3Com Switch 7700 Configuration Manual page 221

After PIM-DM is enabled on an interface, it will send PIM Hello messages
periodically, and process protocol packets sent by PIM neighbors.
Perform the following configuration in VLAN interface view.
Table 25 Enable PIM-DM
Operation
Enable PIM-DM on an interface
Disable PIM-DM on an interface
3Com recommends that you configure PIM-DM on all interfaces. This
configuration is effective only after the multicast routing is enabled in system view.
Once you enable PIM-DM on an interface, PIM-SM cannot be enabled on the
same interface and vice versa.
Entering PIM View
Global parameters of PIM should be configured in PIM view.
Perform the following configuration in system view.
Table 26 Entering PIM View
Operation
Enter PIM view
Return to system view
Use the undo pim command to clear the configuration in PIM view, and to return
to system view.
Configuring the Interface Hello Message Interval
After PIM is enabled on an interface, it will send Hello messages periodically. The
interval at which Hello messages are sent can be modified according to the
bandwidth and type of the network connected to the interface.
Perform the following configuration in VLAN interface view.
Table 27 Configure Hello Message Interval on an Interface
Operation
Configure the hello message interval on an
interface
Restore the interval to the default value
The default interval is 30 seconds. You can configure the value according to
different network environments. Generally, this parameter does not need to be
modified.
This configuration can be performed only after PIM (PIM-DM or PIM-SM) is
enabled in VLAN interface view.
Configuring PIM-DM
Command
pim dm
undo pim dm
Command
pim
undo pim
Command
pim timer hello seconds
undo pim timer hello
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