EDI 101 \ Communication Alternatives

EDI specifications do not require any particular type of transport. There are 4 general methods to choose from:

Point-to-point Communications lines

Wal-Mart is a typical example of a point-to-point communication. Vendors dial into Wal-Mart SNA network via bisynchronous modem. Point-to-point communications lines can be established between the trading partners using standard communications protocols. This connection could either be a leased or a dial-up line. A leased line is purchased on a monthly basis and is always available for transmission.

A dial-up line is established just like a normal telephone call. When the sending party has something to transmit, the call is made and the data is transmitted. When dialup links are used, senders typically batch up their transaction and at certain points make the connection and send the entire batch.

The dial up approach is cheaper when the amount of data is low and sporadic. An expensive leased line can be more cost effective if the amount of transactions is high, and fairly constant throughout the day. Also, faster line speed can be achieved with a leased line and there is no dial delay or need to batch transactions. With a leased line, the transaction can be transmitted as soon as it is created. For some applications, immediate transmission and reply may be appropriate.

Value-added Networks

This is the most widely use method. Samples of VAN (Value Added Networks) are IBM Information Exchange and Sterling Commerce Network. Point-to point links often present a scheduling problem to trading partners. Often, it is not convenient for the receiver to get transactions when the sender chooses to transmit them. The solution to this problem is a value-added network that provides a store-and-forward mailbox service. Compuserve, Telenet, and Tymenet are examples of value added networks.

The sender connects with the value-added network and sends its EDI transactions to the recipient's mailbox where they are stored. The sender then disconnects from the service. At some point that is convenient, the recipient can connect to the network and receive those transactions from their mailbox. With this approach, both sending and receiving parties must use the same EDI standard transactions.