WM1011G01

Introduction to WebSphere MQ

© Copyright IBM Corporation 2011 Course materials may not be reproduced in whole or in part without the prior written permission of IBM.

5.4.1.1

Unit objectives After completing this unit, you should be able to: • Explain the positioning of messaging and queuing in the current business environment • Provide a high-level view of WebSphere MQ functions • Describe the breadth of coverage of WebSphere MQ products

© Copyright IBM Corporation 2011

The enterprise IT environment of today IT environments are increasingly heterogeneous and complex Value chain extranets

Legacy systems and applications Databases

Internet Intranets

Customers

Transactions

Networks

The role of modern middleware is to integrate and simplify © Copyright IBM Corporation 2011

IBM WebSphere reference architecture Business services WebSphere Business Monitor

Development services WebSphere Business Integration Modeler, WebSphere Integration Developer

Interaction services

Process services

WebSphere Portal Server

WebSphere Process Server

Information services WebSphere Information Integrator

Connectivity services, ESB WebSphere MQ WebSphere Enterprise Service Bus, WebSphere Message Broker

Management services

Service registry Partner services WebSphere Partner Gateway

Business application services WebSphere Application Server

Access services WBI and WebSphere Adapters, HATS

Infrastructure services © Copyright IBM Corporation 2011

Why are interfaces so expensive to build and maintain? • Application interface logic is intertwined with business logic • Tightly integrated interfaces are difficult to change • The more interfaces, the more complex the application — interface logic may exceed business logic. • Reuse becomes difficult and impractical


Service-oriented architecture (SOA) Direct connectivity

Message queuing

Traditional message brokering

Connectivity, mediation, and additional logic

Connectivity logic

Connectivity and mediation logic

Mediation and additional logic

Lines of code

Message and service brokering Connectivity, mediation, and additional logic

Additional logic

Application

Application

Application

Connectivity, mediation, and additional logic buried in application

Abstracts connectivity logic from application

Abstracts connectivity and mediation logic from application

SERVICES Reduces application to core business functions (that is, a service)

Degree of flexibility and reuse © Copyright IBM Corporation 2011

Program-to-program communication

B

A

Application

Queue

Application


Synchronous application design model

Queue 1

A

B

Queue 2


Extended asynchronous application design model

A Queue 1

B

C Queue 2


Time independence A

B

Not available

A

A

A

Not available

Not available

B

B

Not available

B


Three styles of communication Conversational A

B Call-and-return A Call B

B Return to A

Messaging A

B


WebSphere MQ eliminates application network concerns Applications

Applications

Applications

MQI

MQI

MCA

Networking interface

Queue manager

Applications

Queue MCA manager



Network


Local and remote queues concept System 1

Program A

MQPUT Q2, QM2

System 2

Program B

MQPUT Q1

Program C

MQGET Q1

MQGET Q2

MQI

Queue manager QM2

Queue manager QM1 QM2: Local queue, transmit queue

Q1: Local queue

Q2: Local queue

Dead letter queue


MQI calls • Major calls

Applications

– MQCONN – – – –

MQI

– MQPUT – MQPUT1 – MQGET

Queue manager

Process definition object

Namelist object

MQCONNX MQDISC MQOPEN MQCLOSE

Queue manager object

– MQSUB – MQSUBRQ

• Minor calls – MQBEGIN – MQCMIT – MQBACK – MQINQ – MQSET © Copyright IBM Corporation 2011

Message composition Message = header + application data

Header

Application data

• Set by application and queue manager • Header – MQMD (message descriptor) • Application data – Any sequence of bytes – Meaningful only to the sending and receiving applications – Not meaningful to the queue manager


Parallel processing application design MQPUT Car MQPUT CAR.RENTAL MQPUT FLIGHT

CAR.RENTAL

MQPUT Flight

MQPUT HOTEL FLIGHT

Reply-to queue Hotel

MQGET reply-to queue

MQPUT HOTEL


Triggering Queue manager Program A

Program B 1

MQPUT A.Q

6 Application queue (A.Q)

MQGET A.Q

2 Process definition object 3 Trigger types: • FIRST • DEPTH • EVERY

Initiation queue (I.Q)

5

4 MQGET I.Q

Trigger monitor © Copyright IBM Corporation 2011

Client/server application model Application clients Insurance data

Insurance agent

Insurance agent

Insurance agent

Insurance quotations

Application server

• Queue = service • Message = request • Reply-to queue name in message descriptor • Multiple instances of server possible


WebSphere MQ client Client system

Server system

WebSphere MQ application

WebSphere queue manager

Client stub

Server connection

Communications stack

Communications stack

Communication link

(no queue manager exists on this system)


Data integrity Synchronous model Unit of work Write Send database Sync point

Receive Write

Two phase commit

Sync point

Unit of work 1 Write database

Put Sync point

Unit of work 2

Database

Asynchronous model Unit of work 3

A.Q (xmitq)

B.Q

Get Write Sync point

Database


Security Local queue manager • Queues • Administrative commands

MCA

Authentication encryption MCA

Remote queue manager MQMD

Application data Database

|USERID|

|

Message context © Copyright IBM Corporation 2011

Unit summary Having completed this unit, you should be able to: • Explain the positioning of messaging and queuing in the current business environment • Provide a high-level view of WebSphere MQ functions • Describe the breadth of coverage of WebSphere MQ products


Checkpoint questions (1 of 2) 1. WebSphere MQ uses an interface for programs to access resources called: a. The program-to-program API. b. The Message Queue Interface. c. The synchronous model. d. Triggering.

2. True or False: WebSphere MQ only supports messaging and queuing in an asynchronous environment. 3. True or False: In WebSphere MQ triggering, the queue manager starts the triggered program.


Checkpoint answers (1 of 2) 1. WebSphere MQ uses an interface for programs to access resources called: a. The program-to-program API. b. The Message Queue Interface. c. The synchronous model. d. Triggering. Answer: b.

2. True or False: WebSphere MQ only supports messaging and queuing in an asynchronous environment. Answer: False. WebSphere MQ also supports messaging and queuing in a synchronous environment.

3. True or False: In WebSphere MQ triggering, the queue manager starts the triggered program. Answer: False. The trigger monitor starts the triggered application.


Checkpoint questions (2 of 2) 4. A message consists of: a. Application data. b. A WebSphere MQ trailer. c. A security header. d. A message descriptor. e. All the above.

5. All WebSphere MQ messages have a header. It is the: a. MQXQH (transmission header). b. MQDLK (dead letter header). c. MQMD (message descriptor). d. MQTH (trigger header).


Checkpoint answers (2 of 2) 4. A message consists of: a. Application data. b. A WebSphere MQ trailer. c. A security header. d. A message descriptor. e. All the above. Answer: a and d, although it is possible for a message to contain only a message descriptor and no application data. Security information, known as the “message context,” is part of the message descriptor.

5. All WebSphere MQ messages have a header. It is the: a. MQXQH (transmission header). b. MQDLK (dead letter header). c. MQMD (message descriptor). d. MQTH (trigger header). Answer: c. The MQMD (message descriptor) is always included a WebSphere MQ message. © Copyright IBM Corporation 2011

WM1011G01

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