PLANET XGS3-24040 - Manual (Page 392)

Chapter 43 Ipv4 Multicast Protocol
43-46
The configuration procedure for SwitchA and SwitchB is as follows:
(1) Configure SwitchA:
Switch(config)#ip pim multicast-routing
Switch (config)#interface vlan 1
Switch(Config-if-Vlan1)#ip address 12.1.1.1 255.255.255.0
Switch(Config-if-Vlan1)#ip pim dense-mode
(2) Configure SwitchB:
Switch(config)#ip pim multicast-routing
Switch(config)#interface vlan1
Switch(Config-if-Vlan1)#ip address 12.1.1.2 255.255.255.0
Switch(Config-if-Vlan1)#ip pim dense-mode
Switch(Config-if-Vlan1)#exit
Switch(config)#interface vlan2
Switch(Config-if-Vlan1)#ip address 20.1.1.1 255.255.255.0
Switch(Config-if-Vlan2)#ip pim dense-mode
Switch(Config-if-Vlan2)#ip igmp version 3
43.9.4 IGMP Troubleshooting
In configuring and using IGMP Protocol, IGMP Protocol might not operate normally caused by physical
connection or incorrect configuration. Therefore, user should pay attention to the following issues:
 Firstly to assure that physical connection is correct;
 Next, to assure the Protocol of Interface and Link protocol is UP (use show interface command);
 Afterwards, to assure to start a kind of multicast protocol on the interface;
 Multicast Protocol requires RPF Check using unicast routing; therefore the correctness of unicast
routing must be assured beforehand.
43.10 IGMP Snooping
43.10.1 Introduction to IGMP Snooping
IGMP (Internet Group Management Protocol) is a protocol used in IP multicast. IGMP is used by multicast
enabled network device (such as a router) for host membership query, and by hosts that are joining a
multicast group to inform the router to accept packets of a certain multicast address. All those operations are
done through IGMP message exchange. The router will use a multicast address (224.0.0.1) that can address
to all hosts to send an IGMP host membership query message. If a host wants to join a multicast group, it will
reply to the multicast address of that a multicast group with an IGMP host membership reports a message.