User manual

C HAPTER 17 | Multicast Filtering
Layer 2 IGMP (Snooping and Query)
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ES-2000 Series
method of attack is launched by an intruder who takes over the role of
querier, and starts overloading multicast hosts by sending a large
number of group-and-source-specific queries, each with a large source
list and the Maximum Response Time set to a large value.
To protect against this kind of attack, routers should not forward
queries. This is easier to accomplish if the query carries the Router
Alert option.
◆ Unregistered Data Flooding – Floods unregistered multicast traffic
into the attached VLAN. (Default: Disabled)
Once the table used to store multicast entries for IGMP snooping and
multicast routing is filled, no new entries are learned. If no router port
is configured in the attached VLAN, and unregistered-flooding is
disabled, any subsequent multicast traffic not found in the table is
dropped, otherwise it is flooded throughout the VLAN.
◆ Version Exclusive – Discards any received IGMP messages which use
a version different to that currently configured by the IGMP Version
attribute. (Default: Disabled)
◆ IGMP Unsolicited Report Interval – Specifies how often the
upstream interface should transmit unsolicited IGMP reports when
proxy reporting is enabled. (Range: 1-65535 seconds, Default: 400
seconds)
When a new upstream interface (that is, uplink port) starts up, the
switch sends unsolicited reports for all currently learned multicast
channels via the new upstream interface.
This command only applies when proxy reporting is enabled.
◆ Router Port Expire Time – The time the switch waits after the
previous querier stops before it considers it to have expired.
(Range: 1-65535, Recommended Range: 300-500 seconds,
Default: 300)
◆ IGMP Snooping Version – Sets the protocol version for compatibility
with other devices on the network. This is the IGMP Version the switch
uses to send snooping reports. (Range: 1-2; Default: 2)
This attribute configures the IGMP report/query version used by IGMP
snooping. Versions 1 - 2 are supported, and version 2 is backward
compatible, so the switch can operate with other devices using either
Version 1 or 2.
◆ Querier Status – When enabled, the switch can serve as the Querier,
which is responsible for asking hosts if they want to receive multicast
traffic. (Default: Disabled)