Subject: [sacm] IM Issue #39: how to indicate special things about information elements

From: "Cokus, Michael S." <[email-masked]>
Date: Fri, 25 Mar 2016 15:19:00 +0000

Hi All,

I'm looking into issue #39 [1].  This pertains to representing "special" properties for information elements in the SACM IM.  

"During the March 9, 2016 Virtual Interim Meeting, there was discussion around how to indicate 
whether or not information elements were useful for designation purposes, represent privacy 
information, or represented metadata. This issue came up when trying to represent information 
model objects, attributes, and metadata using the same IPFIX information element syntax." 

Some options to address issue #39 are noted below, along with examples using IPFIX format:

Option 1:
---
"Add individual properties to indicate an information element is metadata, useful for designation, or 
represents privacy information as well as any other future properties about information elements that 
we may want to track."

Here's an example of how it might work in an element defintion:

elementId: TBD
name: userName
dataType: string
dataTypeSemantics: default
status: current
isMetadata: false
isDesignationRelevant: true
isPrivacyConcern: true
description: User name associated with the flow.

---

Option 2:
---
"We could simply group the information elements in certain sections (e.g. metadata, designation, privacy,
etc.). Of course, this would result in problems because information elements may fall into multiple categories 
(e.g. an information element could be both useful for designation purposes and represent privacy information)."

This approach would be easy to do in the spec structure, but there are potential problems with it:

Section X.1 Designation

<A list of information elements which are useful for designation purposes.>

Section X.2 Privacy

<A list of information elements which are considered to have privacy concerns.>

Section X.3 Metadata

<A list of information elements which are used as metadata for another information element.>

---

Option 3:
---
"Add a new property to handle all of these special things about an information element (similar to 
dataTypeSemantics) or maybe just expand dataTypeSemantics." 

Here's an example of how it might work in an element defintion:

elementId: TBD
name: userName
dataType: string
dataTypeSemantics: default
status: current
specialProperties: designationRelevant, privacyConcern
description: User name associated with the flow.

---

Option 4:
---
Don't indicate special properties as part of the IE definition at all.  Rather, include the
metadata along with the actual information content to be exchanged.  Define the metadata 
components and include them wherever applicable.

---

Please let me know your thoughts concerning these options.  Which seems best?  Do you have any other ideas?

Thanks,

--mike

[1] https://github.com/sacmwg/draft-ietf-sacm-information-model/issues/39

Mike Cokus
Systems Engineer
The MITRE Corporation