
show ip igmp interface
View the enable status of this feature using the command from EXEC Privilege mode, as shown in the example in
.
IGMP Snooping
IGMP snooping enables switches to use information in IGMP packets to generate a forwarding table that associates ports with
multicast groups so that when they receive multicast frames, they can forward them only to interested receivers.
Multicast packets are addressed with multicast MAC addresses, which represent a group of devices, rather than one unique device.
Switches forward multicast frames out of all ports in a virtual local area network (VLAN) by default, even though there may be only
some interested hosts, which is a waste of bandwidth.
If you enable IGMP snooping on a VLT unit, IGMP snooping dynamically learned groups and multicast router ports are made to learn
on the peer by explicitly tunneling the received IGMP control packets.
IGMP Snooping Implementation Information
•
IGMP snooping on Dell Networking OS uses IP multicast addresses not MAC addresses.
•
IGMP snooping is supported on all stack members.
•
IGMP snooping reacts to spanning tree protocol (STP) and multiple spanning tree protocol (MSTP) topology changes by sending
a general query on the interface that transitions to the forwarding state.
•
If IGMP snooping is enabled on a PIM-enabled VLAN interface, data packets using the router as an Layer 2 hop may be dropped.
To avoid this scenario, Dell Networking recommends that users enable IGMP snooping on server-facing end-point VLANs only.
Configuring IGMP Snooping
Configuring IGMP snooping is a one-step process. To enable, view, or disable IGMP snooping, use the following commands.
There is no specific configuration needed for IGMP snooping with virtual link trunking (VLT). For information about VLT
configurations, refer to
.
•
Enable IGMP snooping on a switch.
CONFIGURATION mode
ip igmp snooping enable
•
View the configuration.
CONFIGURATION mode
show running-config
•
Disable snooping on a VLAN.
INTERFACE VLAN mode
no ip igmp snooping
Related Configuration Tasks
•
Removing a Group-Port Association
•
•
Specifying a Port as Connected to a Multicast Router
•
Configuring the Switch as Querier
Example of
ip igmp snooping enable
Command
Dell(conf)#ip igmp snooping enable
Dell(conf)#do show running-config igmp
ip igmp snooping enable
Dell(conf)#
356
Internet Group Management Protocol (IGMP)
Summary of Contents for S4048-ON
Page 1: ...Dell Configuration Guide for the S4048 ON System 9 9 0 0 ...
Page 146: ...Figure 14 BFD Three Way Handshake State Changes 146 Bidirectional Forwarding Detection BFD ...
Page 522: ...Figure 87 Configuring Interfaces for MSDP 522 Multicast Source Discovery Protocol MSDP ...
Page 523: ...Figure 88 Configuring OSPF and BGP for MSDP Multicast Source Discovery Protocol MSDP 523 ...
Page 528: ...Figure 91 MSDP Default Peer Scenario 1 528 Multicast Source Discovery Protocol MSDP ...
Page 529: ...Figure 92 MSDP Default Peer Scenario 2 Multicast Source Discovery Protocol MSDP 529 ...
Page 530: ...Figure 93 MSDP Default Peer Scenario 3 530 Multicast Source Discovery Protocol MSDP ...
Page 633: ...Policy based Routing PBR 633 ...
Page 777: ...Figure 119 Single and Double Tag TPID Match Service Provider Bridging 777 ...
Page 778: ...Figure 120 Single and Double Tag First byte TPID Match 778 Service Provider Bridging ...