==== network_download_content_descriptor

Defined by ARIB in <<ARIB-B21>>.

[source,xml]
----
<network_download_content_descriptor
    reboot="bool, required"
    add_on="bool, required"
    component_size="uint32, required"
    session_protocol_number="uint8, required"
    session_id="uint32, required"
    retry="uint8, required"
    connect_timer="uint24, required">

  <!-- Exactly one of ipv4, ipv6, url -->
  <ipv4 address="IPv4 address, required" port="uint16, required"/>
  <ipv6 address="IPv6 address, required" port="uint16, required"/>
  <url url="string, required"/>

  <!-- At most one compatibility_descriptor -->
  <compatibility_descriptor>

    <!-- Any number of descriptors -->
    <descriptor
        descriptor_type="uint8, required"
        specifier_type="uint8, required"
        specifier_data="uint24, required"
        model="uint16, required"
        version="uint16, required">

      <!-- Any number of subdescriptors -->
      <subdescriptor type="uint8, required">
        Hexadecimal content
      </subdescriptor>
    </descriptor>

  </compatibility_descriptor>

  <!-- At most one -->
  <private_data>
    Hexadecimal content
  </private_data>

  <!-- At most one -->
  <text_info ISO_639_language_code="char3, required" text="string, required"/>

</network_download_content_descriptor>
----
