If you are a large company, geographically dispersed with complex or special business requirements such as traversing WANs and firewalls, with multiple manufacturing sites, large data volumes, and high availability and high security needs, you could use the exampleWindchill ESI deployment illustrated in the following figure.

The preceding figure illustrates a multiple-site scenario. Site A represents the company headquarters, containing product design and manufacturing facilities. Sites B, C, and D represent remote manufacturing sites, either within the corporation (separated by private WAN links), or external to the corporation (such as third-party, contract manufacturers separated through the internet). Site A makes extensive use of clustering and redundancy in the physical servers to facilitate high-availability (that is, fail-over and fail-back capabilities). TIBCO BusinessWorks process engines are deployed on the both the primary and failover servers to provide better performance for concurrent product data publishing operations between Windchill and Oracle. For security reasons, end-users use a separate LAN rather than the back-end systems and communications over the Internet which are brokered by secure routing daemons (RVSRD).