H3C S3610-28P Operation Manual page 819

Operation Manual – Multicast Protocol
H3C S3610&S5510 Series Ethernet Switches
6.8.3 RPs Unable to Join SPT in PIM-SM
I. Symptom
An RPT cannot be established correctly, or the RPs cannot join the SPT to the multicast
source.
II. Analysis
As the core of a PIM-SM domain, the RPs serve specific multicast groups. Multiple
RPs can coexist in a network. Make sure that the RP information on all routers is
exactly the same, and a specific group is mapped to the same RP. Otherwise,
multicast forwarding will fail.
If the static RP mechanism is used, the same static RP command must be
executed on all the routers in the entire network. Otherwise, multicast forwarding
will fail.
III. Solution
1) Check that a route is available to the RP. Carry out the display ip routing-table
command to check whether a route is available on each router to the RP.
2) Check the dynamic RP information. Use the display pim rp-info command to
check whether the RP information is consistent on all routers.
3) Check the configuration of static RPs. Use the display pim rp-info command to
check whether the same static RP address has been configured on all the routers
in the entire network.
6.8.4 No Unicast Route Between BSR and C-RPs in PIM-SM
I. Symptom
C-RPs cannot unicast advertise messages to the BSR. The BSR does not advertise
bootstrap messages containing C-RP information and has no unicast route to any C-RP.
An RPT cannot be established correctly, or the DR cannot perform source register with
the RP.
II. Analysis
The C-RPs periodically send C-RP-Adv messages to the BSR by unicast. If a
C-RP has no unicast route to the BSR, the BSR cannot receive C-RP-Adv
messages from that C-RP and the bootstrap message of the BSR will not contain
the information of that C-RP.
In addition, if the BSR does not have a unicast router to a C-RP, it will discard the
C-RP-Adv messages from that C-RP, and therefore the bootstrap messages of
the BSR will not contain the information of that C-RP.
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Chapter 6 PIM Configuration