H3C Technologies H3C S12500 Series Switches - Manual (Page 154)

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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, do not use this
method of checksum calculation.
When receivers stop receiving multicast data addressed to a certain multicast group through the RP
(indicating that the RP stops providing services for the receivers of that multicast group), or when the RP
starts receiving multicast data from the multicast source along the SPT, the RP sends a register-stop
message to the source-side DR. After receiving this message, the DR stops sending register messages
encapsulated with multicast data and starts a register-stop timer. Before 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 might become source-side DRs.
To configure register-related parameters:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter public network PIM view
or VPN instance PIM view. pim [ vpn-instance
vpn-instance-name ]
N/A
3. Configure a filtering rule for
register messages.
register-policy acl-number
Optional.
No register filtering rule by default.
4. Configure the device to
calculate the checksum based
on the entire register
messages.
register-whole-checksum
Optional.
By default, the checksum is
calculated based on the header of
register messages.
5. Configure the register
suppression time. register-suppression-timeout
interval Optional.
60 seconds by default.
6. Configure the register probe
time.
probe-interval interval
Optional.
5 seconds by default.
Configuring switchover to SPT
CAUTION:
If the switch is an RP, disabling switchover to SPT might cause multicast traffic forwarding failures on the
source-side DR. When disabling switchover to SPT, be sure you fully understand its impact on your
network.
In a PIM-SM network, a multicast stream first flows to the receivers down an RPT. However, because an
RPT is not necessarily the tree that has the shortest path, the multicast forwarding path needs to be