Download presentation
Presentation is loading. Please wait.
Published byZoe Farmer Modified over 9 years ago
1
Chapter 6: Using Middleware Textbook IT Architectures and Middleware, Second Edition Chris Britton and Peter Bye AIT 600 Jeff Schmitt October 20, 2008
2
Questions to explore ● What is middleware for? ● How do we split application functionality among the tiers? ● How do we assemble applications into a wider architecture?
3
What is middleware for? ● Transaction technology – as used in the implementation of business processes and services ● Information retrieval technology – as used to support management oversight and analysis of business performance ● Collaborative technology – for helping people work together, email, discussion forum, wiki ● Internal IT service technology – software distribution, remote system operation
6
How do we split application functionality among the tiers? ● How do we split
9
Distributed Architecture patterns ● How do we assemble applications into a wider architecture? Middleware bus (or ring) – tightly coupled Hub and spoke – medium coupling Loosely coupled – as in Web Services No plan – ad hoc – solve each crisis as it occurs
10
Middleware Bus ● Primary aim: separate presentation channels from the business services ● Advantages Fast – network hardware and software tailored for production workload Secure – barriers against breaking Flexible – new channels added easily ● High-discipline architecture strict standards for service interface, security, system management and failover
13
Hub Architecture ● Messages go through hub giving opportunities for functionality Reouting the message Multicasting the message (broadcast) Reformatting or splitting the message Adding information to the message Perform workflow rules Monitor message flow ● Useful in bridging networks, and in legacy systems where you cannot adapt the application
15
Hub Disadvantages ● Another link in the chain ● Another point of failure ● Potential bottleneck ● Need backup hub and failsafe software
17
Web Services Architecture ● Loosely coupled distributed system ● Dependencies between distributed programs Protocol Configuration Message format Message semantics Session state Security Business process Business object
18
Dimensions of coupling dependencies ● Technological dimension Protocol Configuration Message format ● Application dimension Message semantics Session state ● Wider concerns Security Business process Business object
19
Summary ● Communication among applications Real-time (request and response) Deferrable (send and forget) ● Business processes, collaboration, intelligence ● Tiers – useful concept for program design Presentation tier – support multiple external channels – clear cut Processing and data tier – less clear cut delineation
20
Summary ● Application coupling (loose or tight) has technical dimension and application dimension Technical dimension – example web services Application dimension – example complex dialog to exchange information ● Distributed architecture styles Middleware bus architecture Hub architecture Web services architecture
21
Summary ● Middleware bus architecture Tightly coupled Best performance, resiliency and security but difficult to deploy and change ● Hub architecture Moderately coupled Useful when there is a need to route service requests or to multicast service requests ● Web services architecture Loosely coupled
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.