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First Published: January 8, 2009
The Cisco RF Gateway 10 (RFGW-10) Universal Edge Quadrature Amplitude Modulation (UEQAM) supports the DOCSIS Timing Interface (DTI) Offset feature to enable Data Over Cable Service Interface Specification (DOCSIS) timing offset adjustment.
Your software release may not support all the features documented in this module. For the latest feature information and caveats, see the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the “Feature Information for DTI Offset” section.
Use Cisco Feature Navigator to find information about platform support and Cisco IOS, Catalyst OS, and Cisco IOS XE software image support. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.
The DTI Offset feature enables DOCSIS timing offset adjustment per channel in the Cisco RFGW-10 UEQAM line card. You should measure the actual timing offset adjustment on each QAM channel. To configure all the QAM ports to the same timing offset, use the port range command. With this command, you can configure an entire chassis with the same timing offset.
In a line card redundancy scenario, the timing offset command is synchronized to the redundant line card like other QAM configuration commands. The Standby line card will have the same timing offset setting as the Active line card. If the Active and the Standby line cards have different timing offsets in the hardware, then the operator must adjust the timing offset for every QAM.
This section describes how to configure DTI Offset in Cisco RFGW-10 UEQAM:
This section describes how to set the timing offset adjustment at the RF port level using the CLI.
The prerequisites for setting the timing offset adjustment at RF port level are:
The following example shows how to configure the timing offset adjustment on slot 7, RF port 3:
All the QAM channels in RF port 3 in slot 7 (QAM 7/3.1, QAM 7/3.2, QAM 7/3.2, and QAM 7/3.4) are configured with the new offset value.
In the example, the time stamp is reduced by 950 ticks. If the cable modem attached to QAM channel 1 in RF port 3 shows the timing offset as 2000, the new timing offset value is adjusted to 1050. If the cable modem attached to QAM channel 2 in RF port 3 shows the timing offset as 900, then the new timing offset is –50.
Note If the line card is part of the line card redundancy (LCRED) configuration, qam-red should be used instead of qam for the QAM ports in the interface qam command.
This section describes how to set the timing offset adjustment at the QAM level using the CLI.
The following example shows how to configure the timing offset adjustment on slot 7, RF port 3, channel 1:
The timing offset value of 7/3.1 channel will only be adjusted.
In the above example, the time stamp is adjusted by 150 ticks. If the cable modem attached to slot 7, RF port 3, QAM channel 1 shows the timing offset as 1000, the new timing offset value is adjusted to 850. The timing offset value of the cable modems attached to the other QAM channels in slot 7, RF port 3 are not adjusted.
Note If the line card is part of the line card redundancy (LCRED) configuration, qam-red should be used instead of qam for the QAM interfaces in the interface qam command.
This section describes how to set the same timing offset adjustment at the chassis level using the CLI.
3. interface range qam slot/port range, qam slot/port range,...
The following example shows how to configure the timing offset adjustment on line card slots 3 and 5, RF port range 1 to 12:
The timing offset value of line card slots 3 and 5 is adjusted by 150 ticks.
To display the timing offset value, use the following command:
The following is sample output of the command:
The following sections provide references related to the DTI Offset feature.
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Cisco RF Gateway 10 Command Reference http://www.cisco.com/en/US/docs/cable/rf_gateway/command/reference/RFGW-10_Book.html |
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Cisco RF Gateway 10 Software Feature and Configuration Guide http://www.cisco.com/en/US/docs/cable/rf_gateway/feature/guide/rfgw_scg.html |
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No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature. |
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No new or modified RFCs are supported by this feature, and support for existing RFCs has not been modified by this feature. |
The following commands are introduced or modified in the feature or features documented in this module. For information about these commands, see the Cisco RF Gateway 10 Command Reference at http://www.cisco.com/en/US/docs/cable/rf_gateway/command/reference/RFGW-10_Book.html. For information about all Cisco IOS commands, use the Command Lookup Tool at http://tools.cisco.com/Support/CLILookup or the Cisco IOS Master Command List, All Releases, at http://www.cisco.com/en/US/docs/ios/mcl/allreleasemcl/all_book.html.
Table 1 lists the release history for this feature.
Not all commands may be available in your Cisco IOS software release. For release information about a specific command, see the command reference documentation.
Use Cisco Feature Navigator to find information about platform support and software image support. Cisco Feature Navigator enables you to determine which Cisco IOS, Catalyst OS, and Cisco IOS XE software images support a specific software release, feature set, or platform. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.
Note Table 1 lists only the Cisco IOS software release that introduced support for a given feature in a given Cisco IOS software release train. Unless noted otherwise, subsequent releases of that Cisco IOS software release train also support that feature.
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This feature was introduced in the Cisco IOS Release 12.2(44)SQ to support the Cisco RF Gateway 10. |
DEPI—Downstream External PHY Interface
DOCSIS—Data Over Cable Service Interface Specification
EQAM—Edge Quadrature Amplitude Modulation. A network element, which receives MPEG-TS frames over a network interface such as Ethernet, and modulates them onto QAM carriers for use on an HFC plant.