Most large enterprises have a network of homegrown, legacy mainframe, and packaged applications that need to share information and functionality. Unfortunately, most of these systems are proprietary to the vendor, and were written in different programming languages with different data structures. Integration middleware was developed to allow incompatible systems to communicate. Enterprise Application Integration (EAI) is used to integrate applications inside the firewall. B2B integration extends integration beyond the enterprise to customers, partners, and suppliers. The emerging Web Services model goes even further by defining a single set of standards for integration both inside and outside the enterprise. As a result, vendors in EAI and B2B markets will be profoundly affected by Web Services.

Enterprise Application Integration

Enterprise Application Integration vendors have introduced packaged integration solutions to help the enterprise develop a consistent approach to integration for all applications. EAI solutions generally include:

• Message-oriented Middleware. Message-oriented middleware (MOM) products provide connectivity between applications by message passing. Messages are sent to a queue and are then forwarded to the destination application for processing. This method is known as "store-and-forward" messaging.
  
  
• Application Servers Application servers also provide connectivity between applications, but instead of using a message queue, the client sends a request directly to a server and waits for the server to respond. This method is known as "request/response."
  
  
• Adapters. Most EAI solutions include standard connectors for the most common packaged applications and databases. These adapters alleviate much of the manual coding required to map data formats and object models between applications.
  
  
• Adapter Development Frameworks. Adapter frameworks are the tools that allow developers to build adapters into applications where a standard adapter does not exist or where the amount of customization of the packaged application is significant.
  
  
• Workflow and Process Management Tools. One of the key tenets of EAI is automating transaction processing. Workflow and process management tools allow the developer to define, implement, test and monitor transaction flow associated with specific business processes.
  

B2B Integration

Extending integration to applications outside the boundaries of the enterprise has proved equally complex. Enterprises have typically had two choices for B2B integration:

• Electronic Data Interchange (EDI). EDI enables computer-to-computer exchange of business data in a standard format, and information is organized according to a specified format set by both parties. This allows a "hands-off" computer transaction that requires no human intervention or re-keying on either end. However, EDI was expensive and lacked the flexibility to support the wide range of business processes and data formats that companies needed.
  
  
• XML Trade Vocabularies. With the arrival of eXtensible Markup Language (XML), industry specific trade vocabularies, such as RosettaNet for the electronics industry and ACORD for the insurance industry, have simplified integration between companies and created the B2B Integration market.
  

Web Services

However, there was still no standards-based middleware solution that could eliminate the high cost and complexity of application integration. That began to change when IBM and Microsoft published the Simple Object Access Protocol (SOAP) specification in May of 2000. The Web Services model represents a universal acceptance on the part of software vendors that integration middleware built on open standards is both possible and beneficial. The largest industry players are uniting behind a single set of core standards based on:

• eXtensible Markup Language (XML). XML is a universal syntax for describing and structuring data independent from the application logic. It is really a "meta-language," meaning a language that describes other languages. XML can be used to define unlimited languages for specific industries and applications.
  
  
• Simple Object Access Protocol (SOAP). SOAP is a lightweight XML-based protocol for exchange of information in a decentralized, distributed environment. It functions as a standard envelope for messages passing between different systems.
  
  
• Web Services Description Language (WSDL). WSDL is an XML grammar for specifying a public interface for a Web service. This interface describes the functional and operational requirements for accessing Web Services, such as protocol binding requirements and location information.
  
  
• Universal Description, Discovery and Integration (UDDI). UDDI is the standard that defines the repository in which available web services are stored, indexed, and organized.
  
  
• Web Services Interoperability (WS-I). WS-I in an industry consortium focused on ensuring interoperability between vendor solutions through its Web Services Interoperability Basic Profile. The consortium is also mandated to develop interoperability profiles for security and other products that leverage Web Services.
  
  
• Web Service Extensions. The core standards are being extended to address critical issues, such as reliable messaging, security, process orchestration, and long-running transactions.
  

For more information on choosing the right integration solution for your company, please read our EAI and Web Services First Steps.

Go to Bitpipe Research Guide: EAI and Web Services.