A directory attribute value, the contents of this
integer-valued directory attribute, or zero if
'xcmCommsDirAttributeType' indicates string-valued,
and is NOT 'protocolTyped...'.
Usage: When directory attribute type is 'protocolTyped...' the
particular protocol layer SHALL be specified by placing a
a value from the enumeration 'XcmCommsStackExtProtocol' in
'xcmCommsDirAttributeValue' for this row.