Igmp Snooping Proxying - HP FlexFabric 5950 series Configuration Manual

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If no match is found, the Layer 2 device discards the IGMP leave message.
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If a match is found but the receiving port is not an outgoing interface in the forwarding entry, the
Layer 2 device discards the IGMP leave message.
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If a match is found and the receiving port is not the only outgoing interface in the forwarding
entry, the Layer 2 device performs the following actions:
Discards the IGMP leave message.

Sends an IGMP group-specific query to identify whether the group has active receivers
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attached to the receiving port.
Sets the aging timer for the receiving port to twice the IGMP last member query interval.
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If a match is found and the receiving port is the only outgoing interface in the forwarding entry,
the Layer 2 device performs the following actions:
Forwards the IGMP leave message to all router ports in the VLAN or VSI.

Sends an IGMP group-specific query to identify whether the group has active receivers

attached to the receiving port.
Sets the aging timer for the receiving port to twice the IGMP last member query interval.

After receiving the IGMP leave message on a port, the IGMP querier resolves the multicast group
address in the message. Then, it sends an IGMP group-specific query to the multicast group through
the receiving port.
After receiving the IGMP group-specific query, the Layer 2 device forwards the query through all
router ports and member ports of the group in the VLAN or VSI. Then, it waits for the responding
IGMP report from the directly connected hosts. For the dynamic member port that received the leave
message, the Layer 2 device also performs one of the following actions:
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If the port receives an IGMP report before the aging timer expires, the Layer 2 device resets the
aging timer.
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If the port does not receive an IGMP report when the aging timer expires, the Layer 2 device
removes the port from the forwarding entry for the multicast group.

IGMP snooping proxying

As shown in
upstream device, you can enable IGMP snooping proxying on the edge device. With IGMP snooping
proxying enabled, the edge device acts as a host for the upstream IGMP snooping querier to send
IGMP report and leave messages to Router A. The host IGMP report suppression mechanism on the
edge device does not take effect. For more information about the IGMP report suppression
mechanism, see "Configuring IGMP."
Figure 13 IGMP snooping proxying
IP network
Receiver
Figure 13, to reduce the number of IGMP report and leave messages received by the
IGMP Querier
Proxy
Switch A
Host A
Host B
Router A
Query from Router A
Report from Switch A
Query from Switch A
Report from Host
Host C
Receiver
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