Mr Bancroft Scott
Mr Eduard Lascu
ASN.1 list

I think this question that you have discussed shows that there
is a need to explain to newcomers to ASN.1 to understand the
clear division between writing an ASN.1 specification and
implementing it.

For newcomers trying to understand how they can use ASN.1 to
describe the protocol they are developing there should be
general simple steps to follow.

And in this connection I would like to advocate the "ASN.1 light"
idea where newcomers could be guided to simple uses of ASN.1.

F.ex. many people have had problems with understanding what the
word "DEFAULT" does in a spec.

When Eduard Lascu is looking for a language for a Transportation
Protocol he should as quickly as possible learn that ASN.1 can be
extremely simple and easy to specify.

Its different when newcomers have to implement a protocol from
some standardisation body. Then they have to cope with all the
twists and corners of ASN.1 that you really have to be an afficionado
to appreciate after all these years and versions.

Steen Oluf Karlsen
S�holtvej 6
Vester Vandet
DK-7700 Thisted
Danmark
Tel +45 97 97 72 72
email [EMAIL PROTECTED]



-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of
Bancroft Scott
Sent: 3. april 2002 23:36
To: [EMAIL PROTECTED]
Subject: RE: [ASN.1] Encoding of a sequence with optional and default
data members in BER


On Wed, 3 Apr 2002, Eduard Lascu wrote:

> Thanks to all of you who tried to give me a hint as to what the solution
for
> my problems might be.
>
> As Mr. Bancroft pointed, the syntax I used to describe the structure was
not
> quite conforming to the ASN.1 notation and I apologize for that. I rather
> had in my mind the C++ syntax when I thought how to describe the
structure.
>
> I was asked if I see a big market for OER. I am not an authority in
> ASN.1 tools and I only came across this notation and all the encoding
> rules that can be used with it through my recent involvement in the
> development of some projects. I do know that OER was developed in the
> Traffic Management and Smart Transportation Systems community and,
> from what I understand, at least for these kinds of implementation
> they aim to use it intensively. There is a bunch of emerging standards
> in North America related to Intelligent Transportation Systems that
> recommend using OER when it comes to choose a set of encoding rules.
> In fact, working with one of these projects caused me to bump into all
> these problems. Just as a detail without much importance, OER will
> generate binary images for encoded objects almost half the size of
> those generated using BER.

Note that the Packed Encoding Rules of ASN.1 (PER) is even more compact
than OER.

> Who and how will decide whether to use Automatic Tags? Is this
> something that�s agreed upon before the implementation is started and
> is like a global environment parameter or is dictated by the context
> and nature of the information that is supposed to be exchanged?

Automatic tagging is specified by the organization which created the ASN.1
module that you using in your application.  It is an integral part of the
application's ASN.1 specification, just as the types defined by it are.

BTW, my last name is Scott.

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