This section describes the commands you use to configure IGMP snooping. The switching card software supports IGMP Versions 1, 2, and 3. The IGMP snooping feature can help conserve bandwidth because it allows the switch to forward IP multicast traffic only to connected hosts that request multicast traffic. IGMPv3 adds source filtering capabilities to IGMP versions 1 and 2.
set igmp
This command enables IGMP Snooping on the system (Global Config Mode) or an interface (Interface Config Mode). This command also enables IGMP snooping on a particular VLAN (VLAN Config Mode) and can enable IGMP snooping on all interfaces participating in a VLAN.
If an interface has IGMP Snooping enabled and you enable this interface for routing or enlist it as a member of a port-channel (LAG), IGMP Snooping functionality is disabled on that interface. IGMP Snooping functionality is re-enabled if you disable routing or remove portchannel (LAG) membership from an interface that has IGMP Snooping enabled.
Default: disabled
Format: set igmp
Modes: Global Config/Interface Config
Format: set igmp <vlanid>
Mode: VLAN Config
The IGMP application supports the following activities:
Validation of the IP header checksum (as well as the IGMP header checksum) and discarding of the frame upon checksum error.
Maintenance of the forwarding table entries based on the MAC address versus the IP address.
Flooding of unregistered multicast data packets to all ports in the VLAN.
no set igmp
This command disables IGMP Snooping on the system, an interface or a VLAN.
Format: no set igmp
Modes: Global Config/Interface Config
Format: no set igmp <vlanid>
Mode: VLAN Config
set igmp interfacemode
This command enables IGMP Snooping on all interfaces. If an interface has IGMP Snooping enabled and you enable this interface for routing or enlist it as a member of a port-channel (LAG), IGMP Snooping functionality is disabled on that interface. IGMP Snooping functionality is re-enabled if you disable routing or remove port-channel (LAG) membership from an interface that has IGMP Snooping enabled.
Default: disabled
Format: set igmp interfacemode
Mode: Global Config
no set igmp interfacemode
This command disables IGMP Snooping on all interfaces.
Format: no set igmp interfacemode
Mode: Global Config
set igmp fast-leave
This command enables or disables IGMP Snooping fast-leave admin mode on a selected interface or VLAN. Enabling fast-leave allows the switch to immediately remove the layer 2 LAN interface from its forwarding table entry upon receiving an IGMP leave message for that multicast group without first sending out MAC-based general queries to the interface. You should enable fast-leave admin mode only on VLANs where only one host is connected to each layer 2 LAN port. This prevents the inadvertent dropping of the other hosts that were connected to the same layer 2 LAN port but were still interested in receiving multicast traffic directed to that group. Also, fast-leave processing is supported only with IGMP version 2 hosts.
Default: disabled
Format: set igmp fast-leave
Mode: Interface Config
Format: set igmp fast-leave <vlan_id>
Mode: VLAN Config
no set igmp fast-leave
This command disables IGMP Snooping fast-leave admin mode on a selected interface.
Format: no set igmp fast-leave
Modes: Interface Config
Format: no set igmp fast-leave <vlan_id>
Mode: VLAN Config
set igmp groupmembership-interval
This command sets the IGMP Group Membership Interval time on a VLAN, one interface or all interfaces. The Group Membership Interval time is the amount of time in seconds that a switch waits for a report from a particular group on a particular interface before deleting the interface from the entry. This value must be greater than the IGMPv3 Maximum Response time value. The range is 2 to 3600 seconds.
Default: 260 seconds
Format: set igmp groupmembership-interval <2-3600>
Modes: Global Config/Interface Config
Format: set igmp groupmembership-interval <vlan_id> <2-3600>
Modes: VLAN Config
no set igmp groupmembership-interval
This command sets the IGMPv3 Group Membership Interval time to the default value.
Format: no set igmp groupmembership-interval
Modes: Global Config/Interface Config
Format: no set igmp groupmembership-interval <vlan_id>
Mode: VLAN Config
set igmp maxresponse
This command sets the IGMP Maximum Response time for the system, or on a particular interface or VLAN. The Maximum Response time is the amount of time in seconds that a switch will wait after sending a query on an interface because it did not receive a report for a particular group in that interface. This value must be less than the IGMP Query Interval time value. The range is 1 to 3599 seconds.
Note: The option is valid only for IGMP v1. For v2 and v3 it is set from the query received.
Default: 10 seconds
Format: set igmp maxresponse <1-3599>
Modes: Global Config/ InterfaceConfig
Format: set igmp maxresponse <vlan_id> <1-3599>
Mode: VLAN Config
no set igmp maxresponse
This command sets the max response time (on the interface or VLAN) to the default value.
Format: no set igmp maxresponse
Modes: Global Config/ InterfaceConfig
Format: no set igmp maxresponse <vlan_id>
Mode: VLAN Config
set igmp mcrtrexpiretime
This command sets the Multicast Router Present Expiration time. The time is set for the system, on a particular interface or VLAN. This is the amount of time in seconds that a switch waits for a query to be received on an interface before the interface is removed from the list of interfaces with multicast routers attached. The range is 0 to 3600 seconds. A value of 0 indicates an infinite time-out, i.e. no expiration.
Default: 0
Format: set igmp mcrtrexpiretime <0-3600>
Modes: Global Config/InterfaceConfig
Format: set igmp mcrtrexpiretime <vlan_id> <0-3600>
Mode: VLAN Config
no set igmp mcrtrexpiretime
This command sets the Multicast Router Present Expiration time to 0. The time is set for the system, on a particular interface or a VLAN.
Format: no set igmp mcrtrexpiretime
Modes: Global Config/ Interface Config
Format: no set igmp mcrtrexpiretime <vlan_id>
Mode: VLAN Config
set igmp mrouter interface
This command configures the interface as a multicast router interface. When configured as a multicast router interface, the interface is treated as a multicast router interface in all VLANs.
Default: disabled
Format: set igmp mrouter interface
Mode: Interface Config
no set igmp mrouter interface
This command disables the status of the interface as a statically configured multicast router interface.
Format: no set igmp mrouter interface
Mode: Interface Config
show igmpsnooping
This command displays IGMP Snooping information. Configured information is displayed whether or not IGMP Snooping is enabled.
Format: show igmpsnooping [<unit/slot/port> | <vlan_id>]
Mode: Privileged EXEC
When the optional arguments <unit/slot/port> or <vlan_id> are not used, the command displays the following information:
Admin Mode: Indicates whether or not IGMP Snooping is active on the switch.
Multicast Control Frame Count: The number of multicast control frames that are processed by the CPU.
Interface Enabled for IGMP Snooping: The list of interfaces on which IGMP Snooping is enabled.
VLANS Enabled for IGMP Snooping: The list of VLANS on which IGMP Snooping is enabled.
When you specify the <unit/slot/port> values, the following information appears:
IGMP Snooping Admin Mode: Indicates whether IGMP Snooping is active on the interface.
Fast Leave Mode: Indicates whether IGMP Snooping Fast-leave is active on the interface.
Group Membership Interval: The amount of time in seconds that a switch will wait for a report from a particular group on a particular interface before deleting the interface from the entry.This value may be configured.
Maximum Response Time: The amount of time the switch waits after it sends a query on an interface because it did not receive a report for a particular group on that interface. This value may be configured.
Multicast Router Expiry Time: The amount of time to wait before removing an interface from the list of interfaces with multicast routers attached. The interface is removed if a query is not received. This value may be configured.
When you specify a value for <vlan_id>, the following information appears:
VLAN ID: The VLAN ID.
IGMP Snooping Admin Mode: Indicates whether IGMP Snooping is active on the VLAN.
Fast Leave Mode: Indicates whether IGMP Snooping Fast-leave is active on the VLAN.
Group Membership Interval: The amount of time in seconds that a switch will wait for a report from a particular group on a particular interface, which is participating in the VLAN, before deleting the interface from the entry.This value may be configured.
Maximum Response Time: The amount of time the switch waits after it sends a query on an interface, participating in the VLAN, because it did not receive a report for a particular group on that interface. This value may be configured.
Multicast Router Expiry Time: The amount of time to wait before removing an interface that is participating in the VLAN from the list of interfaces with multicast routers attached. The interface is removed if a query is not received. This value may be configured.
show igmpsnooping mrouter interface
This command displays information about statically configured ports.
Format: show igmpsnooping mrouter interface <unit/slot/port>
Mode: Privileged EXEC
The display parameters for above command are:
Interface: The port on which multicast router information is being displayed.
Multicast Router Attached: Indicates whether multicast router is statically enabled on the interface.
VLAN ID: The list of VLANs of which the interface is a member.
show igmpsnooping mrouter vlan
This command displays information about statically configured ports.
Format: show igmpsnooping mrouter vlan <unit/slot/port>
Mode: Privileged EXEC
The display parameters for above command are:
Interface: The port on which multicast router information is being displayed.
VLAN ID: The list of VLANs of which the interface is a member.
show mac-address-table igmpsnooping
This command displays the IGMP Snooping entries in the MFDB table.
Format: show mac-address-table igmpsnooping
Mode: Privileged EXEC
The display parameters for above command are:
MAC Address: A multicast MAC address for which the switch has forwarding or filtering information. The format is two-digit hexadecimal numbers that are separated by colons, for example 01:23:45:67:89:AB. In an IVL system the MAC address is displayed as a MAC address and VLAN ID combination of 8 bytes.
Type: The type of the entry, which is either static (added by the user) or dynamic (added to the table as a result of a learning process or protocol).
Description: The text description of this multicast table entry.
Interfaces: The list of interfaces that are designated for forwarding (Fwd:) and filtering (Flt:).
