[Fwd: Re: [Fwd: [Fwd: [Fwd: Re: H.323 mobility first darft]]]]

[Edgar Martinez [1]]

The default behaviour of the compiler we use was not to make it a huge
value.  We've now included something which makes it treat it as a huge
value.  If the directive specified is standard then perhaps we should
include it in the ASN.1.  It is in the form of a comment so presumably
compilers that don't understand it will skip it.  This should improve
interoperability, which, after all, is what standards are all about (or
should be!).  At least it could be in the implementor's guide.

Pete

=============================================
Pete Cordell
pete at tech-know-ware.com
=============================================

-----Original Message-----
From: Bancroft Scott <baos at OSS.COM>
To: ITU-SG16 at MAILBAG.INTEL.COM <ITU-SG16 at MAILBAG.INTEL.COM>
Date: 08 September 1999 11:28
Subject: Re: Issues with H.235


>On Wed, 8 Sep 1999, Pete Cordell wrote:
>
>> I'm implementing some of the H.235 stuff and have a few concerns.
>>
>> RandomVal is defined as INTEGER only.  This is not a particularly helpful
>> definition as in theory this could be a million bit + integer if needed.
>> Not many computers support such types!  In fact, a well known ASN.1
compiler
>> maps this to an int which is a signed 32-bit value on our platform.  Is
this
>> sufficient?  Without further discussion about the range of this value I
feel
>> there is a potential for interoperability problems.
>>
>> Perhaps we can say that RandomVal will never be more than 32 bits long,
and
>> then add a type like RandomSeq as an OCTET STRING for cases when we need
a
>> longer random value.
>
>I disagree.  That would be a limitation of the tool and should be
>corrected by the tool vendor.
>
>Note that if the ASN.1 compiler that you are using supports the
>industry-standard compiler directives then you can say:
>
>        --<ASN1.HugeInteger H235-SECURITY-MESSAGES.RandomVal>--
>
>which instructs the ASN.1 compiler to represent RandomVal locally in a
>format suitable for holding extremely large integer values of the kind you
>have in mind.  The encoding of such values are as specified by the
>encoding rules, independent of the local representation.
>
>Such directives were made an industry standard two or three years ago by a
>consortium of companies including Sun, IBM, OSS Nokalva, Hewlett Packard,
>Ericsson and others, and you can expect up to date compilers to support
>them.
>
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