked
|
|||||||||||||||||||||||||||||
| Frequency |
495 MHz
|
441 MHz
|
453 MHz
|
0
|
|||||||||||||||||||||||||||||
| SNR |
40.0 dB
|
40.5 dB
|
40.4 dB
|
38.3 dB
|
|||||||||||||||||||||||||||||
| Power Level |
0.5 dBmV
|
0.1 dBmV
|
0.1 dBmV
|
-3.5 dBmV
|
|||||||||||||||||||||||||||||
| Modulation |
256 QAM
|
256 QAM
|
256 QAM
|
OFDM
|
|||||||||||||||||||||||||||||
|
Upstream
|
Channel Bonding Value | ||||||
| Channel ID |
5
|
6
|
7
|
0
|
0
|
0
|
|
|---|---|---|---|---|---|---|---|
| Lock Status |
Locked
|
Locked
|
Locked
|
||||
| Frequency |
10 MHz
|
16 MHz
|
22 MHz
|
||||
| Symbol Rate |
2560
|
5120
|
5120
|
||||
| Power Level |
35.8 dBmV
|
36.3 dBmV
|
37.0 dBmV
|
||||
| Modulation |
QAM
|
QAM
|
QAM
|
||||
| Channel Type |
ATDMA
|
ATDMA
|
ATDMA
|
||||
| CM Error Codewords | ||||||||||||||||||||||||||||||||
| Channel ID |
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
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0
|
0
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0
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0
|
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Unerrored Codewords |
1059148606
|
1032394038
|
1035564917
|
1037412089
|
1039094226
|
1040837553
|
1042177306
|
1043606049
|
1044965898
|
1046293145
|
1047408245
|
1048500036
|
1049379438
|
1050338058
|
1051105705
|
1051865924
|
1052581077
|
1053302018
|
1053996946
|
1054636993
|
1055153030
|
1055688451
|
1056156465
|
986394638
|
1056848878
|
1057219208
|
1057586263
|
1057976592
|
1058276805
|
1058569925
|
1058865182
|
1059148606
|
| Correctable Codewords |
640
|
449
|
723
|
464
|
499
|
343
|
327
|
292
|
381
|
298
|
267
|
311
|
295
|
293
|
364
|
347
|
322
|
342
|
353
|
305
|
324
|
375
|
325
|
0
|
629
|
612
|
705
|
585
|
636
|
508
|
733
|
640
|
| Uncorrectable Codewords |
1493
|
419
|
1552
|
890
|
934
|
971
|
971
|
959
|
875
|
741
|
775
|
707
|
715
|
721
|
776
|
820
|
821
|
860
|
861
|
916
|
938
|
887
|
1017
|
609603
|
1316
|
889
|
886
|
962
|
1545
|
1027
|
1500
|
1493
|
Example 2
What stats are missing change almost everytime you refresh the page:
Full details of my XB8 Modem
"Software Image Names" I have seen the issue on:
- CGM4981COM_7.6p2s4_PROD_sey
- CGM4981COM_7.6p5s1_PROD_sey
- CGM4981COM_7.6p9s2_PROD_sey
My Xfinity Plan
Observed Channels (before issue)
The table used to show these columns on the page:
Downstream: 32 Channels (256 QAM + OFDM)
Upstream: 8 Channels (QAM)
Suspected Root Cause - Firmware Bug 🐛
I made no change to the XB8 myself. These stats were working fine before it rebooted itself overnight then I observed it went from firmware version "Prod_22.2_d31 & Prod_22.2" to "Prod_23.2_231009 & Prod_23.2_231009", so this almost certainly seems like a firmware bug.
* I am guessing "Software Image Name" changed too, but I didn't happen catch what the old name was.
Troubleshooting
* Tried rebooting the XB8 twice from the Troubleshooting > Reset / Restore Gateway page
* Waited a few minutes after rebooting before checking the stats page
* Refreshed the page many times, most of the noted stats are missing
* Factory reset
- Went to "Troubleshooting > Reset / Restore Gateway" then pressed "Restore Factory Settings".
* Unplugging the XB8 for 30 seconds
* Different browsers and computers / devices
- WIndows 11 - Chrome & Firefox
- Windows 10 - Chrome
- Android - Chrome
- macOS - Safari
* Viewed on ethernet and Wifi
* Inspected the HTML - Fields that are missing data are really not in the HTML
- In the table the <td> tags contain <div> tags, but they have 0 or no string value at all. Stats that are visible in the browser are in the HTML, so I am looking at the correct spot. So in conclusion, not a browser rendering issue.
* Firmware rollback - Can't attempt, Xfinity support said "Unfortunately, we don't have a way to rollback the firmware from our end..."
Reports of this bug
About 10 people in total seem to have reported this bug:
- https://www.dslreports.com/forum/r33952035-Signals-Lost-Internet-and-Now-only-one-Upstream-Channel
- https://www.dslreports.com/forum/r33959469-XB8-down-up-channels-disapearing-then-reappearing
- https://www.dslreports.com/forum/r33227126-Next-Gateway-XB8-Technicolor-CGM4981COM-Wi-Fi-6E~start=1020
- https://www.reddit.com/r/Comcast_Xfinity/comments/1fix8vm/xfinity_hiding_modem_stats/
- Two+ Xfinity Comcast Support Contractors / Employees (they noted this in my chat with them)
- And this post + another in the replies section here.
Work Around - Bridge Mode
If you have your own router you can enable "Bridge Mode" on the XB8, then all these stats correctly show.
* Normally, a setting like this shouldn't effect the stats, but again, thinking this is just some odd firmware bug.
* Confirmed this on firmware "CGM4981COM_7.6p5s1_PROD_sey".
Status
Current - Fixed in "next" Firmware update (2024/10/31)
On 2024/10/31 Comcast support said that "..next firmware update is suggested to provide a fix...". However they didn't say when or what the firmware version it will be fixed on.
History
2024/10/04
On 2024/10/03, I chatted with Xfinity and they were able to reproduce this issue as well. They opened a ticket with the "Advanced Repair Team" so they can look into the issue.
In my chat with support they also noted these stats might be moved to the "Xfinity App", but I personally doubt that, as the app is more high-level / customer friendly where these stats are more "prosumer" focused. I believe Xfinity support just said that as it's probably Xfinity's plan to move more stuff into the app, but they said may/might as they are probably don't know exactly what will be moved.
As a prosumer myself I want these stats to stay accessible from the Cable device itself for two reasons:
- If the connection is bad enough the device won't be able to upload them to Xfinity's server, nor would my devices be able to get a internet connection to fetch the stats through the app to their server either.
- I want keep my automated monitoring of these stats. I use this to know if my internet hiccups are related to coax RF noise or power levels or something else.
2024/10/05
Support got back to me but "Advanced Repair Specialists" could not reproduce the issue. They asked me to try different web browsers (I already put this in my post here) and I let them know that Xfinity support people "XfinityPersonA" and "XfinityPersonB" can reproduce the issue so suggested those to teams might be able to help reproduce faster internally. However I told them I was happy to try more things.
I also noted:
Since your "Advanced Repair Specialists" could not reproduce but those Xfinity support employees can (as well as me, and a few others) there must be some differences in the test setup; such as firmware version, hardware revision, or DOCSIS provisioning.
2024/10/07
A new firmware, CGM4981COM_7.6p5s1_PROD_sey, was discovered in the wild and I asked Xfinity support if they could push a DOCSIS command down to install it on my XB8, to see if it addresses the issue. Xfinity 's support team attempted to send a provisioning signal and rebooted the XB8. (I assume they did this to see if this would trigger the automatic update). They provisioning twice with no luck, so they reached out to the Advanced Repair Team" to see if they can update me to this new firmware.
2024/10/08
Xfinity support let me know they sent the issue over to the "Engineering team" to take a look a this.
2024/10/11
Firmware was updated to CGM4981COM_7.6p5s1_PROD_sey around 3am, however it did not fix this issue. I let support know this detail.
2024/10/13
Found that the XB8's "Bridge Mode" is a work around (added a section above with more details). Also I let the Xfinity Support team know.
2024/10/31
Comcast support said that "..next firmware update is suggested to provide a fix...", however they didn't say when or what the firmware version it will be fixed on.
user_dd7863
Visitor
•
19 Messages
2 months ago
I have had this same issue with 2 different XB8 modems as well. There is no way to fix it until they do another firmware update but, who knows when that will be,
6
GhostlyLurker
1 Message
1 month ago
I as well as of last night now have this graphical bug where the info shows 0's for all the channels and refreshing several times has a few show up again. I'm on CGM4981COM_7.3p7s1_PROD_sey on the XB8-T
1
user_xn7m4m
9 Messages
1 month ago
I found a work around, if you have your own router you can enable "Bridge Mode" on the XB8.
* When using your own router, it's recommend you enable this anyway, for best performance (and to avoid double NAT).
* Normally a setting like this shouldn't affect these stats, but again, thinking this is just some odd firmware bug. Perhaps a bug with the XB8's "router code" causing a bug with the "cable modem code".
I confirmed this work around works on the "CGM4981COM_7.6p5s1_PROD_sey" firmware, but might be a work around for other versions too.
While most people who care about these stats probably have their own router, not everyone does. Also this should work regardless of the "Bridge Mode" setting, so this a bug. Lastly, even if you have your own router you may want to go back to the XB8's normal mode if you have issues and want to debug something, these stats missing makes things harder.
(edited)
1
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