2.2.2 Instant Message Delivery Notification (IMDN) Schema

The IMDN message is sent from the IM MCU to the sender of an IM to indicate the status associated with forwarding the message to the other protocol clients. The IMDN message contains the message-id of the MESSAGE and a list containing status information associated with each attempted forward of the MESSAGE. The XML schema for an IMDN message is defined in section 6.2. An example IMDN message follows:

<?xml version="1.0" encoding="utf-8"?>
<imdn xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  
 xmlns:xsd="http://www.w3.org/2001/XMLSchema"  
 xmlns="http://schemas.microsoft.com/rtc/2005/08/imdn">
  <message-id>2</message-id>
  <recipient       
   uri="&lt;sip:bob@contoso.com
                ;opaque=user:epid:d7NL6_mHNFSL3I1rbITi2gAA;gruu&gt;">
    <status>408</status>
    <entry>
      <key>ms-diagnostics</key>
      <value>6001;source="server.microsoft.com";
             reason="Request Timeout";component="ImMcu"
      </value>
    </entry>
  </recipient>
</imdn>

The message-id element contains the message-id for the MESSAGE request. This SHOULD be the same as the Message-Id header sent in the successful response to the MESSAGE request from the MCU to the protocol client, as specified in section 3.3.2.5.

The IMDN XML contains a list of recipient elements. Each recipient element contains the status information associated with an attempted forward of the MESSAGE request. The uri attribute contains the SIP Uniform Resource Identifier (URI) of the protocol client. The status element in the recipient element contains the SIP status code. In addition, it MAY contain a list of entry elements. Each entry element contains a key value pair. The key element in the entry element is a string element and the value element in the entry element is a string element corresponding to the key.

If the IMDN message does not contain any recipient elements, it implies that the MESSAGE was forwarded successfully to all the other participants. The IMDN message MUST contain all the errors in forwarding the MESSAGE. In addition to this, the IMDN message MAY contain the success information in forwarding the MESSAGE.