Table of Contents

Feature Overview

Benefits
Restrictions
Related Features and Technologies
Related Documents

Supported Platforms
Supported Standards, MIBs, and RFCs
Prerequisites
Configuration Tasks

Preprovisioning a Slot for use with the 8xDMT over ISDN Line Card

Verifying the Preprovisioned Slot

Creating and Associating a DSL Profile with Each Port

Verifying the DSL Profiles

Modifying the DSL Profile
Troubleshooting Tips

Monitoring and Maintaining the 8xDMT over ISDN Line Card
Configuration Examples
Command Reference
alarms
dmt bitrate
dmt check-bytes
dmt margin
dmt minrate-blocking
dmt overhead-framing
dmt rate-adaptation enable
dmt rate-adaptation interval
dmt rate-adaptation margin
slot
Glossary

Octal-Port DMT ATU-C Over ISDN

Feature History

This document describes the Cisco IOS support for the octal-port DMT ATU-C over ISDN (8xDMT over ISDN) line card. It includes information on new and modified commands.

This document includes the following sections:

• Feature Overview

• Supported Platforms

• Supported Standards, MIBs, and RFCs

• Prerequisites

• Configuration Tasks

• Configuration Examples

• Command Reference

• Glossary

Feature Overview

The 8xDMT over ISDN line card provides higher port density for the Cisco 6015 and Cisco 6260. This line card:

• Supports eight ADSL modem connections per card.

• Converts ADSL modulation from the line card into digital data streams to and from the NI-2 card.

• Negotiates the line rate with the customer premises equipment (CPE) when it trains and bases the rate on line quality and distance.

• Provides subscriber and port provisioning through DSL profiles.

  • Allows single latency—Fast or interleaved path selection

  • Supports trellis encoding

• Interoperates with certain CPE. For more detailed information, see the "Supported Platforms" section.

Benefits

G.dmt Support (ITU G.922.1) , Annex B/ETSI

G.dmt support is provided through both the MIB and the CLI.

G.hs Support (ITU G.994.1)

G.hs support is provided through both the MIB and the CLI.

Fast or Interleaved Path Selection

You can configure the parameters for either the fast or interleaved path using the DSL profile configuration commands. Although you can configure both paths, only one path will actually be enabled (dual latency is not supported at this time). Thus the maximum bit rate for the unused path must be zero. For example, to configure and use the fast path, you must specify nonzero maximum bit rates for the fast path. Once you configure the maximum bit rates for the fast path, the rates for the interleave path must be zero. The IOS software ensures that only one path is enabled at a given time.

The fast path provides improved latency characteristics for applications that cannot tolerate latency (for example, voice). Before migrating from interleaved mode to fast path, determine whether the deployed CPEs offer support for the feature.

Trellis Encoding

Trellis encoding is a method of providing better performance in a noisy environment. It enables you to transmit at faster line rates with lower error rates, thus providing a faster overall throughput in a moderately noisy environment. You can enable or disable trellis encoding for a specific DSL profile.

Enhanced Line Quality Monitoring and Management

The 8xDMT over ISDN line card improves the manageability of DMT ports on supported DSLAMs. The following commands are used to configure this functionality:

• dmt minrate-blocking

DMT minrate-blocking customizes the DMT port reaction to lines that train below configured minimum bit rates. Formerly, a line that trained below the configured minimum bit rate generated a minor alarm, but the DMT port remained active. The dmt minrate-blocking command prevents DMT ports from training when bit rates fall below the configured minimum threshold specified in the dmt bitrate minimum command.

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Note   The default configuration, no dmt minrate-blocking, generates a minor alarm when the bit rates on a DMT port violate the minimum allowed bit rates specified in the dmt bitrate minimum command (if alarms are enabled in the DSL profile).

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• dmt rate-adaptation

The dmt rate-adaptation command causes the signal-to-noise ratio (SNR) to be monitored on DSL lines. When enabled, software monitors the upstream and downstream DMT ports for low SNR margins. When the actual upstream or downstream margin falls below the dmt rate-adaptation margin for the duration of the configured rate-adaptation interval, the line drops and attempts to retrain. If the line is able to retrain, it trains to a lower bit rate with improved SNR margins.

Restrictions

Line Card Intermixing

The 8xDMT over ISDN line card currently is only supported on chassis halves as the spectral compatibility with certain ADSL, SDSL, G.SHDSL, or IDSL line cards has not been fully assessed. If you use any of the following cards in the same chassis with an 8xDMT over ISDN line card, place them in the opposite half of the chassis:

• 4xADSL over ISDN

• 4xADSL over POTS (Annex A)

• 8xADSL over POTS (Annex A)

• 8xG.SHDSL

Minimum Line Length

Use line lengths greater than 100 meters.

Maximum Downstream Rate

Provision the maximum downstream rate to 7616 kbps or less.

Overhead Framing Mode

Modes 0, 1, and 2 are not supported. Only framing mode 3 is supported.

CPE Data Line Removal

Do NOT remove the data line from the CPE modem while voice traffic is present because the ISDN line could momentarily drop and terminate the voice line.

Interleaving Delay Parameter

Do NOT select a zero interleaving delay parameter because that parameter is likely to create a high-bit error rate with long loops. Use the default parameter.

Bit Swapping

Bit swapping is not supported.

Related Features and Technologies

The 8xDMT over ISDN line card is compatible with the Cisco 6015 and the Cisco 6260 chassis and is designed for use in a configuration with an ISDN POTS splitter. The 8xDMT over ISDN line card provisions one modem directly and is physically connected to one specific subscriber line through the POTS splitter chassis. Telco equipment includes DMT/ISDN splitters to separate or combine ISDN and DMT signals at the central office (CO) and at the customer site.

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Note   Check with a Cisco customer representative to verify ISDN POTS splitter compatibility with the 8xDMT over ISDN.

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Related Documents

Hardware Documents

A complete list of all DSL hardware product-related documentation is available on the World Wide Web at http://www.cisco.com/univercd/cc/td/doc/product/dsl_prod/index.htm .

Software Documents

A complete list of all DSL IOS software product-related documentation is available on the World Wide Web at http://www.cisco.com/univercd/cc/td/doc/product/dsl_prod/ios_dsl/index.htm .

In the ATM software product-related documentation, look for information pertaining to the Cisco LightStream 1010, which uses the same software base as the NI-2 DSL systems. This documentation is available on the World Wide Web at http://www.cisco.com/univercd/cc/td/doc/product/atm/index.htm .

Supported Platforms

DSLAMs

This feature supports the 8xDMT over ISDN line card on the Cisco 6015 and Cisco 6260 platforms with NI-2. Table 1 lists the total available ADSL modem connections for each chassis.

Supported Standards, MIBs, and RFCs

Standards

The ATU-C transceiver complies with the following standards:

• ITU G.992.1, Annex B (ADSL/ISDN)

• ITU G.994.1. (G.hs)

• ETSI TS 101 388 V.1.1.1/ TM6(98)12 (draft)

• TS102 080 v1.3.2-Support for 2B1Q and 4B3T ISDN

Standard MIBS

To obtain lists of supported MIBs sorted by platform and Cisco IOS release and to download MIB modules, go to the Cisco MIB web site on Cisco Connection Online (CCO) at the following url:

http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml

• IETF RFC 1695, Definitions of Managed Objects for ATM Management Version 8.0 using SMIv2

• IETF RFC 2662, Definitions of Managed Objects for the ADSL Line (obsoletes ADSL Forum TR- 006, SNMP-based ADSL Line MIB)

• ADSL Forum TR-006, SNMP-based ADSL Line MIB)

• ADSL Forum TR-014, DMT Line Code Specific MIB

Cisco-Derived MIBS

• CISCO-ADSL-LINE-MIB

• CISCO-ADSL-DMT-LINE-MIB

To obtain lists of supported MIBs by platform and Cisco IOS release and to download MIB modules, go to the Cisco MIB web site on Cisco Connection Online (CCO) at the following url:

http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml .

Prerequisites

To use the 8xDMT over ISDN line card feature, you must have one of the following DSLAMs with the 8xDMT over ISDN line card, and Cisco IOS Release 12.2(5)DA or above installed:

• Cisco 6015

• Cisco 6260

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  Note   If you are upgrading from Cisco IOS Release 12.1(5)DA1 or earlier images on the NI-2 card to Release 12.2(5)DA, you must reformat the bootflash on the NI-2 card. See the Release Notes for Cisco IOS Release 12.2(5)DA for specific instructions.

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Configuration Tasks

See the following sections for configuration tasks for the 8xDMT over ISDN line card feature. Each task in the list indicates if the task is optional or required.

• Preprovisioning a Slot for use with the 8xDMT over ISDN Line Card (optional)

• Creating and Associating a DSL Profile with Each Port (required)

• Modifying the DSL Profile (optional)

Preprovisioning a Slot for use with the 8xDMT over ISDN Line Card

Starting at the global configuration prompt, use the following commands to preprovision a slot for use with the 8xDMT over ISDN line card:

Tip After you have completed these steps, insert the 8xDMT over ISDN line card to activate the card with your preprovisioned configuration.

Verifying the Preprovisioned Slot

Use the show running-configuration command to verify that you preprovisioned the slot correctly.

Creating and Associating a DSL Profile with Each Port

Before starting this configuration task, install the 8xDMT over ISDN line card. Refer to the Octal-Port DMT ATU-C Over ISDN Line Card FRU Installation and Replacement Notes for information on installing the 8xDMT over ISDN line card.

Starting at the global configuration prompt, use the following procedure to associate a DSL profile with a port:

Verifying the DSL Profiles

You can use the show dsl profile profile-name command or the show running-configuration command to verify that the DSL profile is attached to a port.

Tip If no DSL profile appears in the show running-configuration command output, the default DSL profile is enabled.

Modifying the DSL Profile

It is recommended that you use the default DSL profile values. If you need to change the profile, use the following commands. Starting at the global configuration prompt, use the following procedure to modify the default bit rate for the fast path, change the signal-to-noise ratio, and change the DMT check bytes in your DSL profile:

Caution   Before migrating from interleaved mode to fast path, determine whether the deployed CPEs offer support for the feature.

Troubleshooting Tips

Cisco.com is a starting point for all technical assistance. Customers and partners can obtain documentation, troubleshooting tips, and sample configurations from online tools.

For Cisco.com registered users, additional troubleshooting tools are available from the TAC website. To obtain troubleshooting help, go to the Cisco Troubleshooting Assistant web site on Cisco.com at:

http://www.cisco.com/kobayashi/support/tac/tsa/dslstep.html

Also see the "Monitoring and Maintaining the 8xDMT over ISDN Line Card" section.

Monitoring and Maintaining the 8xDMT over ISDN Line Card

Use the following commands to monitor and maintain the 8xDMT over ISDN line card:

Configuration Examples

The following example shows a profile named 8xDMT/ISDN being created. In the profile, default profile values are used for any parameters not specified.

Command Reference

This section documents the new and modified commands that are specific to the 8xDMT over ISDN line card feature. All other commands used with this feature are documented in the Command Reference for Cisco DSLAMS with NI-2. For information on other Cisco IOS commands that can be used on the NI-2 DSL systems, see the Cisco ATM Switch Router Command Reference.

alarms

To enable alarms in profile command mode, use the alarms command. To disable alarms, use the no form of the command.

Syntax Description

This command has no keywords or arguments.

Defaults

Disabled.

Command Modes

Profile configuration.

Command History

Usage Guidelines

The command affects minor alarms for DSL subscriber ports only. The alarms that this command controls apply to these event classes:

• Near end LOS

• Near end interleaved LOCD

• Near end fast LOCD

• Near end LOF

• No CPE detected

• Bit rates below configured minimum

• Subscriber port failure

• Upstream or downstream bit rate not above minimum bit rate

Enabling or disabling alarms affects the specified profile only. For example, if you disable alarms on the default profile, other profiles are unaffected.

Use alarms and no alarms to enable and disable minor alarms related to DSL subscriber ports. If these alarms are disabled, you receive no notification when alarm conditions exist. (Notification methods include console messages, LEDs, the output of the show facility-alarm command, and relay alarm signals to external systems for audible or visible alarms.) However, you can track the condition of DSL ports on which alarms are disabled, including conditions that ordinarily trigger alarms, using the command show dsl interface atm slot# /port# .

You can suppress minimum bit rate alarms without disabling other alarms for the profile.

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Note   The alarms command has no effect on critical alarms, major alarms, or minor alarms related to subsystems other than the DSL subscriber ports.

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Examples

In this example, the command enables alarms for the default profile:

DSLAM# configure terminal DSLAM(config)# dsl-profile default DSLAM(cfg-dsl-profile)# alarms

Related Commands

Command	Description
dsl-profile profile name	Selects an existing DSL profile for modification.
show dsl interface atm slot# /port#	Displays DSL, DMT, and ATM status for a port.
show dsl profile	Displays a specific profile, all ports to which the profile is currently attached, and those port settings.
show facility-alarm status	Displays the current major and minor alarm status, if any, and display the configuration of the alarm thresholds.

dmt bitrate

To set the maximum and minimum allowed bit rates for the fast or interleaved DMT profile parameters, use the dmt bitrate profile configuration command. To reset this command to the default value, use the no form of this command.

Syntax Description

Defaults

• The default no dmt bitrate maximum interleaved sets the maximum downstream and upstream interleaved bit rate to 640 and 128 kbps respectively. This command causes the port to retrain.

• The default no dmt bitrate maximum fast sets both the maximum downstream and upstream fastpath bit rates to zero. This command causes the port to retrain.

• The default no dmt bitrate minimum interleaved sets both the minimum downstream and upstream interleaved bit rates to zero. This command does not cause the port to retrain.

• The default no dmt bitrate minimum fast sets both the minimum downstream and upstream fastpath bit rates to zero. This command does not cause the port to retrain.

Command Modes

Profile configuration

Command History

Usage Guidelines

Only the alarm subsystem uses the minimum bit rate settings. Cisco IOS asserts an alarm if the line card trains at a rate below the configured minimum bit rate. However, no alarm occurs when you disable alarms. See Alarms in Chapter 2 of the Command Reference for Cisco DSLAMS with NI-2 for more information on enabling and disabling alarms.

Table 2 lists the allowable DMT bit rate ranges and default values.

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Caution   This command causes the port to retrain when you change the value of the bit rate parameter.

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Setting a parameter to its current value does not cause a retrain. If a port is training when you change the parameter, the port stops training and retrains to the new parameter.

Examples

In this example, the command sets the maximum interleaved bit rate of the default profile to 3200 kbps downstream and 640 kbps upstream:

DSLAM# configure terminal DSLAM(config)# dsl-profile default DSLAM(cfg-dsl-profile)# dmt bitrate maximum interleaved downstream 3200 upstream 640

Related Commands

Command	Description
show dsl profile	Displays a specific profile, all ports to which the profile is currently attached, and those port settings.

dmt check-bytes

To set upstream and downstream FEC check (redundancy) bytes, use the dmt-checkbytes profile configuration command. To reset this command to the default value, use the no form of this command.

Syntax Description

Defaults

Interleaved Downstream and Upstream: 16

Fast Downstream and Upstream: 0

Command Modes

Profile configuration

Command History

Usage Guidelines

Caution   This command causes the port to retrain when you change the check-bytes parameter.

Setting a parameter to its current value does not cause a retrain. If a port is training when you change the parameter, the port untrains and retrains to the new parameter.

Conditions on the line, the configured bit rate, and the capabilities of the ATU-R CPE affect the achievable value for this parameter. As a result, the check-bytes value to which the line trains might be smaller than the value you configure. If you want to use more check bytes than the system is allowing you, use the dmt bitrate command to reduce the bit rate.

Use the command show dsl interface atm slot# /port# to display the configured and actual check-bytes values for the connection.

Examples

In this example, the command sets the interleaved FEC check bytes for the default profile to 12 downstream and 6 upstream.

Related Commands

None.

dmt margin

To set upstream and downstream signal-to-noise ratio (SNR) margins for a DMT profile, use the dmt margin command. To reset this command to the default value, use the no form of this command.

Syntax Description

Defaults

Downstream: 6 dB

Upstream: 6 dB

Command Modes

Profile configuration

Command History

Usage Guidelines

Caution   This command causes the port to retrain when you change the parameter.

.Setting a parameter to its current value does not cause a retrain. If a port is training when you change this value, the port untrains and retrains to the new value.

Examples

In this example, the command sets the SNR margins of the default profile to 12 dB downstream and 6 dB upstream:

Related Commands

None.

dmt minrate-blocking

To force a port not to retrain when actual bit rates fall below the values configured in the dmt bitrate minimum command, use the dmt minrate-blocking command. To disable dmt minrate-blocking, use the no form of the command.

Syntax Description

This command has no arguments or keywords.

Defaults

The default configuration, no dmt minrate-blocking, generates a minor alarm when the bit rates on a DMT port violate the minimum allowed bit rates specified in the dmt bitrate minimum command (if alarms are enabled in the DSL profile).

Command Modes

DSL profile configuration

Command History

Usage Guidelines

To specify the bit rate below which a DMT port will not retrain, use the dmt bitrate minimum command.

Examples

The following example shows how to enable dmt minrate-blocking:

Related Commands

None.

dmt overhead-framing

To set the overhead framing mode, use the dmt overhead-framing command. To reset this command to the default value, use the no form of this command.

dmt overhead-framing {mode0 | mode1 | mode2 | mode3}

Syntax Description

mode0	Full overhead framing with asynchronous bit-to-modem timing.
mode1	Full overhead framing with synchronous bit-to-modem timing.
mode2	Reduced overhead framing with separate fast and sync bytes in the fast and interleaved latency buffers respectively.
mode3	Reduced overhead framing with merged fast and sync bytes, using either the fast or interleaved latency buffer.

Defaults

Mode3 is the only supported mode. If you specify another mode, it will be forced to mode3.

Command Modes

Profile configuration

Command History

Release	Modification
12.0(5)DA	This command was introduced.
12.2(5)DA	Support for 8xDMT over ISDN was added.

Usage Guidelines

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Note   Conditions on the line and the capabilities of the ATU-R CPE affect the achievable value for this parameter. As a result, the overhead framing value to which the line trains might not be the same as the value you configure.

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There are two types of ADSL framing:

• Full overhead

• Reduced overhead

There are also two versions of full overhead:

• Asynchronous

• Synchronous

The ADSL framing mode is Mode 3 which specifies reduced overhead framing with merged fast and sync bytes using either the fast or interleaved latency buffer.

There is one overhead byte per frame

If, during the training sequence, the ATU-R indicates a lower framing structure value than that specified by the ATU-C, the ATU-C falls back to the framing structure number indicated by the ATU-R.

Management requirements drive the determination of overhead, full or reduced. Full overhead provides more bandwidth to the embedded operations channel (EOC), enabling higher polling rates. However, reduced overhead provides enough EOC bandwidth to satisfy typical applications.

The dmt overhead-framing command does not cause port retrain when you change the parameter.

Examples

In this example, the command sets the overhead framing mode in the profile named 8xDMT/ISDN:

DSLAM# configure terminal DSLAM(config)# dsl-profile 8xDMT/ISDN DSLAM(cfg-dsl-profile)# dmt overhead-framing mode3

Related Commands

Command	Description
show dsl profile	Displays a specific profile, all ports to which the profile is currently attached, and those port settings.

dmt rate-adaptation enable

DMT rate adaptation monitors upstream and downstream DMT ports for signal-to-noise ratio (SNR) margins during specified time intervals. If an unacceptable SNR margin is detected, the port is retrained at a lower bit rate to improve the SNR margins. To enable rate adaptation on a DMT port, use the dmt rate-adaptation enable command at the DSL profile configuration prompt. To disable dmt rate adaptation, use the no form of the command.

This command has no arguments or keywords.

Defaults

Enabling dmt rate-adaptation assigns the default values to dmt rate-adaptation interval and dmt rate-adaptation margin commands. For information on the default values of dmt rate-adaptation interval and dmt rate-adaptation margin, see the "dmt rate-adaptation interval" section and the "dmt rate-adaptation margin" section.

Command Modes

DSL profile configuration

Command History

Usage Guidelines

If you wish to modify the default configuration of the dmt rate-adaptation interval and dmt rate-adaptation margin, see the "dmt rate-adaptation interval" section and the "dmt rate-adaptation margin" section.

Note   If line conditions improve, the line does not automatically drop and retrain to a higher bit rate. The administrator must execute a shut then a no shut on the port to retrain to a higher bit rate.

Examples

In the following example, dmt rate-adaptation is enabled with default interval and margin values:

Related Commands

dmt rate-adaptation interval

To change the intervals during which a DMT port is monitored for signal-to-noise ratio (SNR) margins, use the dmt rate-adaptation interval command in DSL profile configuration mode. To disable dmt rate-adaptation interval, use the no form of this command.

Syntax Description

Defaults

Following are the default settings for the dmt rate-adaptation interval:

• downstream—10

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  Note   Remember, a downstream value of 10 can yield a monitoring interval of from 1 to 2.5 minutes.

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• upstream—10

Command Modes

DSL profile configuration

Command History

Usage Guidelines

Use the dmt rate-adaptation interval to specify the frequency at which line margins are checked on a DMT port. The dmt rate-adaptation interval command works in conjunction with the dmt rate-adaptation margin command. If, for the duration of time specified in the dmt rate-adaptation interval command, the actual SNR margins on a port remain lower than the margins configured in the dmt rate-adaptation margin command for the duration of time specified in the dmt rate-adaptation interval command, the line drops and retrains to a lower bit rate, to improve SNR margin quality on the line.

Note   If line conditions improve, the line does not automatically drop and retrain to a higher bit rate. The administrator must execute a shut then a no shut on the port to retrain to a higher bit rate.

Examples

In the following example, a downstream monitoring interval of roughly 60 to 150 seconds is configured. The upstream monitoring interval is 20 seconds.

Related Commands

dmt rate-adaptation margin

To configure the minimum acceptable SNR margins on a DMT port, use the dmt rate-adaptation margin command in DSL profile configuration mode. The minimum acceptable SNR margins on a DMT port force the port to retrain when bad margins exist for the duration of the dmt rate-adaptation interval. To disable dmt rate-adaptation margin, use the no form of this command.

Syntax Description

Defaults

The default configuration is derived from the no dmt rate-adaptation enable command. This specifies minimum upstream and downstream SNR margins of 0 dB.

Command Modes

DSL profile configuration

Command History

Usage Guidelines

Use the dmt rate-adaptation margin command to configure the acceptable SNR margin thresholds on a specified port. The dmt rate-adaptation margin command works in conjunction with the dmt rate-adaptation interval command. If, for the duration of time specified in the dmt rate-adaptation interval command, the actual SNR margins on a port remain lower than the margins configured in the dmt rate-adaptation margin command, the line drops and retrains to a lower bit rate, to improve SNR margin quality on the line.

Note   If line conditions improve, the line does not automatically drop and retrain to a higher bit rate. The administrator must execute a shut then a no shut on the affected port to retrain to a higher bit rate.

Examples

The following example shows how to configure dmt rate-adaptation margin:

slot

To provision a slot for a specific card type, or to change the line coding for a flexi line card, use the slot command.

The 8xDMT over ISDN line card is spectrally incompatible with both the 8-port IDSL line card and the 4-port SDSL (STU-C) line card. If you install spectrally incompatible cards in the same chassis, the lines served by those cards can suffer reduced performance. For best performance in a chassis with a mixture of line card types, always install 8xDMT over ISDN line cards on one side of the chassis and IDSL and SDSL cards on the opposite side.

Glossary

ADSL—asymmetric digital subscriber line. A digital subscriber line (DSL) technology in which the transmission of data from server to client is much faster than the transmission from the client to the server.

ADSL Transmission Unit—central office—See ATU-C.

ADSL Transmission Unit—remote—See ATU-R.

asymmetric digital subscriber line—See ADSL.

Asynchronous Transfer Mode—See ATM.

ATM—Asynchronous Transfer Mode. A cell-based data transfer technique in which channel demand determines packet allocation. ATM offers fast packet technology, and real-time, demand-led switching for efficient use of network resources.

ATU-C—ADSL Transmission Unit—central office. Special electronics in support of ADSL and placed in the carrier's CO. The ATU-C has a matching unit on the subscriber premise in the form of an ATU-R. The two units, in combination, support a high data rate over UTP copper cable local loops.

ATU-R—ADSL Transmission Unit—remote. Special electronics in support of ADSL and placed in the customer's premise. The ATU-R has a matching unit in the carrier's CO in the form of an ATU-C. The two units, in combination, support a high data rate over UTP copper cable local loops.

bridge—A device that connects two or more physical networks and forwards packets between them. Bridges can usually be made to filter packets, that is, to forward only certain traffic. Related devices are: repeaters which simply forward electrical signals from one cable to the other, and full-fledged routers which make routing decisions based on several criteria. See router.

CBOS—Cisco Broadband Operating System. An operating system that users access to configure and operate Cisco products.

CCO—Cisco Connection Online. The name of Cisco Systems external Web site.

chassis—The card cage (housing) where modules are placed.

Cisco Connection Online—See CCO.

CLI—command line interface.

CPE—customer premises equipment.

CTC—Common transmit clock.

DDTS—Cisco Distributed Defect Tracking System. Cisco tracks bugs in a variety of products, including router software, communication server software, and network management software, using a system called DDTS. DDTS is also used for bugs in some hardware and microcode products, and for bugs in some internal tools, including the automated test software and various Software Tools.

digital signal level 3—See DS3.

Distributed Defect Tracking System—See DDTS.

DMT—Discrete Multi-tone. Cisco tracks bugs in a variety of products, including router software, communication server software, and network management software, using a system called DDTS. DDTS is also used for bugs in some hardware and microcode products, and for bugs in some internal tools, including the automated test software and various Software Tools.

downstream rate—the line rate for return messages or data transfers from the network machine to the user's CPE.

DS3—Digital signal level 3. A framing specification used for transmitting digital signals at 44.736 Mbps on a T3 facility.

DSLAM—digital subscriber line access multiplexer. A device that concentrates digital subscriber line signals at the telephone service provider location and multiplexes them onto the broadband wide area network. Replaces ADSLAM.

ETSI—European Telecommunications Standards Institute. ETSI is a non-profit organization producing voluntary telecommunications standards used throughout Europe, some of which have been adopted by the EC as the technical base for Directives or Regulations.

frame—A packet as it is transmitted over a serial line. The term derives from character-oriented protocols that involved the addition of special start-of-frame and end-of-frame characters for packet transmission.

FTP—File Transfer Protocol. The Internet protocol (and program) used to transfer files between hosts.

G.992.2—The ITU standard for line coding and framing for splitterless, reduced spectrum ADSL. Also known as G.lite.

G.994.1—The ITU standard for signaling, identification, and negotiation between broadband systems; an integral part of G.dmt and G.lite. Also known as G.hs.

G.997.1—The ITU standard for performance monitoring on DMT access technologies.

G.dmt—Pseudonym for G.992.1.

G.hs—Pseudonym for G.994.1. HandShake (hs).

G.lite—Pseudonym for G.992.2.

handshake—Part of the procedure to set up a data communications link. The handshake can be part of the protocol itself or an introductory process. The computers that are to talk to each other set out the conditions they can operate under. Sometimes, the handshake is just a warning that a communication is imminent.

IETF—Internet Engineering Task Force. Task force consisting of over 80 working groups responsible for developing Internet standards.

IP—Internet Protocol. The network layer protocol for the Internet Protocol suite.

IP address—The 32-bit address assigned to hosts that want to participate in a TCP/IP Internet.

ISDN—Integrated Services Digital Network. Communication protocol offered by telephone companies that permits telephone networks to carry data, voice, and other source traffic.

ITU—The International Telecommunications Union; a telecommunications standards body.

LCD—loss of cell delineation.

LODS—loss of delay synchronization.

LOF—loss of frame.

loopback—A diagnostic test that returns the transmitted signal to the sending device after it has passed through a network or across a particular link. The returned signal can then be compared to the transmitted one. You can use the discrepancies between the two to trace the fault. When trying to locate a faulty piece of equipment, you can repeat loopbacks, eliminating satisfactory machines, until the problem is found.

LOS—loss of signal.

LPR—loss of power.

Management Information Base—See MIB.

MIB—Management Information Base. A collection of objects that can be accessed through a network management protocol, such as SNMP or CMIP (Common Management Information Protocol).

NI-2—A second generation network interface card.

PVC—permanent virtual connection. A fixed virtual connection between two users. The public data network equivalent of a leased line. The creation of a PVC requires no call setup or clearing procedures.

route—The path that network traffic takes from its source to its destination. The route a datagram follows can include many gateways and many physical networks. In the Internet, each datagram is routed separately.

router—A system responsible for making decisions about which of several paths network (or Internet) traffic will follow. To do this, it uses a routing protocol to gain information about the network and algorithms to choose the best route based on several criteria known as "routing metrics." See also bridge.

routing table—Information stored within a router that contains network path and status information. It is used to select the most appropriate route for information forwarding.

Simple Network Management Protocol—See SNMP.

slot—A numbered location within a chassis capable of housing a module.

SNMP—Simple Network Management Protocol. The network management protocol of choice for TCP/IP-based internets.

SVC —switched virtual connection. A temporary virtual connection between two users.

T1.413—The ANSI standard for line coding and framing for full rate ADSL.

TCP—Transmission Control Protocol. The major transport protocol in the Internet suite of protocols providing reliable, connection-oriented, full-duplex streams.

Telnet—The virtual terminal protocol in the Internet suite of protocols. It allows users of one host to log in to a remote host and act as normal terminal users of that host.

TFTP—Trivial File Transfer Protocol. A simple file transfer protocol (a simplified version of FTP) that is often used to boot diskless workstations and other network devices such as routers over a network (typically a LAN). It does not offer password security.

training—The procedure used by the ATU-C and ATU-R to establish an end-to-end ADSL connection.

training mode—A characteristic of a router that allows it to use RADSL technology to adjust its line speed according to noise conditions on the transmission line.

Transmission Control Protocol—See TCP.

trellis encoding—A channel coding technique which provides forward error correction capability.

Trivial File Transfer Protocol—See TFTP.

twisted pair—Two insulated copper wires twisted together with the twists or lays varied in length to reduce potential signal interference between the pairs.

upstream rate—The line rate for message or data transfer from the source machine to a destination machine on the network. Also see downstream rate.

VC—virtual circuit. A logical circuit created to ensure reliable communication between two network devices. A virtual circuit is defined by a VPI/VCI pair, and can be either permanent (PVC) or switched (SVC). In ATM, a virtual circuit is called a virtual channel. Sometimes abbreviated VC. See also PVC, SVC, VCI, and VPI.

VCI—virtual channel identifier. A 16-bit field in the header of an ATM cell. The VCI, together with the VPI, is used to identify the next destination of a cell as it passes through to the ATM switch. Sometimes called virtual channel connection. See also VPI.

virtual circuit—See VC.

VPI—virtual path identifier. An 8-bit field in the header of an ATM cell. The VPI, together with the VCI, is used to identify the next destination of a cell as it passes through the network. See also VCI.

Posted: Mon Jul 15 06:05:29 PDT 2002
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