I am experiencing a similar issue, only getting 31 of 32 locked channels with a Netgear CM1100 modem and unable to sustain speeds more than about 900 mbps. I have also enabled link aggregation on the WAN ports to my router hoping it would allow me to get the full bandwidth, but that has not helped.
Could the lack of all 32 channels locking be the issue? It would be great if a knowledgeable Comcast tech could reply!
Be advised that many, if not most local systems have dropped back from using 32 downstream channels to using 31 since the DOCSIS 3.1 / OFDM channel for the gigabit speed tier was implemented. The gig speed tier is delivered via that channel, not the QAM256 channels.
Is there a downstream channel labeled as *OFDM / PLC* or as *Other* being shown ?
Please post the *Downstream Power Level*, the *Upstream Power Level*, and the *SNR* (Signal to Noise Ratio) numbers.
Also post the error log entries in their entirety.
Hi, thanks for your assistance. Here is what the cable connection screen on the CM1100 cable modem is showing:
Frequency start Value | |
This field below allows you to modify the frequency the cable modem start with its scan during initialization and registration. Enter the new start frequency and restart the cable modem for it to take effect. | |
|
<tabindex=-1>Startup Procedure</tabindex=-1>
Procedure | Status | Comment |
Acquire Downstream Channel | 567000000 Hz | Locked |
Connectivity State | OK | Operational |
Boot State | OK | Operational |
Security | Enable | BPI+ |
IP Provisioning Mode | Honor MDD | IPv6 only |
<tabindex=-1>Downstream Bonded Channels</tabindex=-1>
Channel | Lock Status | Modulation | Channel ID | Frequency | Power | SNR / MER | Unerrored Codewords | Correctable Codewords | Uncorrectable Codewords |
1 | Locked | QAM256 | 29 | 567000000 Hz | 2.4 dBmV | 40.5 dB | 1907365964 | 1863 | 0 |
2 | Locked | QAM256 | 1 | 375000000 Hz | 2.3 dBmV | 42.3 dB | 1906239269 | 143 | 0 |
3 | Locked | QAM256 | 2 | 381000000 Hz | 2.6 dBmV | 42.3 dB | 1906244515 | 175 | 0 |
4 | Locked | QAM256 | 3 | 387000000 Hz | 2.2 dBmV | 42.4 dB | 1906246002 | 180 | 0 |
5 | Locked | QAM256 | 4 | 393000000 Hz | 2.1 dBmV | 42.2 dB | 1906249875 | 179 | 0 |
6 | Locked | QAM256 | 5 | 399000000 Hz | 1.8 dBmV | 42.4 dB | 1906254702 | 197 | 0 |
7 | Locked | QAM256 | 6 | 405000000 Hz | 1.7 dBmV | 42.3 dB | 1906260096 | 235 | 0 |
8 | Locked | QAM256 | 7 | 411000000 Hz | 1.7 dBmV | 42.2 dB | 1906262748 | 262 | 0 |
9 | Locked | QAM256 | 8 | 417000000 Hz | 1.9 dBmV | 42.2 dB | 1906277664 | 241 | 0 |
10 | Locked | QAM256 | 9 | 423000000 Hz | 2.0 dBmV | 42.1 dB | 1906283589 | 253 | 0 |
11 | Locked | QAM256 | 10 | 435000000 Hz | 2.6 dBmV | 42.3 dB | 1906289117 | 252 | 0 |
12 | Locked | QAM256 | 11 | 441000000 Hz | 2.8 dBmV | 42.2 dB | 1906290476 | 368 | 0 |
13 | Locked | QAM256 | 12 | 447000000 Hz | 3.0 dBmV | 42.4 dB | 1906293100 | 324 | 0 |
14 | Locked | QAM256 | 13 | 453000000 Hz | 3.2 dBmV | 42.3 dB | 1906297670 | 357 | 0 |
15 | Locked | QAM256 | 14 | 459000000 Hz | 3.3 dBmV | 42.3 dB | 1906301759 | 381 | 0 |
16 | Locked | QAM256 | 15 | 465000000 Hz | 3.2 dBmV | 42.1 dB | 1906303258 | 464 | 0 |
17 | Locked | QAM256 | 16 | 471000000 Hz | 2.8 dBmV | 42.1 dB | 1906355666 | 457 | 0 |
18 | Locked | QAM256 | 17 | 477000000 Hz | 2.9 dBmV | 42.3 dB | 1906360134 | 468 | 0 |
19 | Locked | QAM256 | 18 | 483000000 Hz | 2.4 dBmV | 42.1 dB | 1906364347 | 536 | 0 |
20 | Locked | QAM256 | 19 | 489000000 Hz | 2.4 dBmV | 42.1 dB | 1906367621 | 575 | 0 |
21 | Locked | QAM256 | 20 | 495000000 Hz | 2.4 dBmV | 41.7 dB | 1906370434 | 749 | 0 |
22 | Locked | QAM256 | 21 | 519000000 Hz | 3.0 dBmV | 39.2 dB | 1906374277 | 1019 | 0 |
23 | Locked | QAM256 | 22 | 525000000 Hz | 3.0 dBmV | 41.9 dB | 1906379487 | 823 | 0 |
24 | Locked | QAM256 | 23 | 531000000 Hz | 2.8 dBmV | 41.9 dB | 1906382915 | 1164 | 0 |
25 | Locked | QAM256 | 24 | 537000000 Hz | 2.8 dBmV | 41.6 dB | 1906386587 | 1407 | 0 |
26 | Locked | QAM256 | 25 | 543000000 Hz | 2.7 dBmV | 41.8 dB | 1906390014 | 1171 | 0 |
27 | Locked | QAM256 | 26 | 549000000 Hz | 2.3 dBmV | 41.5 dB | 1906394090 | 1686 | 0 |
28 | Locked | QAM256 | 27 | 555000000 Hz | 2.5 dBmV | 41.6 dB | 1906397299 | 1489 | 0 |
29 | Locked | QAM256 | 28 | 561000000 Hz | 2.6 dBmV | 41.6 dB | 1906399435 | 1390 | 0 |
30 | Locked | QAM256 | 30 | 573000000 Hz | 2.3 dBmV | 41.5 dB | 1906400948 | 1734 | 0 |
31 | Locked | QAM256 | 31 | 579000000 Hz | 2.0 dBmV | 41.3 dB | 1906400048 | 2199 | 0 |
32 | Not Locked | Unknown | 0 | 0 Hz | 0.0 dBmV | 0.0 dB | 0 | 0 | 0 |
<tabindex=-1>Upstream Bonded Channels</tabindex=-1>
Channel | Lock Status | Modulation | Channel ID | Frequency | Power |
1 | Locked | ATDMA | 9 | 17300000 Hz | 44.3 dBmV |
2 | Locked | ATDMA | 10 | 23700000 Hz | 43.5 dBmV |
3 | Locked | ATDMA | 11 | 30100000 Hz | 45.0 dBmV |
4 | Locked | ATDMA | 12 | 36500000 Hz | 43.8 dBmV |
5 | Not Locked | Unknown | 0 | 0 Hz | 0.0 dBmV |
6 | Not Locked | Unknown | 0 | 0 Hz | 0.0 dBmV |
7 | Not Locked | Unknown | 0 | 0 Hz | 0.0 dBmV |
8 | Not Locked | Unknown | 0 | 0 Hz | 0.0 dBmV |
<tabindex=-1>Downstream OFDM Channels</tabindex=-1>
Channel | Lock Status | Modulation / Profile ID | Channel ID | Frequency | Power | SNR / MER | Active Subcarrier Number Range | Unerrored Codewords | Correctable Codewords | Uncorrectable Codewords |
1 | Locked | 0, 1, 2, 3 | 33 | 690000000 Hz | 0.7 dBmV | 38.8 dB | 1108 ~ 2987 | 3178031654 | 3127634514 | 0 |
2 | Not Locked | 0 | 0 | 0 Hz | 1.1 dBmV | 0.0 dB | 0 ~ 4095 | 0 | 0 | 0 |
<tabindex=-1>Upstream OFDMA Channels</tabindex=-1>
Channel | Lock Status | Modulation / Profile ID | Channel ID | Frequency | Power |
1 | Not Locked | Unknown | 0 | 0 Hz | 0 dBmV |
2 | Not Locked | Unknown | 0 | 0 Hz | 0 dBmV |
The stats are good. Be advised that around 940 (hardwired) is to be the max expected, so you are doing very well at 900.
Great, thanks! My question is, can I use the wan aggregation feature of this modem to further increase the maximum by bonding the two gig connections on the modem? I thought Comcast typically overprovisions the available bandwidth. For example, when I had a 100mbps plan, I was getting rates close to 150 - 200mbps.
I was hoping by using the WAN aggregation feature of this modem and the netgear r7800 router to which it is connected, I could pull at or slightly higher than 1gbps.
The comcast tech who came to the house seemed to be getting around 1.2 using his equipment. He said he thought I may have been rate limited by the central office to no more than 1gbps, but if they are overprovisioning as they typically do, I thought by using wan aggregation, I could make use of this additional provisioned capacity.
Thanks for all your help!
Give it a try. I've seen posts here indicating that some people do indeed get around 1.2 Gbps that way. Good luck !