3Com 10014299 manual Configuring Igmp

506CHAPTER 34: CONFIGURING IGMP

	IGMP is asymmetric between hosts and routers. The host responds to the IGMP
	query message of the multicast router, and makes a response in the membership
	report message. The router periodically sends a general query message. Then it
	determines, based on the response message received, whether a specific group
	has a host access on its own subnet. Meanwhile, when a router exits from a
	group, it sends a message to the multicast router when it exits. When it receives
	the message, the multicast router sends a packet to inquire about the group to
	ensure that the member has already gone.
Configuring IGMP	To configure the IGMP protocol, the multicast routing function is first enabled, and
	then each feature of the IGMP protocol can be configured.
	IGMP configuration includes tasks that are covered in the following sections:
	■ Enabling Multicast Routing
	■ Configuring Router Interfaces as Group Members
	■ Configuring the Version Number of IGMP at the Router Interface
	■ Configuring the Time Interval of IGMP Host Sending Query Messages
	■ Configuring IGMP Maximum Query Response Time
	■ Configuring Subnet Querier Survival Time
Enabling Multicast	Start the IGMP protocol on all interfaces to enable routers to send multicast
Routing	messages. Only after enabling multicast routing can all the other configurations
	related to the multicast be valid.
	Make the following configuration in system view.
	Table 576 Enable/disable Multicast Routing
	Operation	Command
	Enable multicast routing	multicast routing-enable
	Disable multicast routing	undo multicast routing-enable
	By default, the system disables multicast routing.
Configuring Router	Configuring router interfaces as group members can not only enable routers to
Interfaces as Group	access the multicast group by simulating host behaviors, but also enables the static
Members	multicast group to access the multicast group.
	Make the following configuration in the interface view.
	Table 577 Configure Router Interfaces to be Group Members
	Operation	Command
	Configure router interface to be group	igmp host-join groups-address
	members
	Delete router interface from group	undo igmp host-join groups-address
	members

By default, the router interface has no group member.