<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:tns="urn:ietf:params:xml:ns:dialog-info" targetNamespace="urn:ietf:params:xml:ns:dialog-info" elementFormDefault="qualified" attributeFormDefault="unqualified">
<!-- This import brings in the XML language attribute xml:lang-->
  <xs:import namespace="http://www.w3.org/XML/1998/namespace" schemaLocation="http://www.w3.org/2001/03/xml.xsd"/>
  <xs:element name="dialog-info">
    <xs:complexType>
      <xs:sequence>
        <xs:element ref="tns:dialog" minOccurs="0" maxOccurs="unbounded"/>
        <xs:any namespace="##other" processContents="lax" minOccurs="0" maxOccurs="unbounded"/>
      </xs:sequence>
      <xs:attribute name="version" type="xs:nonNegativeInteger" use="required"/>
      <xs:attribute name="state" use="required">
        <xs:simpleType>
          <xs:restriction base="xs:string">
            <xs:enumeration value="full"/>
            <xs:enumeration value="partial"/>
          </xs:restriction>
        </xs:simpleType>
      </xs:attribute>
      <xs:attribute name="entity" type="xs:anyURI" use="required"/>
    </xs:complexType>
  </xs:element>
  <xs:element name="dialog">
    <xs:complexType>
      <xs:sequence>
        <xs:element ref="tns:state" minOccurs="1" maxOccurs="1"/>
        <xs:element name="duration" type="xs:nonNegativeInteger" minOccurs="0" maxOccurs="1"/>
        <xs:element name="replaces" minOccurs="0" maxOccurs="1">
          <xs:complexType>
            <xs:attribute name="call-id" type="xs:string" use="required"/>
            <xs:attribute name="local-tag" type="xs:string" use="required"/>
            <xs:attribute name="remote-tag" type="xs:string" use="required"/>
          </xs:complexType>
        </xs:element>
        <xs:element name="referred-by" type="tns:nameaddr" minOccurs="0" maxOccurs="1"/>
        <xs:element name="route-set" minOccurs="0" maxOccurs="1">
          <xs:complexType>
            <xs:sequence>
              <xs:element name="hop" type="xs:string" minOccurs="1" maxOccurs="unbounded"/>
            </xs:sequence>
          </xs:complexType>
        </xs:element>
        <xs:element name="local" type="tns:participant" minOccurs="0" maxOccurs="1"/>
        <xs:element name="remote" type="tns:participant" minOccurs="0" maxOccurs="1"/>
        <xs:any namespace="##other" processContents="lax" minOccurs="0" maxOccurs="unbounded"/>
      </xs:sequence>
      <xs:attribute name="id" type="xs:string" use="required"/>
      <xs:attribute name="call-id" type="xs:string" use="optional"/>
      <xs:attribute name="local-tag" type="xs:string" use="optional"/>
      <xs:attribute name="remote-tag" type="xs:string" use="optional"/>
      <xs:attribute name="direction" use="optional">
        <xs:simpleType>
          <xs:restriction base="xs:string">
            <xs:enumeration value="initiator"/>
            <xs:enumeration value="recipient"/>
          </xs:restriction>
        </xs:simpleType>
      </xs:attribute>
    </xs:complexType>
  </xs:element>
  <xs:complexType name="participant">
    <xs:sequence>
      <xs:element name="identity" type="tns:nameaddr" minOccurs="0" maxOccurs="1"/>
      <xs:element name="target" minOccurs="0" maxOccurs="1">
        <xs:complexType>
          <xs:sequence>
            <xs:element name="param" minOccurs="0" maxOccurs="unbounded">
              <xs:complexType>
                <xs:attribute name="pname" type="xs:string" use="required"/>
                <xs:attribute name="pval" type="xs:string" use="required"/>
              </xs:complexType>
            </xs:element>
          </xs:sequence>
          <xs:attribute name="uri" type="xs:string" use="required"/>
        </xs:complexType>
      </xs:element>
      <xs:element name="session-description" type="tns:sessd" minOccurs="0" maxOccurs="1"/>
      <xs:element name="cseq" type="xs:nonNegativeInteger" minOccurs="0" maxOccurs="1"/>
      <xs:any namespace="##other" processContents="lax" minOccurs="0" maxOccurs="unbounded"/>
    </xs:sequence>
  </xs:complexType>
  <xs:complexType name="nameaddr">
    <xs:simpleContent>
      <xs:extension base="xs:anyURI">
        <xs:attribute name="display-name" type="xs:string" use="optional"/>
      </xs:extension>
    </xs:simpleContent>
  </xs:complexType>
  <xs:complexType name="sessd">
    <xs:simpleContent>
      <xs:extension base="xs:string">
        <xs:attribute name="type" type="xs:string" use="required"/>
      </xs:extension>
    </xs:simpleContent>
  </xs:complexType>
  <xs:element name="state">
    <xs:complexType>
      <xs:simpleContent>
        <xs:extension base="xs:string">
          <xs:attribute name="event" use="optional">
            <xs:simpleType>
              <xs:restriction base="xs:string">
                <xs:enumeration value="cancelled"/>
                <xs:enumeration value="rejected"/>
                <xs:enumeration value="replaced"/>
                <xs:enumeration value="local-bye"/>
                <xs:enumeration value="remote-bye"/>
                <xs:enumeration value="error"/>
                <xs:enumeration value="timeout"/>
              </xs:restriction>
            </xs:simpleType>
          </xs:attribute>
          <xs:attribute name="code" use="optional">
            <xs:simpleType>
              <xs:restriction base="xs:positiveInteger">
                <xs:minInclusive value="100"/>
                <xs:maxInclusive value="699"/>
              </xs:restriction>
            </xs:simpleType>
          </xs:attribute>
        </xs:extension>
      </xs:simpleContent>
    </xs:complexType>
  </xs:element>
</xs:schema>
