Table of Contents

Release Notes for Cisco IOS Release 12.1(6)DA1 for Cisco DSLAMs with NI-2

Release Notes for Cisco IOS Release 12.1(6)DA1 for Cisco DSLAMs with NI-2

August 29, 2001

These release notes describe features and caveats in Cisco IOS Release 12.1(6)DA1 for the Cisco 6015, Cisco 6100, Cisco 6130, Cisco 6160, and Cisco 6260 digital subscriber line access multiplexers (DSLAMs).

Note   When you upgrade from earlier images on the NI-2 to Release 12.1(6)DA1, you must format the image in bootflash on the NI-2 to the 12.1(6)DA1 dboot image. See the "Update the Image in Bootflash to the 12.1(6)DA1 dboot Image" section.

For pointers to more information about the Cisco 6015, Cisco 6130, Cisco 6160, Cisco 6260, 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 in the "Documentation CD-ROM" section.

Contents

This document contains the following topics:

• System Requirements
  
  
• New and Changed Information
  
  
• Limitations and Restrictions
  
  
• Important Notes
  
  
• Caveats
  
  
• Related Documentation
  
  
• Obtaining Documentation
  
  
• Obtaining Technical Assistance
  
  

System Requirements

Cisco IOS Release 12.1(6)DA1 runs on these DSLAM systems:

• Cisco 6015
  
  
• Cisco 6100 with second-generation network interface (NI-2) module, Cisco 6100-specific system I/O card, and SC jumper card
  
  
• Cisco 6130 with second-generation network interface (NI-2) module and Cisco 6130-specific system I/O card
  
  
• Cisco 6160
  
  
• Cisco 6260
  
  

New and Changed Information

This section provides new and changed information for Cisco IOS releases.

New Features in Release 12.1(6)DA

This section describes new features in Cisco IOS Release 12.1(6)DA.

Cisco 6015 Outside Plant DSLAM

This release includes support for a Cisco 6015 that can be installed in outside plant and other harsh environments. The Cisco 6015 is an ATM-based DSL access multiplexer designed to support from 4 to 48 subscribers per chassis in remote cabinets, smaller COs, and MDU sites in a scalable fashion. Through subtending, multiple Cisco 6015s can be deployed to provide connectivity to more than 48 subscribers. It is a smaller density companion to the Cisco 6100/6130/6160/6260 DSLAM product family.

For more information on the Cisco 6015, see the "Cisco 6015 DSLAM" section.

DS3/2DS3+8xT1 IMA System I/O Card for the Cisco 6160

This release adds support for a DS3 or T1 I/O interface between the NI-2 card and the trunk interfaces. T1 operation is provided with the new Cisco 6160 DS3/2DS3+8xT1 IMA system I/O card combined with the existing DS3+T1/E1 IMA NI-2. When you use the DS3+T1/E1 IMA NI-2 card, the DS3 port 1 or any T1 or IMA group can be used as a trunk interface. See the "T1/E1 Inverse Multiplexing over ATM" section for further information.

Octal-Port DMT ATU-C Line Card

The octal-port DMT (8xDMT) ATU-C line card provides higher port density for the Cisco 6015, Cisco 6160, 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.
  
  
• Supports bit swapping.
  
  
• Interoperates with the Cisco 677, Cisco 678, Cisco 827, Cisco 1417 CPE, and with certain third-party CPE.
  
  
• Supports quad-port flexi ATU-C line card enhancements.
  
  

Quad-Port Flexi ATU-C Line Card Enhancements

The quad-port flexi (4xflexi) ATU-C line card enhancements add a number of improvements to the functionality of Cisco 6130, Cisco 6160, and Cisco 6260 DSLAMs with NI-2 in IOS release 12.1(6). The following improvements were added for IOS release 12.1(6)DA:

• Interoperability between the Cisco 677 ADSL customer premises equipment (CPE) and the 4xflexi line card in the following DSLAM platforms:
  
  
  • Cisco 6130 with NI-2
    
    
  • Cisco 6160 with NI-2
    
    
  • Cisco 6260 with NI-2
    
    
• Improved Interoperability between third-party CPE and the 4xflexi line card.
  
  

IOS 12.1(6)DA adds improved interoperation with CPE based on Alcatel chipsets using Alcatel Microelectronics firmware version 1.4.1.

• Enhanced IOS commands that monitor and manage port responses to adverse line conditions
  
  

Two additions to IOS 12.1(6)DA improve line quality monitoring on DMT ports. You can use the dmt minrate-blocking command to prevent a 4xflexi port from training at a rate below a specified minimum bit rate. With dmt rate-adaptation commands, you can configure a DMT port to react to poor line quality by retraining to current line conditions.

New Features in Release 12.1(5)DA

This section describes new features in Cisco IOS Release 12.1(5)DA.

Fast Path Support for the Quad-Port Flexi ATU-C Line Cards

The fast path feature allows you to configure either the fast or the interleave DMT path via DSL profile configuration commands. Prior to Cisco IOS Release 12.1(5)DA, the operation of all supported DMT line cards was limited to use of the interleave path. Cisco IOS Release 12.1(5)DA supports the use of either the interleave or fast DMT paths with the 4xflexi-DMT line card. The fast path provides improved latency characteristics for applications that cannot tolerate latency (for example, voice).

With fast path enabled, the 4xflexi-DMT line card now has downstream bit swapping enabled. This helps improve line quality on certain loops when running fast path.

New Flexi Line Card Support (DMT Line Encoding Only) for the Cisco 6260

This release adds support for the quad-port flexi line card (ATUC-4-FLX-2) in the 6260 chassis when configured for DMT line encoding. The DMT features for the 4xflexi card in the Cisco 6260 are consistent with the feature set provided in the Cisco 6130 and Cisco 6160 products, and include autodetection of the CPE type and capabilities, compliance with ANSI T1.413 issue 2 (ATM mode), G.992.1 Annex A, G.992.2 Annex A, and configurability between G.lite and G.dmt/T1.413. Please note that CAP line encoding is not supported on the Cisco 6260.

Proxy Element Supporting the Cisco DSL CPE Automated Configuration Solution

The Cisco DSL CPE automated configuration solution automates the configuration process for DSL customer premises equipment (CPEs). The proxy element is a name for the feature set embedded in IOS Release 12.1(5)DA to support the automated configuration solution on the Cisco 6000 series DSLAMs.

The Cisco DSL CPE automated configuration solution dramatically decreases the time and personnel resources required to bring service to a new DSL customer or to change or upgrade services. It allows the DSL provider to preprovision much of the CPE configuration. It eliminates the need for the DSL provider to visit the customer site. It provides a way to automatically deploy service changes or upgrades, and to automatically distribute new software and firmware images.

The DSL end user (the provider's customer) benefits by the shortened implementation time for DSL services, the plug and play style installation, and the automated distribution of new software images to CPE.

The Cisco DSL CPE automated configuration solution is one piece of a larger solution that represents Cisco's support of the OpenDSL initiative. The Cisco solution and the Open DSL initiative are based on the Simple Network Management Protocol (SNMP) and its information unit known as the management information base (MIB).

The proxy element performs the following functions in support of the automated configuration solution:

• Manages the configuration information base (CIB), which is a set of interrelated SNMP MIBs. The CIB stores all configuration information for all of the CPEs under the proxy element's control.
  
  
• Accepts input from the Cisco DSL CPE Manager (CDCM), which is a graphical user interface (GUI) tool for operators at the DSL provider site to add to and update information in the CIB.
  
  
• Handles requests from the CPEs for their configuration information. Every time a CPE in automated configuration mode reboots, it requests its configuration information.
  
  
• Downloads files to the CPEs. Examples of file types that can be accepted by CPEs are operating system software images, firmware images, and configuration files. The types of files that can be downloaded to a CPE depends on the CPE's model.
  
  
• Implements security and access control features in the SNMP version 3 (SNMPv3) to ensure that external users cannot modify the configuration information for a CPE.
  
  

New Features in Release 12.1(4)DA

This section describes new features in Cisco IOS Release 12.1(4)DA.

Cisco 6015 DSLAM

The Cisco 6015 is an ATM-based DSL multiplexer designed to support from 4 to 48 subscribers per chassis in remote cabinets, smaller COs, and MDU sites in a scalable fashion. Through subtending, multiple 6015s can be deployed to provide connectivity to more than 48 subscribers. It is a smaller density companion to the Cisco 6100/6130/6160/6260 DSLAM product family.

Note   Cisco 6015 system support was available in Release 12.1(4)DA; however, at the date of Release 12.1(4)DA, the Cisco 6015 system was not shipping. The Cisco 6015 system is expected to ship within the next quarter. Please contact your sales representative for more information on the Cisco 6015 system availability.

New components supported include:

• Cisco 6015 chassis
  
  
• DS3+T1/E1 inverse multiplexing over ATM (IMA) NI-2
  
  
• DS3+8xT1 I/O module
  
  
• 8xE1 I/O module
  
  
• Cisco 6015 DC PEM
  
  
• Cisco 6015 Fan tray
  
  
• Up to six quad-port Flexi ATU-C line cards
  
  

The Cisco 6015 supports two configurations:

• DS3/T1 IMA
  
  
• E1 IMA
  
  

Both of these configurations are based on the DS3+T1/E1 IMA NI-2.

DS3+T1/E1 IMA NI-2

The DS3+T1/E1 IMA NI-2 supports two new features for Release 12.1(4)DA:

• T1/E1 IMA
  
  
• Trunk selection
  
  

The DS3+T1/E1 IMA NI-2 supports two modes of operation:

• DS3 trunk with 8xT1 IMA trunk/subtend
  
  
• 8xE1 IMA trunk/subtend
  
  

The mode of operation is determined based on the type of I/O module (DS3/T1 or E1) that is detected at system startup.

T1/E1 Inverse Multiplexing over ATM

The T1/E1 inverse multiplexing over ATM (IMA) feature uses IMA technology to aggregate multiple low-speed links (T1/E1) into one or more IMA groups at speeds between 1.5 Mbps to 16 Mbps. IMA breaks up the ATM cell stream and distributes the cells over the multiple physical links of an IMA group and then recombines the cells into a single stream at the other end of the connection. The ATM cells are distributed in a round-robin fashion over the physical links of the IMA group, demultiplexed at the receiving IMA group, and passed in their original form to the ATM layer. Using the multiple links of an IMA group increases the logical link bandwidth to approximately the sum of the individual link rates.

The eight links on the DS3+T1/E1 IMA NI-2 can be independent ATM links or can be configured into one or more IMA groups. There are four static IMA groups. Each IMA group can contain from zero to eight T1/E1 links. Any combination of independent T1/E1 links and IMA groups is allowed, up to eight T1/E1 links total.

Some examples of allowed combinations are

• Two links and one IMA group with six links
  
  
• Four IMA groups with two links in each
  
  
• Four links and two IMA groups with two links in each
  
  

  ---

  Note   E1 IMA group bandwidth is limited to six links. Cell loss will occur if an IMA group has more than six links and more than 12 Mbps are sent through it. The loss only occurs on groups with greater than six E1 links. All eight links can be used in different groups, however (for example, six in group 0, two in group 1). This does not affect T1 operation (that is, all eight T1 links may be used in a group). This problem is described in DDTS report CSCdr45623.

  ---

For detailed information, see the T1/E1 Inverse Multiplexing over ATM feature module.

Trunk Selection

The trunk selection feature allows you to configure any WAN interface (the DS3, any T1 link, any E1 link, or any IMA group) as the trunk. When you configure a T1/E1 link or an IMA group as the trunk, the DS3 port is disabled. When you select the DS3 port as the trunk, the T1/E1 links and IMA groups are all treated as subtended ports.

E3+2E3 I/O Module on the Cisco 6260

This release adds support for an E3 trunk with 2xE3 subtends on the Cisco 6260. E3 operation is provided with the new 6260 E3+2xE3 I/O module combined with the existing DS3/E3+2xDS3/E3 NI-2.

MPLS VPN Mapping of RFC 1483 Routed Sessions

The MPLS VPN mapping of RFC 1483 routed sessions feature enables most Cisco DSLAMs with NI-2 controller cards and connected customer premises equipment (CPE) to participate in MPLS VPNs.

The following DSLAM platforms support MPLS VPN mapping of RFC 1483 routed sessions:

• Cisco 6015 DSLAM with NI-2
  
  
• Cisco 6100 DSLAM with NI-2
  
  
• Cisco 6130 DSLAM with NI-2
  
  
• Cisco 6160 DSLAM with NI-2
  
  
• Cisco 6260 DSLAM with NI-2
  
  

For detailed information on configuring MPLS VPN mapping of RFC 1483 routed sessions see the MPLS VPN Mapping of RFC 1483 Routed Sessions feature module.

New Features in Release 12.1(3)DA

This section provides information about the latest features in Cisco IOS Release 12.1(3)DA.

ATUC-1-4DMT-ISDN Line Card

This release supports the quad port ATUC-1-4DMT-ISDN line card. This line card provides four ADSL/DMT ports per card. With this card, the Cisco 6260 supports operation over POTS and over both 4B3T and 2B1Q ISDN line coding.

New Features in Release 12.1(2)DA

This section provides information about the latest features in Cisco IOS Release 12.1(2)DA.

Eight-Port IDSL ITU-C Line Card

This release supports the 8-port IDSL ITU-C line card. With this 8-port card, the Cisco 6160 can support up to 256 IDSL subscribers. The IDSL line card uses 2B1Q line coding and offers configurable data rates of 56 kbps, 64 kbps, 128 kbps, and 144 kbps. The card also provides PPP (RFC 1549) to PPPoATM (RFC 2364) translation and FRF.8 Frame Relay to ATM service level interworking. In this release, the IDSL line card operates in the Cisco 6160 DSLAM only.

New Features in Release 12.1(1)DA1

This section provides information about the latest features in Cisco IOS Release 12.1(1)DA1.

Software Supports Alcatel DSL Chip Set-Based CPE

This software image implements limited support for interoperability with most CPE devices based on the Alcatel DSL chip set (no new hardware is required). Given current generation chipsets from our suppliers, the best possible performance is still achieved between like-to-like chipsets (ADI to ADI). Although this will improve over time, the current software image is interoperable with most CPE devices based on other chipset technology.

Although this image provides enough performance to support mixed chipset deployment of ADSL services in many actual field conditions, most CPE modems will not perform equally well. It is highly recommended that the customer test to ensure that the performance is acceptable before making a decision to deploy a mixed solution (that is, nonADI to ADI).

Specifically, the three following performance limitations exist when implemented with Alcatel-based CPE with the ATUC-1-4DMT (ADI-based) line card:

• Performance characterization between the ATUC-1-4DMT (ADI-based) line card and Alcatel-based CPE has been limited to the Alcatel 2.5.8 version of firmware. Other firmware revisions may perform differently.
  
  
• The ATUC-1-4DMT (ADI-based) line card performance might be limited when deployed on very short loops (less than 3 thousand feet). This affects most nonADI based CPEs including the Cisco 827.
  
  
• Upstream performance is limited when connecting the ATUC-1-4DMT (ADI-based) line card to Alcatel-based CPE.
  
  

Quad-Port DMT Card Supports G.lite and G.DMT

The ATUC-1-4DMT2 line card now supports the G.992.1 (G.DMT) and G.992.2 (G.lite) standards.

New Features in Release 12.1(1)DA

This section provides information about the latest features in Cisco IOS Release 12.1(1)DA.

Release 12.1(1)DA Supports the Cisco 6160 DSLAM

The Cisco 6160 is a multiservice DSLAM designed for markets in North America. The Cisco 6160 is a NEBS-compliant platform that supports up to 128 subscribers per chassis, with plans to support 256 subscribers in a future release. Initially, subscriber lines can be ADSL with either carrierless amplitude modulation/phase modulation (CAP), discrete multitone (DMT) T1.413-1998, Issue 2-compliant, or SDSL. (IDSL will be available shortly.) Up to 13 Cisco 6160 chassis can be linked together through the use of advanced, fair-service subtending. OC-3c and DS3 trunk and subtending interfaces are available now; T1 IMA will be available in the future. Optional support for analog voice telephony (POTS, or plain old telephone service) is also available through a companion POTS splitter available from ADC. The Cisco 6160 runs the widely deployed Cisco IOS software.

Availability and Compliance

The Cisco 6160 is designed for 23-inch deployments requiring NEBS compliance and compatibility with North American telephone network requirements. Cisco technical and customer service support teams ensure the highest level of customer care and service support available.

Advanced Services ATM Architecture

The Cisco 6160 internal design is based on a high-performance ATM switching architecture that includes more than 1 million cells of buffering, support for multiple ATM quality of service (QoS) levels, and a variety of ATM traffic management and shaping capabilities.

Scalability with Fair-Service Subtending

The Cisco 6160 supports subtending of up to 13 shelves (chassis) of user traffic all concentrated onto a single network WAN interface port. A variety of WAN and subtending interface port configurations are available, allowing for flexible service architecture design and optimized cost. The Cisco 6160 subtending architecture provides fair and prioritized access to network bandwidth for all subscriber traffic, ensuring sustained throughput and performance for all users.

Standards-Compliant ADSL Support

The Cisco 6160 supports a quad-port flexi line card that can be configured for either CAP or DMT T1.413-1998 Issue 2-compliant line encoding, ANSI T1.413 issue 2 (ATM mode), G.992.1 Annex A, G.992.2 Annex A, and configurability between G.lite and G.dmt/T1.413.

Switched Virtual Connections

Support for ITU and ATM Forum UNI 3.0, 3.1, and 4.0 switched virtual connections (SVCs) provides end-user applications with real-time access to bandwidth and QoS. Support for Private Network Node Interface (PNNI) call routing and Call Admission Control (CAC) is also included.

Soft PVC Provisioning

ATM signaling can be used for automated provisioning of ATM virtual circuits. This capability, also referred to as soft permanent virtual connections (soft PVCs), greatly reduces the time and cost of manual, node-by-node PVC provisioning.

Life-line POTS Splitter Support

Optional support for voice telephone service (POTS) is accomplished through use of POTS splitter equipment available from a third party, ADC Telecommunications. This POTS splitter solution is optimized for international copper access networks and is designed to ensure that basic telephone service is always available, a feature known as life-line POTS.

Splitters and cable kits are not OEM from Cisco and are available only through ADC. ADC offers several splitter solutions; contact ADC to get additional information:

Rodney McCrea
Rodney_McCrea@adc.com
(612) 403-8922

New Flexi and SDSL Line Cards

Two new quad-port line cards are introduced in this release for use with the Cisco 6160 and Cisco 6130:

• The flexi line card can be configured for either CAP or DMT line encoding. CAP features are consistent with NI-1 Release 3.0, with configurable line rates up to 7168 kbps downstream and 1088 kbps upstream. DMT features include autodetection of the CPE type and capabilities, compliance with ANSI T1.413 issue 2 (ATM mode), G.992.1 Annex A, G.992.2 Annex A, and configurability between G.lite and G.dmt/T1.413.
  
  
• The symmetrical digital subscriber line (SDSL) line card supports configurable line rates up to 1168 kbps in both directions. The SDSL card uses 2B1Q line encoding.
  
  

With these line cards, the Cisco 6160 supports up to 128 ports per shelf. New eight-port line cards, available soon, will double the capacity of the system to 256 ports. Line card options that are planned for future releases include G.SHDSL.

New DMT Performance MIB Support

This release supports 96 buckets of 15-minute interval, previous and current 1-day interval DMT performance statistics.

Support for New VPI/VCI Combinations

To enable migration from NI-1 to NI-2 without reconfiguring CPEs in the field, in Release 12.1(1)DA the NI-2 DSLAMs support both VPI=1, VCI=1 and VPI=1, VCI=0 configurations on subscriber ports.

Changes to Default Values in DSL Profiles

The following default values have changed:

New Microcode for ATUC-1-4DMT Line Card

Cisco IOS Release 12.1(1)DA includes new DSP microcode for the ATUC-1-4DMT2 line card for Cisco 6260 and Cisco 6130 DSLAMs.

Caution   When you boot the DSLAM for the first time after installing Cisco IOS Release 12.1(1)DA, the DSLAM downloads new microcode to the 4DMT-2 line cards. The microcode download requires about 10 minutes. During the download period, the Active LED on each line card blinks and the DSLAM does not pass data. Until the download is complete, do not remove cards from the chassis. Do not reboot the chassis. If you interrupt the download, the line card's flash memory might be damaged, making it necessary to replace the card. When the download is complete, the Active LEDs on the line cards stop blinking and the lines train as usual.

You can track the status of a microcode download through software using the command show dsl interface atm slot/port. In the resulting display, look at the Line Status field. If the Line Status field says DOWNLOADING MICROCODE, wait a few minutes and check again.

Limitations and Restrictions

This section describes the limitations and restrictions for Cisco IOS DSLAM releases.

Cisco IOS Release 12.1(6)DA

This section describes the limitations and restrictions for Cisco IOS Release 12.1(6)DA. Other restrictions that apply to Release 12.1(6)DA are described in the "Cisco IOS Release 12.1(5)DA" section.

Cisco 6015 OSP Limitation

Cisco IOS Release 12.1(6)DA will not automatically generate a temp-rating mismatch alarm if a nonOSP component is installed in a Cisco 6015 OSP system. To verify the hardware components installed in the system, use the show environment command.

Hardware temperature rating mismatches
            Hardware components NOT hardened(non-ITEMP):
             ATUC-4FLEXI                         ATUC-4FLEXI                         
             STUC-4-2B1Q-DIR-1                   
            Hardware components hardened(ITEMP):
             NI-2-DS3-T1E1-H

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 physical 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). See Figure 1.

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 since SPVCs leverage this feature of PNNI. When the failure occurs, the SPVCs are disconnected and dynamically reconnected across the new path. See Figure 2.

Requirements

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

• You must use SPVCs, PNNI, ATM signaling, and ILMI to enable rerouting. Note that PNNI, ATM signaling, and ILMI are enabled by default. Permanent connections such as PVCs and shaped virtual paths (VPs) will not benefit from the redundant link.
  
  
• You must make the redundant link's PNNI administrative weight higher than the PNNI weight of the primary trunk. Once you change the weight of the redundant link, the subtend tree uses this link only if a failure occurs.
  
  

Limitations

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

• Loss of subtending fairness.
  
  
• Increase in latency as well as an increase in cell delay variation (CDV) between the cells. Delay-sensitive traffic, such as voice and video, or traffic that is susceptible to jitter, such as constant bit rate (CBR) voice, might be comprised. This technique is best realized for unspecified bit rate (UBR) traffic, such as consumer internet access, where no strict Quality of Service (QoS) objectives are required.
  
  

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

• Greater possibility of increased congestion in the DSLAM ATM switch fabric, which may cause loss of data.
  
  
• When the main link is restored, there will be downtime while the path is being rerouted. Once the SPVCs are rerouted to the redundant ATM trunk and the original trunk is repaired or brought back into service, you must manually intervene. You must flap (shut/noshut) the subtend port. Because of retries on the current path, you must keep the trunk down until the maximum retry interval expires.
  
  

Cisco IOS Release 12.1(5)DA

There are no restrictions that specifically apply just to IOS Release 12.1(5)DA. Other restrictions that apply to Release 12.1(5)DA are described in the "Cisco IOS Release 12.1(4)DA" section.

Cisco IOS Release 12.1(4)DA

This section describes the limitations and restrictions for Cisco IOS Release 12.1(4)DA.

Restrictions to MPLS VPN Mapping of RFC 1483 Routed Sessions

This section describes restrictions to Cisco MPLS VPN mapping of RFC 1483 routed sessions.

Note   DSLAMs running MPLS VPN mapping of RFC 1483 sessions are referred to as IP DSL switches.

Number of Configurable MPLS VPNs Limited to 50

Each DSLAM can support up to 50 MPLS VPNs.

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 (LER).

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 Layer 3 Services

The following Layer 3 services are not supported in Cisco IOS Release 12.1(4)DA:

• IP Quality of Service
  
  
• IP Queueing
  
  
• IP Multicast
  
  

Restricted MPLS Features

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

• MPLS Traffic Engineering
  
  
• MPLS Multicast
  
  

DSL Interface Limitations

In IP DSL switches, each DSL interface can support multiple Permanent Virtual Circuits (PVCs), but only one routed MPLS VC.

Configuration of MPLS VPN Mapping of RFC 1483 Routed Sessions not Supported by Cisco DSL Manager (CDM)

CDM users can provision switched VCs, but CDM does not support configuring routed termination of RFC 1483 sessions.

MPLS VPN Mapping of RFC 1483 Routed Sessions not Supported on the Eight-Port IDSL ITU-C Line Card

Routed termination of IDSL connections is not supported in Cisco IOS Release 12.1(4)DA.

Cisco IOS Release 12.1(3)DA

The limitations and restrictions for Cisco IOS Release 12.1(3)DA are the same as those listed for Cisco IOS Release 12.1(2)DA.

Cisco IOS Release 12.1(2)DA

The following restrictions apply to Release 12.1(2)DA:

If you need to fall back to an earlier release, note the following restrictions:

a. You can fall back only to Release 12.0(8)DA1 or greater. The DSLAMs cannot operate under releases prior to 12.0(8)DA1.

b. New 4DMT-2 cards (revision 800-05262-03 or greater) require Cisco IOS Release 12.0(8)DA2 or greater; the cards will not operate under prior releases of software.

Cisco IOS Release 12.1(1)DA1

The limitations and restrictions for Cisco IOS Release 12.1(1)DA1 are the same as those listed for Cisco IOS Release 12.1(1)DA, below.

Cisco IOS Release 12.1(1)DA

The following restrictions apply to this release:

If you need to fall back to an earlier release, note the following restrictions:

a. You can fall back only to Release 12.0(8)DA1 or greater. The DSLAMs cannot operate under releases prior to 12.0(8)DA1.

b. New 4DMT-2 cards (revision 800-05262-03 or greater) require Cisco IOS Release 12.0(8)DA2 or greater; the cards will not operate under prior releases of software.

Important Notes

This section provides important information about Cisco IOS DSLAM releases.

Update the Image in Bootflash to the 12.1(6)DA1 dboot Image

When you upgrade from Cisco IOS Release 12.1(4)DA or later images on the NI-2 to Release 12.1(6)DA1, you must reformat the bootflash image on the NI-2. To format the bootflash, perform the following steps in privileged EXEC mode.

Note   Cisco highly recommends that you have console access to the NI-2 during the update procedure. You can use the console connection to troubleshoot any unexpected events that occur during the upgrade.

DSLAM# dir bootflash:

DSLAM#dir flash:

DSLAM#delete flash:filename

DSLAM#squeeze flash:

DSLAM#copy 
tftp://tftpserver:TFTPBOOT/ni2-dsl-mz.1
21-6.da1 flash:

DSLAM#show running-config | include 
boot system

DSLAM#configure terminal

DSLAM (config)#no boot system flash 
filename

DSLAM (config)#boot system 
flash:ni2-dsl-mz.121-6.da1

DSLAM#end

DSLAM#copy running-config 
startup-config

DSLAM#reload

DSLAM#show version

DSLAM# format bootflash:

DSLAM#copy 
tftp://tftpserver:TFTPBOOT/ni2-dboot-mz
.121-6.da1 bootflash:

DSLAM# reload

Upgrade the Bootflash Image on the NI-2 to the 12.1(5)DA dboot Image

When you upgrade from Release 12.1(3)DA or earlier images on the NI-2 to Release 12.1(5)DA, Cisco recommends that you upgrade the bootflash image on the NI-2 to the 12.1(5)DA dboot image. This is a result of a problem (CSCdr89374) in old bootflash images. This defect may cause the flash application image to fail to self-decompress successfully.

To upgrade the dboot image in bootflash, perform the following steps:

DSLAM>enable

Password: <password>
DSLAM#

DSLAM# delete bootflash:filename

DSLAM# squeeze bootflash

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

DSLAM# show version

DSLAM# configure terminal

DSLAM(config)# config-register 0

DSLAM(config)# exit

DSLAM# copy running-config 
startup-config

DSLAM# reload

rommon> set

rommon > unset BOOTLDR

rommon > sync

rommon > b

DSLAM# configure terminal

DSLAM(config)# config-register value

DSLAM(config)# exit

IDSL Linecard Clocking Problem Fixed in Release 12.1(4)DA

The following problem is fixed in the IOS 12.1(4)DA release. Upgrade to 12.1(4)DA to fix this IDSL problem. The ITUC-1-8IDSL line card is not forwarding traffic after reload/reboot because the ISDN chipset is initializing indefinitely due to network clock synchronization.

Soft PVC Address Changes Upon Upgrade to 12.1(3)DA or 12.1(4)DA

When you upgrade from a previous release to 12.1(3)DA or 12.1(4)DA, the default soft PVC addresses on all interfaces change. This only occurs when you upgrade to release 12.1(3)DA or 12.1(4)DA from a previous release. This will not happen when you upgrade to future releases from 12.1(4)DA.

Workarounds:

• 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 prior to 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 may not come back up after the IDSL line goes down and 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.

Upgrading from Cisco IOS 12.0(x)DA to 12.1(1)DA, 12.1(2)DA, or 12.1(3)DA

After you upgrade a DSLAM from Cisco IOS Release 12.0(x)DA to 12.1(1)DA, 12.1(2)DA, or 12.1(3)DA, you might experience a problem that results from a change in some of the DMT defaults in the DSL profiles. The changes, which are listed in the "Changes to Default Values in DSL Profiles" section, affect the training mode, overhead framing, and DMT margin parameters. This problem is fixed in Release 12.1(4)DA.

The problem is triggered when you edit your DSL configuration profiles after upgrading to Cisco IOS Release 12.1(x)DA.

The system checks its startup configuration file for a release number, and if it finds a number earlier than 12.1, it automatically adds the following commands to the profile whenever you edit the profile. These commands set the profile to use the old default values for training mode, overhead framing, and DMT margin.

dmt training-mode standard
dmt overhead-framing mode1
dmt margin downstream 3 upstream 3
 

The commands are added so that the changed defaults in Cisco IOS Release 12.1(x)DA will not affect your configuration. However, the system continues to add the commands to your configuration every time you edit profiles, unless your startup configuration file contains a 12.1 release stamp.

Workaround: Follow these steps. Start with Step 2 if you have already completed the upgrade.

Step 2   Issue the command copy running-config startup-config. Now the startup configuration file has a 12.1(x)DA stamp in it.

Step 3   Reboot the DSLAM again.

Now you can change the configuration without difficulty. [CSCdr66665]

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 commands.)

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 Chassis in an Equipment Rack

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

Synchronizing the Management Database

If you use both the Cisco DSL Manager (CDM) application and the command line interface (CLI) to configure and manage your DSLAMs, you must the synchronize the CDM to your management database on a regular basis. (If you use only the CDM or only the CLI, you need not synchronize your database.) Refer to the release notes for the Cisco DSL Manager 2.0 or later for more information.

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

This section describes unexpected behavior in the system. A tracking number, if one exists, is provided in square brackets at the end of each description. Please refer to the tracking number if you communicate with Cisco Systems about any of these issues.

Open Caveats—Release 12.1(6)DA

The caveats in this section apply only to IOS Release 12.1(6)DA. Other open caveats that apply to this Release 12.1(6)DA are described in the "Open CaveatsRelease 12.1(5)DA" section, "Open CaveatsRelease 12.1(4)DA" section, the "Open CaveatsRelease 12.1(3)DA" section, the"Open CaveatsRelease 12.1(2)DA" section, "Open CaveatsRelease 12.1(1)DA1" section, and the "Open CaveatsRelease 12.1(1)DA" section.

Cisco 6015 OSP Caveats

Commercial Component does not Trigger Alarm in OSP System

Cisco IOS Release 12.1(6)DA will not automatically generate a temp-rating mismatch alarm if a nonOSP component is installed in a Cisco 6015 OSP system.

Workaround: To verify the hardware components installed in the system, use the show environment command. [CSCdt30959]

Hardware temperature rating mismatches
            Hardware components NOT hardened(non-ITEMP):
             ATUC-4FLEXI                         ATUC-4FLEXI                         
             STUC-4-2B1Q-DIR-1                   
            Hardware components hardened(ITEMP):
             NI-2-DS3-T1E1-H 

E1 IMA Group Continuously Loses Cells When Physical Link Is Removed

Cell loss can be experienced if an E1 IMA group consists of either 1 or 3 active links.

Workaround: None. [CSCdt49728]

Flexi Line Card Caveats

677 2.x Reports Incorrect Up Margin for Cat1 Loop midCSA6

An erroneous upstream margin value is reported by 4xFlexi-DMT when running Cat1 rate-adaptive tests with loop midCSA6. The value observed is 63.5. This occurs only when connected to a Cisco 677 CPE.

Workaround: None. [CSCdt32428]

c677 w/3.0 FW and Cat1 Loop Anomaly with Injected Noise

Layer 1 Cat1 adaptive rate test on ansi#7 loop showed higher downstream rates when noise was injected on CPE side instead of CO side. Injecting noise at both sides simultaneously also yielded better downstream results than for injecting on CO only.

Workaround: None. However, injecting noise at both ends at the same time will give more reasonable results. [CSCdt32401]

Alcatel-Based CPEs Training Odd at High Bit Rates, Interleaved

When using 4xflexi-DMT and a configured downstream max bit rate (interleaved) above 7616 kbps, Alcatel chip set based CPE (for example, Westell, Efficient, Speedtouch, etc) train to a lower bit rate and not always as expected.

Workaround: You can get the desired max rate if you use max rates less than 7616. [CSCdt16528]

Degraded Downstream Bit Rates at Different Lengths from 12.1(5)DA

When flexi-DMT line card is used with Efficient 5262 CPEs, the trained bitrates performance is not comparable to that of Cisco IOS Release 12.1(5)DA.

Workaround: Experiment with different settings of margin, check-bytes, and interleave delay to achieve the bit rate desired.[CSCds81181]

FlexDMT Unable to Train to Maximum. Rates with 677 CPEs

Configured maximum bit rates on a 4xflexi-DMT line card are not attainable when trained against a Cisco 677 CPE.

Workaround: None available. [CSCds76055]

Next: Low Reported Margin for 677 Firmware 2.2

A 4xflexi-DMT reports very low downstream margins when connected to a Cisco 677 CPE.

Workaround: None. [CSCdt28665]

GSI reports that the margin number being reported by the ADI-based CPE and communicated over the EOC channel does not include coding gain and thus appears as a low value. We are not anticipating any new developments on the Cisco 677 CPE front, therefore we are simply documenting this behavior.

Note   Because of this behavior, Cisco cannot recommend SNR-based line quality monitoring when using a Cisco 677 CPE.

Running-config Incorrectly Marked as Changed

When one or more 4xflexi cards are provisioned in a system, a reload command will always result in the following query: System configuration has been modified. Save? [yes/no]:

Workaround: None. [CSCdt41089]

ST Pro in G.lite Mode Fails Several Annex D Test Loops

The 4xflexi line card fails layer 1 G.lite mode-adaptive rate tests.

Workaround: None. [CSCdt34800]

Takes More Time Than Downshift Interval to Meet Rate Adaptation

When rate-adaptation mode is enabled, the configured downshift interval for the downstream direction does not appear accurate.

Workaround: None. [CSCdt03800]

Unable to Attain Interleave Delay with Flexi/Cisco 677

With 4xflexi-DMT and Cisco 677 CPE, actual interleave delay differs from configured interleave delay.

Workaround: None. [CSCds80783]

Westell HEC Errors, Frame Loss for Low Margins (0- to 3)

Downstream HEC errors and uncorrected super frames may occur when the 4xflexi-DMT line card is used with some Alcatel chipset-based CPE if a low target/configured margin is used.

Workaround: Set the configured margin to values higher than 3. The default of 6 is fine. [CSCdt32319]

MIB Caveats

adslAtucPerfInits Returns Invalid Values

The value of adslAtucPerfInits is sometimes incorrect for DMT linecards. The error has only been detected for untrained ports so far.

Workaround: None. [CSCdt02293]

ceAssetFRU Returns 0 for False-Should Return 2.

Setting ceAssetFru returns 0 for false; the correct value for false is 2.

Workaround: None. [CSCdt03362]

Creation of snmpNotifyFilterProfileTable Incorrect—Can Cause Reboot

If rowstatus is set to createAndWait, no indexes are created to allow for configuration of variables in the table. If the table is walked, it will loop. The DSLAM can reload when trying to set any of the variables.

Workaround: None. [CSCds70225]

Extended Profile Values Cannot Be Set Along with RowStatus Value

Some profile settings may not succeed when set along with RowStatus. If parameters in the xDSL profile tables, which are extensions to the adslLineConfProfileTable, are set along with RowStatus, the set for these parameters will not succeed.

Workaround: Set the RowStatus first. Then modify the other profile settings in the usual way. [CSCdt39596]

getbulk Does Not Report All the Rows

E1 entries missing from the IF table. Getbulk request is not returning all rows when some columns are deprecated.

Workaround: Issue the following CLI command prior to using getbulk: no snmp-server sparse-tables. [CSCdt37180]

Invalid values in adslAtuc/AturPerfDataTable

ADSL DMT line cards sometimes return a large value (for example, 65535) for LPRs, LOFs, and LOSs. The total counter adslAturPerf LPRs, LOFs, and LOSs does not show this irregularity.

Workaround: None. [CSCdt02507]

MIB Walk Loops in cIdslPppoaIntervalTable for Interface 6

The MIB walk starts to loop at interface 6. Only IDSL cards are affected.

Workaround: None. [CSCdt08345]

Profile Modification Should be an Atomic Operation

In an SNMP set of multiple variables in a DSL profile, if one fails, they do not all fail. Multiple profile settings in one PDU are not performed as an atomic operation.

Workaround: Verify profile settings after SNMP set of multiple variables. [CSCdt39640]

Row Status in atmVplTable is notInService When PVP is Created Via CLI

Creating a PVP using CLI creates a row in the atmVplTable, but the row status is set as notInService.

Workaround: Set the row to active after row creation. [CSCdt47017]

Miscellaneous Caveats

Filesys space Error When 1st Write Mem After Reload

Filesys space error is displayed when performing the first write mem following a reload.

Workaround: None. The next write mem issued will not produce an error. [CSCdt27044]

MPLS Caveat

Incorrect EIGRP Routes Update with Multiple Paths to the Next Hop.

EIGRP does not work properly on the redundant topology of networks with DSLAMs running code from Cisco IOS 12.1DA. It gives a nonoptimal path the same distance as an optimal path and puts incorrect routes into routing table.

Workaround: Include the delay x command in the trunk interface. The value of 10 is recommended based on the performance measurement reflecting on the order of 10,000 packets per second. [CSCdt35500]

Octal-Port DMT ATU-C Line Card Caveats

8xDMT: 677 2.x Reports Incorrect Up Margin for Test Loop midCSA6

Using a Cisco 677 CPE that contains ADI chipset version 2.x, with an 8xDMT line card, the upstream margin is sometimes reported erroneously as -63.5 db.

Workaround: None. [CSCdt32415]

8xDMT: 8x to 677 3.0 CSF, USF, and Margin Perf May Differ from Flexi

When connecting the 8xDMT card to a Cisco 677 CPE running version 3.0 firmware, the corrected and uncorrected superframe counts and margin performance may differ from that of the flexi card.

Workaround: None. [CSCdt23551]

8xDMT: Actual Margin < Provisioned for G.lite and DMT

This behavior occurs with a Cisco 6015, Cisco 6160, or Cisco 6260 DSLAM equipped with the 8xDMT line card. A port that has been configured for a specific minimum margin may, on occasion, train with a margin 1 or 2 dB less than the configured minimum margin.

Workaround: The configured bit rate may be lowered slightly to allow a greater margin when trained, or the minimum margin downshift feature may be enabled, causing the port to retrain if the margin is below a specified minimum over a specified interval of time. [CSCds51398]

8xDMT: Alcatel Modems: no train when ds<=1024 and Trellis=disabled

When you use a Cisco 827, Efficient 5260, or Westel CPEs with the 8xDMT line card and provisioned with trellis encoding disabled, the downstream bit rates will not train below 1024 kbps.

Workaround: Enable trellis encoding when using one of these CPEs with the 8xDMT line card. [CSCds56646]

8xDMT: Downstream Margin not Reported with Cisco 677 CPE (ADI ver. 2.2)

When you connect the 8xDMT line card to a Cisco 677 CPE running ADI firmware version 2.2, the downstream margin reported is not valid. This ADI firmware version does not support the EOC mechanism used for reporting downstream margin.

Workaround: None. [CSCdt24787]

8xDMT: Downstream USF in Fast Path with Cisco 678

When you use a Cisco 678 CPE with the 8xDMT line cards, if the port is configured for fast latency there may be uncorrected downstream superframes on longer loops.

Workaround: When configuring the port, use interleaved latency if possible. [CSCdt17039]

8xDMT: Fast Latency Will not Train Downstream < 64 kbps

When you configure a Cisco 6015, Cisco 6160, or Cisco 6260 DSLAM equipped with the 8xDMT line cards, configuring fast latency operation with maximum bit rates set to 32 kbps in both upstream and downstream directions causes the port to fail to train.

Workaround: Configure the maximum downstream bit rate to a value greater than 32 kbps. [CSCds69455]

8xDMT: Increased Corrected and Uncorrected SF Counts US with 5262 CPE

This occurs when you connect a Cisco 6015, Cisco 6160, or Cisco 6260 DSLAM equipped with the 8xDMT line cards to an Efficient 5262 CPE. If a port is configured for Interleaved Latency mode when using the 5262, and loop length is in the 8 to 9 Kft range, the upstream data path may occasionally accumulate higher corrected and uncorrected superframe counts.

Workaround: None. [CSCdt23206]

8xDMT: Increased Corrected and Uncorrected SF Counts with Westell CPE

A Cisco 6015, Cisco 6160, or Cisco 6260 DSLAM equipped with the 8xDMT line cards, configured for fast latency mode with a Westell (AME 1.4.1) CPE, will occasionally accumulate higher corrected and uncorrected superframe counts in both upstream and downstream data.

Workaround: None. [CSCdt24780]

8xDMT: LOF, LOS, LPR may be Reported Inaccurately

Performance data, including both totals and interval information, is collected for display through the SNMP. The following statistics may be reported inaccurately: near-end LOF (loss of frame), near-end LOS (loss of sync), far-end LOF, far-end LOS, and far-end LPR (loss of power).

Workaround: None. [CSCdt28479]

8xDMT: The Margin Reported with 678 CPE may Differ from Actual

When a Cisco 6015, Cisco 6160, or Cisco 6260 DSLAM equipped with the 8xDMT line cards is connected to a Cisco 678 CPE, the margin value reported may be slightly greater than the actual trained margin.

Workaround: None. [CSCdt04507]

8xDMT: Trellis Encoding Should be off for 677

Currently, the Cisco 677 does not support trellis encoding. When trellis encoding is enabled, in conjunction with the Cisco 677 CPE, performance may be impacted negatively.

Workaround: Disable trellis encoding when using a Cisco 677 CPE. [CSCdt16929]

8xDMT: Unable to Obtain Requested Int. Delay with /677

When you connect to a Cisco 677 CPE, the actual downstream interleave delay may be slightly greater than the configured delay, when less than 16 ms.

Workaround: Provision the downstream interleave delay to a minimum of 16 ms. [CSCdt16909]

8xDMT: Upstream Margin not Accurate for Alcatel-based CPE and Cisco 678

The DSLAM reports the upstream margin of -63 dB or 63 dB (depending on the DSP firmware version) when operating with Alcatel-based CPEs (tested with Efficient 5260, 5262, and Cisco 827) or with the GSI-based Cisco 678 CPE that is provisioned for fast latency. Due to this problem, the rate-adaptation feature implemented in 12.1.6(DA) will not work properly when the upstream margin is not reported correctly.

This happens when trellis encoding is disabled and the operating mode is in T1.413.

Workaround: For Alcatel-based CPEs, enable trellis encoding when configuring the port. Fast latency is not supported when operating with a GSI-based Cisco 678 CPE. [CSCdt18971]

8xDMT: Variable Train Rates with 677 CPE (12.5 to 13.0 kft)

This behavior occurs with a Cisco 6015, Cisco 6160, or Cisco 6260 DSLAM equipped with the 8xDMT line cards, connected to a Cisco 677 CPE running firmware 3.0. The train rates are not consistent over reach, with multiple trains on the same port occasionally exhibiting variations in rate.

Workaround: None. [CSCdt24795]

Proxy Element Supporting the Cisco DSL CPE Automated Configuration Solution

CIB Save FAILED Message Displayed During NI Boot

During bootup of the DSLAM, a message is displayed that the CIB table cannot be saved to Flash. This is due to SNMP saving configuration information such as the reboot count.

Workaround: None. During bootup, the CIB table should be prevented from getting saved to the Flash. This is the desired behavior. Additional logic will be added to Cisco IOS 12.1(7)DA to prevent the unexpected save request.[CSCdt27246]

DSLAM Lockup with Multiple Slot/no Slot Commands

With CDCM attached, the DSLAM will lockup when multiple slot/no slot commands are issued.

Workaround: Deactivate CDCM prior to issuing slot/no slot commands. [CSCds90782]

Open Caveats—Release 12.1(5)DA

The caveats in this section apply only to IOS Release 12.1(5)DA. Other open caveats that apply to this Release 12.1(5)DA are described in the "Open CaveatsRelease 12.1(4)DA" section, the "Open CaveatsRelease 12.1(3)DA" section, the"Open CaveatsRelease 12.1(2)DA" section, "Open CaveatsRelease 12.1(1)DA1" section, and the "Open CaveatsRelease 12.1(1)DA" section.

Flexi Line Card Caveats

FastPath Working on G.lite

With the 4x flexi-DMT line card configured, the line is able to train up in fast path when in G.lite mode. This was observed with CPEs capable of G.Lite and fast path.

Workaround: Do not enable fast path when in G.Lite operating mode. [CSCds52496]

Fastpath with Trellis off Reports Up Margin of -63 dB

With the 4xflexi-DTM line card configured, the DSLAM reports the upstream margin of -63 dB or 63 dB (depending on the DSP firmware version) when operating with Alcatel based CPEs (tested with Efficient 5260 and 5262).

Workaround: Enable trellis encoding when operating with Alcatel based CPEs. [CSCds54602]

BERT Test Interrupts Upstream Traffic on the Other Card Ports

With the 4xflexi line card configured, other ports on the same line card are unable to pass upstream traffic when one of the ports on the line card is running a BERT test. Once the BERT test completes, the upstream traffic on other ports resumes.

Workaround: Do not initiate the BERT test if there is traffic running on other ports on the same line card. [CSCds73901]

Downstream Frame Loss When Check-bytes Less Than 6 with 5262/Interleave

With the 4xflexi-DMT line card configured for interleave path operation and an FEC value of less than 6, a number of Uncorrected Superframes and thus lost data frames (in the order of 1 in 10,000) in the downstream direction can occur on certain loops. This was observed with line card dsp image version K.29 while connected to an Efficient 5262 CPE.

Workaround: Set an FEC value of 6 or greater.[CSCds76533]

MIB Caveats

adslAturCurrOutputPwr Returns Incorrect Value on CAP Cards

Setting adslAtuc/AturCurrOutputPwr in the ADSL-LINE-MIB returns an incorrect value for short loops ( < 2000 feet ). When Transmit Power reports a negative value, the SNMP query to these variables returns an incorrect value in the response.

Workaround: Use CLI. [CSCds48052]

adslAtucCurrStatus Returns Incorrect Value for CAP and DMT

Setting adslAtucCurrStatus returns an incorrect status for CAP and DMT.

Workaround: Use CLI. [CSCds80863]

adslAturCurrStatus Returns Incorrect Value for DMT

Setting adslAturCurrStatus returns an incorrect status for DMT line cards.

Workaround: Use CLI. [CSCds81122]

cAdslAtuc/AturCapCurrRxGain Returns Invalid Values

Setting cAdslAtuc/AturCapCurrRxGain in the CISCO-ADSL-CAP-LINE-MIB returns an incorrect value for short loops ( < 2000 feet). When Receiver Gain reports a negative value, the SNMP query to these variables returns an incorrect value in the response.

Workaround: Use CLI. [CSCds48063]

Cannot Get or Set Filter in CISCO-ATM-ACCESS-LIST-MIB

The ATM filter created from CLI does not show up in the MIB filter tables. An ATM filter cannot be created from MIB.

Workaround: Use CLI. [CSCds68212]

Creation of snmpNotifyFilterProfileTable Incorrect, Can Cause Reboot

The snmpNotifyFilterProfileTable in snmp-notification-mib cannot be properly created.

Workaround: None. [CSCds70225]

SNMP Walk Loops in CISCO-ATM-SIG-DIAG-MIB

SNMP walk loops in csfRecordTable (CISCO-ATM-SIG-DIAG-MIB) conditions.

Workaround: None. [CSCds64436]

Sonetpath(50) Missing from ifTable

The ifType with a value sonetPath(50) is missing from the ifTable. The ifIndex of MIB variables in sonetPathCurrent and sonetPathInterval tables are mapped to the sonet(39) ifType. The ifIndex of these variables should map to a sonetPath(50) ifType, which is not present in the ifTable.

Workaround: None. [CSCds59504]

Miscellaneous Caveats

SNMP set cmd with string param (IOS CLI) Causes System Failure

Executing an SNMP Set/Inform request with string or ip address parameter through IOS CLI causes an unexpected DSLAM reload. For example:

snmp set v3 ip xxx.xxx.xxx.xxx community pef context pef oid cdcpCibOwner.0 string pef
 

Other parameters, for example, integer work fine.

Workaround: Use other tools to set objects that require a string or ip address input. [CSCds81489]

MPLS Caveats

NI-2 Reload under Destructive VPN Routes Update Test

Running a destructive test by sending more than 30,000 VPN routes across the MPLS network causes the NI-2 to reload.

Workaround: Configure the maximum routes for each VPN to prevent the CE devices or remote PE routers from sending the VPN routes more than it should. [CSCds51409]

Open Caveats—Release 12.1(4)DA

The caveats in this section apply only to IOS Release 12.1(4)DA. Other open caveats that apply to Release 12.1(4)DA are described in the "Open CaveatsRelease 12.1(3)DA" section, "Open CaveatsRelease 12.1(2)DA" section, "Open CaveatsRelease 12.1(1)DA1" section, and "Open CaveatsRelease 12.1(1)DA" section.

IMA Caveats

E1 IMA Group Bandwidth is Limited to Six Links

E1 IMA group bandwidth is limited to six links. Cell loss will occur if an IMA group has more than six links and more than 12 Mbps are sent through it.

The loss only occurs on groups with greater than six E1 links. All eight links can be used in different groups, however (for example, six in group 0, two in group 1). This does not affect T1 operation (that is, all eight T1 links may be used in a group).

Workaround: Do not configure an IMA group with more than six E1 links. [CSCdr45623]

Cell Loss May Occur on Subscriber Ports If Trunk is Down

Cell loss on the subscriber (DSL) ports may be seen if you select an IMA group and the trunk is down. The loss only happens if the trunk IMA group is down. [CSCds02810]

Workarounds:

• Shutdown the trunk IMA group.
  
  
• Bring the trunk IMA group up (by troubleshooting).
  
  
• Reassign the trunk to another interface (changes network topology).
  
  

MPLS VPN Mapping of RFC 1483 Routed Sessions

Attempting to Create a Circuit on VCI 3 or 4 is Allowed by the CLI

The CLI incorrectly accepts configuration input on reserved VCIs 3 and 4 through the atm pvc command.

Example:

DSLAM#configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
DSLAM(config)#interface atm1/3
DSLAM(config-if)#atm pvc 1 4 interface atm0/0 0 120
DSLAM(config-if)#
DSLAM#show running interface atm1/3
Building configuration...
 
Current configuration : 62 bytes
!
interface ATM1/3
 no ip address
 no atm ilmi-keepalive
end                            
 
VC-Table
ATM1/3        1     4      PVC     ATM0/0        0     120   SNAP   DOWN       
 

If you attempt to create virtual channel connections (VCC) 1/3 or 1/4 using the pvc command an error message appears.

DSLAM(config)#interface atm1/3
DSLAM(config-if)#pvc 1/3
%ATM: Invalid VCI of 3 requested: (ATM1/3): Not creating vc:1:3
DSLAM(config-if)#pvc 1/4
%ATM: Invalid VCI of 4 requested: (ATM1/3): Not creating vc:1:4
DSLAM(config-if)#pvc 1/5
DSLAM(config-if-atm-vc)#
 

Workaround: Do not attempt to configure VCIs 3 and 4. [CSCdr99296]

Changing Line Coding or Line Card Type Causes Duplicate VPN References in show ip vrf Output

If you swap a line card or change the line coding on a DSL interface, the show ip vrf command may display duplicate references to a VRF instance.

Workaround: Do not swap line cards with a different type. Do not change line coding on an active interface. [CSCds29146]

Configuring a Large Number of Subinterfaces Causes Service Loss

Configuring more than 32 PVP subinterfaces on the trunk interface of the NI-2 may cause a loss of connectivity to remote peer MPLS routers.

Workaround: Currently, there is no workaround. [CSCdr88865]

Configuring IP MTU or Physical MTU Size has no Effect on Fragmentation

No fragmentation occurs at the IP layer.

Workaround: There is no workaround. The default MTU settings work fine for Layer 3 services on the IP DSL Switch. [CSCds15469]

CRC Errors Appear on CPE DSL Modems if IP DSL Switch Is Running NI-2 Rev02 SAR

ATM cell corruption could be detected on the Customer Premises Equipment (CPE) as a result of running the NI-2 Rev02 (B) SAR. To determine the NI-2 SAR version:

The SAR revision number will be shown in the show controller atm0/0 output.

Workaround: Currently, there is no workaround. A different hardware revision of the NI-2 SAR (Rev03) must be installed. [CSCds05184]

debug atm error Command Generates Invalid Error Messages

Using the debug atm error command generates the following invalid error message:

"ATM(ATM0/1):point-to-point interface does not have a VCD"
 

The message appears when there is no PVC defined on the atm0/1 physical interface.

Workaround: This message can be ignored. Configuring a point-to-point PVC on the physical uplink interface is unnecessary for MPLS functionality. [CSCdr97541]

DSL Interface Resets Under Heavy Stress

DSL interfaces reset when CPU usage approaches 100 percent for an extended period of time.

Workaround: Using the show proc cpu command, identify the CPU hogging interfaces. Move those interfaces to a less taxed IP DSL Switch. verify that the CPU usage exceeds 95 percent. Then, using the show interface accounting command, take successive samplings of packet counters to identify the interfaces with the highest traffic rates. Once these interfaces are identified, move them to a DSLAM with lower CPU usage rates. [CSCds23638]

Erroneous debug atm Error Message When Creating a PVC or MPLS-Switched Interface

Output from the atm debug command returns misleading error messages while configuring a point-to-point PVC or MPLS-switched interface.

The following erroneous message is logged:

c6100_atm_add_vc_to_swsb: Error adding VC to vc-list
 

Workaround: This message can be ignored. The VC creation has taken place. [CSCds15732]

Interface Site-of-Origin Tagging is Not Working

Site-of-Origin tagging does not work when associated with the ip vrf sitemap on customer edge (CE) interfaces.

Workaround: Currently, there is no workaround. [CSCdr93090]

IP DSL Switch Accepts Invalid ATM Syntax on DSL Interfaces

The ATM command syntax atm pvc vpi vci is not parsed correctly by the DSLAM. [CSCds05174]

Workaround: Use the following syntax:

atm pvc vpi vci interface atm [slot/port] vpi vci

Maximum Number of Interior Gateway Protocol (IGP) Routes Supported on the IP DSL Switch is Limited to 3500

The maximum number of Interior Gateway Protocol (IGP) routes on the DSLAM is limited to 3500.

Workaround: Currently, there is no workaround. [CSCdr89959]

Outbound Access Lists Do Not Work

Outbound access lists on uplink and CE interfaces are ignored.

Workaround: Currently, there is no workaround. [CSCds01820]

Packet Sizes of Less Than 512 Bytes Result in Reduced Aggregate Throughput in the NI-2

Aggregate throughput in NI-2s running Layer 3 services is poor when average packet sizes are less than 512 bytes.

Workaround: Currently, there is no workaround. [CSCdr92284]

Sending More than 12,500 RIP Routes in a Single VPN Causes High CPU Usage

With a large number of VPN routes in a single VPN domain, the CPU may approach 100 percent for too long when more than 500 routes expire at the same time. This causes system instability.

Workaround: Segment the network into multiple VPN domains or use the maximum route # command to limit the number of VPN routes into the network. For example: [CSCds27853]

 ip vrf vpn1
  rd 100:1
  route-target export 100:1
  route-target import 100:1
  maximum routes max number of routes Threshold value%

Static IP Routing Tables Break After Line Coding Change

Static routes are not applied to a DSL interface if you change its line coding.

Workaround: Remove all static IP routes using the no ip route and no ip route vrf commands before you change line coding. Recreate the static routes after the line coding is changed. [CSCds38810]

System Generates a MALLOCFAIL Error if You Disable Cisco Express Forwarding While Traffic is Running

Disabling Cisco Express Forwarding (CEF) while MPLS traffic is being passed can destabilize the IP DSL Switch.

Workaround: CEF is a prerequisite to running MPLS. It should never be disabled while MPLS traffic is being passed. Leave CEF enabled. [CSCds29151]

System Generates an Incorrect Error Message When Attempting to Remove VP-tunnel

If you attempt to remove a VP-tunnel interface on the atm0/1 you receive the following incorrect error message:

Example:

DSLAM(config)#interface atm0/1.60
DSLAM(config-subif)#no tag-switching atm vp-tunnel 60
%Invalid tag vpi range for selected VP-tunnel
Hardware does not support the specified VPI, 1
 

Workaround: None. This message can be ignored. [CSCdr89031]

System Generates Unknown Protocol, VRF Error Message Reference During NI-2 Reload

When you create a VPN routing and forwarding instance (VRF) on systems with an older bootflash image, the following message may appear:

% Can't create VRF <VRF-ID>
 

This is message is generated because of an outdated bootflash image.

Workaround: The message can be ignored. It has no impact on MPLS VPN functionality. [CSCdr89698]

Open Caveats—Release 12.1(3)DA

The caveats in this section apply only to IOS Release 12.1(3)DA. Other open caveats that apply to Release 12.1(3)DA are described in the "Open CaveatsRelease 12.1(2)DA" section, "Open CaveatsRelease 12.1(1)DA1" section, and "Open CaveatsRelease 12.1(1)DA" section.

ATUC-1-4DMT-I Line Card Caveats

This section describes problems with the ATUC-1-4DMT-I line card.

With Trellis Enabled, Errored Seconds are High

Enabling DMT trellis line coding on the 4xDMT/ISDN ADI-based line card can decrease link reliability by causing problems passing data due to errored second events and data corruption in the downstream and upstream directions. ADI/Aware has a known problem where high errored seconds may result if trellis encoding is turned on. This problem is not scheduled to be fixed in the 2.0 release, which is currently where the 4xDMT/ISDN code is branched.

On the 4xDMT/ISDN ADI-based line card, having trellis encoding enabled will decrease link reliability by causing problems training or passing data. There is no way to accurately predict when it will be reliable. Therefore, trellis encoding is disabled by default on the NI-2 to ensure that it is not accidentally enabled with the 4xDMT/ISDN line card.

Workaround: DMT trellis line coding is not enabled by default on the NI-2, because it is not supported on the 4xDMT/ISDN ADI-based line card. [CSCdr92590]

Some Trains in Quick Mode will have High Errored Seconds

This problem occurs at long loop lengths (11500 feet and above) when using the quick training mode of the 4xDMT/ISDN ADI-based line card. It can decrease link reliability by causing problems passing data due to errored second events and data corruption in the downstream direction.

On the 4xDMT/ISDN ADI-based line card, using the quick training mode at long loop lengths (3600 m and above) will decrease link reliability. The link will train at a higher data rate, but at lower downstream margins (:for example, 1 or 2 dB) rather than training at a lower data rate and maintaining the requested downstream margin (:for example, 6 dB). This can decrease link reliability by causing errored second events and data corruption in the downstream direction due to the acquired lower downstream margins.

Workaround: Use the standard training mode to train up the link at long loop lengths (11500 feet and above). [CSCdr93540]

Reported Margins do not Match Selected Margins

This problem is identical to the problem described in DDTS report CSCdm89068, which describes the same symptoms that appear when using the ATUC-1-4DMT line card.

In some situations, the reported (actual) margins may be higher than the configured values. Depending on the port configuration, there are effective minimum end-to-end margin values for combinations of parameters including:

• Training mode
  
  
• Framing mode
  
  
• Interleaving delay
  
  
• Trellis encoding
  
  
• Number of FEC checkbytes
  
  

Workaround: If you configure the margins for a port below these effective minimum margins, the system accepts the margin configuration, but the margin values that are actually used and reported are the effective minimum end-to-end values. The actual margins are essentially clipped at these effective minimum values. [CSCdr93546]

The effective minimum margins for the downstream and upstream directions are given in the following tables:

IDSL Line Card Caveats

This section describes problems with the IDSL line card.

Clocking Problem

When you enter the show controllers idsl card/port command after a reload/reboot, an excessive number of network clock losses is reported. This is normal because the network interface module is being reinitialized and network clocking has yet to be established.[CSCdr91534]

Workaround: None.

Miscellaneous

The following are miscellaneous problems with this release.

• The IDSL-associated atm-p interface input counters are not being updated. The per-VC counters are updating properly, but interface-level counters are not.
  
  

Workaround: Use the following CLI commands that display counters:

• show interface idsl card/port
  
  
• show atm vc traffic interface atm-p card/port [CSCdr90732]
  
  

Loopback and Test Caveats

The following are loopback and test problems with this release.

• When you configure an interface for loopback diagnostic operation and this configuration becomes part of the startup-config, the interface might initialize in the down state after DSLAM reload/reboot.
  
  

Workaround: Enter the clear interface idsl card/port command to reinitialize the interface. [CSCds01533]

• On rare occasions, if you issue the remote loopback command, the interface goes down and remains down. You can verify this failure mode by issuing the show controllers IDSL slot/port command and confirming that the C/I state is not 0xF3.
  
  

Workaround: Remove and reissue the loopback remote command. [CSCdr62772]

• On rare occasions, an ITUC-1-8IDSL BERT test will report bit errors and multiple sync losses.
  
  

Workaround: Remove and reissue the loopback remote command. [CSCdr63116]

ATM Traffic Shaping and Policing not Functioning

On the Cisco 6160 DSLAM equipped with IDSL line cards, ATM traffic shaping and policing might not function properly. Shaping is enabled on Frame- Relay and PPP PVCs and soft PVCs with the UPC drop option of the frame-relay pvc, frame-relay soft-vc, ppp pvc, or ppp soft-vc commands. Policing without traffic shaping (that is, tagging of cells exceeding the ATM traffic descriptor parameters) is enabled with the upc tag option of the above four commands.

Specifically, the following problems are known to exist:

• Shaping and policing do not work if the ATM SCR is less than 3 kbps. The behavior is that all traffic is passed and no cells are dropped or tagged.
  
  
• Shaping and policing at higher rates does function, but the rate to which shaping and policing occurs might not match the configured rate.
  
  

There are no workarounds to the above problems.[CSCdr70582]

Two NI-2s have the same ATM Address

When an NI-2 is shipped, the ATM address is blank. When that NI-2 is provisioned in a chassis, an ATM address is generated using the MAC address of the chassis. If that NI-2 is moved to another chassis and a new NI-2 is installed in the original chassis, the two NI-2s will have the same ATM address. [CSCds26889]

Workaround:

Open Caveats—Release 12.1(2)DA

The caveats in this section apply only to IOS Release 12.1(2)DA. Other open caveats that apply to Release 12.1(2)DA are described in the "Open CaveatsRelease 12.1(1)DA1" section, and in the "Open CaveatsRelease 12.1(1)DA" section.

IDSL Line Card Caveats

Frame Relay Configuration Caveats

• The NI-2 cannot terminate IDSL FRF.8 service transparent PVCs. The system accepts commands of the form frame-relay pvc... service transparent interface ATM0/0... encap aal5mux ip, but the PVC is not properly terminated. Only service translation PVCs can be terminated by the NI-2 with an ATM encapsulation of aal5snap. Note that service transparent PVCs can be terminated via any physical ATM interface, however. [CSCdr16342]
  
  
• If you issue the shutdown command on a Cisco 6160 IDSL interface that is attached to a Motorola Vanguard 65, and Frame Relay encapsulation is configured on both devices, a subsequent no shutdown command might not bring the Motorola Vanguard 65 interface back up. This problem does not occur if PPP encapsulation is configured.
  
  

Workaround: Power cycle the Motorola Vanguard 65. [CSCdr32145]

• IDL 144 kbps mode is currently disabled for IDSL interfaces. It will be enabled in a future release. At that time, the command dsl profile idsl bitrate 144 idl will be enabled. Note that 144 kbps non-IDL mode is supported. [CSCdp63832]
  
  
• If you configure Frame Relay encapsulation on an IDSL interface, the interface does not pass Appletalk traffic. There is no workaround. [CSCdp70130]
  
  

Interface State Caveat

On rare occasions, the results of the command show interface idsl slot/port indicate that an interface is up when it is in fact down. You can verify this failure mode by issuing the command show controllers idsl slot/port and confirming that the "C/I" state is not "0xF3".

Workaround: Issue the shutdown command followed by the no shutdown command on the IDSL interface. [CSCdr23602]

Status Display Caveats

• The show dsl interface idsl slot/port command displays excessive HDLC layer performance statistics errors if the line interface cable to the CPE is pulled. This is an aspect of the implementation and does not indicate negative performance. [CSCdr43144]
  
  

Loopback and Test Caveats

• If you issue the no loopback command on an ITUC-1-8IDSL interface on which a loopback command has not previously been issued, the interface goes down and back up. This causes a momentary interruption of service for the affected interface. [CSCdr35443]
  
  
• A Cabletron Flowpoint 144F-16 IDSL router cannot be placed into remote loopback when it is operating in 144kbps mode when you issue the loopback remote command on the Cisco 6160. You can put the Cabletron Flowpoint 144-16 IDSL router into remote loopback if it is operating at 64kbps or 128kbps. There is no workaround. [CSCdr58260]
  
  
• On rare occasio