Table Of Contents

Monitoring and Retraining on Reception of Loss of Margin Messages

Contents

Information About Monitoring and Retraining on Reception of Loss of Margin Messages

ATM Technology

DSL Technology

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

Enabling LOM Monitoring

Verifying LOM Monitoring

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

Enabling LoM Monitoring: Example

Additional References

Related Documents

Standards

MIBs

RFCs

Technical Assistance

Command List

Monitoring and Retraining on Reception of Loss of Margin Messages

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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.

Feature History for the Monitoring and Retraining on Reception of Loss of Margin Messages Feature

Release	Modification
12.3(2)T	This feature was introduced.

Finding Support Information for Platforms and Cisco IOS Software Images

Use Cisco Feature Navigator to find information about platform support and Cisco IOS software image support. Access Cisco Feature Navigator at http://www.cisco.com/go/fn. You must have an account on Cisco.com. If you do not have an account or have forgotten your username or password, click Cancel at the login dialog box and follow the instructions that appear.

Contents

•Information About Monitoring and Retraining on Reception of Loss of Margin Messages

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

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

•Additional References

•Command List

Information About Monitoring and Retraining on Reception of Loss of Margin Messages

To configure the Monitoring and Retraining on Reception of Loss of Margin Messages feature, you should understand the following concepts:

•ATM Technology

•DSL Technology

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

This section contains the following procedure:

•Enabling LOM Monitoring

Enabling LOM Monitoring

To enable LOM monitoring, perform the following steps:

SUMMARY STEPS

1. enable

2. configure terminal

3. interface atm

4. dsl lom number

5. end

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.

Verifying LOM Monitoring

To verify the LOM monitoring configuration, enter the show dsl interface atm command in EXEC mode.

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

This section provides the following configuration example:

•Enabling LoM Monitoring: Example

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

The following sections provide references related to Monitoring and Retraining on Reception of Loss of Margin Messages.

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

Command List

The following commands are introduced or modified in the feature or features documented in this module. For information about these commands, see the Cisco IOS Broadband Access Aggregation and DSL Command Reference at http://www.cisco.com/en/US/docs/ios/bbdsl/command/reference/bba_book.html. For information about all Cisco IOS commands, go to the Command Lookup Tool at http://tools.cisco.com/Support/CLILookup or to the Cisco IOS Master Commands List.

•dsl lom

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