Identification of the message.

Code identifying a type of message as assigned by its controlling agency.

To specify the version number or name of an object.

To specify the release number or release name of an object.

Identification of the agency controlling the specification, maintenance and publication of the message.

An association assigned code to further identify implementation of a message.

To specify a revision number.

To identify a designated class.

To indicate the type of data maintenance operation for an object, such as add, delete, replace.