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A QAM profile describes the common downstream channel modulator settings, referred to as physical layer parameters. This includes QAM constellation, symbol rate, interleaver-depth, spectrum-inversion, and annex.
For more information about the downstream interface configuration, see Downstream Interface Configuration.
But be aware that, if you configure annex A 6MHz or 7MHz in a QAM profile, then this QAM profile cannot be applied to a DOCSIS channel.
A QAM profile describes the common downstream channel modulator settings, referred to as physical layer parameters. This includes QAM constellation, symbol rate, interleaver-depth, spectrum-inversion, and annex.
For more information about the downstream interface configuration, see Downstream Interface Configuration.
But be aware that, if you configure annex A 6MHz or 7MHz in a QAM profile, then this QAM profile cannot be applied to a DOCSIS channel.
To configure the video QAM profile, complete the following procedure:
configure terminal
cable downstream qam-profile id
annex {A freq_spacing|B|C}
modulation value
interleaver-depth value
symbol-rate value
spectrum-inversion {on|off} [interop]
description line
The frequency spacing of 6MHz, 7MHz and 8 MHz can be selected or annex A. In this case, the QAM profile can only be applied to a video channel.
Spectrum inversion happens because of mixing processes in RF or IF electronics. Spectrum inversion allows for the adaptation of older equipment with the new plant. The mixing of I and Q are used to create a quadrant profile. For some set-tops, the inversion of the quadrant profile is needed where the axis are flipped such that I represents the X and Q represents the Y-axis. Most modern equipment can detect and resolve the inversion split.
You can change this spectrum inversion configuration on a user-defined qam-profile. It cannot be changed on a system generated qam-profile from 0 to 5.
Currently, spectrum inversion configuration in QAM profile has different results between Cisco RPD and the RPD from other vendors. Starting from Cisco IOS XE Bengaluru 17.6.1w release, a new option interop is added to the spectrum-inversion configuration command. If you configure the interop keyword, cBR-8 sends a vendor specific TLV to reverse the spectrum inversion inside the RPD. You can configure a single profile for both Cisco RPD and other vendor’s RPD using this configuration. This enables legacy set-up boxes to detect the spectrum inversion automatically.
To configure spectrum inversion on single QAM profile:
cable downstream qam-profile id
spectrum-inversion {on|off} interop cable downstream qam-profile 10
spectrum-inversion off interopWhen using the inversion flag in combination with different annex types, the following table shows the spectrum inversion output on a Cisco RPD:
|
spectrum-inversion command option |
annex A |
annex B |
annex B |
|---|---|---|---|
| on | normal | inverted | normal |
| off | inverted | normal | inverted |
| on interop | inverted | inverted | inverted |
| off interop | normal | normal | normal |
To configure the Video QAM carriers, complete the following procedure:
configure terminal
controller integrated-cable slot/bay/port
rf-channel start-channel – end-channel
type video
start-frequency frequency
rf-output normal
power-adjust number
qam-profile qam-profile number
 Note |
For video provisioning, the carriers must be of type “video” in the controller integrated-cable configuration. |
To verify the RF channel configuration, use the Show controller integrated-cable rf-chan command as shown in the example below:
Router#show controllers integrated-Cable 9/0/7 rf-channel 0-10
Load for five secs: 6%/0%; one minute: 5%; five minutes: 5%
Chan State Admin Frequency Type Annex Mod srate Interleaver dcid power output
0 UP UP 100000000 VIDEO A 256 5361 I12-J17 - 34.0 NORMAL
1 UP UP 106000000 VIDEO A 256 5361 I12-J17 - 34.0 NORMAL
2 UP UP 112000000 VIDEO A 256 5361 I12-J17 - 34.0 NORMAL
3 UP UP 118000000 VIDEO A 256 5361 I12-J17 - 34.0 NORMAL
4 UP UP 124000000 VIDEO A 256 5361 I12-J17 - 34.0 NORMAL
5 UP UP 130000000 VIDEO A 256 5361 I12-J17 - 34.0 NORMAL
6 UP UP 136000000 VIDEO A 256 5361 I12-J17 - 34.0 NORMAL
7 UP UP 142000000 VIDEO A 256 5361 I12-J17 - 34.0 NORMAL
8 UP UP 148000000 VIDEO A 256 5361 I12-J17 - 34.0 NORMAL
9 UP UP 154000000 VIDEO A 256 5361 I12-J17 - 34.0 NORMAL
10 UP UP 160000000 VIDEO A 256 5361 I12-J17 - 34.0 NORMAL
This section provides configuration examples for the QAM video carrier.
The following is a sample for the Video QAM carrier configuration:
Router#enable
Router(config)#cable downstream qam-profile 4
Router(config-qam-prof)#annex A 6MHz
Router(config-qam-prof)#modulation 256
Router(config-qam-prof)#interleaver-depth I32-J4
Router(config-qam-prof)#symbol-rate 5361
Router(config-qam-prof)#spectrum-inversion off
Router(config-qam-prof)#description default-annex-a-256-qam
Router(config-qam-prof)#exit
Router(config)#controller Integrated-Cable 3/0/0
Router(config-controller)#max-carrier 128
Router(config-controller)#base-channel-power 34
Router(config-controller)#freq-profile 0
Router(config-controller)#rf-chan 0 95
Router(config-rf-chan)#type video
Router(config-rf-chan)#frequency 93000000
Router(config-rf-chan)#rf-output NORMAL
Router(config-rf-chan)#power-adjust 0
Router(config-rf-chan)#docsis-channel-id 1
Router(config-rf-chan)#qam-profile 1
Use Cisco Feature Navigator to find information about the platform support and software image support. Cisco Feature Navigator enables you to determine which software images support a specific software release, feature set, or platform. To access Cisco Feature Navigator, go to the https://cfnng.cisco.com/ link. An account on the Cisco.com page is not required.
Note |
The following table lists the software release in which a given feature is introduced. Unless noted otherwise, subsequent releases of that software release train also support that feature. |
|
Feature Name |
Releases |
Feature Information |
|---|---|---|
|
QAM Video Carriers |
Cisco IOS XE Everest 16.6.1 |
This feature was integrated on the Cisco cBR Series Converged Broadband Routers. |
|
Annex A Variable Channel Witdh |
Cisco IOS XE Everest 16.6.1 |
This feature was integrated on the Cisco cBR Series Converged Broadband Routers. |
To configure the video QAM profile, complete the following procedure:
configure terminal
cable downstream qam-profile id
annex {A freq_spacing|B|C}
modulation value
interleaver-depth value
symbol-rate value
spectrum-inversion {on|off} [interop]
description line
The frequency spacing of 6MHz, 7MHz and 8 MHz can be selected or annex A. In this case, the QAM profile can only be applied to a video channel.
Spectrum inversion happens because of mixing processes in RF or IF electronics. Spectrum inversion allows for the adaptation of older equipment with the new plant. The mixing of I and Q are used to create a quadrant profile. For some set-tops, the inversion of the quadrant profile is needed where the axis are flipped such that I represents the X and Q represents the Y-axis. Most modern equipment can detect and resolve the inversion split.
You can change this spectrum inversion configuration on a user-defined qam-profile. It cannot be changed on a system generated qam-profile from 0 to 5.
Currently, spectrum inversion configuration in QAM profile has different results between Cisco RPD and the RPD from other vendors. Starting from Cisco IOS XE Bengaluru 17.6.1w release, a new option interop is added to the spectrum-inversion configuration command. If you configure the interop keyword, cBR-8 sends a vendor specific TLV to reverse the spectrum inversion inside the RPD. You can configure a single profile for both Cisco RPD and other vendor’s RPD using this configuration. This enables legacy set-up boxes to detect the spectrum inversion automatically.
To configure spectrum inversion on single QAM profile:
cable downstream qam-profile id
spectrum-inversion {on|off} interop cable downstream qam-profile 10
spectrum-inversion off interopWhen using the inversion flag in combination with different annex types, the following table shows the spectrum inversion output on a Cisco RPD:
|
spectrum-inversion command option |
annex A |
annex B |
annex B |
|---|---|---|---|
| on | normal | inverted | normal |
| off | inverted | normal | inverted |
| on interop | inverted | inverted | inverted |
| off interop | normal | normal | normal |
To configure the Video QAM carriers, complete the following procedure:
configure terminal
controller integrated-cable slot/bay/port
rf-channel start-channel – end-channel
type video
start-frequency frequency
rf-output normal
power-adjust number
qam-profile qam-profile number
Note |
For video provisioning, the carriers must be of type “video” in the controller integrated-cable configuration. |
To verify the RF channel configuration, use the Show controller integrated-cable rf-chan command as shown in the example below:
Router#show controllers integrated-Cable 9/0/7 rf-channel 0-10
Load for five secs: 6%/0%; one minute: 5%; five minutes: 5%
Chan State Admin Frequency Type Annex Mod srate Interleaver dcid power output
0 UP UP 100000000 VIDEO A 256 5361 I12-J17 - 34.0 NORMAL
1 UP UP 106000000 VIDEO A 256 5361 I12-J17 - 34.0 NORMAL
2 UP UP 112000000 VIDEO A 256 5361 I12-J17 - 34.0 NORMAL
3 UP UP 118000000 VIDEO A 256 5361 I12-J17 - 34.0 NORMAL
4 UP UP 124000000 VIDEO A 256 5361 I12-J17 - 34.0 NORMAL
5 UP UP 130000000 VIDEO A 256 5361 I12-J17 - 34.0 NORMAL
6 UP UP 136000000 VIDEO A 256 5361 I12-J17 - 34.0 NORMAL
7 UP UP 142000000 VIDEO A 256 5361 I12-J17 - 34.0 NORMAL
8 UP UP 148000000 VIDEO A 256 5361 I12-J17 - 34.0 NORMAL
9 UP UP 154000000 VIDEO A 256 5361 I12-J17 - 34.0 NORMAL
10 UP UP 160000000 VIDEO A 256 5361 I12-J17 - 34.0 NORMAL
This section provides configuration examples for the QAM video carrier.
The following is a sample for the Video QAM carrier configuration:
Router#enable
Router(config)#cable downstream qam-profile 4
Router(config-qam-prof)#annex A 6MHz
Router(config-qam-prof)#modulation 256
Router(config-qam-prof)#interleaver-depth I32-J4
Router(config-qam-prof)#symbol-rate 5361
Router(config-qam-prof)#spectrum-inversion off
Router(config-qam-prof)#description default-annex-a-256-qam
Router(config-qam-prof)#exit
Router(config)#controller Integrated-Cable 3/0/0
Router(config-controller)#max-carrier 128
Router(config-controller)#base-channel-power 34
Router(config-controller)#freq-profile 0
Router(config-controller)#rf-chan 0 95
Router(config-rf-chan)#type video
Router(config-rf-chan)#frequency 93000000
Router(config-rf-chan)#rf-output NORMAL
Router(config-rf-chan)#power-adjust 0
Router(config-rf-chan)#docsis-channel-id 1
Router(config-rf-chan)#qam-profile 1
Use Cisco Feature Navigator to find information about the platform support and software image support. Cisco Feature Navigator enables you to determine which software images support a specific software release, feature set, or platform. To access Cisco Feature Navigator, go to the https://cfnng.cisco.com/ link. An account on the Cisco.com page is not required.
Note |
The following table lists the software release in which a given feature is introduced. Unless noted otherwise, subsequent releases of that software release train also support that feature. |
|
Feature Name |
Releases |
Feature Information |
|---|---|---|
|
QAM Video Carriers |
Cisco IOS XE Everest 16.6.1 |
This feature was integrated on the Cisco cBR Series Converged Broadband Routers. |
|
Annex A Variable Channel Witdh |
Cisco IOS XE Everest 16.6.1 |
This feature was integrated on the Cisco cBR Series Converged Broadband Routers. |
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