DDSSEC12 — Provide mechanisms to extend Governance and Permissions files without breaking interoperability

The specification does not state what to do when Permissions and Governance files contain "extra elements" that are not valid according to the XSD.

This is expected to occur both as a result of vendor extensions as well as due to additions in future versions of DDS Security.

Allowing these extensions/additions without breaking compatibility is important. So the spec should be clear in that they are allowed and also provide rules/guidelines on them.

Some possibilities:

• Simply state that elements that are not expected/understood should be ignored
• Same as above but provide some structure for those elements. E.g. specify that they must have a "vendorId" attribute (used to avoid collisions) and a "mustUnderstand" attribute used to force failure in some cases.
• Define an "extensions" element that has known structure (e.g. name/value pairs) which is the one used for the extensions.
• Others to be proposed.

Common approaches are described here: http://www.ibm.com/developerworks/library/x-xtendschema/
This document also discusses various approaches: https://www.xml.com/pub/a/2004/10/27/extend.html

Add mechanism to extend Governance and Permissions document

Define how the Governance and Permission documents could be extended and the rules to apply when processing the document and encountering an extension.