US Cable Support > Comcast HSI > Technical Discussion of Upstream Channel Bonding

Technical Discussion of Upstream Channel Bonding

Well there are many reasons to not bond different types of carrier.

excerpts from my link.

Preambles and Constellations
 
Another key point is that ATDMA preambles are always Quadrature Phase-Shift Keying (QPSK) 0 or 1, where 0 denotes a low-power preamble and 1 denotes a high-power preamble. Original 1.x CMs use a preamble that is the same as the data, whether it is QPSK or 16-QAM. Because the preamble was a consistent pattern between two symbol landings, it was essentially bi-phase shift keying (BPSK). Figure 4 shows the new ATDMA preamble constellations.
 
Figure 4 – ATDMA Preamble Constellations
 

All commands and command outputs are as seen on a uBR10k running Cisco IOS Software Release 12.2(15)BC2a. While in the cable interface configuration, the US port can be assigned a docsis-mode as shown in this example:
 
ubr10k(config-if)# cable upstream 0 docsis-mode ?
 
  atdma       DOCSIS 2.0 ATDMA-only channel
  tdma        DOCSIS 1.x-only channel
  tdma-atdma  DOCSIS 1.x and DOCSIS 2.0 mixed channel
If ATDMA mode is selected, 1.x CMs should not even range on this US, and this information is displayed:
 
ubr10k(config-if)# cable upstream 0 docsis-mode atdma
 
%Docsis mode set to ATDMA-only (1.x CMs will go offline)
%Modulation profile set to 221
These channel widths are available:
 
ubr10k(config-if)# cable upstream 0 channel-width ?
 
  1600000     Channel width 1600 kHz, symbol rate 1280 ksym/s
  200000      Channel width 200 kHz, symbol rate 160 ksym/s
  3200000     Channel width 3200 kHz, symbol rate 2560 ksym/s
  400000      Channel width 400 kHz, symbol rate 320 ksym/s
  6400000     Channel width 6400 kHz, symbol rate 5120 ksym/s
  800000      Channel width 800 kHz, symbol rate 640 ksym/s
If a 6.4 MHz channel width is selected, the minislot changes automatically to 1 tick, and this information is displayed:
 
ubr10k(config-if)# cable upstream 0 channel-width 6400000
 
%With this channel width, the minislot size is now changed to 1 tick
Verify the interface settings with the show controller command:
 
ubr10k# show controller cable6/0/0 upstream 0
 
Cable6/0/0 Upstream 0 is up
Frequency 16 MHz, Channel Width 6.400 MHz, 64-QAM Symbol Rate 5.120 Msps
This upstream is mapped to phy port 0
Spectrum Group is overridden
SNR - Unknown - no modems online.
Nominal Input Power Level 0 dBmV, Tx Timing Offset 0
Ranging Backoff auto (Start 0, End 3)
Ranging Insertion Interval auto (60 ms)
Tx Backoff Start 3, Tx Backoff End 5
Modulation Profile Group 221
Concatenation is enabled
Fragmentation is enabled
part_id=0x0952, rev_id=0x00, rev2_id=0x00
nb_agc_thr=0x0000, nb_agc_nom=0x0000
Range Load Reg Size=0x58
Request Load Reg Size=0x0E
Minislot Size in number of Ticks is = 1
Minislot Size in Symbols = 32
Bandwidth Requests = 0x0
Piggyback Requests = 0x0
Invalid BW Requests= 0x0
Minislots Requested= 0x0
Minislots Granted  = 0x0
Minislot Size in Bytes = 24
Map Advance (Dynamic) : 2180 usecs
UCD Count = 313435
ATDMA mode enabled
 

Dynamic Range Window and Transmit Power Levels for Upstream Channel Bonding
 
The dynamic range window functionality is based on the CableLabs DOCSIS 3.0 MAC and Upper Layer Protocols Interface Specification and DOCSIS 3.0 Specification. This requires a DOCSIS 3.0 CM to have upstream transmit channel power level within a 12 dB range for all channels in its transmit channel set (TCS).
 
DOCSIS 1.x or 2.0 CMs operating with a single upstream channel, in non-MTC mode, have a higher maximum transmit power level than DOCSIS 3.0 CMs operating in the MTC mode with two or more upstream channels. That is, the maximum transmit power level per channel is reduced in the MTC mode.
 
When the upstream attenuation exceeds the maximum transmit power level, a DOCSIS 3.0 CM attempting to register in the MTC mode may fail to come online, or register in partial mode. The CM fails to register when the transmit power level of all upstream channels in its TCS exceeds the maximum transmit power level. If the CM has some upstream channels that are within the maximum transmit power level, the CM may come online in partial mode. However, the upstream channels that exceed the maximum transmit power level are marked as down and cannot be used for upstream traffic.
 
To verify the transmit power levels on a CM, use the show cable modem command with the verbose keyword. This command displays the following transmit power values for each assigned upstream channel:
 
•Reported Transmit Power—This is the reported transmit power level by the CM for each upstream channel.
 
•Minimum Transmit Power—This is the minimum transmit power level that the CM in the MTC mode could transmit at for the upstream channel.
 
•Peak Transmit Power—This is the maximum transmit power level that the CM in the MTC mode could transmit at for the upstream channel.
 
To support upstream channel bonding, the minimum transmit power must be less than or equal to the reported transmit power, and the reported transmit power must be less than or equal to the peak transmit power. The peak transmit power and minimum transmit power levels are derived from the CM TCS assignment and each individual upstream channel configuration.
 
If the minimum transmit power is higher than the reported transmit power, or the reported transmit power is higher than the peak transmit power, the CM may not come online or may register in partial mode.
 
You can troubleshoot this transmit power problem in the following two ways:
 
•Insert an additional amplifier to reduce the upstream attenuation so that the upstream transmit power falls within the allowed transmit power range (12 dB).
 
•Disable the MTC mode. To switch the CM from the MTC mode to non-MTC mode, disable the bonded-bit (bit-0) in type, length, value (TLV) 43.9.3 using the CM configuration file.
 
 

reply to EnasYorl
up bonding does indeed make use of the 16qam.....equalization on that same 16qam is not always turned on, so nodes with noise behind it will still have issues that the modem cannot overcome.
--
I'm better than you!

reply to qam64qam16
Your LED's are BLUE or Green on US indicator?

But my point before was a TDMA carrier wouldn't be bonded based on the info I posted. If you are bonding a channel that is meant for 1.1 DOCSIS modems and 3.0 modems seems like a poor design choice the Return spectrum maybe has too much noise to support multiple 64QAM channels . If both your LED's are blue DS and US, i will admit i'm blown away.

For those whom like to read more on settings in CMTS.

 
cable modulation-profile
 
To define a modulation profile for use on the router, use the cable modulation-profile command in global configuration mode. To remove the entire modulation profile or to reset a default profile to its default values, use the no form of this command.
 
DOCSIS 1.0 and 1.1 Mixed Mode:
 
cable modulation-profile profile {mix | qam-16 | qpsk | robust-mix}
 
no cable modulation-profile profile {iuc | mix | qam-16 | qpsk | robust-mix}
 
cable modulation-profile profile iuc fec-tbytes fec-len burst-len guard-t mod scrambler seed diff pre-len last-cw uw-len
 
DOCSIS 1.x/2.0 Mixed Mode:
 
cable modulation-profile profile {mix-high | mix-low | mix-mid | mix-qam | qam-16 | qpsk | robust-mix-high | robust-mix-mid | robust-mix-qam}
 
no cable modulation-profile profile {iuc | mix-high | mix-low | mix-mid | mix-qam | qam-16 | qpsk | robust-mix-high | robust-mix-mid | robust-mix-qam}
 
cable modulation-profile profile iuc fec-tbytes fec-len burst-len guard-t mod scrambler seed diff pre-len last-cw uw-len
 
DOCSIS 2.0 A-TDMA Mode:
 
cable modulation-profile profile {mix-high | mix-low | mix-mid | mix-qam | qam-8 | qam-16 | qam-32 | qam-64 | qpsk | robust-mix-high | robust-mix-low | robust-mix-mid}
 
no cable modulation-profile profile {iuc | mix-high | mix-low | mix-mid | mix-qam | qam-8 | qam-16 | qam-32 | qam-64 | qpsk | robust-mix-high | robust-mix-low | robust-mix-mid}
 
cable modulation-profile profile iuc fec-tbytes fec-len burst-len guard-t mod scrambler seed diff pre-len last-cw uw-len
 
Cisco IOS Release 12.2(33)SCC and Later
 
DOCSIS 2.0 A-TDMA Mode and DOCSIS 2.0 S-CDMA Mode:
 
cable modulation-profile profile {mix-high | mix-low | mix-mid | mix-qam | qam-16 | qpsk | robust-mix-high | robust-mix-low | robust-mix-mid}
 
no cable modulation-profile profile {iuc | mix-high | mix-low | mix-mid | mix-qam | qam-16 | qpsk | robust-mix-high | robust-mix-low | robust-mix-mid}
 
cable modulation-profile profile iuc fec-tbytes fec-len burst-len guard-t mod scrambler seed diff pre-len last-cw uw-len
 
Syntax Description
 
profile
 
Specifies the modulation profile number. The valid values for the profile number depend on the cable interface being used and the upstream's mode of operation.
 
See Table 1 for a list of valid ranges based on cable interface and modulation type.
 
In Cisco IOS Release 12.2(15)CX and later releases, you can create a maximum of 10 profiles for each mode of operation, for a total of 30 profiles. In earlier software releases, you can create a maximum of 8 profiles only for DOCSIS 1.0 and DOCSIS 1.1 mode.
 
mix
 
(DOCSIS 1.0 and DOCSIS 1.1 mode only) Creates a default QPSK/16-QAM mix modulation profile where short and long grant bursts are sent using 16-QAM, while request, initial ranging, and station maintenance bursts are sent using QPSK). The burst parameters are set to their default values for each burst type.
 
mix-high
 
(DOCSIS 1.x/2.0 mixed and DOCSIS 2.0 modes only) Creates a default QPSK/64-QAM modulation profile.
 
mix-low
 
(DOCSIS 1.x/2.0 mixed and DOCSIS 2.0 modes only) Creates a default QPSK/16-QAM modulation profile.
 
mix-mid
 
(DOCSIS 1.x/2.0 mixed and DOCSIS 2.0 A-TDMA modes only) Creates a default QPSK/32-QAM modulation profile.
 
mix-qam
 
(DOCSIS 1.x/2.0 mixed and DOCSIS 2.0 A-TDMA modes only) Creates a default 16-QAM/64-QAM modulation profile.
 
qam-8
 
(DOCSIS 2.0 A-TDMA mode only) Creates a default 8-QAM modulation profile.
 
This modulation profile is available in hidden and internal mode only from Cisco IOS Release 12.2(33)SCC onwards.
 
qam-16
 
Creates a default 16-QAM modulation profile.
 
qam-32
 
(DOCSIS 2.0 A-TDMA mode only) Creates a default 32-QAM modulation profile.
 
This modulation profile is available in hidden and internal mode only from Cisco IOS Release 12.2(33)SCC onwards.
 
qam-64
 
(DOCSIS 2.0 A-TDMA mode only) Creates a default 64-QAM modulation profile.
 
This modulation profile is available in hidden and internal mode only from Cisco IOS Release 12.2(33)SCC onwards.
 
qpsk
 
Creates a default QPSK modulation profile.
 
robust-mix
 
(DOCSIS 1.0 and DOCSIS 1.1 mode only) Creates a default QPSK/16-QAM modulation profile with a longer preamble that is more robust and more able to deal with noise on the upstream better than the mix profile.
 
robust-mix-high
 
(DOCSIS 1.x/2.0 mixed and DOCSIS 2.0 A-TDMA modes only) Creates a default QPSK/64-QAM mixed modulation profile with a longer preamble that is more robust and more able to deal with noise on the upstream better than the mix-high profile.
 
robust-mix-low
 
(DOCSIS 2.0 A-TDMA mode only) Creates a default QPSK/16-QAM modulation profile with a longer preamble that is more robust and better able to deal with noise on the upstream than the mix-low profile.
 
robust-mix-mid
 
(DOCSIS 1.x/2.0 mixed and DOCSIS 2.0 A-TDMA modes only) Creates a default QPSK/32-QAM modulation profile with a longer preamble that is more robust and better able to deal with noise on the upstream than the mix-mid profile.
 
robust-mix-qam
 
(DOCSIS 1.x/2.0 mixed mode only) Creates a default 16-QAM/64-QAM mixed modulation profile with a longer preamble that is more robust and better able to deal with noise on the upstream than the mix-qam profile.
 
iuc
 
Interval usage code. Valid entries depend on the mode of operation:
 
•If the upstream is configured for DOCSIS 1.0 and DOCSIS 1.1 modulation profiles, the valid values are initial, long, request, reqdata, short, or station.
 
•If the upstream is configured for DOCSIS 1.x and DOCSIS 2.0 mixed modulation profiles, the valid values are a-long, a-short, a-ugs, initial, long, request, reqdata, short, or station.
 
•If the upstream is configured for DOCSIS 2.0 A-TDMA modulation profiles, the valid values are a-long, a-short, a-ugs, initial, long, request, reqdata, short, or station.
 
The reqdata burst type is included as a placeholder for scripts that might reference it, but the DOCSIS MAC scheduler on the Cisco CMTS does not use this type of burst.
 
When you are using the initial and station bursts for DOCSIS 2.0 A-TDMA mode, qam-8, qam-32, and qam-64 modulation profiles are available in hidden mode only.
 
preamble
 
(DOCSIS 1.x/2.0 mixed and DOCSIS 2.0 A-TDMA modes only, for a-long and a-short options) Specifies the preamble format. Valid values are qpsk0 and qpsk1.
 
rs-interleave-depth
 
(DOCSIS 1.x/2.0 mixed and DOCSIS 2.0 A-TDMA modes only, for a-long and a-short options) Specifies the RS interleave depth. The valid range is from 0 to 114.
 
rs-interleave-block
 
(DOCSIS 1.x/2.0 mixed and DOCSIS 2.0 A-TDMA modes only, for a-long and a-short options) Specifies the RS interleave block size. The valid range is from 18 to 2048.
 
fec-tbytes
 
The number of bytes that can be corrected per FEC code word. For DOCSIS 1.0 and DOCSIS 1.1 mode, valid values are from 0 to 10 (decimal), where 0 means no FEC. For DOCSIS 2.0 A-TDMA mode, the valid values are from 0 to 16 (decimal), where 0 means no FEC.
 
fec-len
 
FEC code-word length. Valid values are from 16 to 253.
 
burst-len
 
Maximum burst length in minislots. Valid values are from 0 to 255, where 0 means no limit.
 
guard-t
 
Guard time in symbols. The time between successive bursts, with a range from 22 to 255. (In Cisco IOS Release 12.2(15)BC2 and earlier releases, the minimum guard time was 0 symbols, but we do not recommend using a guard time smaller than 22 symbols.)
 
mod
 
Modulation. Valid entries are 16qam and qpsk for DOCSIS 1.0 and DOCSIS 1.1 upstreams. Valid entries are 8qam, 16qam, 32qam, 64qam, and qpsk for DOCSIS 2.0 upstreams.
 
The qam-8, qam-32, and qam-64 modulation profiles are available in hidden and internal modes only from Cisco IOS Release 12.2(33)SCC onwards.
 
scrambler
 
Enable or disable scrambler. Valid entries are scrambler and no-scrambler.
 
seed
 
(Required if scrambler option used) Scrambler seed in hexadecimal format. Valid values are from 0x0 to 0x7FFF.
 
diff
 
Enable or disable differential encoding. Valid entries are diff and no-diff.
 
In DOCSIS 2.0 mode, differential encoding cannot be enabled for the 8-QAM, 32-QAM, and 64-QAM modulations.
 
The qam-8, qam-32, and qam-64 modulation profiles are available in hidden and internal modes only from Cisco IOS Release 12.2(33)SCC onwards.
 
pre-len
 
Preamble length in bits. Valid values are from 2 to 256.
 
last-cw
 
Handling of FEC for last code word. Valid entries are fixed for fixed code-word length and shortened for shortened last code word.
 
uw-len
 
Upstream unique word length. Enter uw8 for 8-bit unique code words or uw16 for 16-bit unique code words.
 
Command Default
 
Modulation profile 1 is defined as a qpsk Time Division Multiple Access (TDMA) profile.
 
In Cisco IOS Release 12.2(15)CX, Release 12.2(15)BC2 and later releases, additional modulation profiles are defined as the default mixed TDMA/A-TDMA profile and the default Advanced TDMA (A-TDMA) profile. See Table 1 for a list of valid ranges based on cable interface and modulation type.
 
Command Modes
 
Global configuration (config)
 
Command History
 

A interesting read as well
Webview
»docs.google.com/viewer?a=v&q=cac···RAbDv4_Q

PPT link »www.google.com/url?sa=t&rct=j&q=···fxHV8Z2A

reply to EnasYorl

reply to EnasYorl
How about an example from a live uBR10012?

ten01.sacramento.ca#sh cab modem aaaa.bbbb.cccc ver
 
MAC Address                        : aaaa.bbbb.cccc
IP Address                         : 96.xxx.xxx.xxx  
IPv6 Address                       : ---                                    
Dual IP                            : N
Prim Sid                           : 255
Host Interface                     : C5/0/0/UB
MD-DS-SG / MD-US-SG                : 1 / 23
MD-CM-SG                           : 0x117
Primary Wideband Channel ID        : 259 (Wi5/0/0:2)
Primary Downstream                 : Mo5/0/0:7 (RfId : 247)
Wideband Capable                   : Y
RCP Index                          : 3
RCP ID                             : 00 10 00 00 04
Multi-Transmit Channel Mode        : Y
Upstream Channel                   : US0        US1        US2       
Ranging Status                     : sta        sta        sta       
Upstream SNR (dB)                  : 33.1       31.76      35.18     
Received Power (dBmV)              : -0.50      0.50       0.00      
Reported Transmit Power (dBmV)     : 44.50      45.00      45.00     
Peak Transmit Power (dBmV)         : 51.00      51.00      52.00     
Minimum Transmit Power (dBmV)      : 24.00      24.00      21.00     
Timing Offset             (97.6 ns): 6589       6587       6590      
Initial Timing Offset              : 6589       6333       6333      
Rng Timing Adj Moving Avg(0.381 ns): 0          255        255       
Rng Timing Adj Lt Moving Avg       : 0          249        243       
Rng Timing Adj Minimum             : -256       0          0         
Rng Timing Adj Maximum             : 256        65024      65792     
Pre-EQ Good                        : 559242     12225      12225     
Pre-EQ Scaled                      : 2064       0          0         
Pre-EQ Impulse                     : 8          2          0         
Pre-EQ Direct Loads                : 19         0          0         
Good Codewords rx                  : 374766003  4728886    2382610   
Corrected Codewords rx             : 20311862   4280       129       
Uncorrectable Codewords rx         : 361755     1744       679       
Phy Operating Mode                 : atdma*     atdma*     tdma*     
sysDescr                           : ARRIS DOCSIS 3.0 Touchstone WideBand Cable Modem <<HW_REV: 3; VENDOR: Arris Interactive, L.L.C.; BOOTR: 1.2.1.25; SW_REV: 7.1.103; MODEL: WBM760A>>
 

reply to EnasYorl

Re: Technical Discussion of Upstream Channel Bonding

reply to netcool
US0 fighting a ton of noise there. Ton's of Corrected and Uncorrectables

Pre-EQ Good                        : 559242     12225      12225     
Pre-EQ Scaled                      : 2064       0          0         
Pre-EQ Impulse                     : 8          2          0         
Pre-EQ Direct Loads                : 19         0          0         
Good Codewords rx                  : 374766003  4728886    2382610   
Corrected Codewords rx             : 20311862   4280       129       
Uncorrectable Codewords rx         : 361755     1744       679       
Phy Operating Mode                 : atdma*     atdma*     tdma*
 
 

doesnt matter what you think....higher engineers and telecom people are doing it with success.....i work it, troubleshoot it, and make it work....its happening.....

you have them on 1 channel.....that is not a ton of noise...so please back it up.....

i would assume the 16qam is lower in the spectrum those showing more noise due to typical 5-18 garbage.....if you work in the field you know what i mean....
--
I'm better than you!

Pre-EQ Good                        : 559242     12225      12225     
Pre-EQ Scaled                      : 2064       0          0         
Pre-EQ Impulse                     : 8          2          0         
Pre-EQ Direct Loads                : 19         0          0         
Good Codewords rx                  : 374766003  4728886    2382610   
Corrected Codewords rx             : 20311862   4280       129       
Uncorrectable Codewords rx         : 361755     1744       679       
Phy Operating Mode                 : atdma*     atdma*     tdma*
 

reply to EnasYorl
Its hard to argue about something that obviously nobody is familiar with. Their is one thing that is fact not opinion and that is 16Qam is more tolerant to noise than 32 and then 64,128 and so forth.

reply to JPnATL

Re: Technical Discussion of Upstream Channel Bonding