1 / 17

Introduction to Middleware

Explore the logical and physical models of middleware and the synchronous vs asynchronous approaches. Learn about various middleware types including RPC, message-oriented, distributed objects, database-oriented, transaction-oriented, and message brokers.

forrestl
Download Presentation

Introduction to Middleware

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Introduction to Middleware IST 421 Spring 2003 Lecture 8

  2. Middleware • Allows one entity (application or database) to communicate with another entity or entities. • Originally designed for intra-enterprise integration • New demand for inter-enterprise integration

  3. Middleware Models • Logical • How the information moves conceptually • Physical • Depicts the actual method of information movement • Technology employed

  4. Logical Middleware Model • Point-to-Point Middleware • Allow one application to line to another • Uses a procedure call or message • Limited to 1-to-1 application • No middle tier processing – logic or change messages as they flow through • Examples: • MOM products – MQSeries • RPCs like DCE • Need a shared, centralized server • Simple MOM = message-oriented middleware RPC = remote procedure calls

  5. Logical Middleware Model • Many-to-Many Middleware • Most powerful middleware model • Examples: • Message brokers • Transactional middleware • Application servers • TP monitors • Distributed objects

  6. Synchronous vs. Asynchronous • Asynchronous middleware • Moves information between one or many applications • Decoupled from the source or target applications • Message is placed in a queue, response coming at later time

  7. Synchronous vs. Asynchronous • Synchronous middleware • Tightly couples to applications • Applications are dependent on the middleware to process one or more function calls at a remote application • This makes the calling application halt processing in order to wait for the remote application response • Call this “blocking” type middleware • Uses a lot of bandwidth on the network

  8. Connection-Oriented & Connectionless • Direct Communications • accept message from calling program & pass it to remote program • Most RPC • Queued Communications • Require queue manager to place message in queue • Remote application retrieves message • MOM product

  9. Connection-Oriented & Connectionless • Publish / Subscribe • Application shares information with pub/sub engine • Engine redistributes to interested applications • Request / Response • Request is made to application • Middleware responds to the request • Message broker or application server

  10. Connection-Oriented & Connectionless • Fire-and-Forget • Middleware user “fire off” message • “forget” about it • Not concerned if it was received • Broadcast specific types of messages to multiple recipients bypassing auditing and response features • Asynchronous approach

  11. Middleware Types • RPC (Remote Procedure Call) • Easiest to understand & use • Invoke a function within one program & have the function execute within another program on a remote machine • Synchronous process • Best know RPC is the Distributed Computing Environment (DCE) from the Open Software Foundation (OSF)

  12. Middleware Types • RPC (Remote Procedure Call) cont. • DCE is not scalable & difficult to administer • RPCs not well-performing • Require tremendous processing power

  13. Middleware Types • Message-Oriented • MOM is queuing software • Units of information move between applications • Decoupled from applications • Asynchronous communication • Messages have structure (schema) & content (data) • MOM supports point-to-point & message queuing • IBM’s MQSeries & Microsoft MSMQ

  14. Middleware Types • Distributed Objects • CORBA & COM 2 types of distributed objects in use • CORBA (Common Object Request Broker Architecture) is a standard • Rules for developers to follow when creating distributed objects • COM is Microsoft distributed object standard

  15. Middleware Types • Database-Oriented • Facilitates communications with a database • Works with 2 database types: • CLIs – ODBC or JDBC • Native database middleware

  16. Middleware Types • Transaction-Oriented • TP monitors & application servers • Not as effective at simple information sharing • Tend to be tightly coupled

  17. Middleware Types • Message Brokers • “nirvana” of B2B integration • Move information between multiple applications • Account for differences in semantics and platforms • Use common rules and routing engines • Transform schema & content as it flows between applications & databases

More Related