475
Protocol: mld, UpTime: 00:00:11, Expires: 00:03:25
# Display information about the IPv6 PIM multicast routing table on Switch D.
[SwitchD] display pim ipv6 routing-table
VPN-Instance: public net
Total 0 (*, G) entry; 1 (S, G) entry
(4001::100, FF3E::101)
Protocol: pim-ssm, Flag: LOC
UpTime: 00:08:02
Upstream interface: Vlan-interface300
Upstream neighbor: NULL
RPF prime neighbor: NULL
Downstream interface(s) information:
Total number of downstreams: 1
1: Vlan-interface105
Protocol: pim-ssm, UpTime: 00:08:02, Expires: 00:03:25
Troubleshooting IPv6 PIM
This section describes details about troubleshooting IPv6 PIM.
A multicast distribution tree cannot be built correctly
Symptom
None of the routers in the network (including routers directly connected with IPv6 multicast sources
and receivers) have 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 (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
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.