Understanding EAI and the Role of eLink Adapters # Understanding EAI and the Role of eLink Adapters This chapter contains the following topics: BEA eLink Solution Overview Overview of the eLink Adapter for MQSeries ## BEA eLink Solution Overview BEA Enterprise Application Integration (EAI) provides an open solution that allows applications throughout organizations to communicate seamlessly. Using EAI, you gain the long-term flexibility and investment protection you need to keep up with today's ever-changing business environment. Typically, companies use packaged applications to automate internal operations, such as financial, manufacturing, human resources, etc. While they successfully address the needs of these specific areas, these proprietary platforms do not work together. To compete today, you need a much greater exchange of information. Systems need to communicate at both a database and a process level, within your own organization as well as with customer's and supplier's systems. BEA eLink Platform is the underlying basis of BEA eLink, a family of off-the-shelf enterprise application integration (EAI) products that leverage BEA's transaction platform to integrate existing legacy applications with customer-focused and business-to-business e-commerce initiatives. BEA eLink Platform provides a proven, rock-solid infrastructure for integrating applications within the enterprise and across the Web. BEA eLink Platform ensures high-performance, secure transactions and transparent access to mission-critical applications and information throughout the enterprise and across the Web. Figure 1-1 illustrates the eLink logical architecture and shows where the eLink Adapters fit into the process. Figure 1-1 BEA eLink Solution Illustration ### The BEA eLink Platform The BEA eLink Platform (in addition to all options and adapters) is highly scalable. Multiple instances of BEA eLink Platforms can collaborate so that work is divided between eLink instances and domains. BEA eLink includes SNMP integration for enterprise management. The BEA eLink Platform features compliance with the Open Group's X/Open standards including support of the XA standard for Two-phase commit processing, the X/Open ATMI API, and XPG standards for language internationalization. C, C++ and Java (via Jolt) are supported. The BEA eLink Platform connects to any RDBMS, OODBMS, file manager or queue manager. The following components operate with BEA eLink Platform: The Data Integration Option translates data models used by different applications into a common data format. It provides a cost-effective alternative to writing or generating programs to perform this function. It also handles complex translation with greater power and scalability than rules engines and formatters. The Business Process Option helps automate tasks in the business process and dynamically responds to business events and exceptions. The eLink Adapters provide the interface between the BEA eLink Platform and external applications, with out-of-the-box functionality (no programming required). ## Overview of the eLink Adapter for MQSeries The eLink Adapter for MQSeries provides communication between IBM MQSeries applications and BEA TUXEDO applications. The eLink Adapter consists of three TUXEDO servers: ELINKMQO, which manages eLink to MQSeries requests, ELINKMQI, which manages MQSeries to eLink requests, and TMQUEUE_MQM, which handles `tpenqueue()` and`tpdequeue()` requests. These servers are managed in the TUXEDO environment. The following diagram illustrates the flow of data when a `tpcall()` is issued from a TUXEDO client to an MQSeries application. Figure 1-2 Data Flow for `tpcall()` from TUXEDO to MQSeries The TUXEDO client calls the service advertised by the eLink to MQSeries server (ELINKMQO). The configuration of the service dictates the queue manager name, queue name, and ReplyTo queue related to the service. The eLink Adapter then places the request on the MQSeries queue to be processed by the MQSeries application. The eLink Adapter waits on the reply message from the output queue. When the eLink Adapter receives the reply, it returns the response data to the client's outstanding `tpcall()`. The TMQUEUE_MQM server handles `tpenqueue()` and `tpdequeue()` requests from clients who want to place messages on MQSeries queues. The following diagram shows the enqueuing and dequeuing message flows. Figure 1-3 Message Flow for `tpenqueue()` and `tpdequeue()` The MQSeries to eLink server (ELINKMQI), processes service requests from MQSeries applications to TUXEDO servers. The following diagram illustrates the data flow for inbound requests: Figure 1-4 Data flow for inbound service requests The MQSeries to eLink server (ELINKMQI) monitors specified queues for requests. When ELINKMQI receives a request, it issues a `tpcall()` request to the designated server. It then places the response data in the ReplyTo queue specified in the original request. [Table of Contents] [Prev] [Next]