187
RPs unable to join SPT in PIM-SM
Symptom
An RPT cannot be established correctly, or the RPs cannot join the SPT to the multicast source.
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 that 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.
Solution
1.
Verify that a route is available to the RP. Use the
display ip routing-table
command to determine
whether a route is available on each router to the RP.
2.
Verify the dynamic RP information. Use the
display pim rp-info
command to determine whether the
RP information is consistent on all routers.
3.
Verify the configuration of static RPs. Use the
display pim rp-info
command to determine whether
the same static RP address has been configured on all the routers in the entire network.
RPT establishment failure or source registration failure in PIM-
SM
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 registration with the RP.
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 information about that C-RP.
•
If the BSR does not have a unicast route to a C-RP, it will discard the C-RP-Adv messages from that
C-RP. Therefore, the bootstrap messages of the BSR will not contain information about that C-RP.
•
The RP is the core of a PIM-SM domain. Be sure that the RP information on all routers is exactly the
same, a specific group G is mapped to the same RP, and unicast routes are available to the RP.
Solution
1.
Verify that the routes to C-RPs and the BSR are available. Use the
display ip routing-table
command
to determine whether the routes are available on each router to the RP and the BSR and whether a
route is available between the RP and the BSR. Be sure that each C-RP has a unicast route to the
BSR, the BSR has a unicast route to each C-RP, and all the routers in the entire network have a
unicast route to the RP.
2.
Verify the RP and BSR information. PIM-SM needs the support of the RP and BSR. Use the
display
pim bsr-info
command to determine whether the BSR information is available on each router, and
then use the
display pim rp-info
command to determine whether the RP information is correct.
Содержание A5500 EI Switch Series
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