[Again, sorry for spamming the whole TC... Allen/Rick, any progress
on getting the other SC's their lists?]
Quoted below is a note from the CAP Working Group's email list
(archive at <http://www.incident.com/pipermail/cap-list/>) about
potential benefits of framing CAP in ASN.1 terms. As I note, I've
just recently begun to get oriented to ASN.1, but it seems compatible
with our XML focus. Can anyone offer any insights or comments?
- Art
>To: cap-list@incident.com
>From: Art Botterell <acb@incident.com>
>Subject: [CAP] ASN.1 Formatting?
>Date: Thu, 24 Apr 2003 07:08:44 -0700
>
>Friends -
>
>What appears below is an ASN.1 portrayal of the current (v. 0.7) CAP
>message format, generated by running our existing draft XML schema
>through an automated conversion tool.
>
>From the ASN.1 homepage <http://asn1.elibel.tm.fr/en/index.htm>:
>"Abstract Syntax Notation number One (ASN.1) is an international
>standard that aims at specifying data used in communication
>protocols. It is a powerful and complex language: its features are
>designed to describe accurately and efficiently communications
>between homogeneous or heterogeneous systems."
>
>What's interesting about ASN.1 is that its abstract format with
>defined mappings to various real-world encodings, including XML.
>What this means is that a message format from ASN.1 can be
>translated precisely into XML and also into several specialized
>encodings such as the Packed Encoding Rules (PER) "for applications
>that undergo restrictions in terms of bandwidth.These encoding rules
>describe how the values defined in ASN.1 should be encoded for
>transmission ( i.e. , how they can be translated into the bytes
>'over the wire' and reverse), regardless of machine, programming
>language, or how it is represented in an application program."
>(From <http://asn1.elibel.tm.fr/en/introduction/index.htm>.)
>
>You'll note below that our current naming convention could be
>adjusted for improved ASN.1 compatibility by changing all the
>underscores to hyphens. Some other issues may arise... our friend
>Elliot Christian has asked the "asn1xml" working group for their
>advice. Still, the interchange seems to be fairly clean.
>
>At this point I'm just getting to know ASN.1 a bit, personally, so
>I'm not making any recommendation at this point... but I thought it
>might be worth sharing this for discussion. Anyone else have any
>experience, good or bad, with ASN.1?
>
>- Art
>
>
>------------------------------------------------------------
>Generated by xsd2asn1, the XML Schema to ASN.1 translator of France
>Telecom R&D
>
>Cap-0-7 DEFINITIONS AUTOMATIC TAGS ::=
>BEGIN
>
>IMPORTS
> AnyURI, Language, DateTime
> FROM XSD;
>
>-- CAP Alert Message (draft version 0.7)
>Alert ::= -- NAME AS UNCAPITALIZED -- -- NAME AS UNCAPITALIZED -- SEQUENCE {
> msg-id -- NAME AS "msg_id" -- UTF8String ,
> sender-id -- NAME AS "sender_id" -- UTF8String ,
> password UTF8String OPTIONAL,
> source-id -- NAME AS "source_id" -- UTF8String OPTIONAL,
> sent DateTime ,
> msg-status -- NAME AS "msg_status" -- ENUMERATED {actual, exercise, test} ,
> msg-scope -- NAME AS "msg_scope" -- ENUMERATED {public,
>restricted, private} ,
> auth-code -- NAME AS "auth_code" -- UTF8String OPTIONAL,
> msg-type -- NAME AS "msg_type" -- ENUMERATED {alert, update,
>cancel, ack, error} ,
> msg-note -- NAME AS "msg_note" -- UTF8String OPTIONAL,
> ref-id -- NAME AS "ref_id" -- SEQUENCE OF UTF8String OPTIONAL,
> incident-id -- NAME AS "incident_id" -- SEQUENCE OF UTF8String OPTIONAL,
> info -- UNTAGGED -- SEQUENCE OF info -- UNTAGGED -- SEQUENCE {
> language Language DEFAULT "en-US" ,
> event-cat -- NAME AS "event_cat" -- ENUMERATED {geo, met,
>security, rescue, fire, health, env, transport, infra, other,
>safety} ,
> event-type -- NAME AS "event_type" -- UTF8String ,
> urgency ENUMERATED {ongoing, impending, forecast, past, unknown} ,
> severity ENUMERATED {extreme, severe, moderate, minor, unknown} ,
> certainty ENUMERATED {high, moderate, low, minimal, unknown} ,
> audience UTF8String OPTIONAL,
> area -- UNTAGGED -- SEQUENCE OF area -- UNTAGGED -- SEQUENCE {
> area-desc -- NAME AS "area_desc" -- UTF8String ,
> choice -- UNTAGGED -- CHOICE {
> polygon SEQUENCE OF UTF8String ,
> radius SEQUENCE OF UTF8String ,
> geo-code -- NAME AS "geo_code" -- UTF8String } OPTIONAL} ,
> target-code -- UNTAGGED -- SEQUENCE OF target-code -- NAME AS
>"target_code" -- UTF8String ,
> effective DateTime OPTIONAL,
> onset DateTime OPTIONAL,
> expires DateTime OPTIONAL,
> sender-desc -- NAME AS "sender_desc" -- UTF8String OPTIONAL,
> headline UTF8String OPTIONAL,
> event-desc -- NAME AS "event_desc" -- UTF8String OPTIONAL,
> instruction UTF8String OPTIONAL,
> info-url -- NAME AS "info_url" -- AnyURI OPTIONAL,
> image-url -- NAME AS "image_url" -- AnyURI OPTIONAL,
> audio-url -- NAME AS "audio_url" -- AnyURI OPTIONAL,
> contact UTF8String OPTIONAL,
> parameter -- UNTAGGED -- SEQUENCE OF parameter UTF8String } }
>END
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