Advanced-Mode DOCSIS Set-Top Gateway 1.2 for the Cisco CMTS Routers

The Advanced-Mode DOCSIS Set-Top Gateway (A-DSG) Issue 1.2 introduces support for the latest DOCSIS Set-Top specification from CableLabs™, to include the following enhancements:

  • DOCSIS Set-top Gateway (DSG) Interface Specification
  • A-DSG 1.2 introduces support for the DOCS-DSG-IF MIB.

Cisco A-DSG 1.2 is certified by CableLabs™, and is a powerful tool in support of latest industry innovations. A-DSG 1.2 offers substantial support for enhanced DOCSIS implementation in the broadband cable environment. The set-top box (STB) dynamically learns the overall environment from the Cisco CMTS router, to include MAC address, traffic management rules, and classifiers.

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest feature information and caveats, see the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the Feature Information Table at the end of this document.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to http:/​/​tools.cisco.com/​ITDIT/​CFN/​. An account on http:/​/​www.cisco.com/​ is not required.

Contents

Hardware Compatibility Matrix for Cisco cBR Series Routers


Note

The hardware components introduced in a given Cisco IOS-XE Release are supported in all subsequent releases unless otherwise specified.

Table 1 Hardware Compatibility Matrix for the Cisco cBR Series Routers

Cisco CMTS Platform

Processor Engine

Interface Cards

Cisco cBR-8 Converged Broadband Router

Cisco IOS-XE Release 3.15.0S and Later Releases

Cisco cBR-8 Supervisor:

  • PID—CBR-CCAP-SUP-160G

  • PID—CBR-CCAP-SUP-60G1

  • PID—CBR-SUP-8X10G-PIC

Cisco IOS-XE Release 3.15.0S and Later Releases

Cisco cBR-8 CCAP Line Cards:

  • PID—CBR-LC-8D30-16U30

  • PID—CBR-LC-8D31-16U30

  • PID—CBR-RF-PIC

  • PID—CBR-RF-PROT-PIC

Cisco cBR-8 Downstream PHY Modules:

  • PID—CBR-D30-DS-MOD

  • PID—CBR-D31-DS-MOD

Cisco cBR-8 Upstream PHY Modules:

  • PID—CBR-D30-US-MOD

1 Effective with Cisco IOS-XE Release 3.17.0S, CBR-CCAP-SUP-60G supports 8 cable line cards. The total traffic rate is limited to 60Gbps, the total number of downstream service flow is limited to 72268, and downstream unicast low-latency flow does not count against the limits.

Prerequisites for Advanced-Mode DSG Issue 1.2

No special equipment or software is needed to use the Advanced-Mode DSG Issue 1.2 feature.

Restrictions for Advanced-Mode DSG Issue 1.2

This section contains restrictions that are specific to A-DSG 1.2 on a Cisco CMTS router.

DSG Configuration File Transfer Operations

DSG 1.2 does not support the copying of a DSG configuration file from a TFTP server, file system, or bootflash to the running configuration.

Multicast Configuration Restrictions

IP multicasting must be configured for correct operation of A-DSG 1.2. Specifically, IP multicast routing must be set in global configuration. Also, IP PIM must be configured on all bundle interfaces of cable interfaces that are to carry multicast traffic.

See the Configuring the Default Multicast Quality of Service and the Configuring IP Multicast Operations for additional Multicast information and global configurations supporting DSG.

NAT for DSG Unicast-only Mapping

A-DSG 1.2 supports multicast IP addressing. However, it also supports unicast IP destination addresses. On the Cisco cBR-8 router, DSG 1.2 support is provided with the configuration of Network Address Translation (NAT) on the router, to include these settings:

  • WAN interface(s) are configured with the ip nat outside command.
  • Cable interface(s) are configured with the ip nat inside command.
  • For each mapping, additional configuration includes the source static multicast IP address and the unicast IP address.

The unicast IP address is the unicast destination IP address of the DSG packets arriving at the Cisco CMTS router. The multicast IP address is the new destination IP address that is configured to map to one or a set of DSG tunnels.

PIM and SSM for Multicast

When using Source Specific Multicast (SSM) operation in conjunction with A-DSG 1.2, the following system-wide configuration command must be specified:

  • ip pim ssm

Refer to the Configuring IP Multicast Operations.

Subinterfaces

A-DSG 1.2 supports subinterfaces on the Cisco CMTS router.

Information About Advanced-Mode DSG Issue 1.2

A-DSG 1.2 offers these new or enhanced capabilities:

  • A-DSG client and agent modes
  • Advanced-mode MIBs supporting DSG 1.2, including the DOCS-DSG-IF-MIB
  • Advanced-mode tunnels with increased security
  • Cable interface bundling through virtual interface bundling
  • Downstream Channel Descriptor
  • IP multicast support
  • Quality of Service (QoS)

DSG 1.2 Clients and Agents

A-DSG 1.2 supports the DSG client and agent functions outlined by the CableLabs™ DOCSIS Set-top Gateway (DSG) Interface Specification , CM-SP-DSG-I05-050812.

FQDN Support

You can specify either a fully-qualified domain name (FQDN) or IP address for A-DSG classifier multicast group and source addresses using the cable dsg cfr command in global configuration mode. We recommend that you use an FQDN to avoid modification of multicast group and source addresses when network changes are implemented.

This feature allows you to use a hostname (FQDN) in place of the source IP address using the cable dsg cfr command. For example, you have two A-DSG tunnel servers, in two locations, sending multicast traffic to the same multicast address. In this scenario, you can specify a hostname for the source IP address and let the DNS server determine which source is sending the multicast traffic.

If you configure an A-DSG classifier with a hostname, the Cisco CMTS router immediately verifies if the hostname can be resolved against an IP address using the local host cache. If not, the router does not enable the classifier until the hostname is resolved. If the hostname cannot be resolved locally, the router performs a DNS query to verify the DSG classifiers.

The FQDN format does not support static Internet Group Management Protocol (IGMP) join requests initiated on the Cisco CMTS router. The IGMP static group IP address created automatically under a bundle interface at the time of A-DSG configuration is not displayed in the show running-config interface command output. To display the A-DSG static groups configured under a bundle interface, use the show cable dsg static-group bundle command in privileged EXEC mode.

DSG Name Process and DNS Query

Every DNS record contains a time to live (TTL) value set by the server administrator, and this may vary from seconds to weeks. The DSG name process supersedes the TTL value criterion to update A-DSG classifiers on the Cisco CMTS router.

The DSG name process enables the Cisco CMTS router to query the DNS server for faster classifier updates. To enable the Cisco CMTS router to perform a DNS query for an A-DSG classifier verification, you must configure one or more DNS servers using the ip name-server command in global configuration mode. You can also specify the DNS query interval using the cable dsg name-update-interval command in global configuration mode.

During a Cisco IOS software reload or a route processor switchover, the router may fail to query the DNS server if the interfaces are down, and the router may not wait for the interval specified using the cable dsg name-update-interval command to perform a DNS query. In this case, for an unresolved hostname, the router automatically performs a DNS query based on a system-defined (15 seconds) interval to facilitate faster DSG classifier updates. You cannot change the system-defined interval.

A-DSG Forwarding on the Primary Channel

You can disable A-DSG forwarding per primary capable interface using the cable downstream dsg disable command in interface configuration mode. Primary capable interfaces include modular, integrated cable interfaces, and Cisco cBR-8 CCAP cable interfaces.

For example, assume the cable interface 7/1/1 has A-DSG enabled and has four modular channels attached to it. However, you want A-DSG forwarding enabled only on two of these four modular channels. You can exclude the channels of your choice using the cable downstream dsg disable command. For details on how to disable modular channels, see the Disabling A-DSG Forwarding on the Primary Channel.


Note
If A-DSG downstream forwarding is disabled on a primary capable interface, the router does not create multicast service flows on the primary capable interface and stops sending Downstream Channel Descriptor (DCD) messages.

DOCSIS 3.0 DSG MDF Support

Support for DOCSIS 3.0 DSG Multicast DSID Forwarding (MDF) is introduced using DSG DA-to-DSID Association Entry type, length, value (TLV 13) in the MAC domain descriptor (MDD) message to communicate the association between a downstream service identifier (DSID) and a group MAC address used for DSG tunnel traffic. This is automatically supported on the Cisco CMTS router.

DOCSIS 2.0 hybrid CMs and DOCSIS 3.0 CMs use Dynamic Bonding Change (DBC) to get DSID information from the Cisco CMTS router, whereas DOCSIS 2.0 DSG hybrid embedded CMs and DOCSIS 3.0 DSG embedded CMs get DSID information from the Cisco CMTS router through MDD messages.

To disable MDF capability on all DSG embedded cable modems, including DOCSIS 3.0 DSG and DOCSIS 2.0 DSG hybrid modems, use the cable multicast mdf-disable command with the dsg keyword in global configuration mode.

Source Specific Multicast Mapping

Source Specific Multicast (SSM) is a datagram delivery model that best supports one-to-many applications, also known as broadcast applications. SSM is a core networking technology for the Cisco implementation of IP multicast solutions targeted for audio and video broadcast application environments.

The following two Cisco IOS components together support the implementation of SSM:

  • Protocol Independent Multicast source-specific mode (PIM-SSM)
  • Internet Group Management Protocol Version 3 (IGMPv3)

SSM mapping can be configured on Cisco CMTS routers.

For details on how to configure SSM mapping on a Cisco CMTS router, see the Source Specific Multicast (SSM) Mapping feature guide.

How to Configure Advanced-Mode DSG Issue 1.2

Advanced-mode DSG Issue 1.2 entails support for DSG tunnel configuration, to include global, WAN-side, and interface-level settings in support of Multicast.

Configuring the Default Multicast Quality of Service

According to DOCSIS 3.0, you must configure the default multicast quality of service (MQoS) when using the MQoS. This also applies to the DSG, which uses the MQoS by associating a service class name with the tunnel.

If the default MQoS is not configured, the DSG tunnel service class configuration is rejected. Similarly, if no DSG tunnel uses the MQoS, you are prompted to remove the default MQoS.

The CMTS selects the primary downstream channel to forward the multicast traffic when the default MQoS is configured and there is no matching MQoS group configuration. Otherwise, the wideband interface is used to forward the multicast traffic.

Procedure
     Command or ActionPurpose
    Step 1enable


    Example: 
    Router> enable
     

    Enables privileged EXEC mode.

    • Enter your password if prompted.
     
    Step 2configure terminal


    Example: 
    Router# configure terminal


    Example: 
    Router(config)#
     

    Enters global configuration mode.

     
    Step 3cable multicast group-qos default scn service-class-name aggregate


    Example: 
    Router(config)# cable multicast group-qos default scn name1 aggregate
     

    Configures a service class name for the QoS profile.

     
    Step 4end


    Example: 
    Router(config)# end
     

    Returns to privileged EXEC mode.

     
    What to Do Next


    Note
    If you configure or remove the default MQoS while the CMTS is sending multicast traffic, duplicate traffic is generated for approximately 3 minutes (or 3 times the query interval).

    Configuring Global Tunnel Group Settings for Advanced-Mode DSG 1.2

    This procedure configures global and interface-level commands on the Cisco CMTS router to enable DSG tunnel groups. A DSG tunnel group is used to bundle some DSG channels together and associate them to a MAC domain interface.

    Global A-DSG 1.2 Tunnel Settings

    This procedure sets and enables global configurations to support both A-DSG 1.2 clients and agents. Additional procedures provide additional settings for these clients and agents.

    Before You Begin

    When DOCSIS Set-top Gateway (DSG) is configured to have quality of service (QoS) for tunnel, ensure that the default multicast QoS (MQoS) is also configured. For more information, see Configuring the Default Multicast Quality of Service.


    Note

    The DSG tunnel service class configuration is rejected, if default MQoS is not configured.

    Procedure
       Command or ActionPurpose
      Step 1enable


      Example: 
      Router> enable
       

      Enables privileged EXEC mode.

      • Enter your password if prompted.
       
      Step 2configure terminal


      Example: 
      Router# configure terminal
Router(config)#
       

      Enters global configuration mode.

       
      Step 3cable dsg tggroup-id [channelchannel-id |priorityDSG-rule-priority ] [enable|disable]

      Example: 
      Router(config)# cable dsg tg 1 channel 1 priority 1 enable
       

      Command allows the association of a group of tunnels to one or more downstream interfaces on the Cisco CMTS.

       
      Step 4cabledsg tggroup-id [channel channel-id [ucid ID1 ]]

      Example: 
      Router(config)# cable dsg tg 1 channel 1 ucid 1
       

      Sets the upstream channel or channels to which the DSG 1.2 tunnel applies.

       
      Step 5cable dsg tg group-id [channel channel-id [vendor-param vendor-group-id ]]

      Example: 
      Router(config)# cable dsg tg 1 channel 1 vendor-param 1
       

      Sets the vendor-specific parameters for upstream DSG 1.2 channels.

       
      Step 6cable dsg vendor-param group-id vendor vendor-index oui oui value value-in-TLV


      Example: 
      Router(config)# cable dsg vendor-param 1 vendor 1 oui ABCDEA value 0101AB
       

      Configures vendor-specific parameters for A-DSG 1.2. To remove this configuration from the Cisco CMTS, use the no form of this command.

       
      Step 7cable dsg chan-list list-index index entry-index freq freq


      Example: 
      Router(config)# cable dsg chan-list 1 index 1 freq 47000000
       

      Configures the A-DSG 1.2 downstream channel list. The channel list is a list of DSG channels (downstream frequencies) that set-top boxes can search to find the DSG tunnel appropriate for their operation. To remove the A-DSG 1.2 channel list from the Cisco CMTS, us the no form of this command.

       
      Step 8 cable dsg timer inde [Tdsg1 Tdsg1 ] | [ Tdsg2 Tdsg2 ] | [Tdsg3 Tdsg3 ] | [ Tdsg4 Tdsg4 ]


      Example: 
      Router(config)# cable dsg timer 1 Tdsg1 1 Tdsg2 2 Tdsg3 3 Tdsg4 4
       

      Configures the A-DSG 1.2 timer entry to be associated to the downstream channel, and encoded into the Downstream Channel Descriptor (DCD) message. To remove the cable DSG timer from the Cisco CMTS, use the no form of this command.

       
      Step 9end


      Example: 
      Router(config)# end
       

      Returns to privileged EXEC mode.

       
      What to Do Next

      Troubleshooting Tips

      Refer to debug and show commands in the How to Monitor and Debug the Advanced-mode DOCSIS Set-Top Gateway Feature.

      Adding DSG Tunnel Group to a Subinterface

      This procedure adds a DSG tunnel group to a subinterface using the cable dsg tg group-id command. After adding the DSG tunnel-group to a subinterface, appropriate IP Internet Group Management Protocol (IGMP) static joins are created and forwarding of DSG traffic begins, if the downstream DSG is configured.

      Before You Begin

      The downstream DSG should exist to create IGMP static joins.

      Restriction:

      You can associate a DSG tunnel group to only one subinterface within the same bundle interface.

      Procedure
         Command or ActionPurpose
        Step 1enable


        Example: 
        Router> enable
         

        Enables privileged EXEC mode.

        • Enter your password if prompted.
         
        Step 2configureterminal


        Example: 
        Router# configure terminal
Router(config)#
         

        Enters global configuration mode.

         
        Step 3interface bundlebundle-subif-number


        Example: 
        Router(config)# interface bundle 11.2
Router(config-subif)#
         

        Specifies the interface bundle and enters the subinterface configuration mode.

         
        Step 4cable dsg tggroup-id


        Example: 
        Router(config-subif)# cable dsg tg 1
         

        Adds a DSG tunnel group to a subinterface.

         
        Step 5 end

        Example: 
        Router(config-subif)# end
         

        Returns to privileged EXEC mode.

         

        Configuring the DSG Client Settings for Advanced-Mode DSG 1.2

        After the global configurations and DSG client configurations are set for DSG 1.2 on the Cisco CMTS, use the following procedure to continue DSG 1.2 client configurations.

        Restriction:

        The in-dcd ignore option is not supported by DSG-IF-MIBS specification.

        Procedure
           Command or ActionPurpose
          Step 1enable


          Example: 
          Router> enable
           

          Enables privileged EXEC mode.

          • Enter your password if prompted.
           
          Step 2configure terminal


          Example: 
          Router# configure terminal
           

          Enters global configuration mode.

           
          Step 3cable dsg client-list client-list-id id-index id {application-id app-id | ca-system-id sys-id | mac-addr mac-addr | broadcast [broadcast-id ]}


          Example: 
          Router(config)# cable dsg client-list 1 id-index 1 mac-addr abcd.abcd.abcd
           

          Sets the DSG client parameters. This command is changed from earlier Cisco IOS Releases, and for DSG 1.2, this command specifies the optional broadcast ID to client ID broadcast type and vendor specific parameter index.

           
          Step 4cable dsg client-list client-list-id id-index id [vendor-param vendor-group-id ]


          Example: 
          Router(config-if)# cable dsg client-list 1 id-index 1 vendor-param 1
           

          Sets vendor-specific parameters for the DSG client.

           
          Step 5cable dsg tunnel tunnel id mac_addr mac addr tg tunnel-group clients client-list-id [enable | disable]


          Example: 
          Router(config)# cable dsg tunnel mac-addr abcd.abcd.abcd tg 1 clients 1 enable
           

          This command is changed to associate a tunnel group and client-list ID to a DSG tunnel. Also, an optional QoS service class name can be associated to the tunnel.

          Note   

          To associate a cable service class with an A-DSG tunnel on a Cisco CMTS router, use the cable dsg tunnel srv-class command in global configuration mode.

           
          Step 6cable dsg cfr cfr index [dest-ip {ipaddr |hostname}] [tunnel tunnel-index ][dest-port start end ]| [priority priority ][src-ip {ipaddr |hostname} [src-prefix-len length ]] [enable | disable] [in-dcd {yes | no | ignore}]


          Example: 
          Router(config)# cable dsg cfr 1 dest-ip 224.225.225.225 tunnel 1 dest-port 40 50 priority 2 src-ip ciscovideo.com src-prefix-len 24 enable
           

          Specifies the DSG classifier index, with optional support for the DCD parameter, indicating whether or not to include the classifier in the DCD message.

          Note   

          When you use the ignore option, the DSG classifier is not included in the DCD message.

           
          Step 7end


          Example: 
          Router(config)# end
Router#
           

          Returns to privileged EXEC mode.

           
          What to Do Next

          Troubleshooting Tips

          Refer to debug and show commands in the How to Monitor and Debug the Advanced-mode DOCSIS Set-Top Gateway Feature.

          Configuring Downstream DSG 1.2 Settings for Advanced-Mode DSG 1.2

          When the global and client configurations are set for DSG 1.2 on the Cisco CMTS, use the following procedure to continue with DSG 1.2 downstream configurations.

          Procedure
             Command or ActionPurpose
            Step 1enable


            Example: 
            Router> enable
             

            Enables privileged EXEC mode.

            • Enter your password if prompted.
             
            Step 2configureterminal


            Example: 
            Router# configure terminal
             

            Enters global configuration mode.

             
            Step 3interface cable {slot /port |slot /subslot/port }

            Example: 
            Router(config)# interface cable 8/1/1
             

            Enters interface configuration mode.

             
            Step 4cable downstream dsg tg group-id [channel channel-id]


            Example: 
            Router(config-if)# cable downstream dsg tg 1 channel 1
             

            Associates the DSG tunnel group to the downstream interface. To remove this setting, use the no form of this command.

             
            Step 5cable downstream dsg chan-list list-index


            Example: 
            Router(config-if)# cable downstream dsg chan-list 2
             

            Associates the A-DSG channel list entry to a downstream channel, to be included in the DCD message. To remove this setting, use the no form of this command.

             
            Step 6cable downstream dsg timer timer-index


            Example: 
            Router(config-if)# cable downstream dsg timer 3
             

            Associates the DSG timer entry to a downstream channel, to be included in the DCD message. To remove this setting, use the no form of this command.

             
            Step 7cable downstream dsg vendor-param vsif-grp-id


            Example: 
            Router(config-if)# cable downstream dsg vendor-param 2
             

            Associates A-DSG vendor parameters to a downstream to be included in the DCD message. To remove this configuration from the Cisco CMTS, use the no form of this command.

             
            Step 8cable downstream dsg [dcd-enable | dcd-disable]

            Example: 
            Router(config-if)# cable downstream dsg dcd-enable
             

            Enables DCD messages to be sent on a downstream channel. This command is used when there are no enabled rules or tunnels for A-DSG currently on the Cisco CMTS. To disable DCD messages, use the disable form of this command.

             
            Step 9end


            Example: 
            Router(config-if)# end
             

            Returns to privileged EXEC mode.

             

            Configuring IP Multicast Operations

            This section describes how to configure the operation of IP multicast transmissions on the cable and WAN interfaces on the Cisco CMTS. You should perform this configuration on each cable interface being used for DSG traffic and for each WAN interface that is connected to a network controller or Conditional Access (CA) server that is forwarding IP multicast traffic.

            Procedure
               Command or ActionPurpose
              Step 1configure terminal


              Example: 
              Router# configure terminal
               

              Enters global configuration mode.

               
              Step 2ip multicast-routing


              Example: 
              Router(config)# ip multicast-routing
               

              Enables multicast routing on the router.

               
              Step 3 ip pim ssm {default | range{access-list | word }}


              Example: 
              Router(config)# ip pim ssm range 4
               

              Defines the Source Specific Multicast (SSM) range of IP multicast addresses. To disable the SSM range, use the no form of this command.

              Note    When an SSM range of IP multicast addresses is defined by the ip pim ssm command, no Multicast Source Discovery Protocol (MSDP) Source-Active (SA) messages will be accepted or originated in the SSM range.
               
              Step 4 ip cef distributed

              Example: 
              
Router(config)# ip cef distributed
               

              Enables Cisco Express Forwarding (CEF) on the route processor card. To disable CEF, use the no form of this command.

              For additional information about the ip cef command, refer to the following document on Cisco.com:

              • Cisco IOS Switching Services Command Reference , Release 12.3

              http:/​/​www.cisco.com/​en/​US/​docs/​ios/​12_3/​switch/​command/​reference/​swtch_​r.html

               
              Step 5interface bundle bundle-number


              Example: 
              Router(config)# interface bundle 10
               

              Enters interface configuration mode for each interface bundle being used for DSG traffic.

               
              Step 6ip pim {dense-mode | sparse-mode | sparse-dense-mode}

              Example: 
              Router(config-if)# ip pim dense-mode
               

              Enables Protocol Independent Multicast (PIM) on the cable interface, which is required to use the DSG feature:

              Note    You must configure this command on each interface that forwards multicast traffic.
               
              Step 7Repeat Step 5 and Step 6 for each cable interface that is being used for DSG traffic. Also repeat these steps on each W AN interface that is forwarding IP multicast traffic from the DSG network controllers and Conditional Access (CA) servers.    
              Step 8end


              Example: 
              Router(config-if)# end
               

              Exits interface configuration mode and returns to privileged EXEC mode.

               

              Enabling DNS Query and DSG Name Process

              The DSG name process enables the Cisco CMTS router to query the DNS server for faster classifier updates.

              Before You Begin

              Ensure that the IP DNS-based hostname-to-address translation is configured on the Cisco CMTS router using the ip domain-lookup command in global configuration mode. This is configured by default, and the status is not displayed in the running configuration.

              Procedure
                 Command or ActionPurpose
                Step 1configureterminal


                Example: 
                Router# configure terminal
                 

                Enters global configuration mode.

                 
                Step 2ip domain-name name


                Example: 
                Router(config)# ip domain-name cisco.com
                 

                Sets the IP domain name that the Cisco IOS software uses to complete unqualified host names

                 
                Step 3r ip name-serveserver-address[multiple-server-addresses]

                Example: 
                Router(config)# ip name-server 131.108.1.111
                 

                Sets the server IP address.

                 
                Step 4 cable dsg name-update-intervalminutes


                Example: 
                Router(config)# cable dsg name-update-interval 10
                 

                Sets the interval to check the DNS server for any FQDN classifier changes.

                 
                Step 5end


                Example: 
                Router(config)# end
                 

                Returns to privileged EXEC mode.

                 

                Configuring NAT to Support Unicast Messaging

                This section describes how to configure a Cisco CMTS router for Network Address Translation (NAT) to enable the use of IP unicast addresses for DSG messaging. This allows the Cisco CMTS router to translate incoming IP unicast addresses into the appropriate IP multicast address for the DSG traffic.

                For the Cisco cBR-8 router, A-DSG 1.2 can use an external router that is close to the Cisco CMTS to support unicast messaging. In this case, the nearby router must support NAT, and then send the address-translated multicast IP packets to the Cisco CMTS.


                Tip

                This procedure should be performed after the cable interface has already been configured for DSG operations, as described in the Configuration Examples for Advanced-Mode DSG.


                Note
                The Cisco CMTS router supports NAT only when it is running an “IP Plus” (-i-) Cisco IOS software image. Refer to the release notes for your Cisco IOS release for complete image availability and requirements.
                Procedure
                   Command or ActionPurpose
                  Step 1configure terminal


                  Example: 
                  Router# configure terminal
                   

                  Enters global configuration mode.

                   
                  Step 2interface wan-interface


                  Example: 
                  Router(config)# interface FastEthernet0/0
                   

                  Enters interface configuration mode for the specified WAN interface.

                   
                  Step 3ip nat outside


                  Example: 
                  Router(config-if)# ip nat outside
                   

                  Configures the WAN interface as the “outside” (public) NAT interface.

                   
                  Step 4interface bundle bundle-number


                  Example: 
                  Router(config-if)# interface bundle 10
                   

                  Enters interface configuration mode for the specified interface bundle.

                  Note    This interface bundle should have previously been configured for DSG operations.
                   
                  Step 5ip address ip-address mask secondary


                  Example: 
                  Router(config-if)# ip address 192.168.18.1 255.255.255.0 secondary
                   

                  Configures the cable interface with an IP address and subnet that should match the unicast address being used for DSG traffic. This IP address and its subnet must not be used by any other cable interfaces, cable modems, or any other types of traffic in the cable network.

                   
                  Step 6ip nat inside


                  Example: 
                  Router(config-if)# ip nat inside
                   

                  Configures the cable interface as the “inside” (private) NAT interface.

                   
                  Step 7exit


                  Example: 
                  Router(config-if)# exit
                   

                  Exits interface configuration mode and returns to global configuration mode.

                   
                  Step 8ip nat inside source static ip-multicast-address cable-ip-address


                  Example: 
                  Router(config)# ip nat inside source static 224.3.2.1 192.168.18.2
                   

                  Maps the unicast IP address assigned to the cable interface to the multicast address that should be used for the DSG traffic.

                   
                  Step 9 Repeat Step 2 and Step 8 for each cable interface to be configured for DSG unicast traffic.    
                  Step 10end


                  Example: 
                  Router(config)# end
                   

                  Exits global configuration mode and returns to privileged EXEC mode.

                   

                  Configuring WAN Interfaces for Multicast Operations

                  In addition to basic WAN interface configuration on the Cisco CMTS, described in other documents, the following WAN interface commands should be configured on the Cisco CMTS to support IP multicast operations with A-DSG 1.2, as required.

                  • ip pim
                  • ip pim ssm
                  • ip cef

                  These commands are described in the Configuring IP Multicast Operations, and in the following documents on Cisco.com.

                  For additional information about the ip pim command, refer to the following document on Cisco.com:

                  • Cisco IOS IP Command Reference, Volume 3 of 4 : Multicast, Release 12.3

                  http:/​/​www.cisco.com/​en/​US/​docs/​ios/​12_3/​ipmulti/​command/​reference/​iprmc_​r.html

                  For additional information about the ip pim ssm command, refer to the following document on Cisco.com:

                  • Cisco IOS IP Command Reference, Volume 3 of 4: Multicast , Release 12.3 T

                  http:/​/​www.cisco.com/​en/​US/​docs/​ios/​12_3t/​ip_mcast/​command/​reference/​ip3_​i2gt.html

                  For additional information about the ip cef command, refer to the following document on Cisco.com:

                  • Cisco IOS Switching Services Command Reference , Release 12.3

                  http:/​/​www.cisco.com/​en/​US/​docs/​ios/​12_3/​switch/​command/​reference/​swtch_​r.html

                  Configuring a Standard IP Access List for Packet Filtering

                  This section describes how to configure a standard IP access list so that only authorized traffic is allowed on the cable interface.


                  Tip

                  This procedure assumes a basic knowledge of how access lists use an IP address and bitmask to determine the range of IP addresses that are allowed access. For full details on configuring access lists, see the documents listed in the Additional References.

                  Procedure
                     Command or ActionPurpose
                    Step 1configure terminal


                    Example: 
                    Router# configure terminal
                     

                    Enters global configuration mode.

                     
                    Step 2access-list access-list permit group-ip-address [mask ]


                    Example: 
                    Router(config)# access-list 90 permit 228.1.1.1
                     

                    Creates an access list specifying that permits access to the specific multicast address that matches the specified group-ip-address and mask .

                     
                    Step 3access-list access-list deny group-ip-address [mask ]


                    Example: 
                    Router(config)# access-list 90 deny 224.0.0.0 15.255.255.255
                     

                    Configures the access list that denies access to any multicast address that matches the specified group-ip-address and mask .

                     
                    Step 4access-list access-list deny any


                    Example: 
                    Router(config)# access-list 90 deny any
                     

                    Configures the access list so that it denies access to any IP addresses other than the ones previously configured.

                     
                    Step 5interface bundle bundle-number


                    Example: 
                    Router(config)# interface bundle 10
                     

                    Enters interface configuration mode for the specified interface bundle.

                     
                    Step 6ip access-group access-list


                    Example: 
                    Router(config-if)# ip access-group 90
                     

                    (Optional, but recommended) Configures the interface with the access list, so that packets are filtered by the list before being accepted on the interface.

                    Note    Standard Access lists only allow one address to be specified in the earlier step. If you apply an outbound access-list with only the multicast address of the tunnel denied, then the DSG traffic is not allowed to pass.

                    Note    On the Cisco cBR-8 router, inbound access lists on the cable interface do not apply to multicast traffic, so they do not apply here. As a result, the Cisco cBR-8 requires that you use extended access lists that are blocked in the outbound direction for packets originating from the cable modem or CPE device on the network, and destined to the multicast group. The multicast group contains the classifiers associated with A-DSG 1.1 rules enabled on the interface.

                     
                    Step 7end


                    Example: 
                    Router(config-if)# end
                     

                    Exits interface configuration mode and returns to Privileged EXEC mode.

                     

                    Configuring a Standard IP Access List for Multicast Group Filtering

                    This section describes how to configure a standard IP access list so that non-DOCSIS devices, such as DSG set-top boxes, can access only the authorized multicast group addresses and DSG tunnels.


                    Tip

                    This procedure assumes a basic knowledge of how access lists use an IP address and bitmask to determine the range of IP addresses that are allowed access. For full details on configuring access lists, see the documents listed in the Additional References.

                    Procedure
                       Command or ActionPurpose
                      Step 1configure terminal


                      Example: 
                      Router# configure terminal
                       

                      Enters global configuration mode.

                       
                      Step 2access-list access-list permit group-ip-address [mask ]


                      Example: 
                      Router(config)# access-list 90 permit 228.1.1.1
                       

                      Creates an access list specifying that permits access to the specific multicast address that matches the specified group-ip-address and mask .

                       
                      Step 3access-list access-list deny group-ip-address [mask ]


                      Example: 
                      Router(config)# access-list 90 deny 224.0.0.0 15.255.255.255
                       

                      Configures the access list that denies access to any multicast address that matches the specified group-ip-address and mask .

                       
                      Step 4access-list access-list deny any


                      Example: 
                      Router(config)# access-list 90 deny any
                       

                      Configures the access list so that it denies access to any IP addresses other than the ones previously configured.

                       
                      Step 5interface cable interface


                      Example: 
                      Router(config)# interface cable 3/0
                       

                      Enters interface configuration mode for the specified cable interface.

                       
                      Step 6ip igmp access-group access-list [version ]


                      Example: 
                      Router(config-if)# ip igmp access-group 90
                       

                      (Optional, but recommended) Configures the interface to accept traffic only from the associated access list, so that only authorized devices are allowed to access the DSG tunnels.

                       
                      Step 7end


                      Example: 
                      Router(config-if)# end
                       

                      Exits interface configuration mode and returns to privileged EXEC mode.

                       

                      Disabling A-DSG Forwarding on the Primary Channel

                      You can disable A-DSG forwarding per primary capable interface.

                      Procedure
                         Command or ActionPurpose
                        Step 1configure terminal


                        Example: 
                        Router# configure terminal
                         

                        Enters global configuration mode.

                         
                        Step 2interface modular-cable slot /subslot/port :interface-number


                        Example: 
                        Router(config)# interface modular-cable 1/0/0:0
                         

                        Specifies the modular cable interface and enters cable interface configuration mode. Variables for this command may vary depending on the Cisco CMTS router and the Cisco IOS-XE software release.

                         
                        Step 3cable downstream dsg disable


                        Example: 
                        Router(config-if)# cable downstream dsg disable
                         

                        Disables A-DSG forwarding and DCD messages on the primary capable interface.

                         
                        Step 4end


                        Example: 
                        Router(config-if)# end
                         

                        Returns to privileged EXEC mode.

                         

                        How to Monitor and Debug the Advanced-mode DOCSIS Set-Top Gateway Feature

                        This section describes the following commands that you can use to monitor and display information about the Advanced-mode DOCSIS Set-Top Gateway feature:

                        Displaying Global Configurations for Advanced-Mode DSG 1.2

                        The following commands display globally-configured or interface-level DSG settings, status, statistics, and multiple types of DSG 1.2 tunnel information.

                        show cable dsg cfr

                        To verify all DSG classifier details, such as the classifier state, source, and destination IP addresses, use the show cable dsg cfr command.

                        To verify details of a particular DSG classifier, use the show cable dsg cfr cfr-id command.

                        To verify the detailed output for all DSG classifiers, use the show cable dsg cfr verbose command.

                        To verify the detailed output for a single DSG classifier, use the show cable dsg cfr cfr-id verbose command.

                        show cable dsg host

                        To verify the mapping of the DSG hostnames and IP addresses on a Cisco CMTS router, use the show cable dsg host command.

                        To verify the verbose output of the mapping of the DSG hostnames and IP addresses on a Cisco CMTS router, use the show cable dsg host verbose command.

                        show cable dsg tunnel

                        To display tunnel MAC address, state, tunnel group id, classifiers associated to tunnel and its state, use the show cable dsg tunnel command in privileged EXEC mode. This command also displays the number of interfaces to which a tunnel is associated, the clients associated, and the QoS service class name for all the configured tunnels.

                        To display information for a given DSG tunnel, use the show cable dsg tunnel tunnel-id command, specifying the tunnel for which to display information.

                        show cable dsg tunnel tunnel-id [cfr | clients | interfaces | statistics | verbose]

                        • cfr—Shows DSG tunnel classifiers.
                        • clients—Shows DSG tunnel clients.
                        • interfaces—Shows DSG tunnel interfaces.
                        • statistics—Shows DSG tunnel statistics.
                        • verbose—Shows DSG tunnel detail information.

                        show cable dsg tg

                        To display the configured parameters for all DSG tunnel groups, use show cable dsg tg command.


                        Note
                        The Chan state column in the show cable dsg tg command output indicates that a channel belonging to a tunnel group is either enabled or diabled. It is possible that a tunnel group is enabled but a particular channel in that tunnel group is disabled.

                        To display the configured parameters for the specified tunnel group, use show cable dsg tg tg-id channel channel-id command.

                        To display detailed information for the specified tunnel group, use show cable dsg tg tg-id channel channel-id verbose command.

                        show running-config interface

                        To display a tunnel group attached to a subinterface, use the show running-config interface command in privileged EXEC mode, as shown in the example below: 

                        Router# show running-config interface bundle 11.2
!
interface Bundle11.2
 ip address 4.4.2.1 255.255.255.0
 no ip unreachables
 ip pim sparse-mode
 ip igmp static-group 230.1.1.30
 no cable ip-multicast-echo
 cable dsg tg 61
end

                        Note
                        The IGMP static group IP address created automatically at the time of DSG configuration is not displayed in the show running-config interface command output.

                        show cable dsg static-group bundle

                        To verify all DSG static groups configured under a bundle interface, use the show cable dsg static-group bundle command in privileged EXEC mode.

                        Displaying Interface-level Configurations for Advanced-Mode DSG 1.2

                        The following show commands display interface-level configurations for A-DSG 1.2.

                        show cable dsg tunnel interfaces

                        To display all interfaces and DSG rules for the associated tunnel, use the show cable dsg tunnel interfaces command in privileged EXEC mode.

                        show cable dsg tunnel (tunnel-id ) interfaces

                        show interfaces cable dsg downstream

                        To display DSG downstream interface configuration information, to include the number of DSG tunnels, classifiers, clients, and vendor-specific parameters, use the show interfaces cable dsg downstream command in privileged EXEC mode.

                        show interfaces cable dsg downstream dcd

                        To display DCD statistics for the given downstream, use the show interfaces cable dsg downstream dcd command in privileged EXEC mode. This command only displays DCD Type/Length/Value information if the debug cable dsg command is previously enabled.

                        show interfaces cable dsg downstream tg

                        To display DSG tunnel group parameters, and rule information applying to the tunnel group, to include tunnels and tunnel states, classifiers, and client information, use the show interfaces cable dsg downstream tg command in privileged EXEC mode. You can display information for a specific tunnel, if specified.

                        show interfaces cable dsg downstream tunnel

                        To display DSG tunnel information associated with the downstream, use the show interfaces cable dsg downstream tunnel command in privileged EXEC mode.

                        Debugging Advanced-Mode DSG

                        To enable debugging for A-DSG on a Cisco CMTS router, use the debug cable dsg command in privileged EXEC mode.

                        Configuration Examples for Advanced-Mode DSG

                        This configuration example illustrates a sample DSG network featuring these components:

                        • Two Cisco universal broadband routers
                        • IP Multicast for each DSG implementation
                        • Two DSG Clients for each Cisco CMTS
                        • Two DSG Servers (one for each Cisco CMTS)

                        Each Cisco CMTS is configured as follows, and the remainder of this topic describes example configurations that apply to this architecture.

                        CMTS Headend 1

                        • DSG Server #1—Connected to Cisco CMTS via IP Multicast, with DSG Server having IP Address 12.8.8.1
                        • Destination IP Address for the Cisco CMTS—228.9.9.1
                        • DSG Tunnel Address—0105.0005.0005
                        • Downstream #1 Supporting two DSG Clients:
                          • DSG Client #1—ID 101.1.1
                          • DSG Client #2—ID 102.2.2

                        CMTS Headend 2

                        • DSG Server #2—Connected to Cisco CMTS via IP Multicast, with DSG Server having IP Address 12.8.8.2
                        • Destination IP Address for the Cisco CMTS—228.9.9.2
                        • DSG Tunnel Address—0106.0006.0006
                        • Downstream #2 Supporting two DSG Clients:
                          • DSG Client #1—ID 101.1.1
                          • DSG Client #2—ID 102.2.2

                        Example of Two DSG Tunnels with MAC DA Substitution

                        In this configuration, and given the two Cisco CMTS Headends cited above, below are the two sets of DSG rules, with each set applying to each Cisco CMTS, in respective fashion.

                        These settings apply to DSG #1 and two downstreams:

                        • DSG Rule ID 1
                        • DSG Client ID 101.1.1
                        • DSG Tunnel Address 105.5.5

                        These settings apply to DSG Rule #2 and two downstreams:

                        • DSG Rule ID 1
                        • DSG Client ID 102.2.2
                        • DSG Tunnel Address 106.6.6

                        DSG Example with Regionalization Per Downstream

                        In this configuration, and given the two Cisco CMTS Headends cited earlier in this topic, below are two downstream rules that can be configured in this architecture, for example:

                        • Downstream Rule #1
                          • DSG Rule ID #1
                          • DSG Client ID—101.1.1
                          • DSG Tunnel Address—105.5.5
                        • Downstream Rule #2
                          • DSG Rule ID #2
                          • DSG Client ID—102.2.2
                          • DSG Tunnel Address—106.6.6

                        DSG Example with Regionalization Per Upstream

                        In this configuration, and given the two Cisco CMTS Headends cited earlier in this topic, below are two upstream rules that can be configured in this architecture, for example:

                        • Upstream Rule #1
                          • DSG Rule ID #1
                          • DSG Client ID—101.1.1
                          • DSG UCID Range—0 to 2
                          • DSG Tunnel Address—105.5.5
                        • Upstream Rule #2
                          • DSG Rule ID #2
                          • DSG Client ID—102.2.2
                          • DSG UCID Range—3 to 5
                          • DSG Tunnel Address—106.6.6

                        Example of Two DSG Tunnels with Full Classifiers and MAC DA Substitution

                        In this configuration, and given the two Cisco CMTS Headends cited above, below are the two sets of DSG rules, with each set applying to each Cisco CMTS, in respective fashion.

                        These settings apply to DSG #1:

                        • DSG Rule ID 1
                        • Downstreams 1 and 2
                        • DSG Client ID 101.1.1
                        • DSG Tunnel Address 105.5.5
                        • DSG Classifier ID—10
                        • IP SA—12.8.8.1
                        • IP DA—228.9.9.1
                        • UDP DP—8000

                        These settings apply to DSG Rule #2:

                        • DSG Rule ID 2
                        • Downstreams 1 and 2
                        • DSG Client ID 102.2.2
                        • DSG Tunnel Address 106.6.6
                        • DSG Classifier ID—20
                        • IP SA—12.8.8.2
                        • IP DA—228.9.9.2
                        • UDP DP—8000

                        Example of One DSG Tunnel Supporting IP Multicast from Multiple DSG Servers

                        In this configuration, and given the two Cisco CMTS Headends cited earlier in this topic, below is an example of one DSG Tunnel with multiple DSG servers supporting IP Multicast:

                        • DSG Rule ID 1
                        • Downstreams 1 and 2
                        • DSG Client ID 101.1.1 and 102.2.2
                        • DSG Tunnel Address 105.5.5
                        • DSG Classifier ID—10
                          • IP SA—12.8.8.1
                          • IP DA—228.9.9.1
                          • UDP DP—8000
                        • DSG Classifier ID—20
                          • IP SA—12.8.8.2
                          • IP DA—228.9.9.2
                          • UDP DP—8000

                        Example: Enabling DNS Query

                        The following example shows how to enable a DNS query on the Cisco CMTS router: 

                        Router# configure terminal
Router(config)# ip domain-lookup
Router(config)# ip domain-name cisco.com
Router(config)# ip name-server 131.108.1.111
Router(config)# cable dsg name-update-interval 10
Router(config)# end

                        Example: Disabling A-DSG Forwarding on the Primary Channel

                        The following example shows how to disable A-DSG forwarding on a primary capable modular interface on the Cisco CMTS router: 

                        Router# configure terminal
Router(config)# interface modular-cable 1/0/0:0
Router(config-if)# cable downstream dsg disable
Router(config-if)# end

                        Additional References

                        The following sections provide references related to A-DSG 1.2.

                        Technical Assistance

                        Description

                        Link

                        The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

                        http:/​/​www.cisco.com/​cisco/​web/​support/​index.html

                        Feature Information for Advanced-Mode DSG 1.2 for the Cisco CMTS Routers

                        Use Cisco Feature Navigator to find information about platform support and software image support. Cisco Feature Navigator enables you to determine which software images support a specific software release, feature set, or platform. To access Cisco Feature Navigator, go to http:/​/​tools.cisco.com/​ITDIT/​CFN/​. An account on http:/​/​www.cisco.com/​ is not required.


                        Note

                        The below table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

                        Table 2 Feature Information for DOCSIS Set-Top Gateway and A-DSG for the Cisco CMTS Routers

                        Feature Name

                        Releases

                        Feature Information

                        DOCSIS Set-Top Gateway for the Cisco CMTS Routers

                        Cisco IOS-XE Release 3.15.0S

                        This feature was introduced on the Cisco cBR Series Converged Broadband Routers.