Some of the most common use cases of an ESB or SOA Gateway is to act as a proxy to real service implementations, and perform mediation between service requester and service provider instances.

Typical deployment and usage patterns

The UltraESB is most commonly deployed between a service requester (i.e. a "Client") and a service provider (i.e. a "Server"). However, it can also be used to implement real services, or mock service implementations, in which case it will act as a service provider (i.e. a "Server"). When acting as a proxy service, the client may connect to the UltraESB is any of the supported transport protocols of the UltraESB - which includes non-blocking HTTP and HTTPS, JMS, Email (POP3/IMAP) and SFTP, FTP, FTPS and Locally mapped files. Similarly the UltraESB allows the call to the backend service to take place over any of these supported transports again. Thus it is possible to switch between transports used by the client and the server.

Synchronous / Asynchronous mapping

The ability to switch transports allows the UltraESB to expose asynchronous JMS, Email or File based services over synchronous HTTP as an example. This is a common way to expose existing legacy services and artifacts over SOAP, POX or other such protocols over HTTP/S. It is also possible to easily implement the reverse of this, and allow clients over JMS, Email, and File systems to invoke SOAP, POX or other such services over HTTP/S.

Use as a point of entry and exit for incoming and outgoing service interactions

The UltraESB is usually deployed behind the firewall and an optional hardware load balancer, and will intercept all incoming service calls. By analyzing the target address of the messages, transport level headers, message content or external configuration, the UltraESB is able to mediate these messages, optionally transforming the incoming requests, logging certain values for analysis or reporting or validating request payload or security before passing these messages to the backened services.

When backend systems connects to external service endpoints of your partners, the UltraESB could intercept these calls and perform mediation again, such as logging, transforming or applying security etc.