H3C Technologies H3C S12500 Series Switches - Manual (Page 330)

314
Configured IPv6 multicast group policy fails to take effect
Symptom
Although an IPv6 multicast group policy has been configured to allow hosts to join specific IPv6 multicast
groups, the hosts can still receive IPv6 multicast data addressed to other groups.
Analysis
• The IPv6 ACL rule is incorrectly configured.
• The IPv6 multicast group policy is not correctly applied.
• The function of dropping unknown IPv6 multicast data is not enabled, so unknown IPv6 multicast
data is flooded.
Solution
1. Use the display acl ipv6 command to check the configured IPv6 ACL rule. Make sure that the IPv6
ACL rule conforms to the IPv6 multicast group policy to be implemented.
2. Use the display this command in MLD-snooping view or the corresponding interface view to check
whether the correct IPv6 multicast group policy has been applied. If not, use the group-policy or
mld-snooping group-policy command to apply the correct IPv6 multicast group policy.
3. Use the display current-configuration command to check whether the function of dropping
unknown IPv6 multicast data is enabled. If not, use the drop-unknown or mld-snooping
drop-unknown command to enable the function of dropping unknown IPv6 multicast data.
Appendix
Processing of IPv6 multicast protocol messages
With Layer 3 multicast routing enabled, an MLD snooping-enabled switch processes IPv6 multicast
protocol messages differently under different conditions, as follows:
• If only MLD is enabled on the switch, or if both MLD and IPv6 PIM are enabled on the switch, the
switch does the following:
{
Maintains dynamic member ports or dynamic router ports according to MLD packets
{
Maintains dynamic router ports according to IPv6 PIM hello packets
• If only IPv6 PIM is enabled on the switch, the following occurs:
{
The switch broadcasts MLD messages as unknown messages in the VLAN.
{
After receiving an IPv6 PIM hello message, the switch maintains the corresponding dynamic
router port.
• If MLD is disabled on the switch, one of the following occurs:
{
If IPv6 PIM is disabled, the switch deletes all its dynamic member ports and dynamic router
ports.
{
If IPv6 PIM is enabled, the switch deletes only its dynamic member ports but not its dynamic
router ports.