diff --git a/tractor/_addr.py b/tractor/_addr.py
index 66fc49fc..e7b92461 100644
--- a/tractor/_addr.py
+++ b/tractor/_addr.py
@@ -40,6 +40,7 @@ from ._state import (
     get_rt_dir,
     current_actor,
     is_root_process,
+    _def_tpt_proto,
 )
 
 if TYPE_CHECKING:
@@ -461,9 +462,6 @@ class UDSAddress(Address):
         os.unlink(self.sockpath)
 
 
-preferred_transport: str = 'uds'
-
-
 _address_types: bidict[str, Type[Address]] = {
     'tcp': TCPAddress,
     'uds': UDSAddress
@@ -525,11 +523,11 @@ def wrap_address(
         # TODO! BUT THIS WILL MATCH FOR TCP !...
         # -[ ] so prolly go back to what guille had orig XD
         #   a plain ol' `str`?
-        case ((
-            str()|Path(),
-            int(),
-        )):
-            cls = UDSAddress
+        # case ((
+        #     str()|Path(),
+        #     int(),
+        # )):
+        #     cls = UDSAddress
 
         # classic network socket-address as tuple/list
         case (
@@ -541,12 +539,14 @@ def wrap_address(
 
         # likely an unset UDS or TCP reg address as defaulted in
         # `_state._runtime_vars['_root_mailbox']`
+        #
+        # TODO? figure out when/if we even need this?
         case (
             None
             |
             [None, None]
         ):
-            cls: Type[Address] = get_address_cls(preferred_transport)
+            cls: Type[Address] = get_address_cls(_def_tpt_proto)
             addr: UnwrappedAddress = cls.get_root().unwrap()
 
         case _:
diff --git a/tractor/_discovery.py b/tractor/_discovery.py
index d370eabb..157d229c 100644
--- a/tractor/_discovery.py
+++ b/tractor/_discovery.py
@@ -33,7 +33,6 @@ from .ipc import _connect_chan, Channel
 from ._addr import (
     UnwrappedAddress,
     Address,
-    preferred_transport,
     wrap_address
 )
 from ._portal import (
@@ -44,6 +43,7 @@ from ._portal import (
 from ._state import (
     current_actor,
     _runtime_vars,
+    _def_tpt_proto,
 )
 
 if TYPE_CHECKING:
@@ -203,7 +203,7 @@ async def maybe_open_portal(
 async def find_actor(
     name: str,
     registry_addrs: list[UnwrappedAddress]|None = None,
-    enable_transports: list[str] = [preferred_transport],
+    enable_transports: list[str] = [_def_tpt_proto],
 
     only_first: bool = True,
     raise_on_none: bool = False,
diff --git a/tractor/_root.py b/tractor/_root.py
index 77344013..f67d746a 100644
--- a/tractor/_root.py
+++ b/tractor/_root.py
@@ -56,7 +56,6 @@ from ._addr import (
     UnwrappedAddress,
     default_lo_addrs,
     mk_uuid,
-    preferred_transport,
     wrap_address,
 )
 from ._exceptions import (
@@ -139,6 +138,7 @@ async def maybe_block_bp(
             os.environ.pop('PYTHONBREAKPOINT', None)
 
 
+
 @acm
 async def open_root_actor(
     *,
@@ -148,7 +148,9 @@ async def open_root_actor(
     # defaults are above
     arbiter_addr: tuple[UnwrappedAddress]|None = None,
 
-    enable_transports: list[str] = [preferred_transport],
+    enable_transports: list[
+        _state.TransportProtocolKey,
+    ] = [_state._def_tpt_proto],
 
     name: str|None = 'root',
 
diff --git a/tractor/_runtime.py b/tractor/_runtime.py
index 080768a2..f8356582 100644
--- a/tractor/_runtime.py
+++ b/tractor/_runtime.py
@@ -80,7 +80,6 @@ from ._addr import (
     Address,
     default_lo_addrs,
     get_address_cls,
-    preferred_transport,
     wrap_address,
 )
 from ._context import (
@@ -1322,7 +1321,9 @@ class Actor:
 
         '''
         if listen_addrs is None:
-            listen_addrs = default_lo_addrs([preferred_transport])
+            listen_addrs = default_lo_addrs([
+                _state._def_tpt_proto
+            ])
 
         else:
             listen_addrs: list[Address] = [
@@ -1846,7 +1847,7 @@ async def async_main(
                 enable_transports: list[str] = (
                     maybe_preferred_transports_says_rent
                     or
-                    [preferred_transport]
+                    [_state._def_tpt_proto]
                 )
                 for transport_key in enable_transports:
                     transport_cls: Type[Address] = get_address_cls(
diff --git a/tractor/_state.py b/tractor/_state.py
index 4cb7e784..0ec4577e 100644
--- a/tractor/_state.py
+++ b/tractor/_state.py
@@ -26,6 +26,7 @@ import os
 from pathlib import Path
 from typing import (
     Any,
+    Literal,
     TYPE_CHECKING,
 )
 
@@ -164,3 +165,11 @@ def get_rt_dir(
     if not rtdir.is_dir():
         rtdir.mkdir()
     return rtdir
+
+
+# default IPC transport protocol settings
+TransportProtocolKey = Literal[
+    'tcp',
+    'uds',
+]
+_def_tpt_proto: TransportProtocolKey = 'tcp'
diff --git a/tractor/_supervise.py b/tractor/_supervise.py
index e4017c44..ab3a2a94 100644
--- a/tractor/_supervise.py
+++ b/tractor/_supervise.py
@@ -34,7 +34,6 @@ import trio
 from .devx._debug import maybe_wait_for_debugger
 from ._addr import (
     UnwrappedAddress,
-    preferred_transport,
     mk_uuid,
 )
 from ._state import current_actor, is_main_process
@@ -45,7 +44,9 @@ from ._exceptions import (
     is_multi_cancelled,
     ContextCancelled,
 )
-from ._root import open_root_actor
+from ._root import (
+    open_root_actor,
+)
 from . import _state
 from . import _spawn
 
@@ -138,7 +139,7 @@ class ActorNursery:
 
         bind_addrs: list[UnwrappedAddress]|None = None,
         rpc_module_paths: list[str]|None = None,
-        enable_transports: list[str] = [preferred_transport],
+        enable_transports: list[str] = [_state._def_tpt_proto],
         enable_modules: list[str]|None = None,
         loglevel: str|None = None,  # set log level per subactor
         debug_mode: bool|None = None,