For EDI messages to be delivered and recognized, they need addressing information. In ECMap, EDI messages are enclosed in both an outer and an inner envelope that each contains addressing information. The information on these envelopes identifies the intended recipient of the message, allowing the data to be correctly sent and delivered. It also identifies the sender of the message. The outer envelope is referred to as the interchange level envelope, and the inner envelope is referred to as the group level envelope. One outer envelope can contain multiple inner envelopes. One inner envelope can contain multiple messages.
Different standards use different methods to provide the addressing information required for delivery of the message. Sometimes a message is sent in both an inner and an outer envelope. Sometimes a message is sent in only one envelope. And sometimes a message is sent with no envelope at all; instead, the addressing information is included in the header and trailer of the message itself.
