Message Delivery Engine
It forwards the messages through Ozeki 10 by using the rules in the routing table. In other words it makes sure that each message is transferred from a connection's inbox to one or more connections' outbox. The message can be moved between folders according to the delivery status.
Each connection has an Inbox and Outbox folder. Messages from the outside world arrive in the Inbox folder. Then the message delivery engine forwards the message to an Outbox folder of another connection (Figure 1), which will be sent by the connection to the outside world. The Message Delivery Engine simply uses the rules set in the routing table. You can read everything you need to know about the routing table by clicking here.
As you can see even the Inbox and Outbox folders are separated into multiple sub-folders, so you can promptly see what happened to the message when it arrived to connection A's Inbox and how it was forwarded to connection B's Outbox by the message delivery engine according to the message routing table.