Multicast is a technique that allows networking devices to send data to a group of interested receivers in a single transmission. Multicast allows you to more efficiently use network resources, specifically for bandwidth-consuming services. Dell SmartFabric OS10 supports the multicast feature in IPv4 and IPv6 networks and uses the following protocols for multicast distribution:
- Internet Group Management Protocol (IGMP)
- Protocol Independent Multicast (PIM)
To enable multicast routing in Full switch mode, see Dell SmartFabric OS10 user guide. Find the relevant version of the User Guide in the OME-M and OS10 compatibility and documentation table. Beginning with OME-M 1.30.00 and later, configuring Layer 2 Multicast in a SmartFabric is supported.
IGMP snooping
IGMP is a communications protocol that establishes multicast group memberships to neighboring switches and routers using IPv4 networks. OS10 supports IGMPv1, IGMPv2, and IGMPv3 to manage the multicast group memberships on IPv4 networks.
IGMP snooping uses the information in IGMP packets to generate a forwarding table that associates ports with multicast groups. When switches receive multicast frames, they forward them to their intended receivers. OS10 supports IGMP snooping on VLAN interfaces.
To enable IGMP snooping in Full switch mode, see Dell SmartFabric OS10 user guide. Find the relevant version of the User Guide in the OME-M and OS10 compatibility and documentation table.
MLD snooping
IPv6 uses MLD protocol to manage multicast groups. OS10 supports MLDv1and MLDv2 to manage the multicast group memberships on IPv6 networks.
MLD snooping enables switches to use the information in MLD packets and generate a forwarding table that associates ports with multicast groups. When switches receive multicast frames, they forward them to their intended receivers. OS10 supports MLD snooping on VLAN interfaces.
To enable MLD snooping in Full switch mode, see Dell SmartFabric OS10 user guide. Find the relevant version of the User Guide in the OME-M and OS10 compatibility and documentation table.
Configuring L2 Multicast in SmartFabric mode
To enable L2 Multicast, IGMP snooping and MLD snooping in SmartFabric mode, follow the steps mentioned below:
- Access OME-M Console.
- Go to Devices > Fabric and click on the desired Fabric.
- Select the Multicast VLANs tab. Note: This tab shows current IGMP version, MLD version and Flood restrict configuration. Flood restrict enables the switch to forward unknown multicast packets to a multicast router. For it to be effective on the VLAN, IGMP and MLD snooping must be enabled on the VLAN.
- Select L2 Multicast.
- Under IGMP, select VLAN(s) from Available VLANs and shift it to Selected VLANs as per the configuration.
- Select the Add selected VLANs to MLD configuration option for the same VLANs to be configured for MLD snooping.
- Click Next.
- Select the VLANs for MLD snooping then click Finish.
Validation
Run the following commands on MX IOMs in the Fabric to validate the IGMP and MLD snooping.
The show ip igmp snooping summary command shows maximum number of instances and total number interfaces with igmp snooping enabled.
MX9116N-A1# show ip igmp snooping summary
Maximum number of IGMP and MLD Instances: 512
Total Number of interface with IGMP Snooping enabled is: 1
The show ip igmp snooping interface command shows VLANs, IGMP version and all other IGMP snooping details.
MX9116N-A1# show ip igmp snooping interface
Vlan10 is up, line protocol is up
IGMP version is 3
IGMP snooping is enabled on interface
IGMP snooping query interval is 60 seconds
IGMP snooping querier timeout is 130 seconds
IGMP snooping last member query response interval is 1000 ms
IGMP Snooping max response time is 10 seconds
IGMP snooping fast-leave is disabled on this interface
IGMP snooping querier is disabled on this interface
Multicast snooping flood-restrict is enabled on this interface