source: wsdl/fedd_types.xsd @ df783c1

<?xml version="1.0"?>
<xsd:schema targetNamespace="http://www.isi.edu/faber/fedd_types"
  xmlns:tns="http://www.isi.edu/faber/fedd_types"
  xmlns:topdl="http://www.isi.edu/faber/topdl"
  xmlns:xsd="http://www.w3.org/2001/XMLSchema"
  xmlns="http://www.w3.org/2000/10/XMLSchema">

  <xsd:complexType name="IDType">
    <xsd:annotation>
      <xsd:documentation>
        An ID is an identifier for a principal, service, or object.  This type
        is currently polymorphic o allow different implementations of type,
        though running code primarily uses localnames and fedids.
      </xsd:documentation>
    </xsd:annotation>
    <xsd:choice>
      <xsd:element name="uuid" type="xsd:base64Binary"/>
      <xsd:element name="fedid" type="xsd:base64Binary"/>
      <xsd:element name="uri" type="xsd:string"/>
      <xsd:element name="localname" type="xsd:string"/>
      <xsd:element name="kerberosUsername" type="xsd:string"/>
    </xsd:choice>
  </xsd:complexType>

  <xsd:complexType name="nodeType">
    <xsd:annotation>
      <xsd:documentation>
        A node from an Emulab.  It may have 0 or more images or hardware
        types associated with it.  As this description is used for
        acquiring access to the testbed in question, multiple images or
        types are considered options.  Specifying multiple image names
        indicates that the requester is looking for support for any of
        them.
      </xsd:documentation>
    </xsd:annotation>
    <xsd:sequence>
      <xsd:element name="image" type="xsd:string" minOccurs="0"
        maxOccurs="unbounded"/>
      <xsd:element name="hardware" type="xsd:string" minOccurs="0"
        maxOccurs="unbounded"/>
    </xsd:sequence>
    <xsd:attribute name="count" type="xsd:int" use="optional"/>
  </xsd:complexType>

  <xsd:simpleType name="kindType">
    <xsd:annotation>
      <xsd:documentation>
        An indication of how requested networking capacity is measured.
        This will undoubtably expand.
      </xsd:documentation>
    </xsd:annotation>
    <xsd:restriction base="xsd:string">
      <xsd:enumeration value="max"/>
      <xsd:enumeration value="average"/>
    </xsd:restriction>
  </xsd:simpleType>

  <xsd:simpleType name="statusType">
    <xsd:annotation>
      <xsd:documentation>
        The current state of the experiment.
      </xsd:documentation>
    </xsd:annotation>
    <xsd:restriction base="xsd:string">
      <xsd:enumeration value="active"/>
      <xsd:enumeration value="starting"/>
      <xsd:enumeration value="terminating"/>
      <xsd:enumeration value="failed"/>
    </xsd:restriction>
  </xsd:simpleType>

  <xsd:complexType name="capacityType">
    <xsd:annotation>
      <xsd:documentation>
        A strawman network capacity description for access negotiation.
        This will come to include more and more interesting parameters.
      </xsd:documentation>
    </xsd:annotation>
    <xsd:sequence>
      <xsd:element name="rate" type="xsd:double"/>
      <xsd:element name="kind" type="tns:kindType"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:complexType name="accessType">
    <xsd:annotation>
      <xsd:documentation>
        This captures an access credential that will be used to access
        resources.  These are certificates or public keys.  The type is
        used to designate the key to which access should be bound, or on
        a reply has been bound.  Dynamic credentials where new keys have
        been created may also be passed in this kind of field.
      </xsd:documentation>
    </xsd:annotation>
    <xsd:choice>
      <xsd:element name="X509" type="xsd:base64Binary"/>
      <xsd:element name="sshPubkey" type="xsd:base64Binary"/>
      <xsd:element name="pgpPubkey" type="xsd:base64Binary"/>
    </xsd:choice>
  </xsd:complexType>

  <xsd:simpleType name="userRole">
    <xsd:annotation>
      <xsd:documentation>
        This defines the role the user/account is playing in the
        federated experiment.  An account being accessed by the
        federation system to create the experiment is in the
        experimentCreation role and the accounts that experimenters will
        use to access local testbed services (e.g., rebooting a local
        node) are serviceAccess roles.
      </xsd:documentation>
    </xsd:annotation>
    <xsd:restriction base="xsd:string">
      <xsd:enumeration value="serviceAccess"/>
      <xsd:enumeration value="experimentCreation"/>
    </xsd:restriction>
  </xsd:simpleType>


  <xsd:complexType name="userType">
    <xsd:annotation>
      <xsd:documentation>
        The definition of a user principal.  It includes the
        identification of the user as an ID type, the access credential(s)
        that the user will use, and the role of the user, if any.
        Multiple access keys may be used, and it is also possible for
        the user to be anonymous.  Though it is possible to specify a
        user without ID, access, or role, it is difficult to imagine
        such a user being useful.
      </xsd:documentation>
    </xsd:annotation>
    <xsd:sequence>
      <xsd:element name="userID" type="tns:IDType" minOccurs="0"
        maxOccurs="1"/>
      <xsd:element name="access" type="tns:accessType" minOccurs="0"
        maxOccurs="unbounded"/>
      <xsd:element name="role" type="tns:userRole" minOccurs="0" maxOccurs="1"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:complexType name="fedAttrType">
    <xsd:annotation>
      <xsd:documentation>
        A general attribute/value pair for passing federation parameters and
        preferences.  Anything encodable in XML is allowed.  This is a
        point for customization and extension.
      </xsd:documentation>
    </xsd:annotation>
    <xsd:sequence>
      <xsd:element name="attribute" type="xsd:string"/>
      <xsd:element name="value" type="xsd:string"/>
    </xsd:sequence>
  </xsd:complexType>


  <xsd:complexType name="resourcesType">
    <xsd:annotation>
      <xsd:documentation>
        The estimate of resources a requester is looking for, or the
        response of a testbed indicating what it can provide.  This is
        something of a placeholder for a full resource specification,
        and alternative encodings are likely to be imported.
      </xsd:documentation>
    </xsd:annotation>
    <xsd:sequence>
      <xsd:element name="node" type="tns:nodeType" minOccurs="0"
        maxOccurs="unbounded" />
      <xsd:element name="capacity" type="tns:capacityType" minOccurs="0"
        maxOccurs="unbounded"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:complexType name="mapType">
    <xsd:annotation>
      <xsd:documentation>
        Explicit translation of testbed attribute in a federated experiment
        description to the URI at which the controlling federation
        system can be reached.  Used in a creation request.

        This type allows tools to encode experiments in familiar local
        names for experimenters while providing remote federation
        systems the information to map the local name into a service
        location.
      </xsd:documentation>
    </xsd:annotation>
    <xsd:sequence>
      <xsd:element name="testbed" type="tns:IDType"/>
      <xsd:element name="uri" type="xsd:string"/>
    </xsd:sequence>
  </xsd:complexType>


  <xsd:complexType name="projectType">
    <xsd:annotation>
      <xsd:documentation>
        A description of the project used to access a testbed.  Includes
        the testbed being accessed, the project name (often a local
        name, scoped by the testbed), and any users who have been
        granted access or for whom access is being requested.
      </xsd:documentation>
    </xsd:annotation>
    <xsd:sequence>
      <xsd:element name="testbed" type="tns:IDType" minOccurs="0"
        maxOccurs="1"/>
      <xsd:element name="name" type="tns:IDType" minOccurs="0" maxOccurs="1"/>
      <xsd:element name="user" type="tns:userType" minOccurs="0"
        maxOccurs="unbounded"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:complexType name="emulabType">
    <xsd:annotation>
      <xsd:documentation>
        A description of an Emulab sufficient for the federation system
        to create a sub experiment on it.  Note that fedAttrs provide an
        extension mechanism by which testbeds may communicate additional
        information and preferences to federation systems that
        understand it.
      </xsd:documentation>
    </xsd:annotation>
    <xsd:sequence>
      <xsd:element name="project" type="tns:projectType"/>
      <xsd:element name="domain" type="xsd:string"/>
      <xsd:element name="boss" type="xsd:string"/>
      <xsd:element name="ops" type="xsd:string"/>
      <xsd:element name="fileServer" type="xsd:string"/>
      <xsd:element name="eventServer" type="xsd:string"/>
      <xsd:element name="fedAttr" type="tns:fedAttrType" minOccurs="0"
        maxOccurs="unbounded"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:complexType name="federatedExperimentType">
    <xsd:annotation>
      <xsd:documentation>
        Naming and Emulab instantiation information about a federant.
        This is returned by various informational requests and as part
        of a successful creation message.
      </xsd:documentation>
    </xsd:annotation>
    <xsd:sequence>
      <xsd:element name="name" type="tns:IDType" minOccurs="1" 
        maxOccurs="unbounded"/>
      <xsd:element name="emulab" type="tns:emulabType"/>
      <xsd:element name="master" type="xsd:boolean"/>
    </xsd:sequence>
  </xsd:complexType>


  <xsd:complexType name="vtoponodeType">
    <xsd:annotation>
      <xsd:documentation>
        Node in the virtual topology of a federated experiment (Emulab
        legacy).  The fields are the local hostname and the IP addresses
        of the experimental interfaces(colon-separated).
      </xsd:documentation>
    </xsd:annotation>
    <xsd:sequence>
      <xsd:element name="vname" type="xsd:string"/>
      <xsd:element name="ips" type="xsd:string"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:complexType name="vtopolanType">
    <xsd:annotation>
      <xsd:documentation>
        LAN in the virtual topology of a federated experiment (Emulab legacy).
        The fields are the name of the LAN/link (vname) the node that
        this description applies to (vnode), the IP of the connection,
        and performance information.
      </xsd:documentation>
    </xsd:annotation>
    <xsd:sequence>
      <xsd:element name="vname" type="xsd:string"/>
      <xsd:element name="vnode" type="xsd:string"/>
      <xsd:element name="ip" type="xsd:string"/>
      <xsd:element name="bandwidth" type="xsd:int"/>
      <xsd:element name="delay" type="xsd:float"/>
      <xsd:element name="member" type="xsd:string"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:complexType name="vtopoType">
    <xsd:annotation>
      <xsd:documentation>
        The virtual topology of a federated experiment (Emulab legacy).
      </xsd:documentation>
    </xsd:annotation>
    <xsd:sequence>
      <xsd:element name="node" type="tns:vtoponodeType" minOccurs="0" 
        maxOccurs="unbounded" />
      <xsd:element name="lan" type="tns:vtopolanType" minOccurs="0"
        maxOccurs="unbounded"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:complexType name="visnodeType">
    <xsd:annotation>
      <xsd:documentation>
        Node in the visualization of a federated experiment (Emulab
        legacy).  Fields include the local hostname of the node, x,y
        coordinates in a 2-dimensional representation, and whether the
        node in the visualization is a host or a LAN.
      </xsd:documentation>
    </xsd:annotation>
    <xsd:sequence>
      <xsd:element name="name" type="xsd:string"/>
      <xsd:element name="x" type="xsd:int"/>
      <xsd:element name="y" type="xsd:int"/>
      <xsd:element name="type" type="xsd:string"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:complexType name="visType">
    <xsd:annotation>
      <xsd:documentation>
        The visualization of a federated experiment (Emulab legacy)
      </xsd:documentation>
    </xsd:annotation>
    <xsd:sequence>
      <xsd:element name="node" type="tns:visnodeType" minOccurs="0"
        maxOccurs="unbounded"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:complexType name="projectAllocType">
    <xsd:annotation>
      <xsd:documentation>
        The information needed to create a dynamic project, specifically
        a project description and the resources in needs access to.
        This is used by an internal fedd interface.
      </xsd:documentation>
    </xsd:annotation>
    <xsd:sequence>
      <xsd:element name="project" type="tns:projectType"/>
      <xsd:element name="resources" type="tns:resourcesType" 
        minOccurs="0" maxOccurs="1"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:complexType name="experimentDescriptionType">
    <xsd:annotation>
      <xsd:documentation>
        The description of the federated experiment, in extended ns2.
      </xsd:documentation>
    </xsd:annotation>
    <xsd:choice>
      <xsd:element name="ns2description" type="xsd:base64Binary"/>
      <xsd:element name="topdldescription" type="topdl:topologyType"/>
    </xsd:choice>
  </xsd:complexType>

  <xsd:complexType name="requestType">
    <xsd:annotation>
      <xsd:documentation>
        Request for access to a testbed.  It includes the testbed from
        which resources are being requested (a single service may
        provide access to many), the user or project requesting access
        (a testbed making the request will leave both empty), the
        resources needed, the access keys to be used in the subsequent
        instantiation and service use, an allocation ID to identify this
        access in later requests, and scheduling information.
      </xsd:documentation>
    </xsd:annotation>
    <xsd:sequence>
      <xsd:element name="destinationTestbed" type="tns:IDType"
        minOccurs="0" maxOccurs="1" />
      <xsd:choice>
        <xsd:element name="project" type="tns:projectType" minOccurs="0" 
          maxOccurs="1"/>
        <xsd:element name="user" type="tns:userType" minOccurs="0"
          maxOccurs="unbounded"/>
      </xsd:choice>
      <xsd:element name="resources" type="tns:resourcesType" minOccurs="0" 
        maxOccurs="1"/>
      <xsd:element name="createAccess" type="tns:accessType" minOccurs="1" 
        maxOccurs="unbounded"/>
      <xsd:element name="serviceAccess" type="tns:accessType" minOccurs="1" 
        maxOccurs="unbounded"/>
      <xsd:element name="exportProject" type="tns:IDType" 
        minOccurs="0" maxOccurs="1"/>
      <xsd:element name="allocID" type="tns:IDType"/>
      <xsd:element name="when" type="xsd:dateTime" minOccurs="0" maxOccurs="1"/>
      <xsd:element name="until" type="xsd:dateTime" minOccurs="0" 
        maxOccurs="1"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:complexType name="responseType">
    <xsd:annotation>
      <xsd:documentation>
        Response to an access request.  Includes the allocation, the
        information needed to access creation and experiment services
        and scheduling information.
      </xsd:documentation>
    </xsd:annotation>
    <xsd:sequence>
      <xsd:element name="allocID" type="tns:IDType"/>
      <xsd:element name="emulab" type="tns:emulabType"/>
      <xsd:element name="when" type="xsd:dateTime" minOccurs="0" maxOccurs="1"/>
      <xsd:element name="until" type="xsd:dateTime" minOccurs="0" 
        maxOccurs="1"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:complexType name="releaseRequestType">
    <xsd:annotation>
      <xsd:documentation>
        A request to release the access rights allocated by an earlier 
        RequestAccess call.
      </xsd:documentation>
    </xsd:annotation>
    <xsd:sequence>
      <xsd:element name="allocID" type="tns:IDType"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:complexType name="releaseResponseType">
    <xsd:annotation>
      <xsd:documentation>
        Indication that the access has been terminated.
      </xsd:documentation>
    </xsd:annotation>
    <xsd:sequence>
      <xsd:element name="allocID" type="tns:IDType"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:complexType name="createRequestType">
    <xsd:annotation>
      <xsd:documentation>
        A request to embed a federated experiment across testbeds.  Non-
        standard local names for testbeds are included in the
        testbedmap, the user making the request, the experiment
        description, master testbed, and a suggested experiment name are
        included.  More than one name can be suggested, either as
        synonyms (a fedid and a localname) or as choices (multiple
        localnames).
      </xsd:documentation>
    </xsd:annotation>
    <xsd:sequence>
      <xsd:element name="testbedmap" type="tns:mapType" minOccurs="0"
        maxOccurs="unbounded"/>
      <xsd:element name="user" type="tns:userType" minOccurs="1"
        maxOccurs="unbounded"/>
      <xsd:element name="experimentdescription" 
        type="tns:experimentDescriptionType"/>
      <xsd:element name="master" type="xsd:string"/>
      <xsd:element name='exportProject' type="tns:IDType"/>
      <xsd:element name="experimentID" type="tns:IDType" minOccurs="0" 
        maxOccurs="1"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:complexType name="createResponseType">
    <xsd:annotation>
      <xsd:documentation>
        Returned to let the caller know that the request is underway and what
        credentials will eventauly be able to be used to access them.
      </xsd:documentation>
    </xsd:annotation>
    <xsd:sequence>
      <xsd:element name="experimentID" type="tns:IDType" minOccurs="1"
        maxOccurs="unbounded"/>
      <xsd:element name="experimentStatus" type="tns:statusType"/>
      <xsd:element name="experimentAccess" type="tns:accessType" minOccurs="0"
        maxOccurs="1"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:complexType name="vtopoRequestType">
    <xsd:annotation>
      <xsd:documentation>
        Request for an existing experiment's virtual topology.
        Different information may be returned based on the user's rights
        to see the topology.
      </xsd:documentation>
    </xsd:annotation>
    <xsd:sequence>
      <xsd:element name="experiment" type="tns:IDType"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:complexType name="vtopoResponseType">
    <xsd:annotation>
      <xsd:documentation>
        The response to a topology request.  Different information may
        be returned based on the user's rights to see the topology.
      </xsd:documentation>
    </xsd:annotation>
    <xsd:sequence>
      <xsd:element name="experiment" type="tns:IDType"/>
      <xsd:element name="vtopo" type="tns:vtopoType"/>
    </xsd:sequence>
  </xsd:complexType>


  <xsd:complexType name="visRequestType">
    <xsd:annotation>
      <xsd:documentation>
        Request for an existing experiment's visualization.  This is
        largely a compatibility service.  Different information may be
        returned based on the user's rights to see the topology.
      </xsd:documentation>
    </xsd:annotation>
    <xsd:sequence>
      <xsd:element name="experiment" type="tns:IDType"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:complexType name="visResponseType">
    <xsd:annotation>
      <xsd:documentation>
        An existing experiment's visualization.  This is largely a
        compatibility service.  Different information may be returned
        based on the user's rights to see the topology.
      </xsd:documentation>
    </xsd:annotation>
    <xsd:sequence>
      <xsd:element name="experiment" type="tns:IDType"/>
      <xsd:element name="vis" type="tns:visType"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:complexType name="infoRequestType">
    <xsd:annotation>
      <xsd:documentation>
        A combined topology, visualalization, and federant request.
        Different information may be returned based on the user's rights
        to see the topology.
      </xsd:documentation>
    </xsd:annotation>
    <xsd:sequence>
      <xsd:element name="experiment" type="tns:IDType"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:complexType name="infoResponseType">
    <xsd:annotation>
      <xsd:documentation>
        Information on an instantiated experiment.  Different information may
        be returned based on the user's rights to see the topology.  Includes
        the information about federants hosting sub-experiments for service
        access as well as virtual topology and visualization information.  All
        that information is relative to the requester.  ExperimentAccess
        includes credentials with which one can access the experiment.  These
        may include a public key necessary to prove possession of the
        credential and should be treated with care.
      </xsd:documentation>
    </xsd:annotation>
    <xsd:sequence>
      <xsd:element name="federant" type="tns:federatedExperimentType" 
        minOccurs="0" maxOccurs="unbounded"/>
      <xsd:element name="vtopo" type="tns:vtopoType" minOccurs="0"
        maxOccurs="1"/>
      <xsd:element name="vis" type="tns:visType" minOccurs="0"
        maxOccurs="1"/>
      <xsd:element name="experimentID" type="tns:IDType" minOccurs="1"
        maxOccurs="unbounded"/>
      <xsd:element name="allocationLog" type="xsd:string" minOccurs="0" 
        maxOccurs="1"/>
      <xsd:element name="experimentStatus" type="tns:statusType"/>
      <xsd:element name="experimentAccess" type="tns:accessType" minOccurs="0"
        maxOccurs="1"/>
    </xsd:sequence>
  </xsd:complexType>


  <xsd:complexType name="multiInfoRequestType">
    <xsd:annotation>
      <xsd:documentation>
        Gets all information that this user can access on this fedd.
      </xsd:documentation>
    </xsd:annotation>
    <xsd:sequence>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:complexType name="multiInfoResponseType">
    <xsd:annotation>
      <xsd:documentation>
        Multi info response.  A list of infoResponses
      </xsd:documentation>
    </xsd:annotation>
    <xsd:sequence>
      <xsd:element name="info" type="tns:infoResponseType" minOccurs="0"
        maxOccurs="unbounded"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:complexType name="terminateRequestType">
    <xsd:annotation>
      <xsd:documentation>
        Request to terminate an experiment.
      </xsd:documentation>
    </xsd:annotation>
    <xsd:sequence>
      <xsd:element name="experiment" type="tns:IDType"/>
      <xsd:element name="force" type="xsd:boolean" minOccurs="0" maxOccurs="1"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:complexType name="terminateResponseType">
    <xsd:annotation>
      <xsd:documentation>
        Indication that the experiment has been terminated.
      </xsd:documentation>
    </xsd:annotation>
    <xsd:sequence>
      <xsd:element name="experiment" type="tns:IDType"/>
      <xsd:element name="deallocationLog" type="xsd:string" minOccurs="0"
        maxOccurs="1"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:complexType name="ns2SplitRequestType">
    <xsd:annotation>
      <xsd:documentation>
        Request to run the CEDL splitter remotely.  This is primarily an
        internal interface.
      </xsd:documentation>
    </xsd:annotation>
    <xsd:sequence>
      <xsd:element name="description" type="tns:experimentDescriptionType"/>
      <xsd:element name="master" type="xsd:string"/>
      <xsd:element name="include_fedkit" type="xsd:boolean"/>
      <xsd:element name="include_gatewaykit" type="xsd:boolean"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:complexType name="ns2SplitResponseType">
    <xsd:annotation>
      <xsd:documentation>
        Remote splitter output.  Also an internal interface
      </xsd:documentation>
    </xsd:annotation>
    <xsd:sequence>
      <xsd:element name="output" type="xsd:base64Binary"/>
    </xsd:sequence>
  </xsd:complexType>


  <xsd:complexType name="faultType">
    <xsd:annotation>
      <xsd:documentation>
        Indication that a service has failed.  The code values are

          1 access denied
          2 proxy error
          3 badly formed request
          4 server configuration error
          5 internal error
          6 partial instantiation
          7 federant error

        Errstr contains the text above corresponding to the code.  Code
        is always present.  Desc provides additional human-readable data
        about the error.
      </xsd:documentation>
    </xsd:annotation>
    <xsd:sequence>
      <xsd:element name="code" type="xsd:int">
        <xsd:restriction>
          <xsd:enumeration value="1"/>  <!-- access denied -->
          <xsd:enumeration value="2"/>  <!-- protocol error -->
          <xsd:enumeration value="3"/>  <!-- badly formed request -->
          <xsd:enumeration value="4"/>  <!-- server configuration error -->
          <xsd:enumeration value="5"/>  <!-- internal error -->
          <xsd:enumeration value="6"/>  <!-- partial instantiation -->
          <xsd:enumeration value="7"/>  <!-- federant error -->
          <xsd:enumeration value="8"/>  <!-- connect error -->
        </xsd:restriction>
      </xsd:element>
      <xsd:element name="errstr" minOccurs="0" maxOccurs="1" type="xsd:string">
      </xsd:element>
      <xsd:element name="desc" type="xsd:string"/>
    </xsd:sequence>
  </xsd:complexType>
</xsd:schema>