Service Manual

Internet Group Management Protocol (IGMP)
The IGMP commands are supported by the Dell Networking Operating System (OS).
IGMP Snooping Commands
The Dell Networking OS supports IGMP Snooping version 2 and 3 on all Dell Networking systems.
Important Points to Remember for IGMP Snooping
• The Dell Networking OS supports version 1, version 2, and version 3 hosts.
• The Dell Networking OS IGMP snooping implementation is based on IP multicast address (not based on Layer 2 multicast mac address)
and the IGMP snooping entries are in Layer 3 flow table not in Layer 2 forwarding information base (FIB).
• The Dell Networking OS IGMP snooping implementation is based on draft-ietf-magma-snoop-10.
• IGMP snooping is not enabled by default on the switch.
• A maximum of 1800 groups and 600 virtual local area network (VLAN) are supported.
• IGMP snooping is not supported on a default VLAN interface.
• IGMP snooping is not supported over VLAN-Stack-enabled VLAN interfaces (you must disable IGMP snooping on a VLAN interface
before configuring VLAN-Stack-related commands).
• IGMP snooping does not react to Layer 2 topology changes triggered by spanning tree protocol (STP).
• IGMP snooping reacts to Layer 2 topology changes multiple spanning tree protocol (MSTP) triggers by sending a general query on the
interface that comes in the FWD state.
Important Points to Remember for IGMP Querier
• The IGMP snooping Querier supports version 2.
• You must configure an IP address to the VLAN interface for IGMP snooping Querier to begin. The IGMP snooping Querier disables
itself when a VLAN IP address is cleared, and then it restarts itself when an IP address is reassigned to the VLAN interface.
• When enabled, IGMP snooping Querier does not start if there is a statically configured multicast router interface in the VLAN.
• When enabled, IGMP snooping Querier starts after one query interval in case no IGMP general query (with IP SA lower than its VLAN
IP address) is received on any of its VLAN members.
• When enabled, IGMP snooping Querier periodically sends general queries with an IP source address of the VLAN interface. If it receives
a general query on any of its VLAN member, it checks the IP source address of the incoming frame.
• If the IP SA in the incoming IGMP general query frame is lower than the IP address of the VLAN interface, the switch disables its IGMP
snooping Querier functionality.
• If the IP SA of the incoming IGMP general query is higher than the VLAN IP address, the switch continues to work as an IGMP
snooping Querier.
ip igmp access-group
To specify access control for packets, use this feature.
Syntax
ip igmp access-group access-list
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494 Internet Group Management Protocol (IGMP)