Hi Dmitriy, thanks for answering!

I really didn't send any details of my setup, apologies for that.

I'm using OVS with the following configuration:

provider_networks:
  - network:
      container_bridge: br-provider
      container_type: veth
      type: vlan
      range: "100:200"
      net_name: vlan
      group_binds:
        - neutron_openvswitch_agent

  - network:
      container_bridge: br-provider
      container_type: veth
      type: flat
      net_name: flat
      group_binds:
        - neutron_openvswitch_agent

neutron_plugin_type: ml2.ovs
neutron_ml2_drivers_type: "flat,vlan"
neutron_plugin_base:
  - router
  - metering

root@dcn2-utility-container-c45f8b09:/# openstack network agent list

+--------------------------------------+----------------+------+-------------------+-------+-------+------------------------+
| ID                                   | Agent Type     | Host | Availability Zone | Alive | State | Binary                 |
+--------------------------------------+----------------+------+-------------------+-------+-------+------------------------+
| 9a4625ef-2988-4b96-a927-30a9bb0244a4 | Metadata agent | dcn2 | None              | :-)   | UP    | neutron-metadata-agent |
| a222c0ae-c2e5-44cc-b478-ca8176daad19 | Metering agent | dcn2 | None              | :-)   | UP    | neutron-metering-agent |
| c6be1985-a67e-4099-a1d6-fa517810e138 | L3 agent       | dcn2 | nova              | :-)   | UP    | neutron-l3-agent       |
| da97e2a6-535b-4f1e-828d-9b2fbb3e036b | DHCP agent     | dcn2 | nova              | :-)   | UP    | neutron-dhcp-agent     |
+--------------------------------------+----------------+------+-------------------+-------+-------+------------------------+

root@dcn2-utility-container-c45f8b09:/# openstack compute service list
+--------------------------------------+----------------+----------------------------------+----------+---------+-------+----------------------------+
| ID                                   | Binary         | Host                             | Zone     | Status  | State | Updated At                 |
+--------------------------------------+----------------+----------------------------------+----------+---------+-------+----------------------------+
| a0524af5-bc88-4793-aee2-c2c87cd0e8cc | nova-conductor | dcn2-nova-api-container-aac2b913 | internal | enabled | up    | 2023-07-18T12:32:26.000000 |
| c860f25e-bd30-49f9-8289-076b230bbc2d | nova-scheduler | dcn2-nova-api-container-aac2b913 | internal | enabled | up    | 2023-07-18T12:32:27.000000 |
| 6457e0a1-b075-4999-8855-0f36e2e3a95a | nova-compute   | dcn2                             | nova     | enabled | up    | 2023-07-18T12:32:27.000000 |
+--------------------------------------+----------------+----------------------------------+----------+---------+-------+----------------------------+

The br-provider bridge exists and is UP.