diff --git a/neutron_lib/agent/common/__init__.py b/neutron_lib/agent/common/__init__.py
new file mode 100644
index 000000000..e69de29bb
diff --git a/neutron_lib/agent/common/constants.py b/neutron_lib/agent/common/constants.py
new file mode 100644
index 000000000..9433cc54d
--- /dev/null
+++ b/neutron_lib/agent/common/constants.py
@@ -0,0 +1,28 @@
+# Copyright 2022
+# All Rights Reserved.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+
+REG_INGRESS_BW_LIMIT = 3
+REG_MIN_BW = 4
+REG_PORT = 5
+REG_NET = 6
+# for logging remote group rule
+REG_REMOTE_GROUP = 7
+
+INGRESS_BW_LIMIT_REG_NAME = "reg_ingress_bw_limit"
+MIN_BW_REG_NAME = "reg_min_bw"
+PORT_REG_NAME = "reg_port"
+NET_REG_NAME = "reg_net"
+REMOTE_GROUP_REG_NAME = "reg_remote_group"
diff --git a/neutron_lib/agent/common/utils.py b/neutron_lib/agent/common/utils.py
new file mode 100644
index 000000000..2462d17ea
--- /dev/null
+++ b/neutron_lib/agent/common/utils.py
@@ -0,0 +1,50 @@
+# Copyright 2022
+# All Rights Reserved.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+from neutron_lib.agent.common import constants
+
+
+def _replace_register(flow_params, register_number, register_value):
+    """Replace value from flows to given register number
+
+    'register_value' key in dictionary will be replaced by register number
+    given by 'register_number'
+
+    :param flow_params: Dictionary containing defined flows
+    :param register_number: The number of register where value will be stored
+    :param register_value: Key to be replaced by register number
+
+    """
+    try:
+        reg_port = flow_params[register_value]
+        del flow_params[register_value]
+        flow_params['reg{:d}'.format(register_number)] = reg_port
+    except KeyError:
+        pass
+
+
+def create_reg_numbers(flow_params):
+    """Replace reg_(port|net) values with defined register numbers"""
+    _replace_register(flow_params, constants.REG_PORT, constants.PORT_REG_NAME)
+    _replace_register(flow_params, constants.REG_NET, constants.NET_REG_NAME)
+    _replace_register(flow_params,
+                      constants.REG_REMOTE_GROUP,
+                      constants.REMOTE_GROUP_REG_NAME)
+    _replace_register(flow_params,
+                      constants.REG_MIN_BW,
+                      constants.MIN_BW_REG_NAME)
+    _replace_register(flow_params,
+                      constants.REG_INGRESS_BW_LIMIT,
+                      constants.INGRESS_BW_LIMIT_REG_NAME)
diff --git a/neutron_lib/tests/unit/agent/__init__.py b/neutron_lib/tests/unit/agent/__init__.py
new file mode 100644
index 000000000..e69de29bb
diff --git a/neutron_lib/tests/unit/agent/common/__init__.py b/neutron_lib/tests/unit/agent/common/__init__.py
new file mode 100644
index 000000000..e69de29bb
diff --git a/neutron_lib/tests/unit/agent/common/test_utils.py b/neutron_lib/tests/unit/agent/common/test_utils.py
new file mode 100644
index 000000000..3403ef0c8
--- /dev/null
+++ b/neutron_lib/tests/unit/agent/common/test_utils.py
@@ -0,0 +1,41 @@
+# Copyright 2022
+# All Rights Reserved.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+from neutron_lib.agent.common import constants
+from neutron_lib.agent.common import utils
+from neutron_lib.tests import _base
+
+
+class TestCreateRegNumbers(_base.BaseTestCase):
+    def test_no_registers_defined(self):
+        flow = {'foo': 'bar'}
+        utils.create_reg_numbers(flow)
+        self.assertEqual({'foo': 'bar'}, flow)
+
+    def test_all_registers_defined(self):
+        flow = {'foo': 'bar',
+                constants.PORT_REG_NAME: 1,
+                constants.NET_REG_NAME: 2,
+                constants.REMOTE_GROUP_REG_NAME: 3,
+                constants.INGRESS_BW_LIMIT_REG_NAME: 4,
+                constants.MIN_BW_REG_NAME: 5}
+        expected_flow = {'foo': 'bar',
+                         'reg{:d}'.format(constants.REG_PORT): 1,
+                         'reg{:d}'.format(constants.REG_NET): 2,
+                         'reg{:d}'.format(constants.REG_REMOTE_GROUP): 3,
+                         'reg{:d}'.format(constants.REG_INGRESS_BW_LIMIT): 4,
+                         'reg{:d}'.format(constants.REG_MIN_BW): 5}
+        utils.create_reg_numbers(flow)
+        self.assertEqual(expected_flow, flow)
diff --git a/neutron_lib/tests/unit/agent/linux/__init__.py b/neutron_lib/tests/unit/agent/linux/__init__.py
new file mode 100644
index 000000000..e69de29bb
diff --git a/releasenotes/notes/rehome-ovs-firewall-constants-522a307ff8ef4a78.yaml b/releasenotes/notes/rehome-ovs-firewall-constants-522a307ff8ef4a78.yaml
new file mode 100644
index 000000000..94e85713b
--- /dev/null
+++ b/releasenotes/notes/rehome-ovs-firewall-constants-522a307ff8ef4a78.yaml
@@ -0,0 +1,8 @@
+---
+features:
+  - |
+    The neutron ovs_lib related constantswhich represents used
+    OpenFlow registries are now available in the
+    ``neutron_lib.agent.common.constants`` module.
+    The helper function ``create_reg_numbers`` is now available in the
+    ``neutron_lib.agent.common.utils`` module.