User manual

C HAPTER 4 | Configuring the Switch
MLD Snooping
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◆ Snooping Enabled - When enabled, the switch will monitor network
traffic on the indicated VLAN interface to determine which hosts want to
receive multicast traffic. (Default: Disabled)
When MLD snooping is enabled globally, the per VLAN interface settings
for MLD snooping take precedence. When MLD snooping is disabled
globally, snooping can still be configured per VLAN interface, but the
interface settings will not take effect until snooping is re-enabled
globally.
◆ MLD Querier - When enabled, the switch can serve as the MLDv2
Querier if selected in the bidding process with other competing
multicast routers/switches, and if selected will be responsible for asking
hosts if they want to receive multicast traffic. (Default: Disabled)
A router, or multicast-enabled switch, can periodically ask their hosts if
they want to receive multicast traffic. If there is more than one router/
switch on the LAN performing IP multicasting, one of these devices is
elected “querier” and assumes the role of querying the LAN for group
members. It then propagates the service requests on to any upstream
multicast router/switch to ensure that it will continue to receive the
multicast service.
An IPv6 address must be configured on the VLAN interface from which
the querier will act if elected. When serving as the querier, the switch
uses this IPv6 address as the query source address.
The querier will not start or will disable itself after having started if it
detects an IPv6 multicast router on the network.
◆ Compatibility - Compatibility is maintained by hosts and routers
taking appropriate actions depending on the versions of MLD operating
on these devices within a network. (Range: MLD-Auto, Forced MLDv1,
Forced MLDv2; Default: MLD-Auto)
◆ RV - The Robustness Variable allows tuning for the expected packet
loss on a network. A port will be removed from receiving a multicast
service when no MLD reports are detected in response to a number of
MLD queries. The robustness variable sets the number of queries on
ports for which there is no report. (Range: 1-255; Default: 2)
Routers adopt the robustness value from the most recently received
query. If the querier's robustness variable (QRV) is zero, indicating that
the QRV field does not contain a declared robustness value, the switch
will set the robustness variable to the value statically configured by this
command. If the QRV exceeds 7, the maximum value of the QRV field,
the robustness value is set to zero, meaning that this device will not
advertise a QRV in any query messages it subsequently sends.
◆ QI - The Query Interval is the interval at which General Queries are
sent by the Querier. (Range: 1-255 seconds; Default: 125 seconds)
An MLD general query message is sent by the switch at the interval
specified by this attribute. When this message is received by
downstream hosts, all receivers build an IGMP report for the multicast
groups they have joined.