F3726, F3211, F3174, R5135, R3816-HP Firewalls and UTM Devices Network Management Configuration Guide-6PW100

904
[RouterC] 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: Ethernet1/1
Upstream neighbor: NULL
RPF prime neighbor: NULL
Downstream interface(s) information:
Total number of downstreams: 1
1: Ethernet1/2
Protocol: pim-ssm, UpTime: 00:08:02, Expires: 00:03:25
335B
Troubleshooting IPv6 PIM
This section describes common IPv6 PIM problems and how to troubleshoot them.
1010BA multicast distribution tree cannot be built correctly
1819BSymptom
None of the routers in the network (including routers directly connected with IPv6 multicast sources or
receivers) have multicast forwarding entries. In other words, an IPv6 multicast distribution tree cannot be
correctly built and the receivers cannot receive IPv6 multicast data.
1820BAnalysis
• 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.
1821BSolution
1. Use the display ipv6 routing-table command to verify that a unicast route to the IPv6 multicast
source or the RP is available.
2. Use the display pim ipv6 interface command to verify the IPv6 PIM information on each interface,
especially on the RPF interface. If IPv6 PIM is not enabled on the interface, use the pim ipv6 dm or
pim ipv6 sm command to enable IPv6 PIM.
3. Use the display pim ipv6 neighbor command to verify that the RPF neighbor is an IPv6 PIM
neighbor.
4. Verify that IPv6 PIM and MLD are enabled on the interfaces directly connecting to the IPv6
multicast source and to the receiver.
5. Use the display pim ipv6 interface verbose command to verify that the same PIM mode is enabled
on the RPF interface and the corresponding interface of the RPF neighbor router.