Configuring Rpt-To-Spt Switchover - 3Com MSR 50 Series Configuration Manual

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Configuring RPT-to-SPT
Switchover
messages so that the RP can serve specific IPv6 multicast groups. If an (S, G) entry
is denied by the filtering rule, or the action for this entry is not defined in the
filtering rule, the RP will send a register-stop message to the DR to stop the
registration process for the IPv6 multicast data.
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 data addressed to a certain IPv6 multicast group
through the RP (that is, the RP stops serving the receivers of a specific IPv6
multicast group), or when the RP formally starts receiving IPv6 multicast data from
the IPv6 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 IPv6 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 refresh its register-stop
timer; otherwise, the DR will start sending register messages with encapsulated
data again.
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.
Follow these steps to configure IPv6 PIM-SM register messages:
To do...
Enter system view
Enter IPv6 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
Typically, you need to configure the above-mentioned parameters on the
source-side DR or the RP only. Since both the DR and RP are elected, however, you
should carry out these configurations on the routers that may win the DR election
and on the C-RPs that may win RP elections.
Because the RPT is not necessarily the tree that has the shortest path, the IPv6
multicast forwarding path needs to be switched from the RPT to the SPT when the
Use the command...
system-view
pim ipv6
register-policy acl6-number
register-whole-checksum
register-suppression-timeo
ut interval
probe-interval interval
Configuring IPv6 PIM-SM
Remarks
-
-
Optional
No register filtering rule by
default
Optional
Based on the header of
register messages by default
Optional
60 seconds by default
Optional
5 seconds by default
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