---
prelude: >
    The ML2/OVS and ML2/OVN drivers had inconsistencies on how IGMP was
    configured. Prior to this patch Neutron only exposed a single IGMP
    configuration option (``igmp_snooping_enabled``) and other features
    such as flooding IGMP packets, flooding reports and flooding to
    unregistered ports were hard coded differently in each driver.
    This patch introduces Neutron configuration options for those listed
    IGMP features.
    As part of this work, default values in the IGMP snooping
    configuration had to be changed for the ML2/OVS backend. Please
    check in the following sections for more details.
features:
  - |
    New configuration options for IGMP were added in the [OVS] section:
    ``igmp_flood``, ``igmp_flood_reports`` and ``igmp_flood_unregistered``.
    This gives operators full control on how IGMP should be configured for
    their deployments.
upgrade:
  - |
    In order to make IGMP configuration consistent across drivers
    some defaults had to be changed for ML2/OVS. This change did not
    affect the defaults in the ML2/OVN driver.

    If ML2/OVS is used and ``igmp_snooping_enable`` is enabled, in order
    to make the IGMP related traffic run as before please ensure that
    the following configuration options are enabled after the upgrade.

    ``[OVS]/igmp_flood_unregistered`` = True
    ``[OVS]/igmp_flood`` = True
    ``[OVS]/igmp_flood_reports`` = True
