So I have done a lot of changes, reducing upstream power, monitoring frequencies etc but I still have an issue, is it a modem type? I have finally gotten all modems/upstreams to docsis 2.0, but I have modems that come online, bond, then reboot, on the same node I have rock solid modems. Here is one modem I cannot get to stay online, it locks and then reboots.. This is our cleanest plant in apartments and yet.. it won't stay on... so wtf?
CM Initialization Reason : NO_PRIM_SF_USCHAN
MAC Address : 20e5.64e9.7548
IP Address : 10.0.14.160
IPv6 Address : ---
Dual IP : N
Prim Sid : 1620
QoS Profile Index : 2
Host Interface : C8/0/0/U2
MD-DS-SG / MD-US-SG : 1 / N/A
MD-CM-SG : 0x5A0113
Primary Downstream : In8/0/4:2 (RfId : 1058)
Wideband Capable : N
RCP Index : 0
RCP ID : 00 10 00 00 08
Downstream Channel DCID RF Channel : 163 8/0/4:2
Downstream Channel DCID RF Channel : 149 8/0/1:0
Downstream Channel DCID RF Channel : 150 8/0/1:1
Downstream Channel DCID RF Channel : 151 8/0/1:2
Downstream Channel DCID RF Channel : 152 8/0/1:3
Multi-Transmit Channel Mode : N
Extended Upstream Transmit Power : 0dB
Upstream Channel :
Ranging Status :
Upstream Power (dBmV) :
Upstream SNR (dB) :
Upstream Data SNR (dB) :
Received Power (dBmV) :
Timing Offset (97.6 ns):
Initial Timing Offset :
Rng Timing Adj Moving Avg(0.381 ns):
Rng Timing Adj Lt Moving Avg :
Rng Timing Adj Minimum :
Rng Timing Adj Maximum :
Pre-EQ Good :
Pre-EQ Scaled :
Pre-EQ Impulse :
Pre-EQ Direct Loads :
Good Codewords rx :
Corrected Codewords rx :
Uncorrectable Codewords rx :
Phy Operating Mode :
sysDescr : TWC AWG Cable Modem: <>
Downstream Power : 0.80 dBmV (SNR = 39.90 dB)
MAC Version : DOC1.0
QoS Provisioned Mode : DOC1.0
Enable DOCSIS2.0 Mode : Y
Modem Status : {Modem= offline, Security=disabled}
Capabilities : {Frag=N, Concat=Y, PHS=Y}
Security Capabilities : {Priv=, EAE=Y, Key_len=}
L2VPN Capabilities : {L2VPN=Y, eSAFE=N}
Sid/Said Limit : {Max US Sids=16, Max DS Saids=15}
Optional Filtering Support : {802.1P=N, 802.1Q=N, DUT=Y}
Transmit Equalizer Support : {Taps/Symbol= 1, Num of Taps= 24}
Number of CPE IPs : 0(Max CPE IPs = 16)
CFG Max-CPE : 5
Flaps : 148(Nov 22 17:54:53)
Errors : 0 CRCs, 0 HCSes
Stn Mtn Failures : 0 aborts, 3 exhausted
Total US Flows : 1(1 active)
Total DS Flows : 1(1 active)
Total US Data : 0 packets, 0 bytes
Total US Throughput : 0 bits/sec, 0 packets/sec
Total DS Data : 0 packets, 0 bytes
Total DS Throughput : 0 bits/sec, 0 packets/sec
LB group ID assigned (index) : N/A (N/A)
LB group ID in config file (index) : N/A (N/A)
LB policy ID : 0
LB policy ID in config file : 0
LB priority : 0
Tag :
Required DS Attribute Mask : 0x0
Forbidden DS Attribute Mask : 0x0
Required US Attribute Mask : 0x0
Forbidden US Attribute Mask : 0x0
Service Type ID :
Service Type ID in config file :
Active Classifiers : 0 (Max = NO LIMIT)
CM Upstream Filter Group : 0
CM Downstream Filter Group : 0
CPE Upstream Filter Group : 0
CPE Downstream Filter Group : 0
DSA/DSX messages : permit all
Voice Enabled : NO
DS Change Times : 0
Boolean Services : 6
Number of Multicast DSIDs Support : 16
MDF Capability Mode : 2
IGMP/MLD Version : IGMPv3
FCType10 Forwarding Support : Y
Features Bitmask : 0x0
Total Time Online : 00:00 (00:00 since last counter reset)
CM Initialization Reason : NO_PRIM_SF_USCHAN
CFG Max IPv6 CPE Prefix : 16 (-1 used)
interface Cable8/0/0
downstream Integrated-Cable 8/0/0 rf-channel 0-3
downstream Integrated-Cable 8/0/1 rf-channel 0-3
downstream Integrated-Cable 8/0/4 rf-channel 0-3
no cable mtc-mode
cable cm-status enable 3 6-10
cable shared-secret 7 091E1E58490616100709
no cable packet-cache
cable default-phy-burst 0
cable bundle 1
cable upstream max-ports 8
cable upstream 0 connector 0
cable upstream 0 frequency 22800000
cable upstream 0 channel-width 6400000 6400000
cable upstream 0 description Rolloff at 32.8
cable upstream 0 docsis-mode atdma
cable upstream 0 minislot-size 1
cable upstream 0 range-backoff 3 6
cable upstream 0 modulation-profile 221
cable upstream 0 equalization-coefficient
cable upstream 0 shutdown
cable upstream 1 connector 1
cable upstream 1 frequency 29400000
cable upstream 1 channel-width 6400000 3200000
cable upstream 1 docsis-mode atdma
cable upstream 1 minislot-size 2
cable upstream 1 range-backoff 3 6
cable upstream 1 modulation-profile 221 223
cable upstream 1 equalization-coefficient
no cable upstream 1 shutdown
cable upstream 2 connector 2
cable upstream 2 frequency 22800000
cable upstream 2 channel-width 6400000 3200000
cable upstream 2 docsis-mode atdma
cable upstream 2 minislot-size 4
cable upstream 2 range-backoff 3 6
cable upstream 2 modulation-profile 222 223
cable upstream 2 equalization-coefficient
no cable upstream 2 shutdown
cable upstream 3 connector 3
cable upstream 3 frequency 17800000
cable upstream 3 channel-width 3200000 1600000
cable upstream 3 docsis-mode atdma
cable upstream 3 minislot-size 2
cable upstream 3 range-backoff 3 6
cable upstream 3 modulation-profile 221 223
cable upstream 3 equalization-coefficient
no cable upstream 3 shutdown
cable upstream 4 connector 4
cable upstream 4 frequency 15300000
cable upstream 4 channel-width 1600000 1600000
cable upstream 4 docsis-mode atdma
cable upstream 4 minislot-size 4
cable upstream 4 range-backoff 3 6
cable upstream 4 modulation-profile 221 223
cable upstream 4 equalization-coefficient
no cable upstream 4 shutdown
cable upstream 5 connector 5
cable upstream 5 frequency 13600000
cable upstream 5 channel-width 1600000 1600000
cable upstream 5 docsis-mode tdma-atdma
cable upstream 5 minislot-size 4
cable upstream 5 range-backoff 3 6
cable upstream 5 modulation-profile 121
cable upstream 5 equalization-coefficient
cable upstream 5 shutdown
cable upstream 6 connector 6
cable upstream 6 channel-width 3200000 1600000
cable upstream 6 docsis-mode atdma
cable upstream 6 minislot-size 4
cable upstream 6 range-backoff 3 6
cable upstream 6 modulation-profile 221
cable upstream 6 equalization-coefficient
cable upstream 6 shutdown
cable upstream 7 connector 7
cable upstream 7 frequency 17100000
cable upstream 7 channel-width 1600000 1600000
cable upstream 7 docsis-mode atdma
cable upstream 7 minislot-size 4
cable upstream 7 range-backoff 3 6
cable upstream 7 modulation-profile 221
cable upstream 7 equalization-coefficient
cable upstream 7 shutdown
cable privacy accept-self-signed-certificate
cable privacy skip-validity-period
interface Integrated-Cable8/0/0:0
shutdown
cable bundle 1
cable rf-bandwidth-percent 30 remaining ratio 100
!
interface Integrated-Cable8/0/0:1
cable bundle 1
cable rf-bandwidth-percent 30 remaining ratio 100
!
interface Integrated-Cable8/0/0:2
cable bundle 1
cable rf-bandwidth-percent 30 remaining ratio 100
!
interface Integrated-Cable8/0/0:3
cable bundle 1
cable rf-bandwidth-percent 30 remaining ratio 100
!
interface Integrated-Cable8/0/1:0
cable bundle 1
cable rf-bandwidth-percent 10 remaining ratio 100
!
interface Integrated-Cable8/0/1:1
cable bundle 1
cable rf-bandwidth-percent 10 remaining ratio 100
!
interface Integrated-Cable8/0/1:2
cable bundle 1
cable rf-bandwidth-percent 10 remaining ratio 100
!
interface Integrated-Cable8/0/1:3
cable bundle 1
cable rf-bandwidth-percent 10 remaining ratio 100
!
interface Integrated-Cable8/0/2:0
shutdown
cable bundle 1
cable rf-bandwidth-percent 30 remaining ratio 100
!
interface Integrated-Cable8/0/2:1
cable bundle 1
cable rf-bandwidth-percent 30 remaining ratio 100
!
interface Integrated-Cable8/0/2:2
cable bundle 1
cable rf-bandwidth-percent 30 remaining ratio 100
!
interface Integrated-Cable8/0/2:3
cable bundle 1
cable rf-bandwidth-percent 30 remaining ratio 100
!
interface Integrated-Cable8/0/3:0
cable bundle 1
cable rf-bandwidth-percent 30 remaining ratio 100
!
interface Integrated-Cable8/0/3:1
cable bundle 1
cable rf-bandwidth-percent 30 remaining ratio 100
!
interface Integrated-Cable8/0/3:2
cable bundle 1
cable rf-bandwidth-percent 30 remaining ratio 100
!
interface Integrated-Cable8/0/3:3
cable bundle 1
cable rf-bandwidth-percent 30 remaining ratio 100
!
interface Integrated-Cable8/0/4:0
cable bundle 1
cable rf-bandwidth-percent 30 remaining ratio 100
!
interface Integrated-Cable8/0/4:1
cable bundle 1
cable rf-bandwidth-percent 30 remaining ratio 100
!
interface Integrated-Cable8/0/4:2
cable bundle 1
cable rf-bandwidth-percent 30 remaining ratio 100
!
interface Integrated-Cable8/0/4:3
cable bundle 1
cable rf-bandwidth-percent 30 remaining ratio 100
!
interface Wideband-Cable8/0/0:0
cable bundle 1
cable rf-channel 0 bandwidth-percent 20 remaining ratio 100
cable rf-channel 1 bandwidth-percent 20 remaining ratio 100
cable rf-channel 2 bandwidth-percent 20 remaining ratio 100
cable rf-channel 3 bandwidth-percent 20 remaining ratio 100
!
interface Wideband-Cable8/0/1:0
cable bundle 1
cable rf-channel 0 bandwidth-percent 20 remaining ratio 100
cable rf-channel 1 bandwidth-percent 20 remaining ratio 100
cable rf-channel 2 bandwidth-percent 20 remaining ratio 100
cable rf-channel 3 bandwidth-percent 20 remaining ratio 100
!
interface Wideband-Cable8/0/2:0
cable bundle 1
cable rf-channel 0 bandwidth-percent 20 remaining ratio 100
cable rf-channel 1 bandwidth-percent 20 remaining ratio 100
cable rf-channel 2 bandwidth-percent 20 remaining ratio 100
cable rf-channel 3 bandwidth-percent 20 remaining ratio 100
!
interface Wideband-Cable8/0/3:0
cable bundle 1
cable rf-channel 0 bandwidth-percent 20 remaining ratio 100
cable rf-channel 1 bandwidth-percent 20 remaining ratio 100
cable rf-channel 2 bandwidth-percent 20 remaining ratio 100
cable rf-channel 3 bandwidth-percent 20 remaining ratio 100
!
interface Wideband-Cable8/0/4:0
cable bundle 1
cable rf-channel 0 bandwidth-percent 20 remaining ratio 100
cable rf-channel 1 bandwidth-percent 20 remaining ratio 100
cable rf-channel 2 bandwidth-percent 20 remaining ratio 100
cable rf-channel 3 bandwidth-percent 20 remaining ratio 100
Mod IUC Type Pre Diff FEC FEC Scrmb Max Guard Last Scrmb Pre Pre RS
len enco T k seed B time CW offst Type
BYTE BYTE siz size short
21 request qpsk 36 no 0x0 0x10 0x152 0 22 no yes 0 qpsk na
21 initial qpsk 98 no 0x5 0x22 0x152 0 48 no yes 0 qpsk na
21 station qpsk 98 no 0x5 0x22 0x152 0 48 no yes 0 qpsk na
21 short qpsk 64 no 0x3 0x4C 0x152 12 22 yes yes 0 qpsk na
21 long qpsk 64 no 0x9 0xE8 0x152 0 22 yes yes 0 qpsk na
121 request qpsk 36 no 0x0 0x10 0x152 0 22 no yes 0 qpsk na
121 initial qpsk 98 no 0x5 0x22 0x152 0 48 no yes 0 qpsk na
121 station qpsk 98 no 0x5 0x22 0x152 0 48 no yes 0 qpsk na
121 short qpsk 64 no 0x3 0x4C 0x152 12 22 yes yes 0 qpsk na
121 long qpsk 64 no 0x9 0xE8 0x152 0 22 yes yes 0 qpsk na
121 a-short 64qam 64 no 0x6 0x4C 0x152 6 22 yes yes 0 qpsk1 no
121 a-long 64qam 64 no 0x9 0xE8 0x152 0 22 yes yes 0 qpsk1 no
121 a-ugs 64qam 64 no 0x9 0xE8 0x152 0 22 yes yes 0 qpsk1 no
221 request qpsk 36 no 0x0 0x10 0x152 0 22 no yes 0 qpsk0 no
221 initial qpsk 98 no 0x5 0x22 0x152 0 48 no yes 0 qpsk0 no
221 station qpsk 98 no 0x5 0x22 0x152 0 48 no yes 0 qpsk0 no
221 a-short 64qam 64 no 0x6 0x4C 0x152 6 22 yes yes 0 qpsk1 no
221 a-long 64qam 64 no 0x9 0xE8 0x152 0 22 yes yes 0 qpsk1 no
221 a-ugs 64qam 64 no 0x9 0xE8 0x152 0 22 yes yes 0 qpsk1 no
222 request qpsk 36 no 0x0 0x10 0x152 0 22 no yes 0 qpsk0 no
222 initial qpsk 98 no 0x5 0x22 0x152 0 48 no yes 0 qpsk0 no
222 station qpsk 98 no 0x5 0x22 0x152 0 48 no yes 0 qpsk0 no
222 a-short 16qam 64 no 0x4 0x4C 0x152 7 22 yes yes 0 qpsk1 no
222 a-long 16qam 64 no 0xA 0xDC 0x152 0 22 yes yes 0 qpsk1 no
222 a-ugs 16qam 64 no 0xA 0xDC 0x152 0 22 yes yes 0 qpsk1 no
223 request qpsk 36 no 0x0 0x10 0x152 0 22 no yes 0 qpsk0 no
223 initial qpsk 98 no 0x5 0x22 0x152 0 48 no yes 0 qpsk0 no
223 station qpsk 98 no 0x5 0x22 0x152 0 48 no yes 0 qpsk0 no
223 a-short qpsk 64 no 0x3 0x4C 0x152 12 22 yes yes 0 qpsk0 no
223 a-long qpsk 64 no 0x9 0xE8 0x152 0 22 yes yes 0 qpsk0 no
223 a-ugs qpsk 64 no 0x9 0xE8 0x152 0 22 yes yes 0 qpsk0 no
321 request qpsk 64 no 0x0 0x10 0x152 0 0 no yes 0 qpsk0 na
321 initial qpsk 98 no 0x5 0x22 0x152 0 0 no yes 0 qpsk0 na
321 station qpsk 98 no 0x5 0x22 0x152 0 0 no yes 0 qpsk0 na
321 a-short 64qam 64 no 0x6 0x4C 0x152 6 0 yes yes 0 qpsk1 na
321 a-long 64qam 64 no 0x9 0xE8 0x152 0 0 yes yes 0 qpsk1 na
321 a-ugs 64qam 64 no 0x9 0xE8 0x152 0 0 yes yes 0 qpsk1 na
Cable8/0/0/U0 admindown 158 * * * interface is down * * * 0 0
Cable8/0/0/U1 29.400 MHz 158 * * * set to fixed frequency * * * 766990 83348
Cable8/0/0/U2 22.800 MHz 158 * * * set to fixed frequency * * * 1085467 175072
Cable8/0/0/U3 17.800 MHz 158 * * * set to fixed frequency * * * 0 0
Cable8/0/0/U4 15.300 MHz 158 * * * set to fixed frequency * * * 0 0
Cable8/0/0/U5 admindown 158 * * * interface is down * * * 11600651 539439
Cable8/0/0/U6 admindown 158 * * * interface is down * * * 0 0
Cable8/0/0/U7 admindown 158 * * * interface is down * * * 0 0
Fiber-Node 1
Channel(s) : downstream Integrated-Cable 8/0/0: 0-3
Channel ID(s): 145, 146, 147, 148
Channel(s) : downstream Integrated-Cable 8/0/1: 0-3
Channel ID(s): 149, 150, 151, 152
Channel(s) : downstream Integrated-Cable 8/0/4: 0-3
Channel ID(s): 161, 162, 163, 164
upstream Cable 8/0: 0-9
FN Config Status: Configured (status flags = 0x01)
MDD Status: Valid
Why do you have these interfaces shutdown
interface Integrated-Cable8/0/0:0
and
interface Integrated-Cable8/0/2:0
Currently chan 96 is video, so 97,98,99 are data. Moving 96 to 95 and turning that on on dec 5. I didn’t realize mc20x20 controllers required 4 contiguous... have a mix of filters out there... old internet only windows filters that open fm band and above 70. Locals only filters 23-70 so that is another load balancing problem... upstream SNR is great I don’t understand why modems are resetting...I have mtc disables right now as that seemed to be creating one more issue
Not sure that shutting the "interface integrated-cable" is correct way to skip a channel
This may give unexpected results like the 4-way bonding group now being unusable
If it were me, I would probably fully disable like this :
* shutdown that channel in "controller integrated-cable"
* remove that channel from "interface cable" (this will automatically remove it from "interface integrated-cable")
* remove that channel from the "interface wideband-cable", leaving you with 3way bonding for now
* remove that channel from "cable fiber-node"
* remove that channel from "cable load-balance docsis-group"
Awaiting results..
controller integrated-cable shut...
removed from interface cable
removed from wideband
removed from fiber node
removed from load balance
Still getting reports of modems coming online for a few minutes, then restarting. No flap generated, if I ping I can see it drop but I can't seem to get any other info.
There are a few things you can try
1) look at the event log in the affected cable modem to see if there are any clues
2) turn on some debugging in cmts, eg debug cable mac-address xxxx.xxxx.xxxx, debug cable reg, debug cable tlv, term mon, etc
3) upgrade modem firmware to latest
4) simplify cm config file, temporarily remove any fancy vendor specific mibs
5) simplify cmts configs, temporarily remove load-balance, bonding etc
6) enable telnet access on the modem, then telnet in (from LAN side if need be) and watch the boot logs. This is the best way to solve complex problems.
Hey Mbowe is there any chance I can hire you for a consult or? email me ray at sanjuancable dot com please
I don't do paid consulting, but if you wanted to give me a login, I am happy to have a snoop around and see if I can work out your problem.
What problems are you presenting?
So I think my problem may be related to downstream service groups, but I have no idea how to control them. In the following there are 3 fiber nodes represented 8/0/0, 8/1/0, and 8/1/2, all of these show as the same MD-DS-SG or one with !1.
MAC Address IP Address I/F MAC Prim RCC MD-DS-SG/
State Sid ID MD-US-SG
b077.ac90.244c 10.0.14.219 C8/0/0/U2 w-online(pt) 1536 3 !1 / N/A
20e5.64ea.2b76 10.0.14.87 C8/0/0/U2 w-online(pt) 5192 7 2 / N/A
e86d.5271.0c10 10.0.10.127 C8/1/0/U1 w-online(pt) 7054 5 !1 / N/A
cc7d.376b.1003 10.0.10.130 C8/1/0/U2 w-online(pt) 7056 5 2 / N/A
b077.ac8e.e0c7 10.0.11.176 C8/1/2/U1 w-online(pt) 635 5 2 / N/A
20e5.6460.71b3 10.0.10.222 C8/1/2/U2 w-online(pt) 637 5 2 / N/A
e86d.5271.27d3 10.0.11.21 C8/1/2/U1 w-online(pt) 638 5 2 / N/A
show cable fiber-node
---------------------------------------------------------------------------------
Fiber-Node 1
Description: Fiber Node A
Channel(s) : downstream Integrated-Cable 8/0/0: 1-3
Channel ID(s): 146, 147, 148
Channel(s) : downstream Integrated-Cable 8/0/1: 0-3
Channel ID(s): 149, 150, 151, 152
Channel(s) : downstream Integrated-Cable 8/0/4: 0-3
Channel ID(s): 161, 162, 163, 164
upstream Cable 8/0: 0-9
FN Config Status: Configured (status flags = 0x01)
MDD Status: Valid
---------------------------------------------------------------------------------
Fiber-Node 2
Description: Node B
Channel(s) : downstream Integrated-Cable 8/0/2: 1-3
Channel ID(s): 154, 155, 156
Channel(s) : downstream Integrated-Cable 8/0/3: 0-3
Channel ID(s): 157, 158, 159, 160
upstream Cable 8/0: 10-19
FN Config Status: Configured (status flags = 0x01)
MDD Status: Valid
---------------------------------------------------------------------------------
Fiber-Node 3
Description: Noisyt Node 3
Channel(s) : downstream Integrated-Cable 8/1/0: 1-3
Channel ID(s): 146, 147, 148
Channel(s) : downstream Integrated-Cable 8/1/1: 0-3
Channel ID(s): 149, 150, 151, 152
Channel(s) : downstream Integrated-Cable 8/1/4: 0-3
Channel ID(s): 161, 162, 163, 164
upstream Cable 8/1: 0-9
FN Config Status: Configured (status flags = 0x01)
MDD Status: Valid
---------------------------------------------------------------------------------
Fiber-Node 4
Description: Noisy Node 4
Channel(s) : downstream Integrated-Cable 8/1/2: 1-3
Channel ID(s): 154, 155, 156
Channel(s) : downstream Integrated-Cable 8/1/3: 0-3
Channel ID(s): 157, 158, 159, 160
upstream Cable 8/1: 10-19
FN Config Status: Configured (status flags = 0x01)
MDD Status: Valid
show cable mac-domain cable 8/0/0 rcc
RCC-ID RCP RCs MD-DS-SG CMs WB/RCC-TMPL
3 00 00 00 00 00 4 0 1 WB (Wi8/0/4:0)
7 00 00 00 00 00 4 0 0 WB (Wi8/0/1:0)
8 00 00 00 00 00 3 0 0 WB (Wi8/0/0:0)
show cable mac-domain cable 8/0/2 rcc
RCC-ID RCP RCs MD-DS-SG CMs WB/RCC-TMPL
1 00 00 00 00 00 3 0 0 WB (Wi8/0/2:0)
2 00 00 00 00 00 4 0 0 WB (Wi8/0/3:0)
#show cable mac-domain cable 8/0/0 downstream-service-group
Cable MD-DS-SG RF
IF Id Resource Chan Primary Chan
C8/0/0 2 8/0/0 01-03 1 2 3
8/0/1 00-03 0 1 2 3
8/0/4 00-03 0 1 2 3
#show cable mac-domain cable 8/0/2 downstream-service-group
Cable MD-DS-SG RF
IF Id Resource Chan Primary Chan
C8/0/2 2 8/0/2 01-03 1 2 3
8/0/3 00-03 0 1 2 3
Do I need to assign RCC templates or???
1/ You should try to configure 1 downstream-service-group with 8 Downstreams (4 + 4) because your modem have 8 DS and actually they synchronize 4DS due to your DOCSIS 3 configuration and 1DS only (in DOCSIS 2?) with the remaining 4 DS...
2/ You should configure service-group on the upstream part also
3/ you should try to understand syslog messages of your modems (available in your monitoring system)
--------------
DS BONDING
You should NOT configure any 8 way DS bonding on this network, because you don't have 8 contiguous DS channels.
If you configure an 8 way bonding group spanning non-contiguous blocks of 4, then most 8 DS modems will not like this. It is a limitation of the tuner chips in the older 8x4 modems.
Best bet is to work on migrating all your CMTS frequencies into blocks of 8. This will ensure your 8x4 modems will always be happy.
Multiple blocks of 8 can be spread around the channel plan without problem, because 16/24/32 tuner modems are "full band capture" and don't have any such limitation. You can build 16way, 24way and 32way bonding groups from the various blocks of 8.
--------------
US BONDING
US channel bonding has been turned off for now, because the average modem USPWR was too high (bonding reduces the max allowed USPWR)
If you can get the typical modem USPWR down to low/mid 40's, then yes, recommend to go back and turn on US channel bonding. This will give more speed and more even spread of utilisation.
I think you can set 2 blocks of 4 ds with continous frequencies in each blocks to build 8ds bonding . You have 2 dvb tuners in your modems which explain that they actually synchronize 5 ds: 1 block you configure but the other tuner ranged wildly on one other frequencie...
Yes you can have limitations : i used to work with 3 ds modems which synchronize 1 narrow freq and 2 others continous wideband frequencies which must be less that 200Mhz far from the first one
So as long your modems synchronize 5 ds this will explain that they are not happy
Do you use "load-balance"?
After logging in, cmts tries to transfer the modem to another DS (in case of a need), enable debugging of this modem.
Is this a problem with one modem or more?
Customers often exchange power supplies from the router to the modem and the same symptom as you describe.