[Attribute Name] aai [Details] 
is an optional ECMAScript expression which returns a string of application-to-application information to be passed to the destination endpoint when establishing the connection. Note: Even if an implementation platform accepts the aai data, certain protocols and network elements may prevent it's transmission to the target endpoint. If the platform does not support the transmission of aai data it should raise a connection.PROGRESSING event and indicate that the use of aai is not supported.