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Liaison Statement: OMA-LS_834 XML validation issues of IANA copies of XML schemas from RFC 4826

Submission Date: 2009-10-03
From: OMA (Dean Willis)
To: IETF SIMPLE Working Group (simple@ietf.org)
Cc:ben@nostrum.com
rjs@nostrum.com
fluffy@cisco.com
Response Contact: Uwe Rauschenbach
Musa Unmehopa
Kyung-Tak Lee
Technical Contact: Uwe Rauschenbach
Musa Unmehopa
Kyung-Tak Lee
Purpose: For action
Deadline: 2009-11-01 Action Taken
Attachments: PDF of original LS from OMA
Body:
1 Overview

This Liaison Statement reports XML validation problems in the XML
schemas that
were introduced in RFC 4826 and asks for correction. 

2 Proposal

In the specifications of Parlay X (Web Service Interfaces for Parlay)
and PoC
Push to Talk over Cellular), the Open Mobile Alliance references the
XML
schemas that have been developed by IETF in RFC 4826.

This RFC defines two XML schemas: resource-lists
(urn:ietf:params:xml:ns:resource-lists) and rls-services
(urn:ietf:params:xml:ns:rls-services).

During ongoing specification work, the following XML validation
problems have 
been identified in the instances of these schemas that are provided by
IANA in 
the XML schema repository [1].

Validation problems in urn:ietf:params:xml:ns:resource-lists Schema as

available from [2]

This file triggers the following validation errors (using Xerces):

SystemID:http://www.iana.org/assignments/xml-registry/schema/resource-lists.xsd

Position: 4:35

Description: cos-nonambig:
WC[##other:"urn:ietf:params:xml:ns:resource-lists"] 
and WC[##other:"urn:ietf:params:xml:ns:resource-lists"] (or elements
from their 
substitution group) violate "Unique Particle Attribution". During
validation 
against this schema, ambiguity would be created for those two
particles.

URL: http://www.w3.org/TR/xmlschema-1/#cos-nonambig

SystemID:
http://www.iana.org/assignments/xml-registry/schema/resource-lists.xsd
Position: 10:29

Description: cos-nonambig:
WC[##other:"urn:ietf:params:xml:ns:resource-lists"] 
and WC[##other:"urn:ietf:params:xml:ns:resource-lists"] (or elements
from their 
substitution group) violate "Unique Particle Attribution". During
validation 
against this schema, ambiguity would be created for those two
particles.

URL: http://www.w3.org/TR/xmlschema-1/#cos-nonambig 

A comparison has shown that the file in the IANA repository is
different from 
what has been defined in section 3.2 of RFC 4826. Furthermore, it has
been 
noted that the schema in RFC 4826 actually does validate.

Validation problems in urn:ietf:params:xml:ns:rls-services Schema as
available 
from [3]

This XML schema imports the resource-lists schema, however does not
provide a 
schema location for it. Due to this, the rls-services schema does not
validate 
because the validator can not fetch the referenced schema. 

It is therefore suggested to add a schemaLocation attribute to the
<import> 
declaration of the rls-services XML schema instance in the IANA
repository.

OMA ARC and MWG would furthermore like to inform you of the following
finding 
(even though it does not constitute a validation error of the schema):
The 
rls-services schema defined in section 4.2 of RFC 4826 differs from the

instance in [3] in one processing instruction. More precisely, the
version in 
RFC 4826 contains “processContents="lax"” which is not contained in [3]
as 
highlighted below:


    <xs:complexType name="serviceType">

        <xs:sequence>

            <xs:choice>

                <xs:element name="resource-list" type="xs:anyURI"/>

                <xs:element name="list" type="rl:listType"/>

            </xs:choice>

            <xs:element name="packages" type="packagesType"
minOccurs="0"/>

            <xs:any namespace="##other" 

				processContents="lax" minOccurs="0" maxOccurs="unbounded"/>

        </xs:sequence>

        <xs:attribute name="uri" type="xs:anyURI" use="required"/>

        <xs:anyAttribute namespace="##other" processContents="lax"/>

    </xs:complexType>

References
[1] IANA XML Registry, URL:
http://www.iana.org/assignments/xml-registry
/schema.html

[2]
http://www.iana.org/assignments/xml-registry/schema/resource-lists.xsd


[3]
http://www.iana.org/assignments/xml-registry/schema/rls-services.xsd 

3 Requested Action(s)

IETF is kindly requested to fix the issues indicated above.


4 Conclusion

The OMA ARC and MWG groups wish to thank IETF in advance for
considering our 
request, and are looking forward to continued collaboration and
exchange.