Broadband Access Aggregation and DSL Configuration Guide, Cisco IOS Release 12.4T
Virtual Auxiliary Port Feature and Configuration of DSL Settings
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Virtual Auxiliary Port Feature and Configuration of DSL Settings

Last Updated: December 5, 2011

The virtual auxiliary port feature provides support for dial backup and out-of-band management on Cisco 837 and Cisco 831 routers, and provides support for out-of-band management on Cisco SOHO 97 and Cisco SOHO 91 routers. On these routers, the console port and the auxiliary port share the same physical RJ-45 port. The console port must be changed to act as a virtual auxiliary port, using the command-line interface (CLI) before the dial backup and out-of-band management capabilities can be enabled.

In addition, digital subscriber line (DSL) settings can now be configured on the Cisco 837, Cisco 831, Cisco SOHO 97, and Cisco SOHO 91 routers by using the DSL settings commands.

Finding Feature Information

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 Table at the end of this document.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.

Information About the Virtual Auxiliary Port

When the virtual auxiliary port is enabled, the signals directed from the RJ-45 pins are processed by the auxiliary port driver, and the console port is disabled. The virtual auxiliary port can be used to provide the standard Cisco IOS interactive user interface.

How to Configure the Virtual Auxiliary Port and the DSL Settings

Configuring the Virtual Auxiliary Port

Perform these steps to configure the virtual auxiliary port.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    line con0

4.    modem enable


DETAILED STEPS
 Command or ActionPurpose
Step 1
enable


Example:

Router> enable

 

Enables privileged EXEC mode.

  • Enter your password if prompted.
 
Step 2
configure terminal


Example:

Router# configure terminal

 

Enters global configuration mode.

 
Step 3
line con0


Example:

Router(config)# line con0

 

Enters line configuration mode for the console interface.

 
Step 4
modem enable


Example:

Router(config-line)# modem enable

 

Changes the console port to function as an auxiliary port.

 

Configuring the DSL Settings

Perform these steps to configure the DSL settings.


Note
For each DSL setting to take effect, the asymmetric digital subscriber line (ADSL) driver resets the ADSL subsystem, which causes the firmware to be downloaded again.
SUMMARY STEPS

1.    enable

2.    configure terminal

3.    interface atm0

4.    dsl noise-margin decimal

5.    end

6.    enable

7.    configure terminal

8.    interface atm0

9.    dsl max-tone-bits integer

10.    end

11.    enable

12.    configure terminal

13.    interface atm0

14.    dsl gain-setting tx-offset decimal

15.    end

16.    enable

17.    configure terminal

18.    interface atm0

19.    dsl gain-setting rx-offset decimal

20.    end


DETAILED STEPS
 Command or ActionPurpose
Step 1
enable


Example:

Router> enable

 

Enables privileged EXEC mode.

  • Enter your password if prompted.
 
Step 2
configure terminal


Example:

Router# configure terminal

 

Enters global configuration mode.

 
Step 3
interface atm0


Example:

Router(config)# interface atm0

 

Enters interface configuration mode.

 
Step 4
dsl noise-margin decimal


Example:

Router(config-if)# dsl noise-margin 0.5

 

Sets the noise margin offset.

  • Decimal ranges from -3 dB to 3 dB with a granularity of 0.5 dB.
 
Step 5
end


Example:

Router(config-if)# end

 

Exits interface configuration mode and resets the ADSL subsystem.

 
Step 6
enable


Example:

Router> enable

 

Enables privileged EXEC mode.

  • Enter your password if prompted.
 
Step 7
configure terminal


Example:

Router# configure terminal

 

Enters global configuration mode.

 
Step 8
interface atm0


Example:

Router(config)# interface atm0

 

Enters interface configuration mode.

 
Step 9
dsl max-tone-bits integer


Example:

Router(config-if)# max-tone-bits 10

 

Sets the maximum bits per tone limit.

  • Integer ranges from 2 dB to 14 dB with a granularity of 1 dB.
 
Step 10
end


Example:

Router(config-if)# end

 

Exits interface configuration mode and resets the ADSL subsystem.

 
Step 11
enable


Example:

Router> enable

 

Enables privileged EXEC mode.

  • Enter your password if prompted.
 
Step 12
configure terminal


Example:

Router# configure terminal

 

Enters global configuration mode.

 
Step 13
interface atm0


Example:

Router(config)# interface atm0

 

Enters interface configuration mode.

 
Step 14
dsl gain-setting tx-offset decimal


Example:

Router(config-if)# dsl gain-setting tx-offset 0

 

Sets the transmit gain offset.

  • Decimal ranges from -10 dB to 3 dB with a granularity of 0.5 dB.
 
Step 15
end


Example:

Router(config-if)# end

 

Exits interface configuration mode and resets the ADSL subsystem.

 
Step 16
enable


Example:

Router> enable

 

Enables privileged EXEC mode.

  • Enter your password if prompted.
 
Step 17
configure terminal


Example:

Router# configure terminal

 

Enters global configuration mode.

 
Step 18
interface atm0


Example:

Router(config)# interface atm0

 

Enters interface configuration mode.

 
Step 19
dsl gain-setting rx-offset decimal


Example:

Router(config-if)# dsl gain-setting rx-offset 1

 

Sets the receive gain offset.

  • Decimal ranges from -5 dB to 3 dB with a granularity of 0.5 dB.
 
Step 20
end


Example:

Router(config-if)# end

 

Ends the configuration mode.

 

Configuration Example for Configuring the DSL Settings

interface atm0
no ip address
dsl noise-margin 0
dsl max-tone-bits 14
dsl gain-setting tx-offset 0
dsl gain-setting rx-offset 1

Additional References

Related Documents

Related Topic

Document Title

Configuring Dial Backup

Cisco 826, 827, 828, 831, 836, and 837 and Cisco SOHO 76, 77, 78, 91, 96, and 97 Routers Software Configuration Guide

Standards

Standards1

Title

No new or modified standards are supported by this feature. Support for existing standards has not been modified by this feature.

1 Not all supported standards are listed.

MIBs

MIBs2

MIBs Link

No new or modified MIBs are supported by this feature. Support for existing MIBs has not been modified by this feature.

To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator available at the following URL:

http://www.cisco.com/go/mibs

2 Not all supported MIBs are listed.

RFCs

RFCs3

Title

No new or modified RFCs are supported by this feature. Support for existing RFCs has not been modified by this feature.

3 Not all supported RFCs are listed.

Technical Assistance

Description

Link

Technical Assistance Center (TAC) home page, containing 30,000 pages of searchable technical content, including links to products, technologies, solutions, technical tips, and tools. Registered Cisco.com users can log in from this page to access even more content.

http://www.cisco.com/public/support/tac/home.shtml

Feature Information for Configuring the DSL Settings

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.

Table 1Feature Information for Phrase Based on Module Title

Feature Name

Releases

Feature Information

Virtual Auxiliary Port Feature and Configuration of DSL Settings

12.2(8)YN 12.3(2)T

The virtual auxiliary port feature provides support for dial backup and out-of-band management on Cisco 837 and Cisco 831 routers, and provides support for out-of-band management on Cisco SOHO 97 and Cisco SOHO 91 routers. On these routers, the console port and the auxiliary port share the same physical RJ-45 port. The console port must be changed to act as a virtual auxiliary port, using the command-line interface (CLI) before the dial backup and out-of-band management capabilities can be enabled.

In addition, digital subscriber line (DSL) settings can now be configured on the Cisco 837, Cisco 831, Cisco SOHO 97, and Cisco SOHO 91 routers by using the DSL settings commands.

The following commands were introduced or modified: modem enable, dsl max-tone-bits, dsl gain-setting rx-offset, dsl gain-setting rx-offset, dsl gain-setting tx-offset, dsl noise-margin.

Cisco and the Cisco logo are trademarks or registered trademarks of Cisco and/or its affiliates in the U.S. and other countries. To view a list of Cisco trademarks, go to this URL: www.cisco.com/go/trademarks. Third-party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (1110R)

Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.

1 Not all supported standards are listed.
2 Not all supported MIBs are listed.
3 Not all supported RFCs are listed.
© 2011 Cisco Systems, Inc. All rights reserved.