diff --git a/modules/preprocessing.py b/modules/preprocessing.py
index 4d3b6ca6f22f9c545583f4fec33b8f08f4176107..65705dcafbe9751f45fd113a3af08000169c23eb 100644
--- a/modules/preprocessing.py
+++ b/modules/preprocessing.py
@@ -14,4 +14,8 @@ def preprocess(definitions, flags):
     """
 
     """ Creating Border router """
-    create_border_router(definitions)
+    try:
+        create_border_router(definitions)
+    except Exception:
+        print("Could not create border router.")
+        raise
diff --git a/modules/routing.py b/modules/routing.py
index f1b556f0b45f4292075b1c8c56ffe352f2f80ca0..20d6aa8b2bac6e35e0d2f027d8fb275794b54d9a 100644
--- a/modules/routing.py
+++ b/modules/routing.py
@@ -51,7 +51,11 @@ def _create_mappings_to_border_router(definitions):
         
 
 def create_border_router(definitions):
-    """ Adds the definition of border router to definitions """
+    """
+    Adds the definition of border router to definitions.
+
+    :param definitions: device definition structure
+    """
 
     # TODO this should be later moved to input check
     if not _are_br_parameters_free: