Re: [Sipping] I-D ACTION:draft-ietf-sipping-uri-list-message-06.txt

[Jari Urpalainen <[e-mail]>]

ext [e-mail] wrote:

>A New Internet-Draft is available from the on-line Internet-Drafts directories.
>This draft is a work item of the Session Initiation Proposal Investigation Working Group of the IETF.
>
>	Title		: Multiple-Recipient MESSAGE Requests in the Session Initiation Protocol (SIP)
>	Author(s)	: M. Garcia-Martin, G. Camarillo
>	Filename	: draft-ietf-sipping-uri-list-message-06.txt
>	Pages		: 20
>	Date		: 2006-1-31
>	
>This document specifies how to request a SIP URI-list service to send
>   a copy of a MESSAGE to a set of destinations.  The client sends a SIP
>   MESSAGE request with a URI-list to the MESSAGE URI-list service,
>   which sends a similar MESSAGE request to each of the URIs included in
>   the list.
>
>A URL for this Internet-Draft is:
>http://www.ietf.org/internet-drafts/draft-ietf-sipping-uri-list-message-06.txt
>
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>
Still another schema related comment. While there's an increasing amount 
of i-d's that extend a base schema (mime-type defined) there's not a 
BCP, AFAIK, how extension schemas should reference the base schemas. 
With w3c schemas, a simple way to tell this to the validating process, 
is to use <xs:import> or <xs:include> statements within the extension 
schema. So I'd propose to add <xs:import> into this schema to explicitly 
reference xcap-list schema:

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema targetNamespace="urn:ietf:params:xml:ns:capacity"
       xmlns="urn:ietf:params:xml:ns:capacity"
       xmlns:rls="urn:ietf:params:xml:ns:resource-lists"
       xmlns:xs="http://www.w3.org/2001/XMLSchema"
       elementFormDefault="qualified"
       attributeFormDefault="unqualified">

  <xs:import namespace="urn:ietf:params:xml:ns:resource-lists"
     schemaLocation="xcap-list.xsd"/>

....

In pragmatic world, i.e. when you really try to validate a combination 
of schemas you typically also have other means to "tell" this to the 
validator, but this is a "standard w3c schema way". Anyhow, this sort of 
explicit way is imo better than only clarifying text (which is ok and 
desirable, of course).

In addition, this encouraged me to look at 
<http://www.iana.org/assignments/xml-registry/schema.html>. This list 
references schemas which have also namespace registrations, but not e.g. 
those without namespace (Chameleon namespace design). Also relationships 
of schemas are missing (like in this case) and e.g. no registrations for 
RELAX NG schemas. Although this is another story, but there's definitely 
some need for improvement here if the purpose of this table is to help 
implementers, etc...
br, Jari

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