Configuring Multicast Listener Discovery (MLD)
In IPv4, Layer 2 switches use IGMP snooping to limit the flooding of multicast traffic by dynamically configuring Layer 2 interfaces so that multicast traffic forwards only to those interfaces associated with IP multicast address. In IPv6, MLD snooping performs a similar function. With MLD snooping, Netvisor ONE selectively forwards IPv6 multicast data to a list of ports configured to receive the data, instead of flooding to all ports in a VLAN. MLD constructs the list by snooping IPv6 multicast control packets.
IPv6 multicast routers use MLD to discover the presence of multicast listeners (nodes configured to receive IPv6 multicast packets) on directly attached links and to discover which multicast packets interest the neighboring nodes. MLD derives from the IGMP protocol. MLD version 1 (MLDv1) is equivalent to IGMPv2, and MLD version 2 (MLDv2) is equivalent to IGMPv3. MLD is a subprotocol of Internet Control Message Protocol version 6 (ICMPv6), and MLD messages are a subset of ICMPv6 messages, identified in IPv6 packets by a preceding Next Header value of 58.
The switch snoops on both MLDv1 and MLDv2 protocol packets and bridge IPv6 multicast data based on destination IPv6 multicast MAC addresses. The switch can be configured to perform MLD snooping and IGMP snooping simultaneously.
To display MLD routers on the network, use the mld-router-show command:
CLI network-admin@switch > mld-router-show
group-ip:                
node-ip:                 
vlan:                    
port:                    
source:                  
node-type:               
expires:                 
The show ouput displays the following information:
Multicast group IP address in IPv6 format
Host node IP address in IPv6 format
Host VLAN ID
Port number
Multicast traffic source IP address in IPv6 format
Node type as host or router
Expires as the ageout time
To display MLD group membership on the network, use the mld-show command:
CLI network-admin@switch > mld-show
group-ip:                
node-ip:                 
vlan:                    
port:                    
source:                  
node-type:               
expires:                 
 
The show ouput displays the following information:
Multicast group IP address in IPv6 format
Host node IP address in IPv6 format
Host VLAN ID
Port number
Multicast traffic source IP address in IPv6 format
Node type as host or router
Expires as the ageout time
To enable or disable MLD snooping or modify the scope, use the mld-snooping-modify command:
CLI network-admin@switch > mld-snooping-modify
To modify the scope from fabric to local, use the following syntax:
CLI network-admin@switch > mld-snooping-modify scope fabric
To display information about MLD snooping, use the mld-snooping-show command.
Configuring an IGMP Querier IP Address
You can configure an IGMP querier IP address for a VLAN or as a global IGMP querier. The IGMP querier sends IGMP General Query messages. on the network.
If you do not specify a querier IP address, then Netvisor ONE uses 0.0.0.0 as the default value. There can be an unique querier IP for each VLAN, or you can configure the same Querier IP address for all the VLANs participating in IGMP snooping. The Querier IP address should have a local scope and every switch should have a unique Querier IP address.
With a valid source IP address on IGMP Query packets, Netvisor ONE adds the VLAN receiving the Query to an IGMP Snoop switch list, and now reflects in the igmp-switches-show output and the IGMP queries sent to the peer Switch as well. This solicits a report from the hosts listening on the peer switch.
Use these Netvisor ONE commands to configure an IGMP querier IP address.
 
igmp-querier-ip-modify
Modify IGMP Querier IP configuration
querier-ip ip-address
Specify the Snooping Querier IP address
vlans-on-querier-ip vlan-list
Specify the VLAN map.
 
 
igmp-querier-ip-show
Display IGMP Querier IP config
querier-ip is
Specify the Snooping Querier IP address
vlans-on-querier-ip vlan-list
VLAN MAP