diff --git a/config-models/aether-4.x/files/aether-4.0.0.tree b/config-models/aether-4.x/files/aether-4.0.0.tree
index 664e53c..24f7a1b 100644
--- a/config-models/aether-4.x/files/aether-4.0.0.tree
+++ b/config-models/aether-4.x/files/aether-4.0.0.tree
@@ -7,7 +7,7 @@
         +--rw address         ietf:host
         +--rw endpoint* [endpoint-id]
         |  +--rw endpoint-id      yg:yang-identifier
-        |  +--rw port-start       ietf:port-number
+        |  +--rw port-start?      ietf:port-number
         |  +--rw port-end?        ietf:port-number
         |  +--rw protocol?        at:protocol
         |  +--rw mbr
diff --git a/config-models/aether-4.x/files/yang/onf-application.yang b/config-models/aether-4.x/files/yang/onf-application.yang
index e024462..c48cab1 100755
--- a/config-models/aether-4.x/files/yang/onf-application.yang
+++ b/config-models/aether-4.x/files/yang/onf-application.yang
@@ -72,7 +72,6 @@
         }
         leaf port-start {
           type ietf:port-number;
-          mandatory true;
           description
               "First port in range";
         }