The mld-snooping robust-count command configures the robustness variable. The robustness variable decides the number of group-specific Query messages to be sent by the querier.
The undo mld-snooping robust-count command restores the default robustness variable.
By default, the robustness variable is 2.
Usage Scenario
The·mld-snooping·robust-count·command·has·the·following·functions:-·Defines·the·number·of·times·a·querier·sends·group-specific·query·messages,·preventing·packet·loss·on·a·network.·When·a·device·receives·an·MLD·Leave·message·for·a·multicast·group,·it·sends·group-specific·query·messages·for·the·number·of·times·defined·by·robust-count·to·check·whether·there·are·any·other·members·in·this·group.·The·interval·at·which·group-specific·query·messages·are·sent·is·set·using·the·mld-snooping·lastmember-queryinterval·command.-·Changes·the·aging·time·of·member·ports.·After·receiving·a·Report·message·from·a·downstream·device,·a·device·sets·the·aging·time·of·the·corresponding·member·port·based·on·the·following·formula:·Aging·time·of·a·member·port·=·Number·of·times·group-specific·query·messages·are·sent·x·Interval·at·which·general·query·messages·are·sent·+·Maximum·time·for·a·downstream·host·to·respond·to·a·querier.·The·default·aging·time·is·130·seconds.·The·interval·at·which·general·query·messages·are·sent·is·set·using·the·mld-snooping·query-interval·command.·The·maximum·time·for·a·downstream·host·to·respond·to·a·querier·is·set·using·the·mld-snooping·max-response-time·command.·After·receiving·an·MLD·Leave·message·from·a·host,·a·device·sets·the·aging·time·of·the·corresponding·member·port·based·on·the·following·formula:·Aging·time·of·a·member·port·=·Interval·at·which·group-specific·query·messages·are·sent·x·Number·of·times·group-specific·query·messages·are·sent.·By·default,·the·aging·time·is·re-set·to·2·seconds.·The·mld-snooping·robust-count·command·is·used·to·set·the·number·of·times·group-specific·query·messages·are·sent·in·the·preceding·formula.·The·interval·at·which·group-specific·query·messages·are·sent·is·set·using·the·mld-snooping·lastmember-queryinterval·command.·If·the·querier·receives·a·Report·message·for·the·multicast·group·from·another·host·within·the·robust-value·x·lastmember-queryinterval·period,·it·continues·to·maintain·the·memberships·for·the·group.·Otherwise,·the·querier·considers·that·there·is·no·member·of·the·group·on·the·network·segment,·and·does·not·maintain·the·memberships·for·the·group.
Prerequisites
MLD snooping has been enabled using the mld-snooping enable command.
Configuration Impact
If the mld-snooping robust-count command is run more than once in the same view, the latest configuration overwrites the previous one.
Precautions
To use the mld-snooping robust-count configuration as a factor of adjusting the member interface aging time, set the same number of group-specific Query messages to be sent as that specified on its upstream device. Otherwise, multicast data transmission will be interrupted between the Layer 2 and Layer 3 devices.
The mld-snooping robust-count command fails to be run in a VLAN view in any of the following conditions:<HUAWEI> system-view [~HUAWEI] mld-snooping enable [*HUAWEI] mpls [*HUAWEI-mpls] quit [*HUAWEI] mpls l2vpn [*HUAWEI-l2vpn] quit [*HUAWEI] vsi vsi1 [*HUAWEI-vsi-vsi1] pwsignal ldp [*HUAWEI-vsi-vsi1-ldp] vsi-id 200 [*HUAWEI-vsi-vsi1-ldp] quit [*HUAWEI-vsi-vsi1] mld-snooping robust-count 5