diff --git a/python/neutron-understack/neutron_understack/ml2_type_annotations.py b/python/neutron-understack/neutron_understack/ml2_type_annotations.py
new file mode 100644
index 000000000..eb209b720
--- /dev/null
+++ b/python/neutron-understack/neutron_understack/ml2_type_annotations.py
@@ -0,0 +1,164 @@
+from typing import Any
+from typing import Literal
+from typing import NotRequired
+from typing import TypeAlias
+from typing import TypedDict
+
+NetworkTypeName: TypeAlias = Literal["vxlan", "vlan"]
+PortStatusName: TypeAlias = Literal["DOWN", "ACTIVE"]
+
+
+class NetworkSegmentDict(TypedDict):
+    id: str
+    network_id: str
+    network_type: NetworkTypeName
+    physical_network: str | None
+    segmentation_id: int
+
+
+ShortNetworkSegmentDict = TypedDict(
+    "ShortNetworkSegmentDict",
+    {
+        "provider:network_type": NetworkTypeName,
+        "provider:physical_network": str | None,
+        "provider:segmentation_id": int,
+    },
+)
+
+NetworkDict = TypedDict(
+    "NetworkDict",
+    {
+        "admin_state_up": bool,
+        "availability_zone_hints": list,
+        "availability_zones": list,
+        "created_at": str,
+        "description": str,
+        "id": str,
+        "ipv4_address_scope": Any,
+        "ipv6_address_scope": Any,
+        "l2_adjacency": bool,
+        "mtu": int,
+        "name": str,
+        "project_id": str,
+        "provider:network_type": NotRequired[NetworkTypeName | None],
+        "provider:physical_network": NotRequired[str | None],
+        "provider:segmentation_id": NotRequired[int | None],
+        "revision_number": int,
+        "router:external": bool,
+        "segments": NotRequired[list[ShortNetworkSegmentDict]],
+        "shared": bool,
+        "standard_attr_id": int,
+        "status": str,
+        "subnets": list,
+        "tags": list[str],
+        "tenant_id": str,
+        "updated_at": str,
+        "vlan_transparent": Any,
+    },
+)
+
+
+class FixedIpsDict(TypedDict):
+    subnet_id: str
+    ip_address: str
+
+
+PortDict = TypedDict(
+    "PortDict",
+    {
+        "id": str,
+        "name": str,
+        "network_id": str,
+        "tenant_id": str,
+        "mac_address": str,
+        "admin_state_up": bool,
+        "status": PortStatusName,
+        "device_id": str,
+        "device_owner": str,
+        "standard_attr_id": int,
+        "fixed_ips": list[FixedIpsDict],
+        "project_id": str,
+        "security_groups": list[str],
+        "binding:vnic_type": str,
+        "binding:profile": dict,
+        "binding:host_id": str,
+        "binding:vif_type": str,
+        "binding:vif_details": dict,
+        "allowed_address_pairs": list,
+        "extra_dhcp_opts": list,
+        "description": str,
+        "ip_allocation": str,
+        "tags": list,
+        "created_at": str,
+        "updated_at": str,
+        "revision_number": int,
+        "network": NotRequired[NetworkDict],
+    },
+)
+
+example_network: NetworkDict = {
+    "id": "c57e4a02-73bb-4c6e-ab03-537ea11168e3",
+    "name": "provisioning",
+    "tenant_id": "32e02632f4f04415bab5895d1e7247b7",
+    "admin_state_up": True,
+    "mtu": 1500,
+    "status": "ACTIVE",
+    "subnets": ["b0fa63d0-fb0c-446f-bfd3-26c0a50730c0"],
+    "standard_attr_id": 22,
+    "shared": False,
+    "availability_zone_hints": [],
+    "availability_zones": [],
+    "ipv4_address_scope": None,
+    "ipv6_address_scope": None,
+    "router:external": False,
+    "vlan_transparent": None,
+    "description": "",
+    "l2_adjacency": True,
+    "tags": [],
+    "created_at": "2024-09-19T20:55:45Z",
+    "updated_at": "2024-09-24T15:49:54Z",
+    "revision_number": 6,
+    "project_id": "32e02632f4f04415bab5895d1e7247b7",
+    "provider:network_type": "vxlan",
+    "provider:physical_network": None,
+    "provider:segmentation_id": 4010,
+}
+
+
+class NetworkContext:
+    current: NetworkDict
+    original: NetworkDict
+    network_segments: list[NetworkSegmentDict]
+
+
+class PortContext:
+    current: PortDict
+    original: PortDict
+    network: NetworkContext
+    status: str
+    original_status: str
+    _plugin_context: Any
+    _plugin: Any
+    vif_type: str
+    original_vif_type: str
+
+    binding_levels: Any
+    original_binding_levels: Any
+    top_bound_segment: Any
+    original_top_bound_segment: Any
+    bottom_bound_segment: Any
+    original_bottom_bound_segment: Any
+    host: Any
+    original_host: Any
+    vif_details: Any
+    original_vif_details: Any
+    segments_to_bind: Any
+
+    def set_binding(
+        self, new_segment: str, vif_type: str, _: dict, status: str
+    ) -> None: ...
+
+
+class BindingLevelsDict(TypedDict):
+    bound_driver: Literal["understack"]
+    bound_segment: NetworkSegmentDict
diff --git a/python/neutron-understack/neutron_understack/neutron_understack_mech.py b/python/neutron-understack/neutron_understack/neutron_understack_mech.py
index 692ea5985..04639a656 100644
--- a/python/neutron-understack/neutron_understack/neutron_understack_mech.py
+++ b/python/neutron-understack/neutron_understack/neutron_understack_mech.py
@@ -2,7 +2,6 @@
 from uuid import UUID
 
 import neutron_lib.api.definitions.portbindings as portbindings
-from neutron.plugins.ml2.driver_context import PortContext
 from neutron_lib import constants as p_const
 from neutron_lib.api.definitions import segment as segment_def
 from neutron_lib.callbacks import events
@@ -20,6 +19,9 @@
 from neutron_understack.trunk import UnderStackTrunkDriver
 from neutron_understack.undersync import Undersync
 
+from .ml2_type_annotations import NetworkContext
+from .ml2_type_annotations import PortContext
+
 LOG = logging.getLogger(__name__)
 
 config.register_ml2_type_understack_opts(cfg.CONF)
@@ -58,7 +60,7 @@ def subscribe(self):
     def create_network_precommit(self, context):
         pass
 
-    def create_network_postcommit(self, context):
+    def create_network_postcommit(self, context: NetworkContext):
         network = context.current
         network_id = network["id"]
         network_name = network["name"]
@@ -73,6 +75,9 @@ def create_network_postcommit(self, context):
             return
 
         ucvni_group = conf.ucvni_group
+        if segmentation_id is None:
+            raise ValueError("Network %s missing provider:segmentation_id", network_id)
+
         ucvni_response = self.nb.ucvni_create(
             network_id=network_id,
             project_id=project_id,
@@ -93,16 +98,16 @@ def create_network_postcommit(self, context):
         )
         self._create_nautobot_namespace(network_id, external)
 
-    def update_network_precommit(self, context):
+    def update_network_precommit(self, context: NetworkContext):
         pass
 
-    def update_network_postcommit(self, context):
+    def update_network_postcommit(self, context: NetworkContext):
         pass
 
-    def delete_network_precommit(self, context):
+    def delete_network_precommit(self, context: NetworkContext):
         pass
 
-    def delete_network_postcommit(self, context):
+    def delete_network_postcommit(self, context: NetworkContext):
         network = context.current
         network_id = network["id"]
         external = network["router:external"]