With each EPP command you specify a client transaction ID. In the result that you receive from the server, you will find the same client transaction id and an additional server transaction id.
When issuing commands to the EPP service, one command may take longer to complete than another. In 99.9% percent of the cases, when you issue a command, the first answer that is returned will contain the answer to this command, bearing the same client transactionid.
But in a few cases, when commands are fired in rapid succession, the answer to a command may not come directly in return, and a different answer is returned first. For this, please always check if the transaction ID returned matches the transaction ID that was sent. And make sure these ID's are unique. If you keep on sending the same clTRID, you will not be able to check if the returned answer matches the question.
The server transaction ID is used by the registry (or Metaregistrar staff) only to reference a specific message. If a message goes wrong and you contact the Metaregistrar helpdesk about this, please be sure to reference the Server Transaction ID, so the support staff will be able to locate your message and give you a proper response to what went wrong.