Igmp Snooping Troubleshooting - Digitalchina Networks DCS-3950 series Manual

Command: show mac-address-table multicast
Function: Show the multicast MAC address table messages
Parameter: None
Command mode: Admin Mode
Default: Not showing the multicast MAC address and port mapping by system default
Usage Guide: This command shows multicast MAC address table messages of current
switch
Example: Show the multicast mapping in vlan 100
Vlan Mac Address
------ --------------------------- -------- ------------ ------------------------
1 01-00-5e-01-01-01

11.4.2 IGMP Snooping Troubleshooting

When configuring and using IGMP Snooping function, users might find that the IGMP
Snooping work abnormally, probablely because of the reasons like incorrect physical
connection and configuration. So, the user should ensure the following:
Guarantee that the physical connection is corretct;
Ensure that the IGMP Snooping is enabled in global configuration mode （using ip
igmp snooping） ；;
Ensure that vlan has configured with IGMP Snooping in global configuration
mode（using ip igmp snooping vlan <vlan-id>） ；
Ensure that a vlan is configured as a layer 2 general queirer or a static mrouter is
configured in the same segment.
Check the validityof IGMP Snooping information usingcommand'show ip igmp
snooping vlan <vid>'.
If all the above ways cannot solve the problems of IGMP Snooping, please use debug
commands like' debug igmp snooping' , then copy the DEBUG information in
3miniutes and send the information to the technical service center of our company.
DCS-3950 series Ethernet switch manual
Type Creator
MULTI IGMP
Ports
Ethernet0/0/20
206