diff --git a/neutron_lib/plugins/ml2/api.py b/neutron_lib/plugins/ml2/api.py
index 1597aa68e..c6883c901 100644
--- a/neutron_lib/plugins/ml2/api.py
+++ b/neutron_lib/plugins/ml2/api.py
@@ -14,6 +14,8 @@
 
 import abc
 
+from neutron_lib.api.definitions import portbindings
+
 
 # The following keys are used in the segment dictionaries passed via
 # the driver API.
@@ -469,6 +471,16 @@ class MechanismDriver(object, metaclass=abc.ABCMeta):
         """
         return extensions
 
+    @property
+    def connectivity(self):
+        """Return the mechanism driver connectivity type
+
+        The possible values are "l2", "l3" and "legacy" (default).
+
+        :returns: a string in ("l2", "l3", "legacy")
+        """
+        return portbindings.CONNECTIVITY_LEGACY
+
 
 class _TypeDriverBase(object, metaclass=abc.ABCMeta):
 
diff --git a/releasenotes/notes/mechanismdriver-connectivity-00dc679a3f307345.yaml b/releasenotes/notes/mechanismdriver-connectivity-00dc679a3f307345.yaml
new file mode 100644
index 000000000..466004bd3
--- /dev/null
+++ b/releasenotes/notes/mechanismdriver-connectivity-00dc679a3f307345.yaml
@@ -0,0 +1,6 @@
+---
+features:
+  - |
+    Add ``connectivity`` property to ``MechanismDriver``. For more information,
+    see
+    [`Boot a VM with an unaddressed port <https://blueprints.launchpad.net/nova/+spec/boot-vm-with-unaddressed-port>`_].