MQ Series Introduction

• It is an IBM’s award winning middleware for commercial messaging and queuing.
• The MQSeries products enable programs to communicate with each other across a network of unlike components, such as processors,subsystems, operating systems and communication protocols.
• MQSeries programs use a consistent application program interface (API) across all platforms.
• Message queuing is a method of program-to-program communication. Programs within an application communicate by writing and retrieving application-specific data (messages) to/from queues.
• Messaging means that programs communicate with each other by sending data in messages and not by calling each other directly.
• Queuing means that programs communicate through queues. Programs communicating through queues need not be executed concurrently.

A message consists of two parts:

• Data that is sent from one program to another.
• The message descriptor or message header.

Message Types

• Datagram: A message containing information for which no response is expected.
• Request: A message for which a reply is requested.
• Reply: A reply to a request message.
• Report: A message that describes an event such as the occurrence of an error or a confirmation on arrival or delivery.

MQM

• The heart of MQSeries is the message queue manager (MQM), MQSeries’ run-time program.
• Its job is to manage queues and messages for applications.
• It provides the Message Queuing Interface (MQI) for communication with applications. Application programs invoke functions of the queue manager by issuing API calls.For example, the MQPUT API call puts a message on queue to be read by another program using the MQGET API call.