Broadband Access Aggregation and DSL Configuration Guide, Cisco IOS Release 15MT
Monitoring and Retraining on Reception of Loss of Margin Messages
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Monitoring and Retraining on Reception of Loss of Margin Messages

Monitoring and Retraining on Reception of Loss of Margin Messages

Last Updated: December 3, 2012

Loss of Margin (LoM) monitoring allows the router to handle asymmetric digital subscriber line (ADSL) loss of margin messages received from the digital subscriber line access multiplexer (DSLAM). The dsl lom command is used to set digital subscriber line (DSL) LoM monitoring. The no dsl lom command disables LoM monitoring after the router has been configured to monitor LoM messages.

When set to monitor LoM, the router will retrain with the DSLAM when it receives LoM messages consecutively for the number of times specified in the number argument.

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and 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 module.

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 Monitoring and Retraining on Reception of Loss of Margin Messages

ATM Technology

Asynchronous Transfer Mode (ATM) is a technology designed for the high-speed transfer of voice, video, and data through public and private networks using cell relay technology. ATM is an International Telecommunication Union Telecommunication Standardization Sector (ITU-T) standard. Ongoing work on ATM standards is being done primarily by the ATM Forum, which was jointly founded by Cisco Systems, NET/ADAPTIVE, Northern Telecom, and Sprint in 1991.

A cell switching and multiplexing technology, ATM combines the benefits of circuit switching (constant transmission delay, guaranteed capacity) with those of packet switching (flexibility, efficiency for intermittent traffic). To achieve these benefits, ATM uses the following features:

  • Fixed-size cells, permitting more efficient switching in hardware than is possible with variable-length packets
  • Connection-oriented service, permitting routing of cells through the ATM network over virtual connections, sometimes called virtual circuits, using simple connection identifiers
  • Asynchronous multiplexing, permitting efficient use of bandwidth and interleaving of data of varying priority and size

The combination of these features allows ATM to provide different categories of service for different data requirements and to establish a service contract at the time a connection is set up. This means that a virtual connection of a given service category can be guaranteed a certain bandwidth, as well as other traffic parameters, for the life of the connection.

For more details on ATM Technology, refer to the following URL:

http://www.cisco.com/univercd/cc/td/doc/product/atm/c8540/12_1/pereg_1/atm_tech/index.htm

DSL Technology

Digital Subscriber Line (DSL) is a public network technology that delivers high bandwidth over conventional copper wiring at limited distances. There are four types of DSL: Asymmetric DSL (ADSL), High-Data-Rate DSL (HDSL), Single-line DSL (SDSL), and Very-high-data-rate DSL (VDSL). All are provisioned via modem pairs, with one modem located at a central office and the other at the customer site. Because most DSL technologies do not use the whole bandwidth of the twisted pair, there is room remaining for a voice channel.

For more details on DSL Technology, refer to the following URL:

http://www.cisco.com/en/US/tech/tk175/tsd_technology_support_category_home.html

How to Enable Monitoring and Retraining on Reception of Loss of Margin Messages

Enabling LOM Monitoring

To enable LOM monitoring, perform the following steps:

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    interface atm interface-number

4.    dsl lom number number

5.    end

6.    show dsl interface atm


DETAILED STEPS
  Command or Action Purpose
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 atm interface-number


Example:

Router(config)# interface atm 3

 

Configures an ATM interface and enters interface configuration mode.

 
Step 4
dsl lom number number


Example:

Router(config-if)# dsl lom 200

 

Enables LoM monitoring and checks for the specified number of consecutive LoM messages.

 
Step 5
end


Example:

Router(config-if)# end

 

Ends the current configuration session and returns to privileged EXEC mode.

 
Step 6
show dsl interface atm


Example:

Router# show dsl interface atm

 

Verifies the LOM monitoring configuration.

 

Configuration Examples for Monitoring and Retraining on Reception of Loss of Margin Messages

Enabling LoM Monitoring Example

The following example shows LoM monitoring enabled on an ATM interface with retraining configured for 200 counts:

configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
interface atm0
dsl lom 200
end
!
show run interface atm0
00:16:46: %SYS-5-CONFIG_I: Configured from console by consoleint a0
Building Configuration
Current configuration: 209 bytes
!
interface atm0
ip address 1.2.3.4 255.255.255.0
no atm ilmi-keepalive
pvc 1/40
protocol ip 1.2.3.5 broadcast
encapsulation aal5snap
!
dsl operating-mode auto
dsl lom 200
dsl power-cutback 0
end

Additional References

Related Documents

Related Topic

Document Title

Cisco IOS Release 12.3 Configuration Guides and Command References

Cisco IOS Release 12.3 Configuration Guides and Command References

Standards

Standards

Title

None

--

MIBs

MIBs

MIBs Link

  • None

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

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

RFCs

RFCs

Title

None

--

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 Monitoring and Retraining on Reception of Loss of Margin Messages

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 1 Feature Information for Phrase Based on Module Title

Feature Name

Releases

Feature Information

Monitoring and Retraining on Reception of Loss of Margin Messages

12.3(2)T

Loss of Margin (LoM) monitoring allows the router to handle asymmetric digital subscriber line (ADSL) loss of margin messages received from the digital subscriber line access multiplexer (DSLAM). The dsl lom command is used to set digital subscriber line (DSL) LoM monitoring. The no dsl lom command disables LoM monitoring after the router has been configured to monitor LoM messages.

When set to monitor LoM, the router will retrain with the DSLAM when it receives LoM messages consecutively for the number of times specified in the number argument.

The following command was introduced or modified: dsl lom.

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.

© 2012 Cisco Systems, Inc. All rights reserved.