Users Guide

EXEC Privilege mode.
show ip igmp snooping mrouter
Conguring the Switch as Querier
To congure the switch as a querier, use the following command.
Hosts that do not support unsolicited reporting wait for a general query before sending a membership report. When the multicast
source and receivers are in the same VLAN, multicast trac is not routed and so there is no querier. Congure the switch to be the
querier for a VLAN so that hosts send membership reports and the switch can generate a forwarding table by snooping.
• Congure the switch to be the querier for a VLAN by rst assigning an IP address to the VLAN interface.
INTERFACE VLAN mode
ip igmp snooping querier
IGMP snooping querier does not start if there is a statically congured multicast router interface in the VLAN.
The switch may lose the querier election if it does not have the lowest IP address of all potential queriers on the subnet.
When enabled, IGMP snooping querier starts after one query interval in case no IGMP general query (with IP SA lower than its
VLAN IP address) is received on any of its VLAN members.
Adjusting the Last Member Query Interval
To adjust the last member query interval, use the following command.
When the querier receives a Leave message from a receiver, it sends a group-specic query out of the ports specied in the
forwarding table. If no response is received, it sends another. The amount of time that the querier waits to receive a response to the
initial query before sending a second one is the last member query interval (LMQI). The switch waits one LMQI after the second
query before removing the group-port entry from the forwarding table.
• Adjust the last member query interval.
INTERFACE VLAN mode
ip igmp snooping last-member-query-interval
Fast Convergence after MSTP Topology Changes
The following describes the fast convergence feature.
When a port transitions to the Forwarding state as a result of an STP or MSTP topology change, Dell Networking OS sends a
general query out of all ports except the multicast router ports. The host sends a response to the general query and the forwarding
database is updated without having to wait for the query interval to expire.
When an IGMP snooping switch is not acting as a querier, it sends out the general query in response to the MSTP triggered link-layer
topology change, with the source IP address of 0.0.0.0 to avoid triggering querier election.
Egress Interface Selection (EIS) for HTTP and IGMP Applications
You can use the Egress Interface Selection (EIS) feature to isolate the management and front-end port domains for HTTP and IGMP
trac. Also, EIS enables you to congure the responses to switch-destined trac by using the management port IP address as the
source IP address. This information is sent out of the switch through the management port instead of the front-end port.
The management EIS feature is applicable only for the out-of-band (OOB) management port. References in this section to the
management default route or static route denote the routes congured using the management route command. The
management default route can be either congured statically or returned dynamically by the DHCP client. A static route points to the
management interface or a forwarding router.
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Internet Group Management Protocol (IGMP)