3Com S7906E - Switch, Configuration Manual

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When Host A leaves the IPv6 multicast group, it sends an MLD done message to Switch A. Receiving
the message, Switch A removes port GigabitEthernet 2/0/3 from the member port list of the forwarding
entry for the group; however, it does not remove the group or forward the done message to Router A
because Host B is still in the group. Use the display mld-snooping group command to display
information about MLD snooping multicast groups. For example:
# Display information about MLD snooping multicast groups on Switch A.
[SwitchA] display mld-snooping group
Total 1 IP Group(s).
Total 1 IP Source(s).
Total 1 MAC Group(s).
Port flags: D-Dynamic port, S-Static port, C-Copy port
Subvlan flags: R-Real VLAN, C-Copy VLAN
Vlan(id):100.
Total 1 IP Group(s).
Total 1 IP Source(s).
Total 1 MAC Group(s).
Router port(s):total 1 port.
GE2/0/1 (D)
IP group(s):the following ip group(s) match to one mac group.
IP group address:FF1E::101
(::, FF1E::101):
Host port(s):total 1 port.
GE2/0/4 (D)
MAC group(s):
MAC group address:3333-0000-0101
Host port(s):total 1 port.
GE2/0/4
Troubleshooting MLD Snooping
Switch Fails in Layer 2 Multicast Forwarding
Symptom
A switch fails to implement Layer 2 multicast forwarding.
Analysis
MLD snooping is not enabled.
Solution
1) Enter the display current-configuration command to view the running status of MLD snooping.
2) If MLD snooping is not enabled, use the mld-snooping command to enable MLD snooping
globally, and then use mld-snooping enable command to enable MLD snooping in VLAN view.
3) If MLD snooping is disabled only for the corresponding VLAN, just use the mld-snooping enable
command in VLAN view to enable MLD snooping in the corresponding VLAN.