DDEX MLC Messages are exchanged using file transfer protocol. In fact Secure File Transfer Protocol (SFTP) is preferred because it encrypts both the command that execute the file transfer, as well as the data being transferred.
Unique upload and download folders should be created according to the choreography standard. Each batch folder is named according to the DDEX file creation date/time formed as:
Files containing the messages must be placed in a folder together with a manifest. A folder and file naming convention must be adhered to as described in section 6.3 of the standard. The manifest is uploaded into the FTP delivery folder once all the message files in a batch are uploaded, as described in Clause 6.4 of the standard.
Multiple files are used to avoid unmanageable file size. Files ought not exceed 250Mb nor contain more than 100,000 recordings.
Incoming and outgoing files should follow a standardised, descriptive naming convention, including version and/or timestamp. Such a standard reduces the possibility of processing the same file multiple times. These are also defined in the aforementioned standard.
Messages should be ingested in order of folder timestamp.
The recipient uploads an ‘acknowledgement.xml’ file once the messages and manifest have been correctly received. The acknowledgement is set out in section 6.5 of the standard.
DDEX recommends using acknowledgements when using the FTP choreographies to support non-repudiation. Read more here.