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422
C
HAPTER
39: IGMP S
NOOPING
C
ONFIGURATION
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IGMP leave message: Transmitted from the multicast group member to the
multicast router to notify that a host left the multicast group. When received a
leave message of an IP multicast group, the Ethernet switch transmits the
specific query message concerning that group to the port received the
message, in order to check if the host still has some other member of this
group and meanwhile starts a maximum response timer. If the switch has not
receive any report message from the multicast group after the timer expires,
the port will be removed from the corresponding MAC multicast group. If the
MAC multicast group does not have any member, the switch will notify the
multicast router to remove the branch from the multicast tree.
multicast router to notify that a host left the multicast group. When received a
leave message of an IP multicast group, the Ethernet switch transmits the
specific query message concerning that group to the port received the
message, in order to check if the host still has some other member of this
group and meanwhile starts a maximum response timer. If the switch has not
receive any report message from the multicast group after the timer expires,
the port will be removed from the corresponding MAC multicast group. If the
MAC multicast group does not have any member, the switch will notify the
multicast router to remove the branch from the multicast tree.
IGMP Snooping
Configuration
Configuration
The main IGMP Snooping configuration includes:
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Among the above configuration tasks, enabling IGMP Snooping is required, while
others are optional for your requirements.
others are optional for your requirements.
Enabling/Disabling IGMP
Snooping
You can use the following commands to enable/disable IGMP Snooping to control
whether MAC multicast forwarding table is created and maintained on Layer 2.
whether MAC multicast forwarding table is created and maintained on Layer 2.
Perform the following configuration in system view and VLAN view.
By default, IGMP Snooping is disabled.
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CAUTION:
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First enable IGMP Snooping globally in system view, and then enable IGMP
Snooping in VLAN view. Otherwise, IGMP Snooping will not take effect.
Snooping in VLAN view. Otherwise, IGMP Snooping will not take effect.
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Although layer 2 and layer 3 multicast protocols can be configured in pair, they
cannot run on the same VLAN or its corresponding VLAN interface at the same
time. For example, if PIM or IGMP is enabled on a VLAN, then IGMP Snooping
cannot operate on this VLAN.
cannot run on the same VLAN or its corresponding VLAN interface at the same
time. For example, if PIM or IGMP is enabled on a VLAN, then IGMP Snooping
cannot operate on this VLAN.
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If the VLAN VPN is enabled on a port, the IGMP Snooping feature cannot be
enabled on the VLAN for the port or the IGMP feature cannot be enabled on
the corresponding VLAN interface.
enabled on the VLAN for the port or the IGMP feature cannot be enabled on
the corresponding VLAN interface.
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If IGMP Snooping feature is enabled on a VLAN, or IGMP is enabled on the
VLAN interface, you cannot add the member port on which VLAN VPN is
enabled into the VLAN.
VLAN interface, you cannot add the member port on which VLAN VPN is
enabled into the VLAN.
Table 411 Enable/Disable IGMP Snooping
Operation
Command
Enable/disable IGMP Snooping
igmp-snooping { enable | disable }