Describes the IGMPv3 snooping capabilities and mechanisms in APIC that enable constrained multicast flooding and host tracking.
The APIC IGMP snooping function is a network optimization mechanism that
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supports full IGMPv3 snooping with constrained flooding based on (S, G) information in IGMPv3 reports
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enables source-based filtering to constrain multicast traffic to specific ports based on the traffic source, and
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tracks hosts on each VLAN port in the bridge domain by default.
Key features and mechanisms
The IGMP snooping function provides several advanced capabilities:
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Explicit tracking feature: Provides a fast leave mechanism for improved performance
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Report suppression: Limits traffic sent to other multicast-capable routers since every IGMPv3 host sends membership reports
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Proxy reporting: When report suppression is enabled and no IGMPv1 or IGMPv2 hosts request the same group, builds group state from downstream host membership reports and generates reports in response to upstream querier queries
When the last host leaves a group, the software sends a membership query with a configurable last member query interval parameter. If no host responds before the timeout, the IGMP snooping function removes the group state.