Re: [sipcore] Extensions to the reg event package

"Worley, Dale R (Dale)" <dworley@avaya.com> Fri, 17 December 2010 17:04 UTC

From: "Worley, Dale R (Dale)" <dworley@avaya.com>
To: "Thomson, Martin" <Martin.Thomson@andrew.com>, Paul Kyzivat <pkyzivat@cisco.com>, "sipcore@ietf.org" <sipcore@ietf.org>
Date: Fri, 17 Dec 2010 12:01:00 -0500
Thread-Topic: [sipcore] Extensions to the reg event package
Thread-Index: ActxSNxgv9N7FJTlQcWWShNQZ2FghQAJW4oQCydsFBY=
Message-ID: <CD5674C3CD99574EBA7432465FC13C1B2202288B0E@DC-US1MBEX4.global.avaya.com>
References: <CD5674C3CD99574EBA7432465FC13C1B220228896A@DC-US1MBEX4.global.avaya.com> <4CC07E0F.4030508@cisco.com>, <8B0A9FCBB9832F43971E38010638454F03F31EABA6@SISPE7MB1.commscope.com>
In-Reply-To: <8B0A9FCBB9832F43971E38010638454F03F31EABA6@SISPE7MB1.commscope.com>
Accept-Language: en-US
Content-Language: en-US
acceptlanguage: en-US
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
Subject: Re: [sipcore] Extensions to the reg event package
Precedence: list

> From: Thomson, Martin [Martin.Thomson@andrew.com]
> 
> In practice, a processor that uses the original schema definitions is
> likely to reject a document that uses the modified structure.
> 
> For instance, the original might define (A, B, *) where * is an
> extension point, and the extension defines (A, B, C, *).  Because if
> the way that * is defined, it means anything not in this namespace.
> If the original sees C, which claims to be in the same namespace, it
> rejects it.

Then, to phrase it another way, schemas are extensible in that
elements of other namespaces may be inserted, but not new elements of
the existing namespace.

> The size of namespace declarations is a common source of complaints.
> The usual response is to point folks at ASN.1+?ER.  I wouldn't dream
> of being so rude.

The DER and PER encodings do seem to be much denser, but I don't see
any mechanism for extensibility.  XER seems to be essentially what
we're already doing.

Dale

[sipcore] Extensions to the reg event package Worley, Dale R (Dale)
Re: [sipcore] Extensions to the reg event package Paul Kyzivat
Re: [sipcore] Extensions to the reg event package Thomson, Martin
Re: [sipcore] Extensions to the reg event package Worley, Dale R (Dale)