Igmpv1 And Igmpv2 - Cisco Nexus 7000 Series Configuration Manual

IGMPv1 and IGMPv2

Figure 17: IGMP Snooping Switch
The IGMP snooping software operates upon IGMPv1, IGMPv2, and IGMPv3 control plane packets where
Layer 3 control plane packets are intercepted and influence the Layer 2 forwarding behavior.
For more information about IGMP, see Configuring IGMP.
The Cisco NX-OS IGMP snooping software has the following proprietary features:
• Source filtering that allows forwarding of multicast packets based on destination and source IP.
• Multicast forwarding based on IP addresses rather than MAC addresses.
• Beginning with Cisco Release 5.2(1) for the Nexus 7000 Series devices, multicast forwarding alternately
• Optimized multicast flooding (OMF) that forwards unknown traffic to routers only and performs no
For more information about IGMP snooping, see
IGMPv1 and IGMPv2
Both IGMPv1 and IGMPv2 support membership report suppression, which means that if two hosts on the
same subnet want to receive multicast data for the same group, then the host that receives a member report
from the other host suppresses sending its report. Membership report suppression occurs for hosts that share
a port.
If no more than one host is attached to each VLAN switch port, you can configure the fast leave feature in
IGMPv2. The fast leave feature does not send last member query messages to hosts. As soon as the software
receives an IGMP leave message, the software stops forwarding multicast data to that port.
IGMPv1 does not provide an explicit IGMP leave message, so the software must rely on the membership
message timeout to indicate that no hosts remain that want to receive multicast data for a particular group.
Note
The software ignores the configuration of the last member query interval when you enable the fast leave
feature because it does not check for remaining hosts.
Cisco Nexus 7000 Series NX-OS Multicast Routing Configuration Guide
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based on the MAC address
data-driven state creation.
RFC 4541.
Configuring IGMP Snooping