|
|
This feature module describes the Enhancements to the Quad-Port Flexi ATU-C Line Card for NI-2 (4xflexi enhancements). This feature module includes information on the benefits of the new feature, supported platforms, related documentation, and installing and configuring the enhancements.
This document includes the following sections:
The 4xflexi enhancements feature adds a number of improvements to the functionality of the 4xflexi line card for the Cisco 6130, Cisco 6160, and Cisco 6260 DSLAMs with NI-2 in IOS versions 12.1(6) and above. The following improvements were added for IOS versions 12.1(6)DA and above:
 |
Note Owners of the Cisco 6130 with NI-1 who are interested in upgrading to the NI-2 with 4xflexi should contact the Cisco Technical Assistance Center (TAC) by going to the TAC website: http://www.cisco.com/tac |
|
Note CPE that are unable to respond to EOC requests for downstream margin statistics cannot use the rate adaptation features in Cisco IOS 12.1(6)DA. |
Leverages Existing Cisco 677 CPE and Expands Interoperability with Third-party CPE
Many service providers have large deployments of dual-port DMT-2 ATU-C line cards (2xDMT-2) and quad-port DMT-2 ATU-C line cards (4xDMT-2) paired with the Cisco 677 CPE and third-party CPE with ADI chipsets. However, the 4xflexi line card did not interoperate with the Cisco 677 CPE or third-party CPE with ADI chipsets. The 4xflexi enhancements feature enables service providers to leverage their installed Cisco 677 CPE or CPE with similar chipsets while deploying third-party CPE with Alcatel chipsets.
To reconcile interoperability issues between the 4xflexi line card and the Cisco 677, IOS 12.1(6)DA employs different training modes when certain line conditions are detected.
|
Note The 4xflexi enhancements support the Cisco 677 using ADI chipsets with firmware versions 0X3019BE70 (Version 3.0), 0X2219BE04 (Version 2.2), or 0X2019BE2D (Version 2.0). |
The 4xflexi enhancements feature also improves interoperability between the 4xflexi line card and the following CPE using Alcatel Microelectronics firmware version 1.4.1:
Enhanced Line Quality Monitoring and Management
The 4xFlexi enhancements improve the manageability of DMT ports on supported DSLAMs. The following commands are used to configure this functionality:
|
Note The original option, which generates a minor alarm when configured minimum bit rates are not met, is configured by default in DSL profiles. The default configuration is no dmt minrate-blocking. |
|
Note The default configuration is no dmt rate-adaptation enable. |
Line Cards Not Supported by 4xflexi Enhancements
The following subscriber line cards are not supported by the 4xflexi enhancements feature:
Restrictions to Cisco 677 CPE Paired with 4xflexi
The DMT fast path feature should not be used on Cisco 677 CPE with 4xflexi line cards and Cisco IOS 12.1(6)DA.
Cisco recommends disabling TC-PAM line coding with the Cisco 677 CPE.
The 4xflexi enhancements support the Cisco 677 using ADI chipsets with firmware versions 0X3019BE70 (Version 3.0), 0X2219BE04 (Version 2.2), or 0X2019BE2D (Version 2.0).
Restrictions to Cisco 678 CPE with Globespan Chipsets Paired with 4xflexi
The DMT fast path feature should not be used on Cisco 678 CPE with 4xflexi line cards and Cisco IOS 12.1(6)DA.
Cisco recommends enabling trellis-coded pulse amplitude modulation (TC-PAM) line coding with the Cisco 678 CPE.
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
The following documents contain software configuration information for all NI-2 DSLAMs:
In these ATM software guides, look for information pertaining to the Cisco LightStream 1010, which uses the same software base as the NI-2 DSL systems:
DSLAMs
Line Card
4xflexi
IOS Versions
12.1(6)DA and above
CPE
Standards
No new standards are supported by the 4xflexi enhancements feature.
MIBs
The 4xflexi enhancements supports the MIB ADSL-LINE-MIB. For descriptions of supported MIBs and how to use MIBs, see the Cisco MIB web site on CCO at http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml.
RFCs
IETF RFC 2662 defines the ADSL-LINE-MIB listed above in the MIBs section.
To use the 4xflexi enhancements feature, you must have one of the following DSLAMs with the 4xflexi line card, and IOS 12.1(6) or above installed:
See the following sections for configuration tasks for the 4xflexi enhancements feature.
Beginning at the global configuration prompt, use the following procedure to configure dmt minrate blocking:
| Command | Purpose | |
|---|---|---|
Step 1 | DSLAM(config)#dsl profile austin
| Enter DSL profile configuration mode. |
Step 2 | DSLAM(config)#dmt bitrate minimum interleaved
downstream 3200 upstream 640
| Sets the minimum bit rate threshold for the selected DSLprofile. |
Step 3 | DSLAM(dsl-config-prof)#dmt minrate-blocking
enable
| Enables dmt minrate-blocking on the selected DSL profile. If the port trains below the rates configured in Step 2, the port attempts to retrain until it can achieve bit rates exceeding those configured in Step 2. |
Beginning at the global configuration prompt, use the following procedure to configure dmt rate-adaptation:
| Command | Purpose | |
|---|---|---|
Step 1 | DSLAM(config)#dsl profile austin
| Enter DSL profile configuration mode. |
Step 2 | DSLAM(config-if)#dmt rate-adaptation enable
| Configures DMT rate adaptation with the default margin values for port monitoring intervals and margin thresholds. Note The default dmt rate-adaptation interval configuration is 10 and the default dmt rate-adaptation margin configuration is 0 dB. For more information on changing the default rate-adaptation intervals and margin thresholds, see the "dmt rate-adaptation interval" section and the "dmt rate-adaptation margin" section.
|
To verify that you have configured dmt minrate-blocking and dmt rate-adaptation, use the show dsl profile profile-name command. The following text is sample output from the show dsl profile command:
DSLAM#show dsl profile austin
dsl profile austin:
Alarms Enabled: NO
ATM Payload Scrambling: Enabled
DMT profile parameters
Maximum Bitrates:
Interleave Path: downstream: 6400 kb/s, upstream: 768 kb/s
Fast Path: downstream: 0 kb/s, upstream: 0 kb/s
Minimum Bitrates:
Interleave Path: downstream: 6080 kb/s, upstream: 640 kb/s
Fast Path: downstream: 0 kb/s, upstream: 0 kb/s
Margin: downstream: 6 dB, upstream: 6 dB
Interleaving Delay: downstream: 16000 usecs, upstream: 16000 usecs
Check Bytes (FEC):
Interleave Path: downstream: 16, upstream: 16
Fast Path: downstream: 0, upstream: 0
R-S Codeword Size: downstream: auto, upstream: auto
Trellis Coding: Disabled
Overhead Framing: Mode 3
Operating Mode: Automatic
Training Mode: Quick
Minrate blocking: Enabled
SNR Monitoring: Enabled
Minimum Margin: downstream: 5 dB, upstream: 5 dB
Interval Value: downstream: 5 secs, upstream: 5 secs
With the show dsl profile command, you can verify that dmt minrate-blocking and dmt rate-adaptation (SNR monitoring) are enabled. Under the SNR Monitoring field you can verify how you configured the rate adaptation margin and downshift interval values. In the maximum and minimum bit rate fields, you can verify the configuration of the dmt bitrate minimum command.
|
Note The dmt bitrate minimum configuration works in conjunction with the dmt minrate-blocking command. Make sure that you have configured the dmt minimum bitrate settings properly. |
This section provides output from the show running-configuration command. This output illustrates the configuration of dmt minrate-blocking and dmt rate-adaptation in the dsl profile austin. The following show running-configuration output results from the procedures described in the "Configuring dmt minrate-blocking" section and the "Configuring dmt rate-adaptation" section:
...
slot 4 ATUC-4FLEXIDMT
enable password cisco
!
dsl-profile default
!
dsl-profile austin
dmt minrate-blocking
dmt rate-adaptation enable
dmt rate-adaptation margin min downstream 5 upstream 5
dmt rate-adaptation interval downshift downstream 5 upstream 5
dmt bitrate minimum interleaved downstream 6080 upstream 640
dmt bitrate maximum interleaved downstream 6400 upstream 768
!
...
interface ATM0/0
no ip address
no ip route-cache
no ip mroute-cache
atm cac service-category abr deny
atm maxvp-number 0
atm maxvc-number 4096
atm maxvci-bits 12
!
interface Ethernet0/0
ip address 172.21.180.13 255.255.255.0
no ip route-cache
no ip mroute-cache
!
...
interface ATM4/1
no ip address
shutdown
dsl profile austin
no atm ilmi-keepalive
!
interface ATM4/2
no ip address
shutdown
dsl profile austin
no atm ilmi-keepalive
!
interface ATM4/3
no ip address
shutdown
dsl profile austin
no atm ilmi-keepalive
!
interface ATM4/4
no ip address
shutdown
dsl profile austin
no atm ilmi-keepalive
...
The dmt minrate-blocking command prevents ports from training to bit rates lower than those specified in the dmt bitrate minimum command, forcing ports to retrain until they achieve bit rates exceeding those configured in the dmt bitrate minimum command. To enable dmt minrate-blocking use the dmt minrate-blocking command. To disable dmt minrate-blocking, use the no form of the command.
dmt minrate-blockingSyntax 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
IOS 12.1(6)DA This command was introduced.
Release
Modification
Usage Guidelines
To specify the bit rate below which a DMT port will not train, use the dmt bitrate minimum command.
Examples
The following example describes how to enable dmt minrate-blocking:
configure terminal
dsl-profile austin
dmt minrate-blocking
DMT rate adaptation monitors upstream and downstream DMT ports for signal-to-noise ratio (SNR) margins during specified intervals. If an unacceptable SNR margin is detected, the port retrains to current line conditions 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 enable use the no form of the command.
dmt rate-adaptation enableSyntax Description
This command has no arguments or keywords.
Defaults
Enabling dmt rate-adaptation configures the commands dmt rate-adaptation interval and dmt rate-adaptation margin with their default values. 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
IOS 12.1(6)DA This command was introduced.
Release
Modification
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.
CPE that are unable to respond to EOC requests for downstream margin statistics cannot use the rate adaptation features in Cisco IOS 12.1(6)DA.
Examples
The following example enables dmt rate-adaptation with default interval and margin values:
config terminal
dsl-profile austin
dmt rate-adaptation enable
Related Commands
dmt rate-adaptation interval Sets the upstream and downstream time intervals at which a DMT port is monitored for SNR margins. dmt rate-adaptation margin Sets the SNR values below which the DMT port retrains to a lower bit rate.
Command
Description
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 dmt rate-adaptation enable command.
dmt rate-adaptation interval {downshift [downstream number-of eoc-updates upstream seconds]}
Syntax Description
downshift The downshift keyword indicates that a line with low SNR margins retrains to a lower bit rate. downstream The downstream keyword tells IOS to monitor downstream ports for SNR margins exceeding those specified in the dmt rate-adaptation margin command. number-of eoc-updates The number-of eoc-updates argument specifies the monitoring interval in multiples of six seconds on a downstream DMT port. Note The downstream margin (see dmt rate-adaptation margin) is obtained from the CPE via the embedded operations channel (EOC). The downstream number-of eoc-updates parameter specifies a number of consecutive EOC messages. The 4xflexi sends EOC messages requesting downstream margin statistics from CPE. Depending upon the type of CPE, the responses take from 6 to 15 seconds (not counting EOC timeouts). Hence, a downstream downshift interval value of 10 on CPE reporting margins every 6 seconds results in a 1 minute monitoring interval (10 x 6 seconds). Specifying a downstream downshift interval value of 10 on CPE that report margins every 15 seconds (10 x 15 seconds) yields a 2.5 minute monitoring interval. upstream The upstream keyword tells IOS to monitor upstream ports for SNR margins exceeding those specified in the dmt rate-adaptation margin command. seconds The seconds argument specifies the monitoring interval in seconds on an upstream DMT port.
Defaults
Following are the default settings for the dmt rate adaptation interval:
|
Note Remember, a downstream value of 10 can yield a monitoring interval between 1 and 2.5 minutes in length. |
Command Modes
DSL profile configuration
Command History
IOS 12.1(6)DA This command was introduced.
Release
Modification
Usage Guidelines
Use the dmt rate-adaptation interval command to specify the period of time that ports detect low margin conditions before the port is forced to retrain. The dmt rate-adaptation interval command works in conjunction with the dmt rate-adaptation margin command. If 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 according to current line conditions.
|
Note Sometimes the line will train to a lower bit rate to improve SNR margins. If line conditions improve, the line does not automatically drop and retrain to a higher bit rate. If line conditions improve, the administrator must execute a shut then a no shut on the port to retrain to a higher bit rate. |
CPE that are unable to respond to EOC requests for downstream margin statistics cannot use the rate adaptation features in Cisco IOS 12.1(6)DA.
Examples
The following example configures a downstream monitoring interval of roughly 60 to 150 seconds. The upstream monitoring interval is 20 seconds.
config terminal
dsl-profile austin
dmt rate-adaptation interval downshift downstream 10 upstream 20
Related Commands
dmt rate-adaptation enable Turns on rate adaptation. dmt rate-adaptation margin Sets the SNR margins below which a DMT port retrains to a lower bit rate.
Command
Description
To configure the minimum acceptable SNR margins on a DMT port, which force the port to retrain when bad margins exist for the duration of the dmt rate-adaptation interval, use the dmt rate adaptation margin command in DSL profile configuration mode. To disable dmt rate adaptation margin use the no dmt rate-adaptation enable command.
dmt rate-adaptation margin {min [downstream dB upstream dB]}
Syntax Description
min The min keyword specifies that you are configuring the minimum acceptable SNR margins on a port. If the port SNR exceeds the configured value, the port retrains to a lower bit rate. downstream Specifies the minimum acceptable SNR margin for downstream traffic on a port. dB SNR margins measured in decibels. The valid range is -15 to 15. upstream Specifies the minimum acceptable SNR margin for upstream traffic on a port. dB SNR margins measured in decibels. The valid range is -15 to 15.
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
IOS 12.1(6)DA This command was introduced.
Release
Modification
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 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 according to current line conditions.
|
Note If line conditions improve, the line does not automatically drop and retrain to a higher bit rate. If the line conditions improve, the administrator must execute a shut then a no shut on the affected port to retrain to a higher bit rate. |
CPE that are unable to respond to EOC requests for downstream margin statistics cannot use the rate adaptation features in Cisco IOS 12.1(6)DA.
Defaults
The following example describes how to configure dmt rate-adaptation margin:
config terminal
dsl-profile austin
dmt rate-adaptation margin min downstream 10 dB upstream -10
Related Commands
dmt rate-adaptation enable Turns on rate adaptation. dmt rate-adaptation interval Configures the intervals at which DMT ports are monitored for substandard SNR margins.
Command
Description
Posted: Wed Jul 17 08:26:50 PDT 2002
All contents are Copyright © 1992--2002 Cisco Systems, Inc. All rights reserved.
Important Notices and Privacy Statement.