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EnasYorl
Thieves World

join:2001-12-02
West
Reviews:
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1 edit

1 recommendation

Technical Discussion of Upstream Channel Bonding

Split from this topic.
The original post in this topic is a reply to this post. ~sorto'


It is very unlikely that the 16QAM channel (Upstream4) is being bonded. Your modem is just detecting it. One would bond similar Channel Types as they have same modulation scheme and bandwidth.

»www.cisco.com/en/US/tech/tk86/tk···c3.shtml



EG
The wings of love
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join:2006-11-18
Union, NJ
kudos:9

1 edit

said by EnasYorl:

It is very unlikely that the 16QAM channel (Upstream4) is being bonded. Your modem is just detecting it. One would bond similar Channel Types as they have same modulation scheme and bandwidth.

»www.cisco.com/en/US/tech/tk86/tk···c3.shtml

Please point out something specific in that article. My understanding has been that dissimilar channels can indeed be bonded.


EnasYorl
Thieves World

join:2001-12-02
West
Reviews:
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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
 

And

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
 

Also there level differences when using different modulation schemes.

This article talks more about the modulation power of bonding channels. »www.cisco.com/en/US/docs/ios/cab···p1181735

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.
 
 

So in short maybe it can be done in a lab (I've yet to see anyone show it done), but I would bet money that no one bonds those different modulation schemes in the real world deployment.


netcool
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1 edit

said by EnasYorl:

So in short maybe it can be done in a lab (I've yet to see anyone show it done), but I would bet money that no one bonds those different modulation schemes in the real world deployment.

You would lose that bet.

Look through this thread, many many people have bonded channels using different modulation profiles.

I myself have two channels bonded, one TDMA and one ATDMA. It also helps that I can login to the CMTS to verify as well


EnasYorl
Thieves World

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said by netcool:

said by EnasYorl:

So in short maybe it can be done in a lab (I've yet to see anyone show it done), but I would bet money that no one bonds those different modulation schemes in the real world deployment.

You would lose that bet.

Look through this thread, many many people have bonded channels using different modulation profiles.

I myself have two channels bonded, one TDMA and one ATDMA. It also helps that I can login to the CMTS to verify as well ;)

So in GW, CO you are saying your bonding 1.1 and 2.0 upstreams?

Care to show your modem?

DownstreamBonding Channel Value
Channel ID101 102 103 104 
Frequency567000000 Hz 573000000 Hz 579000000 Hz 585000000 Hz 
Signal to Noise Ratio35 dB 35 dB 35 dB 35 dB 
Downstream ModulationQAM256 QAM256 QAM256 QAM256 
Power Level
The Downstream Power Level reading is a snapshot taken at the time this page was requested. Please Reload/Refresh this Page for a new reading
-3 dBmV  -3 dBmV  -4 dBmV  -4 dBmV  
UpstreamBonding Channel Value
Channel ID4 3 
Frequency22800000 Hz 32400000 Hz 
Ranging Service ID7409 7409 
Symbol Rate5.120 Msym/sec 5.120 Msym/sec 
Power Level49 dBmV 49 dBmV 
Upstream Modulation[3] QPSK
[3] 64QAM
 [3] QPSK
[3] 64QAM
 
Ranging StatusSuccess Success 
Signal Stats (Codewords)Bonding Channel Value
Channel ID101 102 103 104 
Total Unerrored Codewords197599661448 25800590019 25800424592 25800201713 
Total Correctable Codewords2663474 3045577 3211190 3432391 
Total Uncorrectable Codewords2718 2495 2439 1619 
 

Now looking at this data from my two upsteams what modulation is Really in use QPSK or 64 QAM? is the Modem accurate with it's data or is it false? I can tell you for a long time I had both carriers present but they were not bonded until recently as my modem is one of the few that will indicate true bonding.

Upstream Bonding Channel Value
Channel ID 4 3
Frequency 22800000 Hz 32400000 Hz
Ranging Service ID 7409 7409
Symbol Rate 5.120 Msym/sec 5.120 Msym/sec
Power Level 49 dBmV 49 dBmV
Upstream Modulation [3] QPSK
[3] 64QAM
[3] QPSK
[3] 64QAM

I will throw in the CMTS command info as well
cable upstream docsis-mode
 
To configure an upstream to use DOCSIS 1.x, DOCSIS 2.0 or DOCSIS 3.0 modulation profiles, use the cable upstream docsis-mode command in cable interface configuration mode. To reset the upstream to its default configuration, use the no form of this command.
 
cable upstream n docsis-mode {atdma | scdma | scdma-d3 | tdma | tdma-atdma}
 
no cable upstream n docsis-mode {atdma | scdma | scdma-d3 | tdma | tdma-atdma}
 
Syntax Description
 
n
 
Specifies the upstream port. Valid values start with 0 for the first upstream port on the cable interface line card.
 
atdma
 
Configures the upstream only for DOCSIS 2.0 Advanced Time Division Multiple Access (A-TDMA) modulation profiles.
 
scdma
 
Configures the upstream for DOCSIS 2.0 Synchronous Code Division Multiple Access (S-CDMA) modulation profiles only.
 
scdma-d3
 
Configures the upstream for DOCSIS 3.0 S-CDMA modulation profiles. The scdma-d3 option uses channel type 4SR mode.
 
tdma
 
Configures the upstream only for DOCSIS 1.0/DOCSIS 1.1 Time Division Multiple Access (TDMA) modulation profiles (default).
 
tdma-atdma
 
Configures the upstream for both A-TDMA and TDMA operations (mixed mode). If you are using abbreviations at the command line, you must specify at least the tdma to select the mixed mode. If you choose a shorter abbreviation, you select TDMA-only mode.
 
Command Default
 
All upstreams are configured TDMA-only mode (DOCSIS 1.0/DOCSIS 1.1).
 
Command Modes
 
Interface configuration (config-if)
 
Command History
 
Release
Modification
12.2(15)CX
 
This command was introduced to support DOCSIS 2.0 A-TDMA and mixed modulation profiles on the Cisco uBR-MC16U/X and Cisco uBR-MC28U/X cable interface line card on the Cisco uBR7246VXR router.
 
12.2(15)BC2
 
Support was added for the Cisco uBR-MC5X20S/U cable interface line cards on the Cisco uBR10012 router.
 
12.3BC
 
This command was integrated into Cisco IOS Release 12.3BC.
 
12.2(33)SCA
 
This command was integrated into Cisco IOS Release 12.2(33)SCA.
 
12.2(33)SCC
 
This command was modified with the addition of scdma and scdma-d3 keyword options and support was added for the Cisco UBR-MC20X20V cable interface line card on the Cisco uBR10012 router.
 
Usage Guidelines
 
The DOCSIS 2.0 specification builds on the existing TDMA to support advanced modulation profiles that increase potential upstream bandwidth. The A-TDMA profiles support higher QAM rates of up to 64-QAM and wider channel widths of up to 6.4 MHz (5.12 Msymbols).
 
NoteThe advanced hardware-based spectrum management features for the Cisco uBR-MC16S/U/X, Cisco uBR-MC28U/X, and Cisco uBR-MC5X20S/U cards are supported only in the DOCSIS 1.0/1.1 TDMA-only mode. They cannot be used in the mixed or A-TDMA-only modes.
The DOCSIS 2.0 specification allows an upstream to be configured in one of the following three modes:
 
•A-TDMA only mode—Upstreams only support cable modems that register using A-TDMA modulation profiles. The CMTS does not allow DOCSIS 1.0 and DOCSIS 1.1 cable modems to register and come online on these upstreams. The Cisco uBR-MC5X20S/U, Cisco uBR-MC16U/X, and Cisco uBR-MC28U/X cards also support 6,400,000 Hz (5,120,000 symbols/sec) when operating in DOCSIS 2.0 (A-TDMA-only) mode.
 
Changing the DOCSIS mode to A-TDMA only mode automatically changes the symbol rate to 5.12 megasymbols per second and the channel width to 6.4 MHz. It also automatically disables the dynamic upstream modulation.
 
In addition, the following are required to support the DOCSIS 2.0 A-TDMA features:
 
–Cable modems must be DOCSIS 2.0 compliant.
 
–The DOCSIS configuration file for the cable modem must either omit the DOCSIS 2.0 Enable field (TLV 39), or it must set TLV 39 to 1 (enable). If you set TLV 39 to 0 (disable), a DOCSIS 2.0 CM uses the TDMA mode.
 
–The upstream must be configured for either A-TDMA-only or mixed TDMA/A-TDMA mode.
 
•TDMA-only mode—Upstreams only support cable modems that register using TDMA modulation profiles. DOCSIS 2.0 cable modems can register on these upstreams only by using a DOCSIS 1.0/DOCSIS 1.1 modulation profile (which typically would happen only when a DOCSIS 2.0 cable modem cannot find an A-TDMA channel in its DOCSIS domain).
 
Changing the DOCSIS mode to TDMA-only mode automatically changes the symbol rate to 1.28 megasymbols per second and the channel width to 3.2 MHz. It also automatically disables the dynamic upstream modulation.
 
•Mixed mode—Upstreams support both DOCSIS 1.0/DOCSIS 1.1 cable modems using TDMA modulation profiles and DOCSIS 2.0 cable modems using A-TDMA modulation profiles. (The maximum channel width in mixed mode is 3.2 MHz.)
 
Changing the DOCSIS mode to mixed mode also automatically changes the symbol rate to 1.28 megasymbols per second and the channel width to 3.2 MHz. Dynamic upstream modulation is also automatically disabled.
 
NoteMixed mode upstreams do not support the 6.4 MHz channel width.
The DOCSIS 3.0 specification allows an upstream to be configured in one of the following modes:
 
•SCDMA-d3 mode—Upstreams only support cable modems that register using DOCSIS 3.0 S-CDMA modulation profiles.
 
•SCDMA mode—Upstreams only support cable modems that register using DOCSIS 2.0 S-CDMA modulation profiles.
 
NoteThe DOCSIS 3.0 option scdma-d3 (4SR) is available only when the CMTS is configured to operate in the global modulation profile format and is not available in the default mode. This option is available only for the Cisco UBR-MC20X20V cable interface line card, and not for other legacy line cards.
Refer to the cable upstream channel-width command for valid values of supported channel widths and DOCSIS modes for cable interfaces.
 
http://www.cisco.com/en/US/docs/ios/cable/command/reference/cbl_10_cable_u_to_cable_w.html#wp1090928

Based on the vendor information I don't believe you've proven your point.

Especially when scdma-d3 is what is needed to bond.

Configures the upstream for DOCSIS 3.0 S-CDMA modulation profiles. The scdma-d3 option uses channel type 4SR mode.


qam64qam16

@scansafe.net

1 edit

Click for full size
My modem in Aurora Colorado has shown 64qam and 16qam bonded for a loooong time now, maybe over a year


gar187er
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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.
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EnasYorl
Thieves World

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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
 
http://www.cisco.com/en/US/docs/ios/cable/command/reference/cbl_06_cable_m.html


EnasYorl
Thieves World

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Reviews:
·Anveo

1 recommendation

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



NetFixer
Snarl For The Camera Please
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reply to EnasYorl

said by EnasYorl:

It is very unlikely that the 16QAM channel (Upstream4) is being bonded. Your modem is just detecting it. One would bond similar Channel Types as they have same modulation scheme and bandwidth.

»www.cisco.com/en/US/tech/tk86/tk···c3.shtml

It may be "unlikely" in your opinion, but it is indeed done.



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We need to witness our own limits transgressed, and some life pasturing freely where we never wander.


netcool
Premium,VIP
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Englewood, CO
kudos:64
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>>
 
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netcool
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1 edit
reply to EnasYorl

Re: Technical Discussion of Upstream Channel Bonding

said by EnasYorl:

Now looking at this data from my two upsteams what modulation is Really in use QPSK or 64 QAM? is the Modem accurate with it's data or is it false?

The modem is only using QPSK to transmit station maintenance data. All other data coming from the modem is using 64QAM. So technically it's using both.

See this for additional info on configuring modulation profiles:

»www.cisco.com/en/US/tech/tk86/tk···b0.shtml


EnasYorl
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1 edit
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*
 
 

Thanks for sharing.

Reading for the geeks »www.nanog.org/meetings/nanog46/p···_N46.pdf

And just because you can do something doesn't mean you should.

This hits on some of my thoughts. »www.google.com/url?sa=t&rct=j&q=···AJmIKOvw


gar187er
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Dover, DE
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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....
--
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EnasYorl
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said by gar187er:

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....

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*
 

Simple math 0.1% of the codewords are being dropped on US0
5.4% of all traffic is being corrected from errors.

That is a large amount compared to US1 and US2

Not to mention that just 2% packet loss can cause robotic issues or gaming issues on UDP sessions.

Yes it's not an issue for TCP sessions.

33db SNR is not horrible but that looks like some noise in band.

JPnATL

join:2011-11-16
Bethlehem, GA

2 edits
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.

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EnasYorl
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reply to JPnATL

Re: Technical Discussion of Upstream Channel Bonding

said by JPnATL:

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.

This is true and the TDMA carrier listed is the 16QAM the other two are DOCSIS2.0/3.0 most likely 32 or 64QAM The issue I referred to is on the US0 ATDMA carrier.