Visitor
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13 Messages
Frequent Packet Loss and High Latency with Netgear CM3000
***Repost since I forgot to edit out personal information.
I recently "upgraded" my cable modem from my Arris S33 to the Netgear CM3000. In nearly 2 years of use I never noticed a single major issue with the S33 - it has been extremely stable for online gaming and other usage.
The only reason I purchased the CM3000 was to take advantage of the "Next Gen Upload Speeds." For whatever reason the S33 has been capped at ~40 Mbps upload by Xfinity even though the modem is perfectly capable of handling much faster upload speeds. With the CM3000 I get roughly 350 Mbps upload - a nearly 9 fold increase in upload speeds is great! The problem is that I have been having daily issues with packet loss and high latency.
A cable diagnostic as follows:
Cable Diagnostic
Status: Good
Action:
Your setup looks fine. If you can't access the internet, make sure you properly activated the modem. If modem has been activated and you still can't access the internet, contact your service provider for troubleshooting help.
If you can access the internet but has other internet issue, the Netgear Cable Knowledge Base can provide additional troubleshooting info.
CM Status: Good
Downstream Status: Good
Downstream Power Level: Good
Downstream SNR Level: Good
Upstream Status: Good
Upstream Power Level: Good
Current Time: Sat Dec 14 11:08:03 2024
Startup Procedure
Acquire Downstream Channel: 621000000 Hz Locked
Connectivity State: OK Operational
Boot State: OK Operational
Security: Enabled BPI+
IP Provisioning Mode: Honor MDD IPv6 only
Downstream Bonded Channels
Channel LockedStatus Modulation ChannelID Frequency Power SNR Correctables Uncorrectables
1 Locked QAM256 44 621000000 Hz -6.6 41.3 1 0
2 Locked QAM256 13 435000000 Hz -5.6 42.7 1 0
3 Locked QAM256 14 441000000 Hz -5.5 42.7 0 0
4 Locked QAM256 15 447000000 Hz -5.3 42.8 1 0
5 Locked QAM256 16 453000000 Hz -5.4 42.7 1 0
6 Locked QAM256 17 459000000 Hz -5.3 42.8 1 0
7 Locked QAM256 18 465000000 Hz -5.4 42.6 0 0
8 Locked QAM256 19 471000000 Hz -5.5 42.5 0 0
9 Locked QAM256 20 477000000 Hz -5.4 42.5 7 0
10 Locked QAM256 21 483000000 Hz -5.6 42.3 1 0
11 Locked QAM256 22 489000000 Hz -5.7 42.1 0 0
12 Locked QAM256 23 495000000 Hz -5.9 42 2 0
13 Locked QAM256 24 501000000 Hz -6.2 41.8 1 0
14 Locked QAM256 25 507000000 Hz -6.2 41.8 0 0
15 Locked QAM256 26 513000000 Hz -6.1 41.8 1 0
16 Locked QAM256 27 519000000 Hz -6.2 41.6 1 0
17 Locked QAM256 28 525000000 Hz -6 41.7 1 0
18 Locked QAM256 29 531000000 Hz -5.9 41.8 1 0
19 Locked QAM256 30 537000000 Hz -5.7 42 2 0
20 Locked QAM256 31 543000000 Hz -5.5 42.1 2 0
21 Locked QAM256 32 549000000 Hz -5.6 42 1 0
22 Locked QAM256 33 555000000 Hz -5.5 42 1 0
23 Locked QAM256 34 561000000 Hz -5.7 41.9 1 0
24 Locked QAM256 35 567000000 Hz -5.6 41.8 1 0
25 Locked QAM256 36 573000000 Hz -6.1 41.7 1 0
26 Locked QAM256 37 579000000 Hz -6.2 41.5 0 0
27 Locked QAM256 38 585000000 Hz -6.4 41.5 2 0
28 Locked QAM256 39 591000000 Hz -6.8 41.2 2 0
29 Locked QAM256 40 597000000 Hz -6.7 41.2 10 0
30 Locked QAM256 41 603000000 Hz -7.1 41 15 0
31 Locked QAM256 42 609000000 Hz -6.9 41 12 0
32 Locked QAM256 43 615000000 Hz -6.6 41.3 1 0
Upstream Bonded Channels
Channel LockedStatus ChannelType ChannelID SymbolRate Frequency Power
1 Locked ATDMA 3 5120 Ksym/sec 29200000 Hz 45.8 dBmV
2 Locked ATDMA 2 5120 Ksym/sec 22800000 Hz 45.3 dBmV
3 Locked ATDMA 1 5120 Ksym/sec 16400000 Hz 44.8 dBmV
4 Locked ATDMA 4 5120 Ksym/sec 35600000 Hz 46.8 dBmV
5 Not Locked Unknown 0 0 0 0.0
6 Not Locked Unknown 0 0 0 0.0
7 Not Locked Unknown 0 0 0 0.0
8 Not Locked Unknown 0 0 0 0.0
Downstream OFDM Channels
Channel LockedStatus ProfileID ChannelID Frequency Power SNR/MER ActiveSubcarrier Unerror Correctable Uncorrectable
1 Locked 0 ,1 ,2 ,3 193 722000000 Hz -5.82 dBmV 41.1 dB 208 ~ 3887 1292306681 1205132840 0
2 Locked 0 ,1 ,2 ,3 194 957000000 Hz -7.52 dBmV 39.4 dB 148 ~ 3947 1297628449 1122766902 7
Upstream OFDMA Channels
Channel LockedStatus ProfileID ChannelID Frequency Power
1 Locked 12 ,13 41 36200000 Hz 42.5 dBmV
2 Not Locked 0 0 0 Hz 0 dBmV
Event Log
Time Priority Description
Sat Dec 14 06:19:00 2024 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out
Fri Dec 13 23:50:19 2024 Notice (6) US profile assignment change. US Chan ID: 41; Previous Profile: 11 13; New Profile: 12 13
Fri Dec 13 23:40:49 2024 Notice (6) US profile assignment change. US Chan ID: 41; Previous Profile: 12 13; New Profile: 11 13
Fri Dec 13 23:30:19 2024 Notice (6) US profile assignment change. US Chan ID: 41; Previous Profile: 11 13; New Profile: 12 13
Fri Dec 13 23:20:19 2024 Notice (6) US profile assignment change. US Chan ID: 41; Previous Profile: 10 13; New Profile: 11 13
Fri Dec 13 12:36:49 2024 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out
Fri Dec 13 06:20:04 2024 Notice (6) US profile assignment change. US Chan ID: 41; Previous Profile: 12 13; New Profile: 10 13
Thu Dec 12 18:36:49 2024 Notice (6) US profile assignment change. US Chan ID: 41; Previous Profile: 11 13; New Profile: 12 13
Thu Dec 12 18:30:04 2024 Notice (6) US profile assignment change. US Chan ID: 41; Previous Profile: 12 13; New Profile: 11 13
Thu Dec 12 17:41:49 2024 Notice (6) US profile assignment change. US Chan ID: 41; Previous Profile: 11 13; New Profile: 12 13
Thu Dec 12 17:36:48 2024 Notice (6) US profile assignment change. US Chan ID: 41; Previous Profile: 12 13; New Profile: 11 13
Thu Dec 12 14:51:48 2024 Notice (6) US profile assignment change. US Chan ID: 41; Previous Profile: 11 13; New Profile: 12 13
Thu Dec 12 14:43:03 2024 Notice (6) US profile assignment change. US Chan ID: 41; Previous Profile: 12 13; New Profile: 11 13
Thu Dec 12 08:06:40 2024 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out
Thu Dec 12 08:04:00 2024 Notice (6) DS profile assignment change. DS Chan ID: 33; Previous Profile: ; New Profile: 1 2 3
Thu Dec 12 08:03:58 2024 Notice (6) DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1 2 3
Thu Dec 12 08:03:53 2024 Notice (6) TLV-11 - unrecognized OID
Time Not Established Notice (6) Honoring MDD; IP provisioning mode = IPv6
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing
Thu Dec 12 08:01:45 2024 Critical (3) Resetting the cable modem due to docsDevResetNow
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing
Sat Dec 07 09:52:48 2024 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out
Sat Dec 07 06:17:47 2024 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out
Fri Dec 06 06:17:50 2024 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing
Wed Dec 04 11:20:01 2024 Critical (3) Resetting the cable modem due to docsDevResetNow
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing
Wed Dec 04 11:17:47 2024 Critical (3) Resetting the cable modem due to docsDevResetNow
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing
Time Not Established Critical (3) No Ranging Response received - T3 time-out
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing
Time Not Established Critical (3) Resetting the cable modem due to docsDevResetNow
I tried testing my S33 again a couple days ago to see if I was having the same issues with packet loss and higher latency. When I had it reinstalled, I did a speed test and I was getting barely over 700 Mbps (when I was getting over 2300 before on my Gigabit X2 plan) and only 6 Mbps upload... No idea why my speeds were so poor when attempting to retest my old S33. I ended up not testing packet loss/latency with it since the speeds were very confusingly so low. Plugged the CM3000 back in and speeds were normal.
Would really appreciate to hear back from an Xfinity representative about this issue. I would just go back to the S33 and return the CM3000 but I'm not going to deal with less than 1/3 of the download speed I am paying for and roughly 1/7 of the upload - especially when I'm gaming and streaming focused.
Thanks for your time!
XfinityMarcos
Official Employee
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2.3K Messages
4 months ago
Hello Cameron0390, thank you for reaching out regarding your connectivity issues, I can see how those would be annoying when you're depending on your network for streaming and gaming. Let's jump right in, have you noticed any patterns to this issue or is it constant? Also, what troubleshooting steps have you taken on your end, so we can avoid repeating things.
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EG
Expert
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110K Messages
4 months ago
@Cameron0390 @XfinityRaul
Please circle back here and post any possible solutions for the issue here in these open public forums so that all readers here may benefit from the exchange / info. This is in keeping with the spirit for which these public help forums were originally intended. Thank you.
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user_z6elh2
1 Message
2 months ago
I am in the exact same position as the OP. I had the S33 and x2 plan. I was only seeing about 40Mbps up. I had a tech come out and they "confirmed" it was the modem that was limiting the upload speed. He referred me to the next gen tier modems and I decided to get the CM3000. I just swapped out the modem and fired it up. I'm still only getting 40 Mbps up. I am not expecting much more than 800 Mbps down because I have an older router, but that's okay by me. Did the OP ever get anywhere with this? TIA.
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