Disabling Spt Switchover - HP 4800G Series Configuration Manual

In view of information integrity of register messages in the transmission process, you can configure the
device to calculate the checksum based on the entire register messages. However, to reduce the
workload of encapsulating data in register messages and for the sake of interoperability, this method of
checksum calculation is not recommended.
When receivers stop receiving multicast data addressed to a certain multicast group through the RP
(that is, the RP stops serving the receivers of that multicast group), or when the RP formally starts
receiving multicast data from the multicast source, the RP sends a register-stop message to the
source-side DR. Upon receiving this message, the DR stops sending register messages encapsulated
with multicast data and starts a register-stop timer. When the register-stop timer expires, the DR sends
a null register message (a register message without encapsulated multicast data) to the RP. If the DR
receives a register-stop message during the register probe time, it will reset its register-stop timer;
otherwise, the DR starts sending register messages with encapsulated data again when the
register-stop timer expires.
The register-stop timer is set to a random value chosen uniformly from the interval (0.5 times
register_suppression_time, 1.5 times register_suppression_time) minus register_probe_time.
Configure a filtering rule for register messages on all C-RP routers and configure them to calculate the
checksum based on the entire register messages. Configure the register suppression time and the
register probe time on all routers that may become source-side DRs.
Follow these steps to configure register-related parameters:
To do...
Enter system view
Enter PIM view
Configure a filtering rule for
register messages
Configure the device to
calculate the checksum based
on the entire register messages
Configure the register
suppression time
Configure the register probe
time

Disabling SPT Switchover

If a 3Com Switch 4800G acts as an RP or the receiver-side DR, it initiates an SPT switchover process
(by default) upon receiving the first multicast packet along the RPT. You can disable the switchover from
RPT to SPT.
Perform the following operations to disable the SPT switchover:
To do...
Enter system view
Enter PIM view
Use the command...
system-view
pim
register-policy acl-number
register-whole-checksum
register-suppression-timeou
t interval
probe-interval interval
Use the command...
system-view
pim
1-27
Remarks
—
—
Optional
No register filtering rule by
default
Optional
By default, the checksum is
calculated based on the header
of register messages
Optional
60 seconds by default
Optional
5 seconds by default
Remarks
—
—