3Com Switch 8800 Advanced Software V5 Configuration Guide

Troubleshooting IPv6 PIM Configuration 705
# View the IPv6 PIM multicast routing table information on Switch D.
[SwitchD] display pim ipv6 routing-table
Vpn-instance: public net
Total 1 (*, G) entry; 1 (S, G) entry
(*, FF0E::101:101)
RP: 2004::2 (local)
Protocol: pim-sm, Flag: WC
UpTime: 00:16:56
Upstream interface: Register
Upstream neighbor: NULL
RPF prime neighbor: NULL
Downstream interface(s) information:
Total number of downstreams: 2
1: Vlan-interface103
Protocol: pim-sm, UpTime: 00:16:56, Expires: 00:02:34
2: Vlan-interface104
Protocol: pim-sm, UpTime: 00:07:56, Expires: 00:02:35
(2001::5, FF0E::101:101)
RP: 2004::2 (local)
Protocol: pim-sm, Flag: SWT ACT
UpTime: 00:02:54
Upstream interface: Vlan-interface102
Upstream neighbor: FE80::9D62:0:FDC4:2
RPF prime neighbor: FE80::9D62:0:FDC4:2
Downstream interface(s) information:
Total number of downstreams: 2
1: Vlan-interface103
Protocol: pim-sm, UpTime: 00:02:54, Expires: -
2: Vlan-interface104
Protocol: pim-sm, UpTime: 00:02:54, Expires: 00:02:36
Troubleshooting IPv6
PIM Configuration
Failure of Building a
Multicast Distribution
Tree Correctly
Symptom
None of the devices in the network 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.
■ The RPF interface must support IPv6 PIM. 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.