What Is Message Oriented Middleware? How Does It Work?

Businesses, institutions, and technologies are constantly changing, so the software systems that serve them must accommodate them.

Modern systems function in complex environments with multiple programming languages, hardware platforms, and operating systems. With continuous evolution, businesses need dynamic, agile deployments with 24/7 reliability, high performance, and security.

The easiest way to integrate disparate software components isn’t to make them all the same but to provide a layer that lets them communicate despite their differences. This layer, known as middleware, allows the interaction of independently developed components that run on different networked platforms.

One type of middleware that is beneficial for message passing is message-oriented middleware (MOM). MOM provides a platform-agnostic mechanism for applications to exchange messages using message queue software asynchronously. This means that apps can communicate regardless of whether they run on the same or different systems.

Message-driven processing is necessary for a client/server setup employing a unique message broker application. A client delivers a message to the message broker, which manages several messages from various clients and passes them to the relevant server application. The middleware establishes a connectivity layer that shields developers from the complexities of multiple operating systems and networking technologies.

MOM allows asynchronous communication by passing messages between applications instead of calling directly. This has several advantages, including decoupling applications so they are not dependent on each other, increasing reliability and scalability, and reducing complexity.

Importance of message-oriented middleware

MOM is especially useful when massive changes occur in an enterprise, such as introducing different systems and components. Rebuilding the IT infrastructure and making sure all old and new services function seamlessly is time-consuming and resource-intensive.

MOM addresses these challenges and improves communication across several systems and applications without overhauling the organization's IT infrastructure.

Companies starting a new service, subscribing to a new service, or moving through an acquisition or merger can look to MOM solutions to create cohesive systems without affecting other components of their networks.

In short, message-oriented middleware enables rapid, reliable asynchronous messaging and message delivery, including receipt alerts and transaction controls. MOM is a suitable business solution if an organization's distributed systems are dispersed, have inadequate network connectivity, or have stringent requirements for flexibility, scalability, and dependability.

MOM systems are a great way to accommodate dispersed deployments since they’re flexible and durable.

How does message-oriented middleware work?

Messaging middleware improves inter-component communication for complex IT systems and makes development effortless in a distributed environment.

The message queue is a crucial component in message-oriented middleware platforms. Message queuing helps MOM-based systems retain messages in the architecture. With the help of queues, a message-oriented middleware architecture can send and receive data.

Queues are also necessary for developing asynchronous communication in a message-oriented middleware architecture. The queue stores messages in a particular order using the first-in-first-out (FIFO) standard. The message sent initially to the queue will be the first to be retrieved from the queue using FIFO.

A queue's identity, size, queue save threshold, message filtering mechanism, and other properties are all configurable. In most circumstances, each app has its own queue; however, in some cases, the setup allows it to share queues. Message-oriented middleware systems can support a range of queues.

The most popular messaging models in message-oriented middleware architectures are publish/subscribe (pub/sub) and point-to-point (P2P) models. Both of these approaches rely on message exchange via a queue. A typical system combines these approaches to achieve various messaging goals and objectives.

Features of message-oriented middleware

Message-oriented middleware is a great way to facilitate communication between different software components. It’s platform-agnostic and allows for a versatile form of exchanging messages. Some of the critical features of message-oriented middleware are as follows:

• Asynchronous messaging: When a target app is disconnected or busy, the system temporarily saves message queues with this functionality. Most asynchronous systems offer storage for message queue backup, enabling senders and receivers to link to networks simultaneously. It also resolves issues caused by intermittent connectivity.
• Assured message delivery: Message-sending applications don't need to connect to the network simultaneously. MOM ensures message delivery when links are established and the receiving application issues a query for transmitted messages.
• Routing: Message queues are used in many MOM systems for routing. When enabled, some empower the message layer to supply routing logic. In contrast, others rely on client applications to provide routing information, and some require a hybrid of the two approaches.
• Transformation: MOM platforms with integrated intelligence can modify and route information to fit the demands of the source or the recipient. Additionally, many MOM-based solutions offer powerful message transformation capabilities that let programmers define rules for easy drag-and-drop GUI actions.
• Transaction support: MOM provides transaction support and is intimately connected with transaction services. When transaction services are available, they can participate in a MOM transaction.
• Notification services: Although MOM permits async message transmission, the sender app might want to know the message delivery status in some cases. As a result, the MOM gives the sender the choice of reviewing responses, letting another service manage them, or ignoring them altogether. Some MOM systems can also journal messages to offer audit trails.
• Additional features: Other aspects that most MOM systems provide include provisioning and monitoring, unified messaging, dynamic scaling, secure communication, management and control tools, flexible service quality, and interaction with other devices.

Types of middleware

Middleware is the layer that allows different software components to interact with each other, but what are the different types of middleware? And what are some reasons for choosing each one? Let's discuss this below.

• Message-oriented middleware is an architecture that enables the reception and relaying of messages between application components. It supports software deployment across several platforms and simplifies the process of developing applications that span multiple operating systems and network protocols. It has several advantages over other middleware options (such as hard coding logic) and is one of the most extensively used forms of middleware.
• Object middleware, also known as an object request broker, allows applications to exchange objects and access services through an object-oriented system. In a nutshell, it controls object communication in a distributed computing system.
• Remote procedure call (RPC) middleware, or RPC-based middleware, allows procedures in one app to invoke procedures in other apps as if they were local calls. This middleware includes a linking mechanism that locates remote operations and transparently makes them available to clients. RPC-based middleware historically handled procedure-based systems but now incorporates object-based components.
• Transaction processing (TP) middleware includes systems such as transaction processing monitors and web application servers. Its objective is to create an environment for developing and deploying various applications.
• Database middleware enables direct database access. It helps bring about direct interaction with databases and includes several database gateways and connecting options.
• Embedded middleware, or integration middleware, helps businesses develop and deliver a better integration framework via a program or hardware interface. It serves as a bridge between embedded apps and the real-time operating system.
• Portals, also known as enterprise portals, are not technically middleware. However, they are classified as middleware since they permit front-end integration and promote interaction between a client machine and back-end platforms.
• Content-centric middleware acquires content through provider-consumer abstraction and is widely applied in content-based systems. It’s comparable to publish/subscribe middleware, another software frequently used as a component of web-based applications.

MOM vs. RPC

The communication mechanism we employ to link the different components of a distributed application is an important consideration when designing it. Some middleware systems, such as web services, support two key communication frameworks: message-oriented middleware (MOM) and remote procedure call (RPC).

With message-oriented middleware, service consumers can detach physically and temporally from service providers. Interactions between providers and consumers are asynchronous, as they exchange messages from defined message queues.

MOM implementation examples include IBM Web Sphere MQ and Microsoft Message Queuing (MSMQ). Asynchronous messaging systems eliminate the need for the app to wait for the response – it just transmits the message and executes its asynchronous activities.

Another feature of MOM is its Offline Mode, which allows the client and the service provider to go offline at any moment without losing any messages in the queue.

They can recover all pending messages once they’re back online. Furthermore, MOM supports an event-driven architecture; the administrator can grade customers based on their service level agreement (SLA) and request varying Quality of Service (QoS). However, this makes MOM systems demand resource-intensive devices, particularly in terms of memory, to retain continuous queues of messages received but not yet processed.

On the other hand, RPC provides synchronous communication between components to request remote service execution. Consumers must stop using the service until they get a response from the source.

MOM and RPC both have benefits and drawbacks. MOM systems are more resilient to failures than RPC systems, allowing service requesters to continue processing while service providers act on their requests. Developing MOM-based applications is more difficult since distribution is not as clear to the developer as it is with RPCs.

MOM standards

Historically, there has been a scarcity of regulations governing the implementation of message-oriented middleware; this has posed issues. Most leading providers have versions with application programming interfaces (API) and administration tools.

The X/Open group's XATMI specification is one of the long-standing guidelines for MOM-based applications. It clearly defines APIs for inter-process interactions. Known implementations include ATR Baltic's Enduro/X middleware and Oracle Tuxedo.

The Advanced Message Queuing Protocol (AMQP) is a benchmark that outlines the protocols and formats used by participating software elements to ensure interoperability. AMQP uses flexible routing schemes, including point-to-point, fan-out, publish/subscribe, and request-response messaging paradigms. AMQP offers transaction management, queuing, security, administration, clustering, federation, and heterogeneous multi-platform support.

The High-Level Architecture (HLA IEEE 1516) is a simulation interoperability standard developed by the Institute of Electrical and Electronics Engineers (IEEE). It specifies a range of services accessible via an API in C++ or Java.

The standard defines pub/sub-based information exchanges. Synchronized data exchanges, time advance facilities, and sync points are also based on logical simulation time. Additional services include data distribution optimization, ownership transfer, and management and monitoring of participating systems.

The Java programming environment offers a standard API called the Java Message Service (JMS) for sending and receiving messages in a vendor-independent way using the Java programming language. The JMS API reduces the enterprise messaging expertise necessary for a Java developer to build extensive messaging applications while keeping some portability among JMS provider implementations.

The eXtensible Messaging and Presence Protocol (XMPP) is an extensible markup language (XML) based communications protocol for message-oriented middleware. The protocol, designed to be flexible, is also being used for pub/sub systems, signaling for VoIP, file transfer, video, gaming, social networking platforms, and Internet of Things (IoT) applications such as smart grids.

Advantages of message-oriented middleware

Message-oriented middleware software simplifies the development of applications that span several software packages and networking protocols. It shields the app developer from the specifics of the multiple operating systems and network components.

MOMs boost an architecture's flexibility by offering API versions that expand seamlessly across multiple platforms and networks. This enables programs to communicate freely without knowing which system or processor the other application is running on.

Let’s look at other benefits of using MOMs in your infrastructure.

• Simple and convenient: MOM-based systems are user-friendly, making it easier for developers to build with and, consequently, boost productivity.
• Streamlines business operations: MOM systems help many companies enhance efficiency and streamline numerous common business practices.
• Adaptable: MOM systems seamlessly integrate and communicate across diverse platforms, even when individual applications run separately or asynchronously. Applications are independently maintained in each environment but can be upgraded individually.
• Developer-friendly: MOMs make it easier for developers to design many types of distributed systems.
• Time and location-independent: Since MOMs queue data even when subscribers are offline, the sender and the recipient don’t have to be online simultaneously. Furthermore, message senders and recipients are separated by location and can be moved from device to device at runtime. Patching software and hardware from any site means business operations can continue uninterrupted.
• Wide range of software systems: Message-oriented middleware supports a variety of software structures, including mobile application support, distributed objects and components, and message-oriented communication.
• Event-driven system support: Message-oriented middleware solutions enable the development of apps in an event-driven architecture.
• Scalability: MOM systems often scale effectively according to the number of message recipients. For example, if many clients submit requests but only one system handles them, you can scale transaction processing capacity by adding more systems that work in the same queue.

Disadvantages of message-oriented middleware

Using message-oriented middleware has numerous benefits, but there are also some drawbacks.

• MOMs require an additional architectural element. The existence of a message transfer agent or broker is one of the main cons of message-oriented middleware. Adding components can decrease a system's performance, increasing maintenance costs and complexity.
• MOMs have high development costs. Many organizations cannot operate a message-oriented middleware system due to high development costs.
• MOMs need improvement. Many MOM systems are still not wholly designed for optimal operations, which can threaten a system's real-time performance in some conditions.

MOM to the rescue

If you want to improve communication between your software systems, message-oriented middleware is an excellent option. MOM-based systems can handle traffic spikes while providing a flexible and resilient solution for dispersed deployments.

The calling app doesn't need access to remote systems to send a message. A loose coupling between client and vendor allows agile systems to expand and adapt based on demand.

Learn how stream analytics software can help your business analyze data in transfer between systems or through APIs.

This article was originally published in 2022. It has been updated with new information. robust