3Com Switch 7700 Configuration Manual page 210

202 C 6: M
HAPTER ULTICAST
P
ROTOCOL
Configure the Times of Sending IGMP Group-Specific Query Packet
Table 11
Operation
Restore the times of sending IGMP
Group-Specific Query packet to the default
value
By default, the robust-value is 2.
This command is only available on an IGMP query router running IGMP v2. For a
host running IGMP v1, this command cannot take effect, because the host may
not send the IGMP Leave message when it leaves a group.
Configuring the Limit of IGMP Groups on an Interface
You limit the number of multicast groups, from 0 to 1024, on an interface using
the following configuration.
Perform the following configuration in VLAN interface view.
Configure the Limit of IGMP Groups on an Interface
Table 12
Operation
Configure the limit of IGMP groups on an
interface
Restore the limit of IGMP groups on an
interface to the default value
Configuring a Router to be a Member of a Group
Usually, the host operating IGMP will respond to IGMP query packet of the
multicast router. In case of a response failure, the multicast router will consider
that there is no multicast member on this network segment and will cancel the
corresponding path. Configuring one interface of the router as a multicast
member can avoid such a problem. When the interface receives an IGMP query
packet, the router will respond, ensuring that the network segment is connected
and can receive multicast packets.
Perform the following configuration in VLAN interface view.
Table 13 Configure a Router to Be a Member of a Group
Operation
Configure a router to be a member of a group igmp host-join group-address
Cancel the configuration that a router is a
member of a group
By default, a router does not join a multicast group.
Limiting Access to IP Multicast Groups
A multicast router learns whether there are members of a multicast group on the
network when it receives an IGMP membership message. A filter can be set on an
interface to limit the range of allowed multicast groups.
Command
undo igmp robust-count
Command
igmp group-limit limit
undo igmp group-limit
Command
undo igmp host-join group-address