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Cisco ME 3800X and 3600X Switch Software Configuration Guide
OL-23400-01
Chapter 33 Configuring IP Multicast Routing
Configuring Advanced PIM Features
To return to the default setting, use the no ip pim spt-threshold {kbps | infinity} global configuration
command.
Modifying the PIM Router-Query Message Interval
PIM routers and multilayer switches send PIM router-query messages to find which device will be the
DR for each LAN segment (subnet). The DR is responsible for sending IGMP host-query messages to
all hosts on the directly connected LAN.
With PIM DM operation, the DR has meaning only if IGMPv1 is in use. IGMPv1 does not have an IGMP
querier election process, so the elected DR functions as the IGMP querier. With PIM SM operation, the
DR is the device that is directly connected to the multicast source. It sends PIM register messages to
notify the RP that multicast traffic from a source needs to be forwarded down the shared tree. In this
case, the DR is the device with the highest IP address.
Beginning in privileged EXEC mode, follow these steps to modify the router-query message interval.
This procedure is optional.
Step 3
ip pim spt-threshold {kbps | infinity}
[group-list access-list-number]
Specify the threshold that must be reached before moving to
shortest-path tree (spt).
•
For kbps, specify the traffic rate in kilobits per second. The
default is 0 kbps.
Note
Because of switch hardware limitations, 0 kbps is the only
valid entry even though the range is 0 to 4294967.
•
Specify infinity if you want all sources for the specified group
to use the shared tree, never switching to the source tree.
•
(Optional) For group-list access-list-number, specify the access
list created in Step 2. If the value is 0 or if the group-list is not
used, the threshold applies to all groups.
Step 4
end
Return to privileged EXEC mode.
Step 5
show running-config
Verify your entries.
Step 6
copy running-config startup-config
(Optional) Save your entries in the configuration file.
Command
Purpose
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
interface interface-id
Specify the interface to be configured, and enter interface configuration
mode.
Step 3
ip pim query-interval seconds
Configure the frequency at which the switch sends PIM router-query
messages.
The default is 30 seconds. The range is 1 to 65535.
Step 4
end
Return to privileged EXEC mode.
Step 5
show ip igmp interface [interface-id]
Verify your entries.
Step 6
copy running-config startup-config
(Optional) Save your entries in the configuration file.
