Configuring MLD Options on Interfaces

Multicast Listener Discovery (MLD) has options that are configured on interfaces.

The following MLD parameters can be configured at the interface level:

  • Version: The default MLD version when IPv6 PIM Sparse Mode (PIM-SM) is enabled is MLDv1. You must configure MLDv2 on an interface to enable MLDv2.
  • Port version: The MLD version can be set on a virtual Ethernet (VE) interface.
  • MLD tracking: When MLD tracking is enabled, a Layer 3 device tracks all clients that send membership reports. When a leave message is received from the last client, the device immediately stops forwarding to the physical port (without waiting 3 seconds to confirm that no other clients still want the traffic).
  • MLD group addresses: The maximum number of MLD group addresses available, either for the default VRF or for a specified non-default VRF instance.

The following steps show how to configure these options for various interfaces.

  1. Enter global configuration mode. 
    device# configure terminal
  2. Enable IPv6 PIM-SM globally. 
    device(config)# ipv6 router pim
  3. Return to global configuration mode to configure MLD on an interface. 
    device(config-ipv6-pim-router)# exit
  4. Configure virtual Ethernet interface 10. 
    device(config)# interface ve 10
  5. Enable MLDv2 on the virtual interface using one of the two following methods:
    • Set the MLD version on an interface. 
      device(config-vif-10)# ipv6 mld version 2
    • Set the MLD port version on an interface. 
      device(config-vif-10)# ipv6 mld port-version 2
    In both these examples, MLDv2 is enabled. MLDv1 is enabled by default when IPv6 PIM-SM is configured.
  6. Configure the maximum number of MLD group addresses for the virtual interface. 
    device(config-vif-10)# ipv6 mld max-group-address 1000

The following example configures IPv6 PIM-SM, enables MLDv2 for virtual Ethernet interface 10, and enables MLD tracking on the interface. It also configures a maximum of 1000 MLD group addresses for the VE interface.

device# configure terminal
device(config)# ipv6 router pim
device(config-ipv6-pim-router)# exit
device(config)# interface ve 10
device(config-vif-10)# ipv6 mld version 2
device(config-vif-10)# ipv6 mld tracking
device(config-vif-10)# ipv6 mld max-group-address 1000
Parent topic: Multicast Listener Discovery and Source-specific Multicast Protocols