Subject: Re: Differences between ABNF and ASN.1 in ActionReply

From: John Segers <[email-masked]>
Date: Wed, 1 Nov 2000 10:31:34 +0100

Terry,

Having already responded to your first question, I only comment on the
second point that you raised in this message.

The difference between the ASN.1 and ABNF was not intentional.  It is
indeed the intention that the SEQUENCE of CommandReply be left empty if
there is an error at the action level (section 8.2.2 has some text on
what error codes to include at which level in a reply if malformed
requests are received).

As far as I can tell, the ABNF also allows an action reply to contain
contextProperties AND commandReply:

actionReply          = CtxToken EQUAL ContextID LBRKT
                       ( errorDescriptor / commandReply ) RBRKT

commandReply       = (( contextProperties [COMMA commandReplyList] ) /
                        commandReplyList )

allows an action reply to contain contextProperties plus, optionally a
list of command replies.

Cheers,

John

Terry L Anderson wrote:
[snip]
> 2. earlier today Sankar Raman asked about ActionReply.  In the ASN.1
> ActionReply contains
> commandReply    SEQUENCE OF CommandReply
> which is required and a
> contextReply which is optional
> while in the ABNF
> an ActionReply that contained an errorDescriptor cannot contain either a
> contextProperties or a commandReplyList
>
> Is this intentional? Perhaps since SEQUENCE OF can be of zero length so
> not really contain a CommandReply, but there is still the minor
> difference that the ASN.1 permits a contextProperties and a commandReply
> while the ASN.1 does not.
>
> --
> ------------------------------------------------------------
> Terry L Anderson              mailto:[email-masked]
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John Segers                                  email: [email-masked]
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---

From: Terry L Anderson <[email-masked]>
Date: Wed, 1 Nov 2000 10:13:52 -0500

> allows an action reply to contain contextProperties plus, optionally a

My point was that ASN.1 permits an actionReply to contain an errorDescriptor
as well as a commandReply or an errorDescriptor as well as a contextReply,
while the ABNF does not - perhaps only an unuseful difference.  Writing the
ASN.1 to disallow the combination would have made it more complex.