Igmp Ssm Mapping - HP FlexFabric 5950 series Configuration Manual

IGMPv3 is compatible with IGMPv1 and IGMPv2 and supports IGMP general queries and
IGMP group-specific queries. It also introduces IGMP group-and-source-specific queries.
A general query does not carry a group address or a source address.
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A group-specific query carries a group address, but no source address.
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A group-and-source-specific query carries a group address and one or more source
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addresses.
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Reports containing multiple group records
Unlike an IGMPv1 or IGMPv2 report, an IGMPv3 report is destined to 224.0.0.22 and contains
one or more group records. Each group record contains a multicast group address and a
multicast source address list.
Group records include the following categories:
IS_IN—The current filtering mode is Include. The report sender requests the multicast data
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only from the sources specified in the Source Address field.
IS_EX—The current filtering mode is Exclude. The report sender requests the multicast
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data from any sources except those specified in the Source Address field.
TO_IN—The filtering mode has changed from Exclude to Include.
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TO_EX—The filtering mode has changed from Include to Exclude.
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ALLOW—The Source Address field contains a list of additional sources from which the
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receiver wants to obtain data. If the current filtering mode is Include, these sources are
added to the multicast source list. If the current filtering mode is Exclude, these sources are
deleted from the multicast source list.
BLOCK—The Source Address field contains a list of the sources from which the receiver no
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longer wants to obtain data. If the current filtering mode is Include, these sources are
deleted from the multicast source list. If the current filtering mode is Exclude, these sources
are added to the multicast source list.

IGMP SSM mapping

An IGMPv3 host can explicitly specify multicast sources in its IGMPv3 reports. From the reports, the
IGMP router can obtain the multicast source addresses and directly provide the SSM service.
However, an IGMPv1 or IGMPv2 host cannot specify multicast sources in its IGMPv1 or IGMPv2
reports.
The IGMP SSM mapping feature enables the IGMP router to provide SSM support for IGMPv1 or
IGMPv2 hosts. The router translates (*, G) in IGMPv1 or IGMPv2 reports into (G, INCLUDE, (S1,
S2...)) based on the configured IGMP SSM mappings.
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