OASIS Mailing List ArchivesView the OASIS mailing list archive below
or browse/search using MarkMail.

 


Help: OASIS Mailing Lists Help | MarkMail Help

emergency message

[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [List Home]


Subject: Re: [Fwd: [emergency] Questions on ASN.1 and IPAWS Profile / CAP1.2]


Thanks Alessandro,

I appreciate the explanation.

Happy Holidays,
Rex

Alessandro Triglia wrote:
> Has the backward-compatibility issue been reported in some TC document or
> email?
>
> Without having it at hand right now, I'll make the following observation.
>
> The X.694 standard, which was used to create the ASN.1 schemas in CAP 1.1
> and CAP 1.2, specifies a rigorous mapping from XML Schema to ASN.1.  The
> mapping rules are so rigorous that they ensure that one can seamlessly
> translate between an XML encoding and a PER encoding just by applying the
> standard encoding rules (PER and EXER) to the ASN.1 schema.  This makes it
> easy to build an application that can handle both encodings, so long as the
> application uses conforming ASN.1 encoder/decoders.
>
> The downside of following strict mapping rules from XML Schema to ASN.1 is
> that when the original XML schema is modified, the new ASN.1 schema may not
> be backward-compatible with the old ASN.1 schema.  This can happen even in
> case of seemingly minor changes such as a new item being added to an
> enumeration, or a required attribute or child element becoming optional, or
> vice versa.  In the case of CAP 1.2 vs. 1.1, the changes made to the XML
> schema cause the PER encodings to change significantly.
>
> But again, the upside of using X.694 is that applications will be able to
> easily translate back and forth between ASN.1/PER and XML.
>
> We cannot just have both benefits, and the X.694 standard determines which
> one we can have.
>
> Alessandro
>
>
>   
>> -----Original Message-----
>> From: Rex Brooks [mailto:rexb@starbourne.com] 
>> Sent: Tuesday, December 22, 2009 23:16
>> To: tony@yaanatech.com
>> Cc: TIMOTHY.D.GILMORE@saic.com; 
>> emergency@lists.oasis-open.org; MARTENA.M.GOOCH@saic.com; 
>> Olivier DUBUISSON; Elysa Jones; Jacob Westfall
>> Subject: Re: [Fwd: [emergency] Questions on ASN.1 and IPAWS 
>> Profile / CAP 1.2]
>>
>> Thanks Tony,
>>
>> I misstated myself.  I didn't mean to give the impression 
>> that I thought
>> ASN.1 was mainly aimed at European communities, but that the 
>> ASN.1 representation of CAP 1.1 was. That  was why I said 
>> that this was the "first time I heard ASN.1 encoded CAP 
>> messages in relation to any US-specific implementation..."  
>>
>> That was my perception of it, but I was not involved with 
>> that effort except that it occurred at the same time as the 
>> CAP 1.1 errata, which I did work on, was working its way 
>> through the OASIS process.
>>
>> I don't think the current situation is related to The 
>> CAP-IPAWS profile except insofar as it prompted the effort to 
>> update CAP to 1.2 with the new <avoid> response type. I have 
>> added Elysa Jones and Jacob Westfall to this message, and I 
>> would like to draw everyone's attention to Tim Gimore's 
>> message to the EM TC email list this morning 
>> http://www.oasis-open.org/apps/org/workgroup/emergency/email/a
>> rchives/200912/msg00023.html
>> because this is the message to which I was responding.
>>
>> At this point it is probably best if I don't dig myself in 
>> any deeper. I invite Elysa and/or Jacob to weigh in if they 
>> wish. As the principle author of CAP v1.2, Jacob is most 
>> knowledgeable. We have followed the OASIS TC Process 
>> scrupulously and provided ample opportunity for issues such 
>> as those which have been brought up recently  to be addressed. 
>> However, the ASN.1 backward compatibility issue surfaced 
>> after the initial 60-Day Public Review, so were out of scope 
>> for the second 15-Day Review which recently ended, and after 
>> which we have continued to move CAP v1.2 forward.
>>
>> Best Regards,
>> Rex
>>
>>
>>     
>>> Hi Rex,
>>>
>>> My ITU-T colleague Olivier Dubuisson forwarded you email message.
>>> My group in ITU-T is responsible for X.1303 - which not only 
>>> globalizes the CAP specification, but also usually provides a much 
>>> more efficient and compact ASN.1 version, as well as a new global 
>>> identifier space for its use.  The namespace includes uses for 
>>> parties, messages and policies, and was done with multiple 
>>>       
>> agencies, especially including the WMO.
>>     
>>> As a side note, I'm U.S. based, as well as a former SAIC 
>>>       
>> employee and 
>>     
>>> appointed member of the FCC WARN Act advisory committee.
>>>
>>> ASN.1 is definitely not a "European thing."  In fact, it 
>>>       
>> was developed 
>>     
>>> in the 1980s as a global standard and for years was 
>>>       
>> mandated by both 
>>     
>>> DOD and the U.S. telecommunications industry.  I'll admit to not 
>>> following current IPAWS activity, but there is no reason 
>>>       
>> why the ASN.1 
>>     
>>> equivalent could not be used, as long as translations were 
>>>       
>> ensured at 
>>     
>>> requisite interfaces where the XML versions are necessary.  
>>>       
>> The ASN.1 
>>     
>>> version of CAP is definitely much more compact - which work in its 
>>> favor in both one-to-many architectures, as well as small 
>>>       
>> form factor 
>>     
>>> devices.
>>>
>>> Hope this helps,
>>> --tony
>>>
>>>
>>>       
>>>> -------- Original Message --------
>>>> Subject: Re: [emergency] Questions on ASN.1 and IPAWS 
>>>>         
>> Profile / CAP 
>>     
>>>> 1.2
>>>> Date: Tue, 22 Dec 2009 06:00:11 -0800
>>>> From: Rex Brooks <rexb@starbourne.com>
>>>> Reply-To: rexb@starbourne.com
>>>> Organization: Starbourne Communications Design
>>>> To: Gilmore, Timothy <TIMOTHY.D.GILMORE@saic.com>
>>>> CC: emergency@lists.oasis-open.org,  "Gooch, Martena M." 
>>>> <MARTENA.M.GOOCH@saic.com>
>>>>
>>>> Hi Tim,
>>>>
>>>> This is the first time that I've heard ASN.1 encoded CAP 
>>>>         
>> messages in 
>>     
>>>> relation to any US-specific implementation, so I'll have to plead 
>>>> ignorance on this. I was under the impression that while this is 
>>>> allowable, e.g. not specifically discouraged, in US-Canada, it was 
>>>> mainly aimed at European countries/communities.
>>>>
>>>>         
>>>
>>>       
>> --
>> Rex Brooks
>> President, CEO
>> Starbourne Communications Design
>> GeoAddress: 1361-A Addison
>> Berkeley, CA 94702
>> Tel: 510-898-0670
>>
>>
>> ---------------------------------------------------------------------
>> To unsubscribe from this mail list, you must leave the OASIS TC that
>> generates this mail.  Follow this link to all your TCs in OASIS at:
>> https://www.oasis-open.org/apps/org/workgroup/portal/my_workgr
>> oups.php 
>>
>>     
>
>
> ---------------------------------------------------------------------
> To unsubscribe from this mail list, you must leave the OASIS TC that
> generates this mail.  Follow this link to all your TCs in OASIS at:
> https://www.oasis-open.org/apps/org/workgroup/portal/my_workgroups.php 
>
>
>
>   

-- 
Rex Brooks
President, CEO
Starbourne Communications Design
GeoAddress: 1361-A Addison
Berkeley, CA 94702
Tel: 510-898-0670



[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [List Home]