4.2. Configuring MLD with CLI

This section provides information to configure MLD using the command line interface.

4.2.1. MLD Configuration Overview

The routers use MLD to manage membership for a given multicast session. MLD is not enabled by default. When enabled, at least one interface must be specified in the MLD context as MLD is an interface function. Creating an interface enables MLD. Traffic can only flow away from the router to an MLD interface and to and from a PIM interface. A router directly connected to a source must have PIM enabled on the interface to that source. The traffic travels in a network from PIM interface to PIM interface and arrives finally on an MLD enabled interface.

The MLD CLI context allows you to specify an existing IP interface and modify the interface-specific parameters. Static MLD group memberships can be configured to test multicast forwarding without a receiver host. When MLD static group membership is enabled, data is forwarded to an interface without receiving membership reports from host members.

When static MLD group entries on point-to-point links that connect routers to a rendezvous point (RP) are configured, the static MLD group entries do not generate join messages toward the RP. When a host wants to receive multicast sessions it sends a join message for each multicast group it wants to join. Then, a leave message may be sent for each multicast group it no longer wishes to participate with.

A multicast router keeps a list of multicast group memberships for each attached network, and an interval timer for each membership. Hosts issue a Multicast Group Membership Report when they want to receive a multicast session. The reports are sent to all multicast routers.

4.2.2. Basic MLD Configuration

Perform the following basic multicast configuration tasks:

  1. Enable MLD (required)
  2. Configure MLD interfaces (required)
  3. Specify MLD version on the interface (optional)
  4. Configure static (S,G)/(*,G) (optional)
  5. Configure SSM translation (optional)

4.2.3. Configuring MLD Parameters

4.2.3.1. Enabling MLD

Use the following CLI syntax to enable MLD.

CLI Syntax:
config>router# mld

The following example displays the detailed output when MLD is enabled:

A:LAX>config>router>mld# info detail 
----------------------------------------------
        no grp-if-query-src-ip
        query-interval 125
        query-last-listener-interval 1
        query-response-interval 10
        robust-count 2
        no shutdown
----------------------------------------------
A:LAX>config>router>mld#

4.2.3.2. Configuring an MLD Interface

To configure an MLD interface:

CLI Syntax:
config>router# mld
interface ip-int-name
import policy-name
max-groups value
version version
no shutdown

Use the following CLI syntax to configure MLD interfaces:

Example:
config>router#
config>router>mld# interface "lax-vls"
config>router>mld>if? no shutdown
config>router>mld>if# exit
config>router>mld# interface "p1-ix"
config>router>mld>if? no shutdown
config>router>mld>if# exit
config>router>mld# interface "lax-sjc"
config>router>mld>if? no shutdown
config>router>mld>if# exit

The following example displays the MLD configuration:

A:LAX>config>router>mld# info
----------------------------------------------
        interface "lax-sjc"
        exit
        interface "lax-vls"
        exit
        interface "p1-ix"
        exit
----------------------------------------------
A:LAX>config>router>mld# exit

4.2.3.3. Configuring Static Parameters

To add an MLD static multicast source:

CLI Syntax:
config>router# mld
interface ip-int-name
no shutdown
static
group grp-ipv6-address
source ipv6-address

Use the following CLI syntax to configure static group addresses and source addresses for the SSM translate group ranges:

Example:
config>router>mld# interface lax-vls
config>router>mld>if# static
config>router>mld>if>static# group ff05:db8:1
config>router>mld>if>static>group# source 2001:db8:2016:10ff::4

The following example displays the configuration:

A:LAX>config>router>mld# info
----------------------------------------------
        interface "lax-sjc"
        exit
        interface "lax-vls"
            static
                group ff05:db8:1ff05:db8:1
                    source 2001:db8:2016:10ff::4
                exit
            exit
        exit
        interface "p1-ix"
        exit
----------------------------------------------
A:LAX>config>router>mld#

To add an MLD static starg entry:

CLI Syntax:
config>router# mld
interface ip-int-name
no shutdown
static
group grp-ipv6-address
starg

Use the following CLI syntax to configure static group addresses and add a static (*,G) entry:

Example:
config>router>mld# interface lax-sjc
config>router>mld>if# static
config>router>mld>if>static# group ff06:db8:1
config>router>mld>if>static>group# starg

The following example displays the configuration:

A:LAX>config>router>mld# info
----------------------------------------------
        interface "lax-sjc"
            static
                group ff06:db8:1
                    starg
                exit
            exit
        exit
        interface "lax-vls"
            static
                group ff05:db8:1
                    source 2001:db8:2016:10ff::4
                exit
            exit
        exit
        interface "p1-ix"
        exit
----------------------------------------------
A:LAX>config>router>mld#

4.2.3.4. Configuring SSM Translation

To configure MLD parameters:

CLI Syntax:
config>router# mld
ssm-translate
grp-range start end
source ipv6-address

The following example displays the command usage to configure MLD parameters.

Note:

The group range will not be created until the source is specified.

Example:
config>router# mld
config>router>mld# ssm-translate
config>router>mld>ssm# grp-range ff0e::db8:9 ff0e::db8:c
config>router>mld>ssm>grp-range# source 2001:db8::1

The following example displays the SSM translation configuration:

A:LAX>config>router>mld# info
----------------------------------------------
        ssm-translate
            grp-range ff0::db8:9 ff0e:db8:c
                source 2001:db8::1
            exit
        exit
        interface "lax-sjc"
            static
                group ff0:db8:1
                    starg
                exit
            exit
        exit
        interface "lax-vls"
            static
                group ff0:db8:1
                    source 2001:db8:2016:10ff::4
                exit
            exit
        exit
        interface "p1-ix"
        exit
----------------------------------------------
A:LAX>config>router>mld# exit

4.2.4. Disabling MLD

Use the following CLI syntax to disable MLD.

CLI Syntax:
config>router#
mld
shutdown

The following example displays the command usage to disable MLD.

Example:
config>router# mld
config>router>mld# shutdown