3Com 5500G-EI Command Reference Guide - Page 259

IGMP Configuration Commands 259 View VLAN Interface View Parameter robust-value: IGMP robust value, number of sending the IGMP group query message after the IGMP query router receives the IGMP Leave message from the host. It is in the range of 2 to 5. The default is 2. Description Use igmp robust-count command to set the number of sending the IGMP group query message after the IGMP Querier receives the IGMP Leave message from the host. Use the undo igmp robust-count command to restore the default value. In the shared network, that is, a network segment including multiple hosts and multicast routers, the IGMP Querier is responsible for maintaining the IGMP group membership on the interface. When an IGMP v2 host leaves a group, it sends an IGMP Leave message. When the IGMP Leave message is received, the IGMP Querier must send an IGMP group specific query message a specified number of times (set using the igmp robust-count command, with a default value of 2) in a specified time interval. (Set using the igmp lastmember-queryinterval command, with default value of 1 second). If other hosts which are interested in the specified group receive the IGMP group specific query message from the IGMP Querier, they send back an IGMP Membership Report message within the specified maximum response time interval. If the IGMP Querier receives the IGMP Membership Report message within the defined period (equal to robust-value seconds), the IGMP Querier continues to maintain the membership of this group. When no IGMP Membership Report messages are received from any hosts within the defined period, the IGMP Querier considers it a timeout and stops membership maintenance for the group. This command only takes effect on an IGMP Querier running IGMP v2. For a Querier running IGMP v1, this command cannot take effect because the IGMP group members cannot send an IGMP Leave message when they leave a group. Related command: igmp lastmember-queryinterval and display igmp interface Example Set the robust value at the Vlan-interface 10 as 3. system-view System View: return to User View with Ctrl+Z [SW5500]interface Vlan-interface 10 [SW5500-Vlan-interface10]igmp robust-count 3 igmp timer Syntax other-querier-present igmp timer other-querier-present seconds undo igmp timer other-querier-present