Editing Electronic data interchange (section)

==<span lang="ace" dir="ltr">Transmission</span>: Direct EDI and VANs==

Trading partners are free to use any method for the transmission of documents (as described above in the Transmission protocols section). Further, they can either interact directly or through an intermediary.

===Direct EDI: peer-to-peer===

Trading partners can connect directly to each other. For example, an automotive manufacturer might maintain a modem-pool that all of its hundreds of suppliers are required to dial into to perform EDI.  However, if a supplier does business with several manufacturers, it may need to acquire a different modem (or VPN device, etc.) and different software for each one.

As EDI and web technology have evolved, new EDI software technologies have emerged to facilitate direct (also known as point-to-point) EDI between trading partners. Modern EDI software can facilitate exchanges using any number of different file transmission protocols and EDI document standards, reducing costs and barriers to entry.

===Value-added networks===

To address the limitations in peer-to-peer adoption of EDI, [[Value-added network|VANs (value-added networks)]] were established decades ago. A VAN acts as a regional post office. It receives transactions, examines the 'from' and the 'to' information, and routes the transaction to the final recipient. VANs may provide a number of additional services, e.g. retransmitting documents, providing third party audit information, acting as a gateway for different transmission methods, and handling telecommunications support. Because of these and other services VANs provide, businesses frequently use a VAN even when both trading partners are using Internet-based protocols. Healthcare clearinghouses perform many of the same functions as a VAN, but have additional legal restrictions.

VANs may be operated by various entities:
* telecommunication companies;
* industry group consortia;
* a large company interacting with its suppliers/vendors;
*managed services providers.

=== Costs, trade-offs and implementation ===
It is important to note that there are key trade-offs between VANs and Direct EDI,<ref>{{Cite web|url=https://www.rssbus.com/resources/edi/|title=EDI: The Complete Guide and Resource Center|access-date=2018-12-04|archive-date=2018-12-05|archive-url=https://web.archive.org/web/20181205060658/https://www.rssbus.com/resources/edi/|url-status=live}}</ref> and in many instances, organizations exchanging EDI documents can in fact use both in concert, for different aspects of their EDI implementations. For example, in the U.S., the majority of EDI document exchanges use AS2, so a direct EDI setup for AS2 may make sense for a U.S.-based organization. But adding OFTP2 capabilities to communicate with a European partner may be difficult, so a VAN might make sense to handle those specific transactions, while direct EDI is used for the AS2 transactions.

In many ways, a VAN acts as a service provider, simplifying much of the setup for organizations looking to initiate EDI. Due to the fact that many organizations first starting out with EDI often do so to meet a customer or partner requirement and therefore lack in-house EDI expertise, a VAN can be a valuable asset.

However, VANs may come with high costs. VANs typically charge a per-document or even per-line-item transaction fee to process EDI transactions as a service on behalf of their customers. This is the predominant reason why many organizations also implement an EDI software solution or eventually migrate to one for some or all of their EDI.

On the other hand, implementing EDI software can be a challenging process, depending on the complexity of the use case, technologies involved and availability of EDI expertise. In addition, there are ongoing maintenance requirements and updates to consider. For example, EDI mapping is one of the most challenging EDI management tasks. Companies must develop and maintain EDI maps for each of their trading partners (and sometimes multiple EDI maps for each trading partner based on their order fulfilment requirements).