[CAP] CAP Implementation Analogies

[Mick Jagger]

Hi,
	The OASIS EM committee put a lot of hard work into producing CAP and now with a standard in hand, implementers have begun putting CAP into practice.  In doing so, a number of issues have begun to arise such as the HazCollect instruction field, index formats, custom values, legacy interop, and language translation.  Many of these issues fall outside the bounds of a standard and into implementation details.  I'd like to suggest that an implementation guideline be developed to accompany the CAP standard.
	So to get things started I'd like to offer the following implementation analogy both for the technical and non-technical users of CAP, to serve as an introduction to the guideline.  Please provide some feedback on this analogy and any improvements you'd like to suggest.  I'll compile them all and edit something together to start a new section on the CAP wiki for the implementation guide.

	The CAP standard is like vanilla ice cream.  Who doesn't like ice cream, and vanilla accounts for more than half of all consumed ice cream.  Its eaten by itself, or mixed with a vast number of ingredients and put into all kinds of products.  Vanilla is the building block of the ice cream world, just like CAP is for emergency alerts.  If you aren't starting out with a pure CAP compliant message, then you're using the wrong kind of ice cream and your message is going to taste funny and probably melt.
	Now think of the various message transmission formats as the ice cream container.  Something like a siren alert is 1 scoop on a paper towel.  It can't hold much info, hence the 1 scoop, and it goes out fast and doesn't stick around, hence the paper towel.  Or maybe its a big tub of ice cream like a web page, which can hold lots of info and you can put it in the freezer for storage.  The point being that each container all holds the same vanilla CAP message, but they have their own restrictions on what they can offer and in what form.
	Finally think of custom CAP enhancements like parameters, resources, and eventcodes as the ice cream toppings.  They all serve to make the ice cream look and taste better.  Each person has their own preferences such as sprinkles, or nuts, and the same goes for various CAP systems.  To make your ice cream more enticing to a particular system you provide different toppings, enabling better compatibility with their system and less intervention by someone who has to add the missing toppings.  Of course there should be a full menu available with all of the various toppings clearly defined.
	So to make your Hazcollect message you start with 2 scoops (message size restrictions) of vanilla (CAP 1.1) in a tall frosted glass (DMIS submission) and add some coloured sprinkles (EAS codes).

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