Index: UMPA/branch/link-layer-integration/umit/umpa/_sockets.py
===================================================================
--- UMPA/branch/link-layer-integration/umit/umpa/_sockets.py (revision 5594)
+++ UMPA/branch/link-layer-integration/umit/umpa/_sockets.py (revision 5595)
@@ -87,5 +87,15 @@
     return sent_bytes
 
-class SocketL2(object):
+class _Socket(object):
+    """
+    Raw socket superclass.
+
+    This is an abstract class.
+    """
+
+    def __init__(self, **kwargs):
+        raise NotImplementedError("this is an abstract class")
+
+class SocketL2(_Socket):
     """
     Level 2 (link-layer) socket class.