07
Thu, Nov
7 New Articles

Introduction to WebSphere MQ

Typography
  • Smaller Small Medium Big Bigger
  • Default Helvetica Segoe Georgia Times

 

Heterogeneity is a hallmark of today's information systems in all but the smallest of enterprises. Business, non-profit, and government organizations typically run several disparate applications that were developed in-house and/or bought from a variety of vendors. Each application may use a different DBMS, run under a different operating system, and reside on different hardware. Tying these diverse systems together so that they function as a cohesive whole that efficiently serves the enterprise, its supply chain, and its customers--integrating information in near real-time when necessary, without the need to redundantly enter data at different points--can be a challenge. One way to meet this challenge is through the use of messaging as supported by IBM's WebSphere MQ.

WebSphere MQ is not new. It was launched by IBM as MQ Series more than a decade ago and was rebranded as WebSphere MQ in May 2001. The latest release, V6.0, was announced in April of this year, with general availability provided in June.

WebSphere MQ is middleware that can connect disparate applications through the exchange of messages, without regard to platform differences between the sender and receiver systems. Using the Message Queue Interface (MQI), a consistent, multi-platform API provided by WebSphere MQ, applications can share information without having a common architecture. Because messages are sent and received through the API rather than exchanged directly with other applications, programmers do not have to be aware of the design of the applications with which their programs will communicate.

In addition to MQI, WebSphere MQ also supports the industry-standard Java Message Service (JMS), including its publish-and-subscribe model for directing message flows.

WebSphere MQ supports most of the major hardware and operating systems used by businesses today.

Guaranteed Delivery

A key feature of WebSphere MQ is its guarantee that every message will be delivered not more than once. This is clearly critical for most applications. For example, in banking systems, unwittingly repeating a message could result in the double crediting or debiting of funds to or from a customer's account.

"Not more than once" is not the same as "always once." In WebSphere MQ, messages can be either persistent or nonpersistent. Persistent messages are logged and can be recovered in the event of a WebSphere MQ failure. Thus, persistent messages are guaranteed to be delivered once and only once. Nonpersistent messages are not logged. WebSphere still guarantees to deliver them not more than once, but it does not promise to deliver them once.

Terminology

Some terms are essential to understanding WebSphere MQ. First and most obvious is the concept of a message. A message is simply a string of data of almost any size, up to 100 megabytes. Each message consists of two parts, a header and the application data. The header consists of a mandatory component, the MQ Message Descriptor (MQMD), and some optional headers specific to the type of message and its use. The application data portion of the message, which is determined solely by the application, is private to the sending and receiving applications.

WebSphere MQ stores messages in queues. Because messages go into an intermediate store, application interaction doesn't happen in real-time. However, under normal circumstances, the time that messages reside in a queue is generally insignificant. Thus, the total end-to-end message transmission is close enough to real-time for most applications. In fact, many banks use it for debit transactions in their ATM networks. Typically, messages stay in queues for lengthy periods only if the network or the receiving application is unavailable.

WebSphere MQ supports a number of types of queues, the following being among the most common:

  • As the name implies, a local queue resides on the local system.
  • A remote queue is a queue managed by a different queue manager. (Queue managers are described below.)
  • A transmission queue holds messages before they move across a network. Transmission queues are solely for WebSphere MQ's use and, as such, applications do not put messages directly into them.
  • An alias queue is not a physical queue, but rather a pointer to a local queue.

The use of queues means that the sending and receiving applications can operate asynchronously. A sending application that does not require a response to a message, such as a human resources application informing a payroll application of a salary increase, can continue to operate normally even if the receiving application or the network is unavailable, confident in the knowledge that messages will be sent as soon as the receiving application comes back online.

By default, messages in a queue are processed on a FIFO basis, but this is configurable.

Message queueing services are provided by queue managers, which control the administration of objects such as queues and channels. Queue managers can also start required applications or channels when messages arrive in the queues. Queue managers can be run on a variety of operating systems, including AIX, OS/400, i5/OS, HP-UX, Solaris, Windows NT/2000/XP, and Linux on Intel-compatible systems, zSeries, and iSeries.

WebSphere MQ communicates between queue managers or between queue managers and client applications using channels. Message channels, required for communication between two queue managers, are unidirectional and, as such, are typically defined in pairs.

To simplify setup, administration, and load balancing, WebSphere MQ provides for the definition of clusters, which are named collections of queue managers connected through special channels. Each queue manager can operate standalone or belong to one or more clusters.

WebSphere MQ supports both point-to-point and publish/subscribe messaging models. Point-to-point messaging establishes a direct line between two applications through a message queue. Using this model, a message's destination application is identified by the source application or in the messaging artifacts defined locally to the source; thus, modifying the destination of the message will affect the source application.

Integrating more than one application in this fashion requires the definition of individual point-to-point connections between all participating applications. Using this model, if all applications must be connected directly to all others, the number of connections grows exponentially with the number of applications.

Point-to-point architectures can be set up in a number of ways. For example, a hub-and-spoke structure, which connects all points to a central application but not to each other, can be used to reduce the number of required connections. Using request/reply messaging, an application sends a message that includes a request for a reply and information on where the reply should be sent (the sending application can then either continue processing or wait for the reply). Using fire-and-forget messaging, the source application sends a message and does not expect a reply or a confirmation that the message has been received.

In the publish/subscribe model, applications publish data, which can be categorized into topics, to a message broker. Receiving applications send subscriptions for the data, along with the necessary delivery information, to the message broker. The message broker is then responsible for managing these subscriptions. This provides a much more flexible structure in that the sending application does not need to know anything about the recipients. Furthermore, changing the destinations of the messages will not have any effect on the sending application.

With WebSphere MQ, client applications can connect to a remote queue manager, although the definition of clients and servers in WebSphere MQ may not be entirely intuitive. The primary distinction between a client and a server in WebSphere MQ is that a client doesn't have any local queues and, therefore, can't store messages. If the network is unavailable, the client can't connect to the server queue manager, meaning that the application must try to connect again later or resolve the issue in some other way. While there may be some efficiency, storage, and platform reasons for choosing to use a client, it should not be used on a network that is frequently unavailable or for an application that needs assured delivery of messages.

Web Services

WebSphere MQ can be used as a transport mechanism in a Web Services environment. The latest version provides for the flow of industry-standard Simple Object Access Protocol (SOAP) interactions between Web Services requesters and providers. In addition, because it is platform neutral, WebSphere MQ can also be used to provide connectivity between J2EE and .NET.

Using WebSphere MQ as the transport layer for SOAP messages, rather than the more common HTTP protocol, offers the benefit of guaranteeing once-and-only-once delivery of messages, something that HTTP does not offer.

Security and Administration

To ensure the security and privacy of messages, WebSphere MQ supports the use of Secure Sockets Layer (SSL) for the authentication, message integrity checking, and encryption of data sent across the Internet.

An available upgrade to WebSphere MQ, WebSphere MQ Extended Security Edition, enhances this security by enabling enterprise-wide, remote management of security policies. It can be deployed without modifying existing WebSphere MQ applications.

Configuration, monitoring, and administration of WebSphere MQ is accomplished through a console, WebSphere MQ Explorer. The console enables the administration of all WebSphere MQ environments from a single point. That point can, if necessary, be remote to the various applications that use messaging.

New in V6

With V6.0, IBM has replaced the Windows-based MQ Explorer administration console with an Eclipse-based WebSphere MQ Explorer console. Eclipse is an open-source platform for tool integration that is supported by the Eclipse Foundation, a non-profit corporation that includes a number of major software vendors among its strategic developers and consumers. The new console runs on Windows and Linux86 systems, but it is not currently supported on Linux for iSeries.

V6.0 adds support for sending files using the FTP protocol, meaning that organizations no longer need separate FTP software. A further benefit is that, using this feature, FTP transfers operate under the more secure WebSphere MQ security environment.

To improve performance, V6.0 adds support for 64-bit addressing on many platforms and supports data compression on all channel types. WebSphere MQ also now supports more messaging queues and larger queue sizes, including up to 4 GB queues.

V6.0 has also enhanced connectivity with CICS, including support for multiple CICS bridges. In addition, it is now possible to emit messages directly from CICS to WebSphere MQ.

Related Products

A number of related products offered under the IBM WebSphere Business Integration banner can expand on the capabilities of WebSphere MQ. The following briefly describes a few of them.

  • WebSphere Business Integration Message Broker (formerly WebSphere MQ Integrator Broker) is an information broker that provides a one-to-many connectivity model that, like WebSphere MQ, facilitates the exchange of messages among applications, but it also allows for the transformation of messages before delivery (so that not only the platforms, but also the message designs can differ between the sending and receiving applications), intelligent routing, and information flow modeling across multiple, disparate business systems. It also offers remote telemetry devices and a publish/subscribe model that can support mobile clients.
  • WebSphere MQ Everyplace connects mobile and wireless applications to enterprise applications while providing assured message delivery and WebSphere MQ levels of security. It is complementary to WebSphere MQ, adding functions designed specifically for lightweight platforms, devices, and unmanaged networks.
  • WebSphere MQ Workflow is a business process management system that allows administrators to define, initiate and change complete business processes that can span disparate systems and applications.
  • WebSphere Business Integration Server Foundation provides a standards-based integration platform for building and deploying Business Process Execution Language for Web Services (BPEL) and Web Service-based composite applications.

Joel Klebanoff is a consultant, a writer, and president of Klebanoff Associates, Inc., a Toronto, Canada-based marketing communications firm. Joel has 25 years experience working in IT, first as a programmer/analyst and then as a marketer. He holds a Bachelor of Science in computer science and an MBA, both from the University of Toronto. Contact Joel at This email address is being protected from spambots. You need JavaScript enabled to view it..

Joel Klebanoff

Joel Klebanoff is a consultant, writer, and formerly president of Klebanoff Associates, Inc., a Toronto-based marketing communications firm. He has 30 years' experience in various IT capacities and now specializes in writing articles, white papers, and case studies for IT vendors and publications across North America. Joel is also the author of BYTE-ing Satire, a compilation of a year's worth of his columns. He holds a BS in computer science and an MBA, both from the University of Toronto.


MC Press books written by Joel Klebanoff available now on the MC Press Bookstore.

BYTE-ing Satire BYTE-ing Satire
Find out the hilarious answer to the eternal question: "Is technology more hindrance than help?"
List Price $14.95

Now On Sale

BLOG COMMENTS POWERED BY DISQUS

LATEST COMMENTS

Support MC Press Online

$

Book Reviews

Resource Center

  • SB Profound WC 5536 Have you been wondering about Node.js? Our free Node.js Webinar Series takes you from total beginner to creating a fully-functional IBM i Node.js business application. You can find Part 1 here. In Part 2 of our free Node.js Webinar Series, Brian May teaches you the different tooling options available for writing code, debugging, and using Git for version control. Brian will briefly discuss the different tools available, and demonstrate his preferred setup for Node development on IBM i or any platform. Attend this webinar to learn:

  • SB Profound WP 5539More than ever, there is a demand for IT to deliver innovation. Your IBM i has been an essential part of your business operations for years. However, your organization may struggle to maintain the current system and implement new projects. The thousands of customers we've worked with and surveyed state that expectations regarding the digital footprint and vision of the company are not aligned with the current IT environment.

  • SB HelpSystems ROBOT Generic IBM announced the E1080 servers using the latest Power10 processor in September 2021. The most powerful processor from IBM to date, Power10 is designed to handle the demands of doing business in today’s high-tech atmosphere, including running cloud applications, supporting big data, and managing AI workloads. But what does Power10 mean for your data center? In this recorded webinar, IBMers Dan Sundt and Dylan Boday join IBM Power Champion Tom Huntington for a discussion on why Power10 technology is the right strategic investment if you run IBM i, AIX, or Linux. In this action-packed hour, Tom will share trends from the IBM i and AIX user communities while Dan and Dylan dive into the tech specs for key hardware, including:

  • Magic MarkTRY the one package that solves all your document design and printing challenges on all your platforms. Produce bar code labels, electronic forms, ad hoc reports, and RFID tags – without programming! MarkMagic is the only document design and print solution that combines report writing, WYSIWYG label and forms design, and conditional printing in one integrated product. Make sure your data survives when catastrophe hits. Request your trial now!  Request Now.

  • SB HelpSystems ROBOT GenericForms of ransomware has been around for over 30 years, and with more and more organizations suffering attacks each year, it continues to endure. What has made ransomware such a durable threat and what is the best way to combat it? In order to prevent ransomware, organizations must first understand how it works.

  • SB HelpSystems ROBOT GenericIT security is a top priority for businesses around the world, but most IBM i pros don’t know where to begin—and most cybersecurity experts don’t know IBM i. In this session, Robin Tatam explores the business impact of lax IBM i security, the top vulnerabilities putting IBM i at risk, and the steps you can take to protect your organization. If you’re looking to avoid unexpected downtime or corrupted data, you don’t want to miss this session.

  • SB HelpSystems ROBOT GenericCan you trust all of your users all of the time? A typical end user receives 16 malicious emails each month, but only 17 percent of these phishing campaigns are reported to IT. Once an attack is underway, most organizations won’t discover the breach until six months later. A staggering amount of damage can occur in that time. Despite these risks, 93 percent of organizations are leaving their IBM i systems vulnerable to cybercrime. In this on-demand webinar, IBM i security experts Robin Tatam and Sandi Moore will reveal:

  • FORTRA Disaster protection is vital to every business. Yet, it often consists of patched together procedures that are prone to error. From automatic backups to data encryption to media management, Robot automates the routine (yet often complex) tasks of iSeries backup and recovery, saving you time and money and making the process safer and more reliable. Automate your backups with the Robot Backup and Recovery Solution. Key features include:

  • FORTRAManaging messages on your IBM i can be more than a full-time job if you have to do it manually. Messages need a response and resources must be monitored—often over multiple systems and across platforms. How can you be sure you won’t miss important system events? Automate your message center with the Robot Message Management Solution. Key features include:

  • FORTRAThe thought of printing, distributing, and storing iSeries reports manually may reduce you to tears. Paper and labor costs associated with report generation can spiral out of control. Mountains of paper threaten to swamp your files. Robot automates report bursting, distribution, bundling, and archiving, and offers secure, selective online report viewing. Manage your reports with the Robot Report Management Solution. Key features include:

  • FORTRAFor over 30 years, Robot has been a leader in systems management for IBM i. With batch job creation and scheduling at its core, the Robot Job Scheduling Solution reduces the opportunity for human error and helps you maintain service levels, automating even the biggest, most complex runbooks. Manage your job schedule with the Robot Job Scheduling Solution. Key features include:

  • LANSA Business users want new applications now. Market and regulatory pressures require faster application updates and delivery into production. Your IBM i developers may be approaching retirement, and you see no sure way to fill their positions with experienced developers. In addition, you may be caught between maintaining your existing applications and the uncertainty of moving to something new.

  • LANSAWhen it comes to creating your business applications, there are hundreds of coding platforms and programming languages to choose from. These options range from very complex traditional programming languages to Low-Code platforms where sometimes no traditional coding experience is needed. Download our whitepaper, The Power of Writing Code in a Low-Code Solution, and:

  • LANSASupply Chain is becoming increasingly complex and unpredictable. From raw materials for manufacturing to food supply chains, the journey from source to production to delivery to consumers is marred with inefficiencies, manual processes, shortages, recalls, counterfeits, and scandals. In this webinar, we discuss how:

  • The MC Resource Centers bring you the widest selection of white papers, trial software, and on-demand webcasts for you to choose from. >> Review the list of White Papers, Trial Software or On-Demand Webcast at the MC Press Resource Center. >> Add the items to yru Cart and complet he checkout process and submit

  • Profound Logic Have you been wondering about Node.js? Our free Node.js Webinar Series takes you from total beginner to creating a fully-functional IBM i Node.js business application.

  • SB Profound WC 5536Join us for this hour-long webcast that will explore:

  • Fortra IT managers hoping to find new IBM i talent are discovering that the pool of experienced RPG programmers and operators or administrators with intimate knowledge of the operating system and the applications that run on it is small. This begs the question: How will you manage the platform that supports such a big part of your business? This guide offers strategies and software suggestions to help you plan IT staffing and resources and smooth the transition after your AS/400 talent retires. Read on to learn: