[ONOS-7566] Implementation of NetconfProxySession

Change-Id: I01cbe0b10ac36cb6db53127555b551f405acdeb1
diff --git a/protocols/netconf/api/src/main/java/org/onosproject/netconf/NetconfDevice.java b/protocols/netconf/api/src/main/java/org/onosproject/netconf/NetconfDevice.java
index 639f0a8..8c756e5 100644
--- a/protocols/netconf/api/src/main/java/org/onosproject/netconf/NetconfDevice.java
+++ b/protocols/netconf/api/src/main/java/org/onosproject/netconf/NetconfDevice.java
@@ -24,13 +24,22 @@
 
     /**
      * Returns whether a device is a NETCONF device with a capabilities list
-     * and is accessible.
+     * and is accessible, through a secure transport session or a proxy session.
      *
      * @return true if device is accessible, false otherwise
      */
     boolean isActive();
 
     /**
+     * Returns whether the device has secure transport session.
+     *
+     * @return true if secure transport session exists, false otherwise
+     */
+    default boolean isMasterSession() {
+        return isActive();
+    }
+
+    /**
      * Returns a NETCONF session context for this device.
      *
      * @return netconf session