Clarify protocol port-range docs for usnistgov#2065

Author: aj-stein-gsa

src/metaschema/oscal_implementation-common_metaschema.xml

@@ -279,17 +279,17 @@
       </define-assembly>
       <define-assembly name="port-range">
             <formal-name>Port Range</formal-name>
-            <description>Where applicable this is the IPv4 port range on which the service operates.</description>
-            <define-flag name="start" as-type="non-negative-integer">
+            <description>Where applicable this is the transport layer protocol port range an IPv4-based or IPv6-based service uses.</description>
+            <define-flag name="start" as-type="nonNegativeInteger">
                   <formal-name>Start</formal-name>
-                  <description>Indicates the starting port number in a port range</description>
+                  <description>Indicates the starting port number in a port range for a transport layer protocol</description>
                   <remarks>
                         <p>Should be a number within a permitted range</p>
                   </remarks>
             </define-flag>
             <define-flag name="end" as-type="non-negative-integer">
                   <formal-name>End</formal-name>
-                  <description>Indicates the ending port number in a port range</description>
+                  <description>Indicates the ending port number in a port range for a transport layer protocol</description>
                   <remarks>
                         <p>Should be a number within a permitted range</p>
                   </remarks>