diff --git a/extensions/openpower-pels/dbus_types.hpp b/extensions/openpower-pels/dbus_types.hpp
index 8743f8f..9532177 100644
--- a/extensions/openpower-pels/dbus_types.hpp
+++ b/extensions/openpower-pels/dbus_types.hpp
@@ -19,5 +19,7 @@
 using DBusPathList = std::vector<DBusPath>;
 using DBusPropertyMap = std::map<DBusProperty, DBusValue>;
 using DBusInterfaceMap = std::map<DBusInterface, DBusPropertyMap>;
+using DBusSubTree =
+    std::map<DBusPath, std::map<DBusService, DBusInterfaceList>>;
 
 } // namespace openpower::pels