3Com 6000 manual Administering IP, Multicast, Interfaces

Administering IP Multicast Interfaces A-3

Top-Level Menu
system
ethernet	interface
fddi	route	dvrmp
atm	arp	➧igmp
bridge	atmArpServer	interface
➧ip	➧multicast	tunnel
ipx	udpHelper	routeDisplay
appletalk	routing	cacheDisplay
snmp	icmpRouterDiscovery
analyzer	rip
script	ping
logout	statistics

When you select the IGMP option, the interface prompts you to enable or disable IGMP snooping mode and IGMP query mode. Both are enabled by default. Under most conditions, IGMP snooping mode and IGMP query mode should remain enabled.

To enable or disable IGMP, from the top level of the Administration Console, enter:

ip multicast igmp

The interface prompts you to enable or disable IGMP query mode and IGMP snooping mode.

Example:

Enter igmp snooping mode

(enabled/disabled)[enabled]:enabled

Enter igmp query mode (enabled/disabled) [enabled]: enabled

Administering IP	The IP multicast interface selections allow you to enable and disable
Multicast	multicast characteristics on previously defined IP interfaces. A multicast
Interfaces	interface has three characteristics, explained next.
	DVMRP Metric Value
	The DVMRP metric value determines the cost of a multicast interface. The
	higher the cost, the less likely it is that the packets will be routed over the
	interface. The default value is 1.
	Time To Live (TTL) Threshold
	The TTL threshold determines whether the interface will forward multicast
	packets to other switches and routers in the subnetwork. If the interface TTL
	is greater than the packet TTL, then the interface does not forward the
	packet. The default value is 1, which means that the interface will forward
	all packets.