H3C Technologies H3C S10500 Series Switches - Manual (Page 69)

54
Total 1 entry
Total 1 entry matched
00001. (1.1.1.1, 224.1.1.1)
MID: 0, Flags: 0x0:0
Uptime: 00:08:32, Timeout in: 00:03:26
Incoming interface: Vlan-interface101
List of 1 outgoing interfaces:
1: Vlan-interface104
Matched 19648 packets(20512512 bytes), Wrong If 0 packets
Forwarded 19648 packets(20512512 bytes)
The output shows that Switch A maintains a multicast forwarding entry for multicast packets from Source
1 to 224.1.1.1. No forwarding entry exists for packets from Source 2 to 224.1.1.1, which indicates that
multicast packets from Source 2 are blocked.
Troubleshooting IGMP snooping
Layer 2 multicast forwarding cannot function
Symptom
Layer 2 multicast forwarding cannot function.
Analysis
IGMP snooping is not enabled.
Solution
1. Use the display current-configuration command to display the running status of IGMP snooping.
2. If IGMP snooping is not enabled, use the igmp-snooping command to enable IGMP snooping
globally, and then use the igmp-snooping enable command to enable IGMP snooping in VLAN
view.
3. If IGMP snooping is disabled only for the corresponding VLAN, use the igmp-snooping enable
command in VLAN view to enable IGMP snooping in the corresponding VLAN.
Configured multicast group policy fails to take effect
Symptom
Although a multicast group policy has been configured to allow hosts to join specific multicast groups, the
hosts can still receive multicast data addressed to other multicast groups.
Analysis
• The ACL rule is incorrectly configured.
• The multicast group policy is not correctly applied.
• The function of dropping unknown multicast data is not enabled, so unknown multicast data is
flooded.