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UBR10k MC20x20 Docsis 3.0 bonding...

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windwaterwaves
UBR10k MC20x20 Docsis 3.0 bonding...

So I have been working on this for a few weeks, done a lot of reading through the forums, read a lot of mbowe's posts and have things sort of working but I have a lot of questions. I also converted to docsis load-balancing which seems to have given me some problems. The main problem is now I have random modems that worked before but now sync then reboot and the states are odd and nowhere to be found on the internet... Last night I went to a clients house his modem offline, tried a different modem offline, checked multiple outlets no go (apartment) took it to the mdu panel, both modems lit up, go back inside, no go, go back to mdu runs perfect. this is a new facility and the other 5 apartments are fine. (is there a modem file i can force on some of these to get them online for diag?) I am using tdma, tdma-atdma and atdma modes across the 7 upstream channels.

I need diagnostic commands and some sense as to wth is going on, I am finally getting used to the controller, mac, integrated, wideband organization (which is shit btw)

I will post the config at the end for one of the i/f

Here is my show cable modem offline,

Interface MAC address Prim Previous Offline Rx Rx SM
Sid State Time Power SNR Exhaust
Count
C8/0/0/U0 e483.9920.0a72 1204 cc-pending Nov 9 08:33:03 -0.50 36.1 4
C8/0/2/U7 0025.f1e9.e225 79 reject(c) Nov 7 23:22:33 -0.50 36.1 96
C8/0/2/U5 0012.2586.8fec 86 online(pt) Nov 8 15:06:28 !-1.00 36.1 14
C8/0/2/U6 0018.c0d7.1f22 25 cc-pending Nov 9 08:26:45 !-4.00 36.1 33
C8/0/2/U6 b077.ac90.244c 92 cc-pending Nov 9 08:25:45 !-2.00 36.1 1
C8/1/0/U1 0016.b52f.a43a 56 online(pt) Nov 8 14:56:50 1.00 36.1 6
C8/1/0/U0 0025.f123.8610 67 online(pt) Nov 8 16:52:32 0.50 32.5 1
C8/1/2/UB 20e5.645f.20cc 17 reject(na) Nov 8 18:44:35 !0.00 33.6 33

Here is one of the modems verbose .. upstream power shows 54 yet rx pwr says !-4.00. This is an ANCIENT plant I am upgrading although I have one brand new section (2012) where I am having similar problems..

show cable modem 0018.c0d7.1f22 verbose

MAC Address : 0018.c0d7.1f22
IP Address : 10.0.14.135
IPv6 Address : ---
Dual IP : N
Prim Sid : 25
Host Interface : C8/0/2/U6
MD-DS-SG / MD-US-SG : 1 / N/A
MD-CM-SG : 0x5C0100
Primary Downstream : In8/0/2:3 (RfId : 1011)
Wideband Capable : N
RCP Index : 0
RCP ID : 00 00 00 00 00
Downstream Channel DCID RF Channel : 148 8/0/2:3
Multi-Transmit Channel Mode : N
Extended Upstream Transmit Power : 0dB
Upstream Channel : US6
Ranging Status : sta
Upstream Power (dBmV) : 54.00
Upstream SNR (dB) : 36.12
Upstream Data SNR (dB) : --
Received Power (dBmV) :!-4.00
Timing Offset (97.6 ns): 1465
Initial Timing Offset : 1465
Rng Timing Adj Moving Avg(0.381 ns): -136
Rng Timing Adj Lt Moving Avg : -65
Rng Timing Adj Minimum : -256
Rng Timing Adj Maximum : 0
Pre-EQ Good : 289
Pre-EQ Scaled : 0
Pre-EQ Impulse : 0
Pre-EQ Direct Loads : 0
Good Codewords rx : 112654
Corrected Codewords rx : 4
Uncorrectable Codewords rx : 7
Phy Operating Mode : atdma
sysDescr : <>
Downstream Power : -1.00 dBmV (SNR = 33.40 dB)
MAC Version : DOC2.0
QoS Provisioned Mode : DOC1.1
Enable DOCSIS2.0 Mode : Y
Modem Status : {Modem= online(pt), Security=assign(tek)}
Capabilities : {Frag=Y, Concat=Y, PHS=Y}
Security Capabilities : {Priv=BPI+, EAE=N, Key_len=56}
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 : 1(Max CPE IPs = 16)
CFG Max-CPE : 5
Flaps : 262(Nov 9 08:31:53)
Errors : 0 CRCs, 0 HCSes
Stn Mtn Failures : 0 aborts, 34 exhausted
Total US Flows : 1(1 active)
Total DS Flows : 1(1 active)
Total US Data : 5793 packets, 1438537 bytes
Total US Throughput : 12501 bits/sec, 5 packets/sec
Total DS Data : 6348 packets, 6043065 bytes
Total DS Throughput : 25209 bits/sec, 6 packets/sec
LB group ID assigned (index) : 8020 (82)
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 : 0
Number of Multicast DSIDs Support : 16
MDF Capability Mode : 1
IGMP/MLD Version : IGMPv3
FCType10 Forwarding Support : Y
Features Bitmask : 0x0
Total Time Online : 02:57 (02:57 since last counter reset)
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
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 bonding-group 80
upstream 0
upstream 6
upstream 7
attributes 80000000
cable upstream 0 connector 0
cable upstream 0 frequency 19600000
cable upstream 0 channel-width 3200000 3200000
cable upstream 0 docsis-mode atdma
cable upstream 0 minislot-size 2
cable upstream 0 range-backoff 3 6
cable upstream 0 modulation-profile 221
cable upstream 0 equalization-coefficient
no cable upstream 0 shutdown
cable upstream 1 connector 1
cable upstream 1 frequency 12150000
cable upstream 1 channel-width 1600000 1600000
cable upstream 1 docsis-mode tdma-atdma
cable upstream 1 minislot-size 4
cable upstream 1 range-backoff 3 6
cable upstream 1 modulation-profile 121
cable upstream 1 equalization-coefficient
no cable upstream 1 shutdown
cable upstream 2 connector 2
cable upstream 2 frequency 22900000
cable upstream 2 channel-width 3200000 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 221
cable upstream 2 equalization-coefficient
cable upstream 2 shutdown
cable upstream 3 connector 3
cable upstream 3 frequency 13800000
cable upstream 3 channel-width 1600000 1600000
cable upstream 3 docsis-mode atdma
cable upstream 3 minislot-size 4
cable upstream 3 range-backoff 3 6
cable upstream 3 modulation-profile 221
cable upstream 3 equalization-coefficient
no cable upstream 3 shutdown
cable upstream 4 connector 4
cable upstream 4 frequency 26200000
cable upstream 4 channel-width 3200000 3200000
cable upstream 4 docsis-mode tdma-atdma
cable upstream 4 minislot-size 4
cable upstream 4 range-backoff 3 6
cable upstream 4 modulation-profile 121
cable upstream 4 equalization-coefficient
no cable upstream 4 shutdown
cable upstream 5 connector 5
cable upstream 5 frequency 15450000
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
no cable upstream 5 shutdown
cable upstream 6 connector 6
cable upstream 6 frequency 29500000
cable upstream 6 channel-width 3200000 1600000
cable upstream 6 description HighFlapRate
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
no cable upstream 7 shutdown
cable privacy accept-self-signed-certificate
cable privacy skip-validity-period

controller Integrated-Cable 8/0/0
rf-channel 0 cable downstream channel-id 145
rf-channel 0 frequency 99000000 annex B modulation 256qam interleave 32
rf-channel 0 rf-power 48.0
rf-channel 0 rf-shutdown
rf-channel 1 cable downstream channel-id 146
rf-channel 1 frequency 105000000 annex B modulation 256qam interleave 32
rf-channel 1 rf-power 48.0
no rf-channel 1 rf-shutdown
rf-channel 2 cable downstream channel-id 147
rf-channel 2 frequency 111000000 annex B modulation 256qam interleave 32
rf-channel 2 rf-power 48.0
no rf-channel 2 rf-shutdown
rf-channel 3 cable downstream channel-id 148
rf-channel 3 frequency 117000000 annex B modulation 256qam interleave 32
rf-channel 3 rf-power 48.0
no rf-channel 3 rf-shutdown
description KwinaNode
!
controller Integrated-Cable 8/0/1
rf-channel 0 cable downstream channel-id 149
rf-channel 0 frequency 525000000 annex B modulation 256qam interleave 32
rf-channel 0 rf-power 50.0
no rf-channel 0 rf-shutdown
rf-channel 1 cable downstream channel-id 150
rf-channel 1 frequency 531000000 annex B modulation 256qam interleave 32
rf-channel 1 rf-power 50.0
no rf-channel 1 rf-shutdown
rf-channel 2 cable downstream channel-id 151
rf-channel 2 frequency 537000000 annex B modulation 256qam interleave 32
rf-channel 2 rf-power 50.0
no rf-channel 2 rf-shutdown
rf-channel 3 cable downstream channel-id 152
rf-channel 3 frequency 543000000 annex B modulation 256qam interleave 32
rf-channel 3 rf-power 50.0
no rf-channel 3 rf-shutdown
!
controller Integrated-Cable 8/0/2
rf-channel 0 cable downstream channel-id 145
rf-channel 0 frequency 99000000 annex B modulation 256qam interleave 32
rf-channel 0 rf-power 48.0
rf-channel 0 rf-shutdown
rf-channel 1 cable downstream channel-id 146
rf-channel 1 frequency 105000000 annex B modulation 256qam interleave 32
rf-channel 1 rf-power 48.0
no rf-channel 1 rf-shutdown
rf-channel 2 cable downstream channel-id 147
rf-channel 2 frequency 111000000 annex B modulation 256qam interleave 32
rf-channel 2 rf-power 48.0
no rf-channel 2 rf-shutdown
rf-channel 3 cable downstream channel-id 148
rf-channel 3 frequency 117000000 annex B modulation 256qam interleave 32
rf-channel 3 rf-power 48.0
no rf-channel 3 rf-shutdown
description Robertson
!
controller Integrated-Cable 8/0/3
rf-channel 0 cable downstream channel-id 157
rf-channel 0 frequency 525000000 annex B modulation 256qam interleave 32
rf-channel 0 rf-power 52.0
no rf-channel 0 rf-shutdown
rf-channel 1 cable downstream channel-id 158
rf-channel 1 frequency 531000000 annex B modulation 256qam interleave 32
rf-channel 1 rf-power 52.0
no rf-channel 1 rf-shutdown
rf-channel 2 cable downstream channel-id 159
rf-channel 2 frequency 537000000 annex B modulation 256qam interleave 32
rf-channel 2 rf-power 52.0
no rf-channel 2 rf-shutdown
rf-channel 3 cable downstream channel-id 160
rf-channel 3 frequency 543000000 annex B modulation 256qam interleave 32
rf-channel 3 rf-power 52.0
no rf-channel 3 rf-shutdown
!
controller Integrated-Cable 8/0/4
rf-channel 0 cable downstream channel-id 161
rf-channel 0 frequency 141000000 annex B modulation 256qam interleave 32
rf-channel 0 rf-power 48.0
no rf-channel 0 rf-shutdown
rf-channel 1 cable downstream channel-id 162
rf-channel 1 frequency 147000000 annex B modulation 256qam interleave 32
rf-channel 1 rf-power 48.0
no rf-channel 1 rf-shutdown
rf-channel 2 cable downstream channel-id 163
rf-channel 2 frequency 153000000 annex B modulation 256qam interleave 32
rf-channel 2 rf-power 48.0
no rf-channel 2 rf-shutdown
rf-channel 3 cable downstream channel-id 164
rf-channel 3 frequency 159000000 annex B modulation 256qam interleave 32
rf-channel 3 rf-power 48.0
no rf-channel 3 rf-shutdown

cable load-balance docsis-group 8000
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
upstream Cable8/0/0 0-7

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-Cable8/0/4:0
shutdown
cable bundle 1
cable rf-bandwidth-percent 30 remaining ratio 100
!
interface Integrated-Cable8/0/4:1
shutdown
cable bundle 1
cable rf-bandwidth-percent 30 remaining ratio 100
!
interface Integrated-Cable8/0/4:2
shutdown
cable bundle 1
cable rf-bandwidth-percent 30 remaining ratio 100
!
interface Integrated-Cable8/0/4:3
shutdown
cable bundle 1
cable rf-bandwidth-percent 30 remaining ratio 100
!
.. abbreviated I am trying to only do docsis 3 on wideband 8/0/4:0

interface Wideband-Cable8/0/0:0
shutdown
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
shutdown
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

mbowe
Some feedback

Hi, some feedback for you :

------------------------------
1/ POWER LEVELS :

The CMTS wants all modems to be received at the same level (0dBmV)

CMTS will keep track of the receive levels for each modem, and if they are not 0, it will individually instruct the modem to increase or decrease its transmit power appropriately

In your example, the modem is being received at -4, so the CMTS will say to that modem, hey please increase your power by 4

But that modem has got trouble, it is already transmitting at 54, which is the max it can do

The CMTS has asked the modem to increase power multiple times, the modem cannot do it, so the CMTS has marked that modem with the ! symbol as a warning to you

US channel bonding can have an impact here too. The more channels you bond, the less the max transmit level will be.

Ideally modems will be transmitting in the low 40's. If there are just some sections of the network with this high transmit problem, then perhaps have a look at your attenuation / reverse-align / amplifier balance etc in that section. If it's all modems then probably you need to remove some attenuation in the headend for your upstream paths.

------------------------------
2/ CC-PENDING

If you have DOCSIS load-balancing enabled, the CMTS is trying to evenly distribute the modems across the DS and US channels. If there is an imbalance it will ask the modem to change channel

You can see the list of modems currently being changed :
"show cable load-balance pending"

If you do "show cable modem" during a change, you will often see the modem "cc-pending" (change channel pending). If everything is working correctly, this state is pretty brief, maybe a couple of seconds only.

If the modem gets stuck in this state, there can be a few reasons such as :
* the modem is in the process of trying to change, but can't for some reason (destination upstream channel is not working or has bad signal levels)
* the modem has a bug (we saw this recently on our network with EPC3940 and US load-balance init-tech 0). We temporarily worked around that until by telling CMTS not to use that particular method, until we got the vendor to fix the bug / patch their firmware.

------------------------------
3/ reject(c), reject(n/a)

Reject means registration failed

Can be due to things like :
* CM config file refers to a service-class which does not exist on the CMTS
* missing DOCSIS stanzas in the CM config file, eg some modems require all the BPI config lines to be present
* some sort of invalid MIB in the CM config files

If you have telnet access to the modem, just telnet in and watch it spit the error

If you dont have telnet access, you can start remarking more and more stuff from the config file until you hopefully find the offending lines(s).

Another trick can be to debug on the CMTS eg
debug cable mac-address xxxx.xxxx.xxx
debug cable reg
debug cable tlv
term mon
etc

------------------------------
4/ Network design

Can you please describe what you are trying to achieve :
* are you sharing the cable plant with other equipment eg TV
* how many nodes do you have connected to this CMTS?
* how many linecards do you have in this CMTS?
* are your nodes connected to CMTS via fiber? Or is it only coax.
* what is your upstream split (max upstream frequency). Probably 42MHz.
* what sort of modems do you have deployed : DOCSIS 1.0, DOCSIS 1.1, DOCSIS2.0, DOCSIS 3.0
* how many channels downstream bonding do you want? 4, 8, 12 ?
* how many channels upstream bonding? 2, 3, 4 ?
* what version IOS does your ubr10k have. eg 12.2(33)SCH4
* what model PRE does your ubr10k have. eg PRE2, PRE4

I see you have pasted most of the required fragments. You didn't paste your cable fiber-node stanza. You have a few parts shut down. Cant really provide much useful commentary though until you give some more information on the design you are trying to achieve.

windwaterwaves
Wow great info thank you

Yes this is a very old analog system, so we have TV & data. we have many old sections with 440, so tilt can be pretty bad.
Ouch.. we standardized at 0db/50db so 85% of our modems are over 50db sounds like I have some work to do. On d1.1/2.0 we see +/-10rx, +60max Tx
4 nodes, 2 fiber, 2 coax
2 mc20x20 - ds 0,1,4 wired to large coverage, 2,3 wired to smaller on both cards. one node only has an old SA with 38mhz cut? otherwise 5/42
SB5100,5101,sbg901,sbg900, sbg941 (1.1/2.0) testing sbg6580, sb6141 (d3)
I am trying to maximize throughput across the system, just added controller 4 to two segments. bond 4 is fine but can there be multiple groups.. and load balancing.
upstream I was trying to bond 4 can I mix tdma/atdma. All modems are currently running 10/1 our docsis 2.0 bus class is 20/4 but it doesn't do well. I want the D3 to be 25/5, and offer a 50/10.
PRE4 card

mbowe
edit: moved my comment to

edit: moved my comment to your next reply

windwaterwaves
Upstream disable

So I put no mtc-mode on a couple of interfaces and those units came online! It is definitely a power issue, I noticed extended power mode as well.

What do I put in the modem config file to prevent it if I want to enable it only for certain customers.... :)

mbowe
Your modem list is all DOCSIS

Your modem list is all DOCSIS 2.0 or better, so you don't need to keep TDMA. Just run only ATDMA on all upstreams. This is more efficient than mixed-mode ("tdma-atdma").

How many DS channels are available for the CMTS to use? I see you are currently using 12 channels :
* 99, 105, 111, 117
* 525, 531, 537, 543 <-- Don't deploy this block into any nodes that have 440 cutoff!
* 141, 147, 153, 159
Have you got any more spectrum available in your channel plan which could be used by the CMTS?
Ideally you want 1 or more blocks of 8 contiguous channels (even if you have to renumber some TV channels).
Even better, if you can get 1 x block of 12 contiguous channels it opens up some really good/efficient options for 20x20 card wiring.
Otherwise, some more blocks of 4 would be better than nothing.

Yes you can have multiple bonding groups configured for each node.
Like what you have already done with your 3 x interface wideband8/0/x:0
You just need to unshut your interface Wideband-Cable8/0/0:0 and interface Wideband-Cable8/0/1:0
Each primary downstream channel ("downstream Integrated-Cable x/x/x:x" listed inside "interface cable x/x/x") should be covered by at least 1 bonding group.

For your upstreams, you want to stay as high frequency as possible. Frequencies below 20MHz are usually going to be pretty noisy.
If it were me, I would start up near cutoff eg 40MHz if you have a 42MHz cut, and then start creating 6.4MHz channels from the top down. eg
US0 - 36.8 width 6.4, fallback width 3.2. 64QAM, fallback 16QAM.
US1 - 30.4 width 6.4, fallback width 3.2. 64QAM, fallback 16QAM.
US2 - 24.0 width 6.4, fallback width 3.2. 64QAM, fallback 16QAM.
Perhaps leave 0.5MHz between the channels if you need somewhere to put some sweep insertion points.
As you go lower in frequency, then start dropping the default width and/or QAM.
If US2 above is always noisy, then perhaps replace it with 2 x 3.2MHz channels.
3.2MHz will give you 3dB better SNR compared to 6.4MHz.
1.6MHz will give you 3dB better SNR compared to 3.2MHz.

Keep in mind that 1 x 6.4MHz channel is more efficient than 2 x 3.2MHz channels.
And 1 x 3.2MHz channel is more efficient than 2 x 1.6MHz channels.
Less wasted space for the guard bands.
And less ports used on the CMTS, which allows for more channels to be deployed (more speed) and/or less return path combining (less noise)

2 x MC20x20V going to 4 nodes, with PRE4. This is sufficient resources to allow speeds of 50/10. Particularly if you can find some more DS spectrum for the CMTS to use.

50dB average is pretty high but may work OK single US channel, but that level isn't going to be good if you want to deploy US channel bonding. Hopefully you can remove some headend attenuation to allow a bit more headroom (but watch out, as it also reduces your US SNR).

As a compromise, rather than running 4 x US bonding, you could create multiple 2 x channel groups instead. This gains you some of the efficiencies of bonding without causing too much impact to the max modem transmit levels. Most DOCSIS 3.0 modems also support another feature called extended upstream transmit power, which is a setting you put in the CM config file, and you can allow the modems to run a few dB higher transmit than the default.

Worst case, I suppose you could just not deploy US channel bonding. Instead try and get some 6.4MHz 64QAM US channels going. No bonding is not great though, as you can end up with some channels getting hammered, while others are sitting idle. (You would know this already with your DOCSIS 2.0 modems...) Channel bonding is a lot better because it spreads the load more evenly across the channels.

windwaterwaves
Fallback? Modulation profiles?

How do you do the fallbacks and modulation profiles? I have one section now running all atdma but getting all modems online is a challenge, I will change upstream padding and watch snr.

mbowe
tweaks

interface cable 8/0/0
! upstream defaults to 6.4 width, fallback to 3.2 if bad SNR, CNR, or uncorrectables
cable upstream 0 channel-width 64000000 32000000
! default minislot-size is 1 for 6.4 width. Better performance if you set it to 2.
cable upstream 0 minislot-size 2
! default modulation is 64QAM, will drop to 16QAM if bad SNR, CNR, or uncorrectables
cable upstream 0 modulation-profile 221 223
! atdma only. Don't need tdma if you have only docsis2.0 or better modems deployed.
cable upstream 0 docsis-mode atdma