Comment 6 for bug 1884723

Reviewed: https://review.opendev.org/c/openstack/neutron/+/770794
Committed: https://opendev.org/openstack/neutron/commit/5d21998524514c0cab6a40e7fa415d9ff6a88f4a
Submitter: "Zuul (22348)"
Branch: stable/rocky

commit 5d21998524514c0cab6a40e7fa415d9ff6a88f4a
Author: Slawek Kaplonski <email address hidden>
Date: Thu Dec 10 00:10:38 2020 +0100

    Fix multicast traffic with IGMP snooping enabled

    In the ML2/OVS when igmp_snooping is enabled but there is no
    external querier multicast traffic will stop working after few minutes
    as packets will not be flooded to tunnel/external bridges.

    So this patch sets "mcast-snooping-disable-flood-unregistered" option
    of the br-int to False (default value) even when igmp_snooping is
    enabled in the neutron-ovs-agent's config file.

    Additionally it configures "mcast-snooping-flood-reports" and
    "mcast-snooping-flood" on patch ports in br-int to True.

    That way we can provide best effort snooping: multicast isolation where
    IGMP queriers are available and flood everywhere else?

    Conflicts:
        neutron/plugins/ml2/drivers/openvswitch/agent/ovs_neutron_agent.py
        neutron/tests/functional/agent/common/test_ovs_lib.py
        neutron/tests/unit/plugins/ml2/drivers/openvswitch/agent/test_ovs_neutron_agent.py
        neutron/tests/unit/plugins/ml2/drivers/openvswitch/agent/test_ovs_tunnel.py

    Closes-Bug: #1884723
    Change-Id: Iefa0044dba9e92592295a79448e5d57d9e14a40b
    (cherry picked from commit b4070c975274f53a4a2caaabeb5af55683232d3d)