HP 6125G HP 6125G & 6125G/XG Blade Switches IP Multicast Configuration - Page 33

Enabling IGMP snooping fast-leave processing, Disabling a port from becoming a dynamic router port

Page 33 highlights

Step 3. Configure a port as a simulated member host. Command igmp-snooping host-join group-address [ source-ip source-address ] vlan vlan-id Remarks Not configured by default. Enabling IGMP snooping fast-leave processing IGMP snooping fast-leave processing enables the switch to process IGMP leave messages quickly. With IGMP snooping fast-leave processing enabled, when the switch receives an IGMP leave message on a port, it immediately removes that port from the forwarding entry for the multicast group specified in the message. Then, when the switch receives IGMP group-specific queries for that multicast group, it does not forward them to that port. On a port that has only one host attached, you can enable IGMP snooping fast-leave processing to save bandwidth and resources. However, on a port that has multiple hosts attached, you should not enable IGMP snooping fast-leave processing if you have enabled dropping unknown multicast data globally or for the port. Otherwise, if a host on the port leaves a multicast group, the other hosts attached to the port in the same multicast group cannot receive the multicast data for the group. Enabling IGMP snooping fast-leave processing globally Step 1. Enter system view. 2. Enter IGMP-snooping view. 3. Enable IGMP snooping fast-leave processing. Command system-view igmp-snooping fast-leave [ vlan vlan-list ] Enabling IGMP snooping fast-leave processing on a port Remarks N/A N/A Disabled by default Step 1. Enter system view. 2. Enter Layer 2 Ethernet interface view or Layer 2 aggregate interface view. 3. Enable IGMP snooping fast-leave processing. Command system-view interface interface-type interface-number igmp-snooping fast-leave [ vlan vlan-list ] Remarks N/A Use either command. Disabled by default. Disabling a port from becoming a dynamic router port The following problems might exist in a multicast access network: • After receiving an IGMP general query or a PIM hello message from a connected host, a router port becomes a dynamic router port. Before its timer expires, this dynamic router port receives all multicast packets within the VLAN where the port belongs, and forwards them to the host, affecting normal multicast reception of the host. 22

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22
Step
Command
Remarks
3.
Configure a port as a
simulated member host.
igmp-snooping host-join
group-address
[
source-ip
source-address
]
vlan
vlan-id
Not configured by default.
Enabling IGMP snooping fast-leave processing
IGMP snooping fast-leave processing enables the switch to process IGMP leave messages quickly. With
IGMP snooping fast-leave processing enabled, when the switch receives an IGMP leave message on a
port, it immediately removes that port from the forwarding entry for the multicast group specified in the
message. Then, when the switch receives IGMP group-specific queries for that multicast group, it does not
forward them to that port.
On a port that has only one host attached, you can enable IGMP snooping fast-leave processing to save
bandwidth and resources. However, on a port that has multiple hosts attached, you should not enable
IGMP snooping fast-leave processing if you have enabled dropping unknown multicast data globally or
for the port. Otherwise, if a host on the port leaves a multicast group, the other hosts attached to the port
in the same multicast group cannot receive the multicast data for the group.
Enabling IGMP snooping fast-leave processing globally
Step
Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter IGMP-snooping view.
igmp-snooping
N/A
3.
Enable IGMP snooping
fast-leave processing.
fast-leave
[
vlan
vlan-list
]
Disabled by default
Enabling IGMP snooping fast-leave processing on a port
Step
Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter Layer 2 Ethernet
interface view or Layer 2
aggregate interface view.
interface
interface-type
interface-number
Use either command.
3.
Enable IGMP snooping
fast-leave processing.
igmp-snooping
fast-leave
[
vlan
vlan-list
]
Disabled by default.
Disabling a port from becoming a dynamic router port
The following problems might exist in a multicast access network:
After receiving an IGMP general query or a PIM hello message from a connected host, a router port
becomes a dynamic router port. Before its timer expires, this dynamic router port receives all
multicast packets within the VLAN where the port belongs, and forwards them to the host, affecting
normal multicast reception of the host.