Table of Contents

Release Notes for Cisco IOS Release 12.2(12)DA3 for Cisco DSLAMs with NI-2 Cards
System Requirements
New and Changed Information
Installation Notes
Limitations and Restrictions
Important Notes
Related Documentation
Obtaining Documentation
Obtaining Technical Assistance

Release Notes for Cisco IOS Release 12.2(12)DA3 for Cisco DSLAMs with NI-2 Cards

October 31, 2003

These release notes describe features and caveats in Cisco IOS Release 12.2(12)DA3 for the Cisco 6015, Cisco 6160, and Cisco 6260 digital subscriber line access multiplexers (DSLAMs).

Cisco IOS Release 12.2(12)DA3 is based on Cisco IOS Release12.2(12)DA2, and includes all of the new features and corrections made in 12.2(12)DA2, 12.2(12)DA1 and 12.2(12)DA. To see the release notes for Cisco IOS Release 12.2(12)DA2, go to and click Products & Services > Switches > Cisco 6000 Series IP DSL Switches > Technical Documentation > Instructions and Guides > Release Notes > Release Notes for Cisco IOS Release 12.2(12)DA2 for Cisco DSLAMs with NI-2 Cards.

Note   When you upgrade from Cisco IOS Release 12.1(5)DA2 or earlier images on the NI-2 card to Release 12.2(12)DA3, you must format the bootflash on the NI-2 card before loading the Release 12.2(12)DA3 dboot image. See the "Limitations and Restrictions" section on.

For pointers to more information about the Cisco 6015, Cisco 6160, and Cisco 6260 DSLAMs, and their software, refer to the "Related Documentation" section. To learn more about caveats, visit the Cisco web site—see the "Obtaining Documentation" section for details. Information about electronic documentation can be found in both the "Obtaining Documentation" section and the "Documentation CD-ROM" section.


This document contains the following topics:

System Requirements

Cisco IOS Release 12.2(12)DA runs on these DSLAMs:

New and Changed Information

The following sections provide new and changed information for Cisco IOS Release 12.2(12)DA3, 12.2(12)DA2, 12.2(12)DA1, 12.2(12)DA, and 12.2(10)DA.

Cisco IOS Release 12.2(12)DA3

Cisco IOS Release 12.2(12)DA3 is based on Cisco IOS Release 12.2(12)DA2 and includes all of the new features and corrections in Release 12.2(12)DA2, 12.2(12)DA1, and 12.2(12)DA. In addition, this release fixes the bugs described in the "Resolved Caveats—Release 12.2(12)DA3" section.

Cisco IOS Release 12.2(12)DA2

Cisco IOS Release 12.2(12)DA2 is based on Cisco IOS Release 12.2(12)DA1 and includes all of the new features and corrections in Release 12.2(12)DA1, and 12.2(12)DA. In addition, this release fixes the bugs described in the "Resolved Caveats—Release 12.2(12)DA2" section.

Cisco IOS Release 12.2(12)DA1

Cisco IOS Release 12.2(12)DA1 is based on Cisco IOS Release 12.2(12)DA and includes all of the new features introduced in that release. In addition, this release fixes the bugs described in the "Resolved Caveats—Release 12.2(12)DA1" section.

New Hardware Features in Release 12.2(12)DA

Cisco IOS Release 12.2(12)DA introduces the following new hardware feature:

Use the enhanced NI-2 card if you plan to deploy more than 16 G.SHDSL line cards in a Cisco DSLAM.

Note   A Cisco DSLAM can support either legacy or enhanced NI-2 cards.

The new NI-2 cards (NI-2-155SM-155SM2 and NI-2-155MM-155MM2) support Cisco IOS Release 12.1(7)DA2 or later; however, the card's new features are only enabled in Release 12.2(12)DA or later.

Enhanced Cisco OC-3c/OC-3c NI-2 Card Overview

This section describes how the Cisco OC-3c/OC-3c NI-2 card was enhanced to support QoS in a fully loaded chassis of G.SHDSL SHTU-C (8xG.SHDSL) line cards.

To accommodate these enhancements, the following changes were made to the legacy NI-2 card:

The DSLAM automatically builds the upstream QoS tables using the QoS values defined by commands such as atm connection-traffic-table-row and atm pvc. (See the "New and Changed Software for New Cisco OC-3c/OC-3c NI-2 Cards" section for a list of atm commands used to set upstream QoS table values.)

Supported Cisco DSLAM Chassis

The enhanced NI-2 card can be installed in the following Cisco DSLAM chassis:

Cisco 6100 DSLAM
Cisco 6130 DSLAM
Cisco 6015 DSLAM
Cisco 6160 DSLAM
Cisco 6260 DSLAM

OC-3c/OC-3c NI-2 Card Memory Enhancements

Table 1 shows the memory enhancements made to the new Cisco OC-3c/OC-3c NI-2 card.

Table 1   NI-2 Memory Enhancements

Memory Type  New NI-2 Card  Legacy NI-2 Card 


128 MB

64 MB


16 MB

16 MB


8 MB

4 MB

New and Changed Software for New Cisco OC-3c/OC-3c NI-2 Cards

The following list describes the software changes made to accommodate the enhanced NI-2 card:


atm clp-drop
atm connection-traffic-table-row
atm input-queue
atm input-threshold
atm pvc
atm soft-vc


Cisco OC-3c/OC-3c NI-2 Card Requirements

The following requirements apply to legacy and enhanced Cisco OC-3c/OC-3c NI-2 cards:

Enhanced NI-2 Card Requirements

Note    The old dboot image does not work on enhanced NI-2 cards. If you load a dboot image onto a new NI-2 card, the NI-2 card becomes inoperable. (See the "Correcting Bootup Problems" section for instructions on how to recover if this happens.)

Legacy NI-2 Card Requirements

New Software Features in Release 12.2(12)DA

Cisco IOS Release 12.2(12)DA introduces the following new software feature:

Note    Alcatel-based CPEs and Cisco SOHO 76 and 826 CPEs require Cisco IOS Release 12.2(4)YA2 or later. We also recommend that you issue the dsl operating-mode annexb-ur2 command at the CPE to enable DMT operating mode on these CPEs.

New Hardware Features in Release 12.2(10)DA

No new hardware features were introduced in Cisco IOS Release 12.2(10)DA.

New Software Features in Release 12.2(10)DA

The following new software features were introduced in Cisco IOS Release 12.2(10)DA.

DMT Power-Management-Additional-Margin

The 8xDMT line card can run in power-management mode in the G.dmt or the T1.413 mode. The resulting power cutback produces a reduction in power dissipation and crosstalk. Only 8xDMT line cards support power management. All CPEs may not support the DSL functionality for power management to function correctly. Check with a Cisco customer representative to verify CPE compatibility with the 8xDMT power management.

You control the power management feature by including a dmt power-management-additional-margin command in a profile and assigning that profile to a line card interface. This Cisco IOS software command allows you to set the additional margin for each channel from 0 dB (off) to 15 dB. This sets the additional margin that will be added to the target margin. If the sum of the target margin and additional margin exceeds 15dB, it is capped at 15dB. If the actual margin of the line is higher than the sum of the configured target and additional margin, and all the above conditions are met, then power management attempts to reduce the actual margin, and as a consequence the power level as well.

Not all CPE support power management. If you connect an unsupported CPE to a port on which power management is turned on, you will not see a reduction in the actual margin or power level. The operating modes supported by power management are T1.413and G-992-1 (G.DMT). Table 2 shows the CPE and specifies which operating mode supports them.

Table 2   CPEs and Power Management Support

CPE  G.DMT  T1.413 

Cisco 677 CPE

not supported

not supported

Cisco 678 CPE

not supported


Cisco SOHO 77/Cisco 827 CPEs



ADSL WAN Interface Card (WIC)



Alcatel chipset based modem



A reduction in the power level occurs if there is excess margin on the line. For the downstream direction, if there is excess margin, then IOS displays a reduction in margin for the modes listed above, and a reduction in transmit power for T1.413 mode. For the upstream direction, if there is excess margin, then Cisco IOS software displays a reduction in the margin for G-992-1 mode only. Cisco IOS software does not display a reduction in transmit power for the upstream direction.

ATM OAM Cells Supported in Fast Path Mode

The NI-2 card now supports ATM OAM cells through fast path mode. Also, you can now use the ping atm utility command in fast path mode.

Enhanced ATM OAM Segment Cells Support

A new command, atm oam intercept segment, allows you to enable or disable receiving ATM OAM segment cells on valid connections. By default, ATM OAM cells received on unconfigured or down connections are dropped. For more information, see the Command Reference for Cisco DSLAMs with NI-2 .

MIB Object Changes

This release contains changes to the following Management Information Base (MIB) objects:

The power management feature is configurable through the CISCO-ADSL-DMT-LINE-MIB. The MIB object cAdslAtucDmtConfPMAddSnrMgn configures the downstream component and the MIB object cAdslAturDmtConfPMAddSnrMgn configures the upstream component on that particular DSL profile. Both objects have a default value of 0 and can be configured from 0 to 150 tenths of a dB in increments of 10. Using SNMP to set the objects to 0 disables the power management feature on the ports.

Installation Notes

The following sections provide useful information for Cisco IOS Release 12.2(12)DA3 installation and operation:

Upgrading Bootflash on a Legacy NI-2 Card to the 12.2(12)DA3 dboot Image

When you upgrade from Cisco IOS Release 12.1(5)DA1 or earlier images on a legacy NI-2 card to Release 12.2(12)DA3, you must reformat the bootflash on the NI-2 card.

If you are upgrading from Cisco IOS Release 12.1(7)DA3, 12.2(1b)DA1, 12.2(5)DA1, 12.2(7)DA, 12.2(10) DA, 12.2(12)DA, 12.2(12)DA1, or 12.2(12)DA2 you do not need to reformat the bootflash. You can skip this section and follow the DSLAM upgrade procedure at the following URL:

Note   We recommend that you have console access to the NI-2 card during the upgrade procedure. You can use the console connection to troubleshoot any unexpected events that occur during the upgrade.

To upgrade the boot image on a legacy NI-2 card, perform the following steps in privileged EXEC mode:

  Command  Purpose 
Step 1 
DSLAM# show hardware

Verify the type of Cisco OC-3c/OC-3c NI-2 card installed in the chassis to determine whether to download a new dboot image:

  • NI2-155MM-155MM2 or NI2-155SM-SM2—Indicates a new Cisco OC-3c/OC-3c NI-2 card, which is shipped with the correct image (dboot2) preinstalled. Skip this procedure and the following procedure.
  • Any other value—Indicates a legacy NI-2 card, which may need to be updated with a new image. Continue with this procedure.
Step 2 
DSLAM# dir bootflash:

Verify that the bootflash image is ni2-dboot-mz.121-5.da1 or ni2-dboot-mz.121-4.da. If it is neither, go to the "Upgrade Bootflash on a Legacy NI-2 Card to the 12.1(5)DA1 dboot Image" section and perform the instructions there, and then return to this step. This is required because of a problem (CSCdr89374) in old bootflash images.

Step 3 
DSLAM# dir flash:

Determine the name of the flash file that begins with ni2- and use it as filename in Step 4.

Step 4 
DSLAM# delete flash:filename

Delete the flash file name found in Step 3. Repeat Step 3 and Step 4 until all files in the flash file have been deleted.

Step 5 
DSLAM# squeeze flash:

Recover available space in flash memory.

Step 6 
DSLAM# copy tftp://tftpserver:TFTPBOOT/ni2- dsl-mz.122-12.da3.bin flash:

Copy the Cisco IOS software image from a TFTP server to flash.

Step 7 
DSLAM# configure terminal
DSLAM (config)# no boot system
DSLAM (config)# boot system flash:ni2-dsl-mz.122-12.da3.bin
DSLAM# end

Enter global configuration mode.

Disable the boot from system.

Specify the name of the system image to load at startup.

Exit global configuration mode.

Step 8 
DSLAM# copy running-config startup-config

Save your changes to the startup configuration.

Step 9 
DSLAM# reload

Reload the system to upgrade the image.

Step 10 
DSLAM# show version

Confirm that the running image is ni2-dsl-mz.122-12.da3.bin. If it is not, go to Step 6.

Step 11 
DSLAM# format bootflash:

Erase all information in bootflash memory. Answer y to all confirm questions. When the DSLAM returns to the EXEC prompt, bootflash memory is successfully formatted and ready for use.

Ensure that the bootflash is 3.8 MB total. If it is not, go to Step 5.

Step 12 
DSLAM# copy tftp://tftpserver:TFTPBOOT/ni2- dboot-mz.122-12.da3.bin bootflash:

Copy the boot image from a TFTP server to the bootflash.

Step 13 
DSLAM# reload

Reload the system to upgrade the image.

Upgrade Bootflash on a Legacy NI-2 Card to the 12.1(5)DA1 dboot Image

When you upgrade from Release 12.1(3)DA or earlier images on a legacy NI-2 card to Release 12.1(5)DA1, we recommend that you upgrade the bootflash image on the NI-2 card to the 12.1(5)DA1 dboot image.

To upgrade the dboot image in bootflash on a legacy NI-2 card, perform the following steps:

  Command  Purpose 
Step 1 
DSLAM> enable
Password: <password>

Enter enable mode.

Enter the password.

The enable mode prompt is DSLAM#.

Step 2 
DSLAM# delete bootflash:filename

Make room in the bootflash by deleting the name of the current boot image.

Step 3 
DSLAM# squeeze bootflash

Recover available space in bootflash using the squeeze bootflash command.

Step 4 
DSLAM# copy tftp://[server name] /[directory]/ni2-dboot-mz.121-5.da1 bootflash:

Copy the boot image to the bootflash.

Step 5 
DSLAM# show version

Record the current value of the config-register that appears on the last line of the show version display.

Step 6 
DSLAM# configure terminal

Enter global configuration mode, which has a prompt of DSLAM(config)#.

Step 7 
DSLAM(config)# config-register 0

Set the config register to 0x0000 so that the NI-2 card reboots in the ROM monitor.

Step 8 
DSLAM(config)# exit

Exit global configuration mode.

Step 9 
DSLAM# copy running-config startup-config

Save the running configuration.

Step 10 
DSLAM# reload

Reset the system.

Step 11 
rommon> set

If you see BOOTLDR after you enter this command, the image in bootflash is already being used as the bootstrap image; go to Step 15. Otherwise, go to Step 12 and enter the commands in Steps 12 through 14 to force the system to use ni2-dboot-mz.121-5.bin as the bootstrap image.

Step 12 
rommon> unset BOOTLDR

Unset BOOTLDR to remove the variable.

Step 13 
rommon> sync

Sync to save the state of rommon.

Step 14 
rommon> b

When the NI-2 card boots, it uses ni2-dboot-mz.121-5da.bin as the bootstrap image.

Step 15 
DSLAM# configure terminal

Enter global configuration mode, which has a prompt of DSLAM(config)#.

Step 16 
DSLAM(config)# config-register value

Set the config-register to the value you recorded in Step 5.

Step 17 
DSLAM(config)# exit

Return to enable mode.

Go to the "Limitations and Restrictions" section.

Booting the Enhanced OC-3/OC-3 NI-2 Card

Before attempting to boot the DSLAM, consider the following:

Caution   New NI-2 cards support Cisco IOS Release 12.2(12)DA and later, and release 12.1(7)DA2 to 12.2(10)DA. However, to run release 12.1(7)DA2 to 12.2(10)DA, you must load the dboot2 image before you load the Cisco IOS software image. Otherwise, the DSLAM becomes inoperable.

To boot the enhanced Cisco OC-3/OC-3 NI-2 card, follow the instructions in the Configuration Guide for Cisco DSLAMs with NI-2. See the section "Booting from Flash Memory Configuration Tasks" in chapter 9, "Loading System Software Images and Configuration Files," at the following URL:

Correcting Bootup Problems

If you attempt to run an incorrect dboot or dboot2 image, or you attempt to boot a new NI-2 card with legacy Cisco IOS software before booting the new dboot2 image, the DSLAM becomes inoperable. If this occurs, see the following sections for information about how to correct the problem and make the DSLAM operational:

Running Cisco IOS Release 12.1(7)DA2 to 12.2(10)DA on a New NI-2 Card

You can run Cisco IOS Releases 12.1(7)DA2 to 12.2(10)DA on the new NI-2 cards (NI2-155MM-155MM2 and NI2-155SM-155SM2). However, before you attempt to boot the Cisco IOS software from flash, you must first boot the ni2-dboot2-mz (dboot2) image from bootflash.

Note   To run Cisco IOS releases earlier than Release 12.2(12)DA on a new NI-2 card, do not boot from flash until you have booted the ni2-dboot2-mz image from bootflash. Otherwise, the DSLAM becomes inoperable.

If you encounter problems booting Cisco IOS Release 12.1(7)DA2 to 12.2(10)DA on the new NI-2 cards, perform the following steps to correct the problem and make the DSLAM operational:

Step 1   Issue the following command in to ensure that the correct dboot2 image is loaded in bootflash memory:

DSLAM> show ni2-switch register

Step 2   Check the command output to make sure the FPGA major revision is 3 (see highlighted text below). This indicates that the dboot2 image is loaded.

Upstream FPGA revision MAJ:3 Minor:0

Step 3   Issue the following command in global-configuration mode to set the configuration register to load the DSLAM image from the boot system commands in the startup configuration file:

DSLAM(config)# config-register 0x2102

Step 4   Exit configuration mode and reload (reboot) the DSLAM to make the DSLAM operational. This process loads the images in the correct order: dboot2 and then the legacy Cisco IOS software.

DSLAM(config)# end
DSLAM# reload

Using Rommon to Recover from Corrupted dboot2 Images

This procedure describes how to use ROM monitor (rommon) mode to recover from problems caused by an invalid or corrupt dboot2 image. This procedure uses the xmodem command to retrieve a valid dboot2 image from a PC or network server.

Note   The xmodem command used in this procedure is extremely slow. Therefore, only perform this procedure if all other attempts to obtain a dboot2 image fail. Also note that the command is supported only on the new NI-2 cards (NI2-155MM-155MM2 and NI2-155SM-155SM2).

Step 1   Log in to the DSLAM through a console port. The rommon prompt (rommon>) should be displayed. If it is not, get into configuration mode and issue the command config-register 0x0 end write reload.

Step 2   Issue the following command at the rommon prompt.

rommon> config-register 0x2102

Step 3   Issue the following command to manually boot the DSLAM from bootflash.

rommon> boot bootflash: [filename]

Step 4   If Step 3 worked, you need not perform the rest of this recovery procedure. Instead, you should boot the Cisco IOS software and proceed to Step 7.

If Step 3 did not work, the rommon prompt is returned and you must proceed to Step 5 to continue with the recovery procedure.

Step 5   If the correct dboot2 image is not in bootflash or the image is corrupt, perform the following steps to use the xmodem command to download a valid dboot2 image to use to boot the DSLAM:

    a. Open a terminal emulation window (such as Hyper Terminal) on a PC that is connected to the DSLAM through a console port.

    b. Configure the following terminal emulation settings: port = com1 or com2, data rate = 9600, bits = 8, parity = none, stop bits = 1. You must use these values for the recovery procedure to work.

    c. Make sure that the PC contains a valid dboot2 image or is connected to a network where a dboot2 image is stored on a server.

    d. On the DSLAM, issue the following command to copy the dboot2 image to the specified filename. The command creates a temporary copy of the dboot2 image on the DSLAM; therefore, you must copy the image to bootflash or it will be lost when you reload the DSLAM (Step 6).

rommon> xmodem filename

    e. Wait for a prompt indicating that rommon is ready to receive the file.

    f. In the Hyper Terminal window on the PC, click Transfer in the menu bar at the top of the window and select Send File.

    g. Select Xmodem as the protocol, and specify the name of the dboot2 image to copy to the DSLAM.

    h. Click Send to start the copy.

Note    It may take 1 hour or more for the copy to complete.

    i. When the download completes, the DSLAM boots automatically.

Step 6   To complete the recovery procedure, copy the dboot2 image to bootflash memory (for example, using TFTP). If you do not perform this step, the dboot2 image will be lost when you reload the DSLAM.

Step 7   To finish booting the DSLAM, issue the following command:

DSLAM> reload

Limitations and Restrictions

The following sections describe the limitations and restrictions for Cisco IOS software DSLAM releases.

Redundant NI-2 Card Operation

When using NI-2 cards in a redundant fashion, we recommend that you issue the command redundancy reload-peer on the active NI-2 card after the system has loaded. This causes the redundant NI-2 to reload and ensures that the redundant configuration is operational.

In rare instances during testing, a redundant NI-2 card sometimes appeared to be functional but was not. Issuing the redundancy reload-peer command corrected the problem every time.

Attainable Bit Rate Is Conservative on 4xflexi-DMT and 8xDMT

The reported DMT aggregate bit rate is less than the true attainable bit rate.


Due to line condition variations between trains, the effect of trellis encoding, interleave delay, FEC check bytes, and so forth, the attainable bit rate estimate is not always 100 percent accurate. A conservative approach was taken in making the estimate; therefore, in general, you can get a higher rate than what the estimate suggests. For a fast-path scenario, the results should track fairly closely for the downstream rate and err on the conservative side for the upstream rate. For an interleave path scenario, the results are highly dependent on configurations.

At a higher reach or where line conditions are not optimal, trellis encoding, interleave delay, and FEC check bytes can provide a much higher rate than was estimated (greater than 128 kbps).


There is no workaround. The aggregate bit rate calculation is an estimate, which does not accurately model all of the line conditions that affect the true attainable bit rate for a given profile. The calculations for aggregate bit rate are performed as follows:

CPE Performance Issues with Overhead Framing Modes 0, 1 and 2

The CPE does not train or perform reliably when the Discrete Multitone (DMT) profile is set to use overhead framing mode 0, 1, or 2.

Overhead framing modes 0, 1, and 2 are not supported at this time.


Overhead framing mode 3 is designed for use with ATM. While overhead framing mode 1, which is not currently supported, is designed for Synchronous Transport Module (STM) mode. Configure your profiles to use overhead framing mode 3. Overhead framing mode 3 uses only 32 bytes of administrative overhead. Compared with overhead framing mode 1, it allows more bandwidth to be allocated to user data.

Trellis Encoding Enable Default Recommendations

Trellis encoding is disabled by default on the NI-2 card because it is not supported on the 4xDMT (ATUC-1-4DMT) line card. However, trellis encoding is supported on the 4xFlexiDMT (ATUC-4FLEXIDMT) line card and the 8xDMT (ATUC-1-DMT8 and ATUC-1-DMT8-I) line cards.

Note    If you are unsure if your CPE supports trellis encoding, check with the manufacturer.

For information about how to change trellis encoding settings on the NI-2 card, see the documentation at the following location:

Restrictions on IP Services

This section describes restrictions on the Cisco NI-2 card IP services.

Restricted Layer 3 Services

Cisco IOS Release 12.2(12)DA2 does not support the following Layer 3 services (or else these services are limited, as noted):

Integrated Routing and Bridging Not Supported

MPLS VPN mapping of RFC 1483 routed sessions must not be confused with Integrated Routing and Bridging (IRB). IRB is not supported by MPLS VPN mapping of RFC 1483 routed sessions.

VPN Interfaces Restricted to Trunk Interfaces

Do not configure subtended interfaces for MPLS VPN services. Only trunk interfaces support MPLS VPN mapping of RFC 1483 routed sessions.

MPLS ATM-Label Switch Router Functionality Not Supported

DSLAMs are not meant for use as MPLS ATM-Label Switch Routers (ATM-LSRs). When designing your network, keep in mind that DSLAMs act only as Label Edge Routers (LERs).

Performance Restrictions for MPLS VPN Traffic

MPLS VPN-enabled interfaces do not perform as well as switched VCs. Please take this into consideration when deploying MPLS VPNs in your networks.

Restricted MPLS Features

The following MPLS-related features are not part of the MPLS VPN mapping of RFC 1483 routed sessions:

DSL Interface Limitations

In DSLAMs, each DSL interface can support multiple permanent virtual circuits (PVCs), but we recommend that you use one routed MPLS VC if a dynamic routing protocol (such as RIP) is used between the customer equipment and the provider equipment.

MPLS VPN Mapping Not Supported on the Eight-Port IDSL ITU-C Line Card

Routed termination of IDSL connections has not been supported since Cisco IOS Release 12.2(1b)DA.

Frame Relay PVCs/Soft PVCs on an IDSL Interface

The number of Frame Relay PVCs/Soft PVCs on an IDSL interface is restricted to 1 if you use the default row in a frame-relay connection traffic table (FR-CTT).

When upgrading to Release 12.2(12)DA2 from earlier releases, you must first create a new row in the FR-CTT with the desired CIR value and use the resultant row number during PVC/Soft PVC creation. If you do not create a new row, the second FR PVC/Soft PVC command is not parsed and installed on the IDSL interface.

Use of a Ring Topology in a DSLAM Subtend Environment to Achieve ATM Trunk Redundancy

Ring topology is achieved when a node in the subtend tree is attached to the ATM access to provide a physically redundant loop. Thus, when the primary ATM access or one of the ATM trunks in the subtend tree fails, the soft permanent virtual circuits (SPVCs) can be dynamically rerouted through the use of Private Network-Network Interface (PNNI) (Figure 1).

Figure 1   SPVCs Prior to Failure

This redundancy requires the use of SPVCs. If you use permanent virtual circuits (PVCs) or permanent virtual paths (PVPs), redundancy cannot be provided. The use of the SPVCs allows traffic to be rerouted around the failed access point, because SPVCs leverage this feature of PNNI. When the failure occurs, the SPVCs are disconnected and dynamically reconnected across the new path (Figure 2).

Figure 2   SPVCs Dynamically Rerouted


If you implement ring topology in a DSLAM subtend to achieve ATM trunk redundancy, the following requirements apply:


When the redundant link is active, the following occurrences are problems:

Once the redundant link is active, the following occurrences are potential problems:

Cisco DSL Manager

If you are using versions of Cisco DSL Manager (CDM) earlier than CDM Release 3.4—from CDM Release 1.0 to CDM Release 3.3(3)—do not upgrade the DSLAMs to this new Cisco IOS release.

If you use both the CDM network management application and the Cisco IOS command line interface to manage your Cisco DSLAMs, you should be aware of certain configuration and procedural implications. Refer to the Release Notes for the Cisco DSL Manager, Release 3.4, for this information.

Important Notes

This section provides important information about Cisco IOS software releases for DSLAMs.

Line Card Features

Table 3 shows which line card features are available on the 4xDMT, 4xFlexi, and 8xDMT line cards.

Table 3   Line Card Features

Feature  4xDMT  4xFlexi  8xDMT 









Min rate blocking

alarm only



SNR margin

alarm only

alarm and retrain capable

alarm and retrain capable

Trellis encoding



Disable on ADI based CPEs.


Ignores profile setting. The line card firmware automatically controls trellis encoding based on the CPE type.

Overhead framing

Mode 0,1,2,3 with ADI based CPE

Mode 3 is recommended with other CPE.

Mode 3 only

Mode 3 only

Power Management Additional Margin




Operating mode




Training mode

Quick recommended

No affect

No affect

Cisco 677 CPE support




Cisco 678 CPE support




Alcatel-based CPEs

limited performance



NI-2 Card IP Services

During system startup, the following protocol warning messages display. You can ignore these messages.

%AAAA-4-SERVUNDEF: The server-group "radius" is not defined. Please define it. 

% Can't create VRF 

Soft PVC Address Changes upon Upgrade from Release 12.1(4)DA or Earlier

When you upgrade from Cisco IOS Release 12.1(4)DA or earlier to Release 12.2(12)DA3, the default soft PVC addresses on all interfaces change. This occurs only when you upgrade to Release 12.2(12)DA3 from Release 12.1(4)DA or earlier.


Reconfigure the soft PVCs associated with all interfaces.

Assign a (nondefault) address to the interfaces.

Configuring Cisco Routers for Use with IDSL

If you wish to use a Cisco router for an IDSL application and the router is running a Cisco IOS release earlier than Release 12.1, you must configure the ISDN switch type. If you do not configure the ISDN switch type on the Cisco router, the router's BRI interface might not come back up after the IDSL line goes down and comes back up.

To prevent this problem from occurring, execute the isdn switch-type basic-ni command in global configuration mode on the router.

This problem does not occur if the Cisco router is running Cisco IOS Release 12.1 or later.

Assigning VPI Values to Shaped VP Tunnels

This release supports the full range of VPI values: 0 to 255. However, if you configure VP tunnels with traffic shaping, you can use only 32 VPIs out of that range. If you have not yet assigned any VPIs, all values from 0 to 255 are available. Once you start assigning VPIs, however, the assigned VPIs limit the VPIs that remain. (You assign VPIs using the atm pvp or atm pvc command.)

After a particular VPI value is assigned to a shaped VP tunnel, every 32nd VPI value above and below the first one is eliminated—that is, the original value modulo 32. For example, if you assign VPI 94 to a shaped VP tunnel, the following VPI values become unavailable for any purpose: 30, 62, 126, 158, 190, and 222.

To avoid problems, choose a block of 32 consecutive VPI values (for example, 0 to 31 or 101 to 132). The software rejects invalid VPI values.

Installing Multiple Cisco 6160 DSLAMs in an Equipment Rack

You can install multiple Cisco 6160 DSLAMs in a Telco equipment rack. A standard 7-foot equipment rack can house four Cisco 6160 DSLAMs, stacked one on top of another. This configuration maximizes the DSL density within a 7-foot rack. However, if space is available or you are interested in using any multiservice capabilities that the DSLAM might support in the future, we recommend that you install no more than three Cisco 6160 DSLAMs in a 7-foot rack. Leave a space of at least 2.5 rack units (4.375 inches, or 11.1 cm) beneath each DSLAM for future cable management use.

Console Logging

Turn console logging off if you plan to reboot the DSLAM. Turn console logging back on after the system comes up. (Console logging is turned on by default.) Use the global configuration commands no logging console (to turn the feature off) and logging console (to turn it on).

If console logging is on when the system reboots, the large volume of console messages consumes CPU time. As a result, the system comes back up more slowly and line cards might reload repeatedly, causing further delays.


Caveats describe unexpected behavior in Cisco IOS software releases. Caveat numbers and brief descriptions are listed in the following tables. For details about a particular caveat and for information on caveats in previous Cisco IOS releases that also apply to this release, go to Bug Toolkit at:

To access this location, you must have an account on If you have forgotten or lost your account information, e-mail the Contact Database Administration group at . If you do not have an account on, go to and follow the directions to set up an account.

Note   If you have an account with, you can use Bug Navigator II to find caveats for a release. To reach Bug Navigator II, go to and click Login. Then go to Software Center > Cisco IOS Software > Cisco Bugtool Navigator II. Alternatively, you can go to:

For information on caveats in Cisco IOS Release 12.2, see Caveats for Cisco IOS Release 12.2 , which lists severity 1 and 2 caveats and select severity 3 caveats for Cisco IOS Release 12.2. It is located on  and the Documentation CD-ROM.

Resolved Caveats—Release 12.2(12)DA3

Table 4 lists the caveats resolved in Cisco IOS Release 12.2(12)DA3.

Table 4   Resolved Caveats in Cisco IOS Release 12.2(12)DA3

Caveat Number  Description 


This DDTS has been created to track improvements in IP processing. Please use the following URL for further information: .

Resolved Caveats—Release 12.2(12)DA2

Table 5 lists the caveats resolved in Cisco IOS Release 12.2(12)DA2.

Table 5   Resolved Caveats in Cisco IOS Release 12.2(12)DA2

Caveat Number  Description 


crossInterface can be seen correctly using CLI, but when using SNMP... crossIfIndex (1) is reported being the main interface (ATM0/1) instead of the logical interface (ATM0/1.1), ifIndex 187.


TraceBacks when trying to set ciscoAtmIfIlmiAutoConfiguration. Spurious accesses appear when configuring new customers.


Ftp sessions on NI2 will abort the file transfers occasionally without any error messages or notifications to the user.


For 12.2(10) image, in 6015, traceback comes while rebooting the DSLAM and trying to initialize the interface. But it is not seen in any DSLAM other than 6015. This traceback does not appear in versions prior to 12.2(10).


A mismatch between the customer cpe train status and the modem train status on the 8xDMT linecard of a DSLAM occurs sporadically.

Resolved Caveats—Release 12.2(12)DA1

Table 6 lists the caveats resolved in Cisco IOS Release 12.2(12)DA1.

Table 6   Resolved Caveats in Cisco IOS Release 12.2(12)DA1

Caveat Number  Description 


A DSLAM reload no longer causes the SHDSL target margin in a DSL profile to be reset to 2 dB when adaptive rate is used.


Heavy traffic through the SAR chipset IDT77V252 no longer causes cell corruption in the Tx path. This problem previously occurred on NI-2 cards with the product numbers NI-2-DS3-T1E1 and NI-2-DS3-T1E1-H.


Issuing the no slot command in PVC submode now works correctly. Previously, concurrency issues caused the DSLAM to reload when the command was issued while another user session was active in PVC submode.

Open Caveats—Release 12.2(12)DA

Table 7 lists the open caveats in Cisco IOS Release 12.2(12)DA.

Table 7   Open Caveats in Cisco IOS Release 12.2(12)DA

Caveat Number  Description 


After the CPE trains with the 8xDMT-ISDN line card, the number of DMT check bytes allocated for forward error correction (FEC) on the line card does not match the number of DMT check bytes provisioned. This problem occurs in both interleaved and fast path mode.

Workaround: None.

Resolved Caveats—Release 12.2(12)DA

Table 8 lists the caveats resolved in Cisco IOS Release 12.2(12)DA.

Table 8   Caveats Resolved in Cisco IOS Release 12.2(12)DA

Caveat Number  Description 


FTP fails with the traceback: SYS-2-LINEPROCDEAD: Killing process.


Clearing the interface counters on a Cisco 6260 DSLAM now works correctly. Previously, the counters might not have been cleared and could instead show high input and cyclic redundancy check (CRC) errors.


On an OC-3 interface, the show interface command "packets output" count does not match the show controller command "cells transmitted" count, but both should be the same.

Workaround: None.


The show dsl interface atm command now shows the correct value for the Last Change field for G.SHDSL ports. Previously, if the system clock value was altered after the G.SHDSL port trained, this field might show an erroneous value.


Issuing the clear counters command on an OC-3 interface no longer causes SNMP to incorrectly show ifTable counters equal to 0.


SNMP now checks to ensure that you specify a valid value for Upstream Checkbytes on a DSL profile. Previously, SNMP allowed you to specify any value for cAdslAturDmtConfInterleaveFecSize (CISCO-ADSL-DMT-LINE-MIB), even though valid values are 0 through 16, in multiples of 2.


The 8xDMTISDN line card no longer drops the connection after it trains with a Cisco 826 CPE when the line card's downstream bit rate is less than 5504 kilobits per second (kbps). Previously, this problem caused constant link flapping.

Open Caveats—Release 12.2(10)DA

All of the caveats listed in Table 9 are open in Cisco IOS Release 12.2(10)DA. This table lists only severity 1 and 2 caveats and some severity 3 caveats.

Table 9   Open Caveats in Cisco IOS Release 12.2(10)DA

Caveat Number  Description 


3db downstream margin configured ports on 8xDMT do not achieve max configured downstream rate on loops that should achieve max configured downstream rate.

Workaround: Use of DSL's recommended 6db downstream margin will achieve max configured rate on loops expected to achieve max rate.


8xDMT cards with interleaving delay configurations of 2000 microseconds or less can have problems holding the training rate or having less than expected upstream training rates.

Workaround: Avoid interleaving delay values of 2000 microseconds and less with 8xDMT cards. For interleaving mode configurations, use a 4000 microsecond delay or better. If lower delays are required, use fast path mode if it is supported by the CPE.


The connection between the modem on a 4xDMT line card and the CPE is lost when an NI-2 card redundancy switchover occurs.

Workaround: None.


When you copy a configuration file from a TFTP server to the startup_config through SNMP, ccCopyState (CISCO-CONFIG-COPY-MIB) stays in the Running state forever. It does not change to the Failed state.

The show startup command displays the following output:

%% Non-volatile configuration memory is being accessed, Try again

Workaround: Make sure there is enough space available in NVRAM before copying, using SNMP or CLI.


Upgrades from Cisco IOS Release 12.1.(7) DA to newer Cisco IOS software images cause G.SHDSL ports to occasionally drop and retrain. The error is listed as LOSQ (Loss of Signal Quality) due to CRC errors detected or LOS when Loss of Frame Sync is detected.

Workaround: Newer versions of G.SHDSL firmware have been adjusted to meet the ratified standards. This may require some fixed-rate loops to not hold train at the current configured rate used with Cisco IOS Release 12.1.(7)DA. In some cases, reducing the configured rate resolves the issue. Random drops might still occur on some ports.

Resolved Caveats—Release 12.2(10)DA

The problems listed in Table 10 are fixed in Cisco IOS Release 12.2(10)DA.

Table 10   Caveats Resolved in Cisco IOS Release 12.2(10)DA

Caveat Number  Description 


Periodically, the system generates a serial management bus cyclic redundancy check (SMBCRC) error message such as this:

%NI2-5-LC_NOTICE:Slot[15] SMBCRC (1 days, 3 hours, 37 minutes, 6 seconds)

These messages are informational only and do not affect performance.


The entry for the atmSoftPVccRetryThreshold feature has an incorrect default value of 0, rather than the default value of 1 that is shown in the ATM soft PVC Management Information Base (MIB). A value of zero indicates that an infinite number of call attempts are required to increment the atmSoftPvcCallFailures object and thus disables alarms for the soft PVC.


Adding and deleting a profile from different sessions (for example, in two Telnet sessions, one user is adding while at the same time another is deleting the same profile) has the potential of causing an unexpected system reload.


The ceAssetTag cannot be set for 8xDMT and SHDSL line cards.


Following a redundancy switchover, the standby card may reload twice before reaching the STANDBY-READY state. Once the standby is in the STANDBY-READY state it will not continue to reload.


Some VCs (PVCs/PVPs/Soft PVCs/Soft PVPs) are missing on reload even when they are stored in the startup configuration. This problem occurs if you create VCs by using internal CTT rows that do not appear in the show running-config command but do appear in the show atm connection-traffic-table command.


When you configure the ATUC-1-4DMT line card for loopback diagnostic, cells are dropped by the interface.


The commands no tag-switching ip and tag-switching ip from the global configuration mode remove the tag-switching atm vp-tunnel 13 vci-range 33-65535 line on the sub interfaces.


Not all IMA group/link alarms are shown in the event browser.


If you try to enable tag-switching ip, the following message appears: %VP-tunnel vpi is not free for Tag-switching.


The NI-2 card does not support OAM F5 seg-loopback cells, in the fast path.


PNNI fails to establish a connection. The show atm controller atm 0/0 command displays a status of C.


Unable to train with 3Com OCR-810. With the 4xDMT line card, the CPE exhibited line errors and failures in training with Release 12.2(7)DA. Trellis encoding is enabled in the DSL profile.


When you change the operation of the linecard from ATUC-1-DMT8 to STUC-8-TCPAM, the indexes appear in the incorrect order.


The system stops responding indefinitely after you provisioning or unprovision slots.


In Cisco IOS Release 12.2(7)DA, the value of the "Microseconds handling network interrupts" is not saved correctly to the NVRAM when configured through the scheduler allocate exec command.


The NI-2 card unexpectedly reloads when you try to clear a card mismatch from CLI using the command no slot x, where x is the slot number.


Adtran CPEs do not train with a Cisco 6260 DSLAM that is running Cisco IOS Release 12.2(7)DA.

Open Caveats—Release 12.2(7)DA

All open caveats in Cisco IOS Release 12.2(7)DA have been resolved.

Resolved Caveats—Release 12.2(7)DA

The problems listed in Table 11 are fixed in Cisco IOS Release 12.2(7)DA.

Table 11   Caveats Resolved in Cisco IOS Release 12.2(7)DA

Caveat Number  Description 


The input queue field in the output of the show interface atm slot/port occasionally shows a negative number.


The cAdslAtuc/AturCapCurrRxGain in the CISCO-ADSL-CAP-LINE-MIB returns an incorrect value for short loops (less than 2000 feet).


For the STUC G.SHDSL line card, all far end (STUR) statistics that appear through the CLI or SNMP are reported as zero.


The G.SHDSL line card does not support rate adaption.


The ifSpeed object from the ifTable returns an incorrect speed at the ATM layer for a 4xFlexi DMT line card.


Packet loss occurs when you police with abr for MCR values greater than 18.


The Init event counter toggles between 0 and 4294967295 several times in a minute for a 4xFlexi DMT line card.


An ARP packet received by the router that has the router's own interface address but with a different MAC address can overwrite the router's own MAC address in the ARP table, causing that interface to stop sending and receiving traffic. This attack is successful only against interfaces on the Ethernet segment that is local to the attacking host.


The error message ERROR: Irrecoverable IDT 252 RCQ last Cell problem detected! appears and is repeated several times. ATM OAM cells are not handled correctly and these error messages finally lead to system reload.


Far End LPR Events are not incrementing on the ATUC-4FLEXI-DMT line card when the power is removed from a CPE that supports the dying gasp feature of the DMT standard.


VPI/VCI values for provisioned PVC do not match the provisioned values when you select a VCI value of 0 for any non-terminating PVC (that is, a PVC not terminating at atm0/0).


The shdsl profile has a different format between Cisco IOS Release 12.1(7)DA and Cisco IOS Release 12.2(5).


When you configure an interface bandwidth statement on a Cisco 6260 DSLAM ATM interface, the default bandwidth value for the interface as seen in the show interface atm command may appear in the show running-config output.


Cisco 6260 DSLAM SNMP agent returns incorrect ifType for SHDSL interfaces.


Using the command show atm vc interface atm slot/port vpi vci where vpi and vci are the VPI and VCI numbers in a SVC configuration can cause the DSLAM to reload. This usually happens when the CPE is connected but the SVC is not yet established.


Invalid cells are passed to network port on a valid VC. The 4xDMT line card does not discard cells with HEC errors and stamps each cell going to the DSLAM with a valid HEC. The switch can then pass these corrupt cells out the WAN interface if they appear to have a valid and provisioned VPI and VCI.


After 54 days of uptime, the system experienced an unexpected reload immediately preceded by the messages: System reloads with message SYS-2-WATCHDOG process=IMA CORE.


An NI-2 DSLAM reloads after a few ALIGN-1-FATAL error messages.


An error can occur with management protocol processing. Please use the following URL for further information:

Related Documentation

The software described in these release notes runs on several Cisco NI-2 DSLAM platforms, including the Cisco 6015, Cisco 6160, and Cisco 6260 DSLAMs.

A complete list of all DSL hardware product related documentation is available at the following URL:

A complete list of all DSL Cisco IOS product related documentation is available at the following URL:

In the Cisco ATM software manuals, look for information pertaining to the LightStream 1010, which uses the same software base as the Cisco NI-2 DSLAMs. ATM manuals are available at the following URL:

Obtaining Documentation

The following sections describe how to obtain documentation from Cisco Systems.

World Wide Web

You can access the most current Cisco documentation on the World Wide Web at the following sites:

Documentation CD-ROM

Cisco documentation and additional literature are available in a CD-ROM package, which ships with your product. The Documentation CD-ROM is updated monthly and may be more current than printed documentation. The CD-ROM package is available as a single unit or as an annual subscription.

Ordering Documentation

Cisco documentation is available in the following ways:

Documentation Feedback

If you are reading Cisco product documentation on the World Wide Web, you can submit technical comments electronically. Click Feedback in the toolbar and select Documentation. After you complete the form, click Submit to send it to Cisco.

You can e-mail your comments to

To submit your comments by mail, use the following address:

Attn. Document Resource Connection
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We appreciate your comments.

Obtaining Technical Assistance

Cisco provides as a starting point for all technical assistance. Customers and partners can obtain online documentation, troubleshooting tips, and sample configurations from online tools by using the Cisco Technical Assistance Center (TAC) Web Site. registered users have complete access to the technical support resources on the Cisco TAC Web Site. is the foundation of a suite of interactive, networked services that provides immediate, open access to Cisco information, networking solutions, services, programs, and resources at any time, from anywhere in the world. is a highly integrated Internet application and a powerful, easy-to-use tool that provides a broad range of features and services to help you with these tasks:

If you want to obtain customized information and service, you can self-register on To access, go to this URL:

Technical Assistance Center

The Cisco Technical Assistance Center (TAC) is available to all customers who need technical assistance with a Cisco product, technology, or solution. Two levels of support are available: the Cisco TAC Web Site and the Cisco TAC Escalation Center.

Cisco TAC inquiries are categorized according to the urgency of the issue:

The Cisco TAC resource that you choose is based on the priority of the problem and the conditions of service contracts, when applicable.

Cisco TAC Web Site

You can use the Cisco TAC Web Site to resolve P3 and P4 issues yourself, saving both cost and time. The site provides around-the-clock access to online tools, knowledge bases, and software. To access the Cisco TAC Web Site, go to this URL:

All customers, partners, and resellers who have a valid Cisco service contract have complete access to the technical support resources on the Cisco TAC Web Site. The Cisco TAC Web Site requires a login ID and password. If you have a valid service contract but do not have a login ID or password, go to this URL to register:

If you are a registered user, and you cannot resolve your technical issues by using the Cisco TAC Web Site, you can open a case online by using the TAC Case Open tool at this URL:

If you have Internet access, we recommend that you open P3 and P4 cases through the Cisco TAC Web Site.

Cisco TAC Escalation Center

The Cisco TAC Escalation Center addresses priority level 1 or priority level 2 issues. These classifications are assigned when severe network degradation significantly impacts business operations. When you contact the TAC Escalation Center with a P1 or P2 problem, a Cisco TAC engineer automatically opens a case.

To obtain a directory of toll-free Cisco TAC telephone numbers for your country, go to this URL:

Before you call, check with your network operations center to determine the level of Cisco support services to which your company is entitled: for example, SMARTnet, SMARTnet Onsite, or Network Supported Accounts (NSA). When you call the center, have your service agreement number and your product serial number available.

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