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Each PIM router in the VLAN, whether interested in the multicast data or not, can receive all
multicast data and all PIM messages except PIM hello messages.
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When the Layer 2 switch runs both IGMP snooping and PIM snooping, it performs the following
actions:
a.
Examines whether a PIM router is interested in the multicast data addressed to a multicast
group according to the received PIM messages that the router sends.
b.
Adds only the ports that connect to the router and are interested in the data to a PIM
snooping routing entry.
c.
Forwards PIM messages and multicast data to only the routers that are interested in the
data, which saves network bandwidth.
For more information about IGMP snooping and the router port, see "
PIM snooping can run in PIM-SM and PIM-SSM networks. Do not configure PIM snooping in
PIM-DM or BIDIR-PIM networks.
Configuring PIM snooping
To configure PIM snooping for a VLAN, enable IGMP snooping globally on the Layer 2 device and
enable IGMP snooping and PIM snooping for the VLAN.
After you enable PIM snooping for a VLAN, PIM snooping works only on the member interfaces of
the VLAN.
To configure PIM snooping:
Step Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enable IGMP snooping
globally and enter
IGMP-snooping view.
igmp-snooping
By default, IGMP snooping is
disabled.
3.
Return to system view.
quit
N/A
4.
Enter VLAN view.
vlan vlan-id
N/A
5.
Enable IGMP snooping for
the VLAN.
igmp-snooping enable
By default, IGMP snooping is
disabled in a VLAN.
6.
Enable PIM snooping for the
VLAN.
pim-snooping enable
By default, PIM snooping is disabled
in a VLAN.
7.
(Optional.) Set the aging
time for the PIM snooping
global neighbor ports on the
new master device in IRF
master election.
pim-snooping
graceful-restart
neighbor-aging-time
interval
The default setting is 105 seconds.
A global neighbor port is a Layer 2
aggregate interface that acts as a
neighbor port.
8.
(Optional.) Set the aging
time for the PIM snooping
global downstream ports
and global router ports on
the new master device in
IRF master election.
pim-snooping
graceful-restart
join-aging-time
interval
The default setting is 210 seconds.
A global downstream port or a global
router port is a Layer 2 aggregate
interface that acts as a downstream
port or router port.
Displaying and maintaining PIM snooping
Execute
display
commands in any view and
reset
commands in user view.