H3C Technologies H3C S10500 Series Switches - Manual (Page 318)

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Upstream port: GE1/0/1
Total number of downstream ports: 1
1: GE1/0/3
Expires: 00:03:01, FSM: J
(*, FF2E::101)
Upstream neighbor: FE80::1
Upstream port: GE1/0/2
Total number of downstream ports: 1
1: GE1/0/4
Expires: 00:01:05, FSM: J
The output shows that Switch A will forward the multicast data intended for IPv6 multicast group
FF1E::101 to only Router C, and forward the multicast data intended for IPv6 multicast group FF2E::101
to only Router D.
Troubleshooting IPv6 PIM snooping
IPv6 PIM snooping does not work
Symptom
IPv6 PIM snooping does not work.
Analysis
MLD snooping or IPv6 PIM snooping is not enabled on the switch.
Solution
1. Use the display current-configuration command to check the status of MLD snooping and IPv6 PIM
snooping.
2. If MLD snooping is not enabled, enter system view and use the mld-snooping command to enable
MLD snooping globally. Then, enter VLAN view and use the mld-snooping enable and
pim-snooping ipv6 enable commands to enable MLD snooping and IPv6 PIM snooping in the
VLAN.
3. If IPv6 PIM snooping is not enabled, enter VLAN view and use the pim-snooping ipv6 enable
command to enable IPv6 PIM snooping in the VLAN.
Some downstream IPv6 PIM-capable routers cannot receive
multicast data
Symptom
In a network with fragmented join/prune messages, some downstream IPv6 PIM-capable routers cannot
receive multicast data.
Analysis
IPv6 PIM snooping cannot reassemble messages, and it cannot maintain the status of downstream
routers that the join/prune message fragments carry. To ensure the normal operation of the system, IPv6
PIM snooping must broadcast join/prune message fragments in the VLAN. However, if the VLAN has a
IPv6 PIM-capable router that has the join suppression function enabled, the broadcast join/prune
message fragments might suppress the join messages of other IPv6 PIM-capable routers in the VLAN. As