H3C Technologies H3C SecPath F1000-E - Manual (Page 222)

59
Downstream interface(s) information:
Total number of downstreams: 1
1: GigabitEthernet1/1
Protocol: mld, UpTime: 00:00:11, Expires: 00:03:25
The information on Device B and Device C is similar to that on Device A.
# View the IPv6 PIM multicast routing table information on Device D.
[DeviceD] display pim ipv6 routing-table
Total 0 (*, G) entry; 1 (S, G) entry
(4001::100, FF3E::101)
Protocol: pim-ssm, Flag: LOC
UpTime: 00:08:02
Upstream interface: GigabitEthernet1/1
Upstream neighbor: NULL
RPF prime neighbor: NULL
Downstream interface(s) information:
Total number of downstreams: 1
1: GigabitEthernet2/0
Protocol: pim-ssm, UpTime: 00:08:02, Expires: 00:03:25
Troubleshooting IPv6 PIM
Failure of Building a Multicast Distribution Tree Correctly
Symptom
None of the routers in the network (including routers directly connected with IPv6 multicast sources and
receivers) has IPv6 multicast forwarding entries. That is, a multicast distribution tree cannot be built
correctly and clients cannot receive IPv6 multicast data.
Analysis
• An IPv6 PIM routing entry is created based on an IPv6 unicast route, whichever IPv6 PIM mode is
running. Multicast works only when unicast does.
• IPv6 PIM must be enabled on the RPF interface. An RPF neighbor must be an IPv6 PIM neighbor as
well. If IPv6 PIM is not enabled on the RPF interface or the RPF neighbor, the establishment of a
multicast distribution tree will surely fail, resulting in abnormal multicast forwarding.
• IPv6 PIM requires that the same IPv6 PIM mode, namely DM or SM, must run on the entire network.
Otherwise, the establishment of a multicast distribution tree will surely fail, resulting in abnormal
multicast forwarding.
Solution
Step1 Check IPv6 unicast routes. Use the display ipv6 routing-table command to check whether a unicast
route exists to the IPv6 multicast source or the RP.
Step2 Check that the RPF interface is IPv6 PIM enabled. Use the display pim ipv6 interface command to
view the IPv6 PIM information on each interface. If IPv6 PIM is not enabled on the interface, use the pim
ipv6 dm or pim ipv6 sm command to enable IPv6 PIM.