ROS 2 vs ROS 1: What Changed and Why It Matters?

Is ROS 1 still the right choice for your next robotics project, with its well-established tools and wide community support? Or, given the growing demand for real-time performance, scalability, and modern middleware, is it finally time to make the move to ROS 2?

As of the end of this month—May 2025—official support for ROS 1 will come to a close. This marks a major turning point in the robotics software ecosystem. For over a decade, ROS 1 (Robot Operating System) has served as the backbone of robotic development across research and industry. But the shift to ROS 2 is more than just an upgrade—it’s a rethinking of the platform from the ground up.

This article provides a clear look at the changes introduced in ROS 2, why ROS 1 is being sunset, and what this means for developers, researchers, and organizations working in robotics.

What is ROS?

ROS (Robot Operating System) is a flexible framework for writing robot software. Despite the name, it’s not a full-fledged OS but a middleware layer that sits on top of your actual operating system, handling the complexity of communication, modularity, and distributed execution.

At its core, ROS provides:

• A message-passing architecture for processes (nodes) to communicate.
• Tools to visualize data, record logs, and debug system behavior.
• Packages to handle everything from perception and motion planning to hardware abstraction.

It’s the glue that connects sensors, control logic, actuators, and high-level decision-making in a robotics application. In ROS, each node performs a specific task—say, reading from a LIDAR sensor or planning a path—and publishes/subscribes to messages over topics. This enables a clean, modular architecture where components are reusable and decoupled.

Why ROS? What Difference Does It Make?

Building robot software is not like writing a web app or scripting a microcontroller. Robots deal with real-world inputs—noisy data, real-time constraints, hardware failures—and are inherently distributed systems. Without a framework like ROS, you’d have to write your own communication protocols, serialization formats, data pipelines, logging infrastructure, and process management tools.

ROS abstracts these repetitive tasks. It provides:

• Standardized communication: Publish/subscribe and service-based interaction.
• Sensor integration: Drivers for cameras, IMUs, GPS, and more.
• Visualization: RViz, rqt, and introspection tools.
• Hardware abstraction: URDF and ROS Control for modeling and interfacing with robot hardware.

With ROS, developers focus on algorithms and behavior, not the plumbing. It also offers a large open-source ecosystem, so you’re rarely starting from scratch. Whether you’re working on SLAM, navigation, or perception, someone’s likely already done 70% of the work.

Why ROS 1 Was Right (and Also Wrong)

ROS 1 got a lot of things right. It gave researchers a shared language, simplified complex system integration, and accelerated robotics development. But its architecture was never built with real-time guarantees, security, or modern networking in mind.

What ROS 1 did well:

• Made robotics accessible and modular.
• Encouraged rapid prototyping and experimentation.
• Built a massive ecosystem and developer base.
• Created tools like rosbag, RViz, and rqt that became industry standards.

Where ROS 1 struggled:

• Communication relied on a centralized ROS Master node, a single point of failure.
• No support for real-time scheduling or deterministic behavior.
• Lacked Quality of Service (QoS) configuration for topics.
• Poor multi-robot support—nodes weren’t namespace-aware by default.
• No native support for embedded devices or resource-constrained platforms.
• No built-in security model—data over the network was unencrypted and unauthenticated.

These issues became roadblocks as robotics moved out of the lab and into industrial, consumer, and mission-critical environments.

What Changed? Why ROS 2 is Better

ROS 2 was designed to address the structural limitations of ROS 1. It’s a complete architectural rewrite based on modern software engineering practices and real-world deployment needs.

Here’s a deeper look at what’s new:

DDS-Based Communication (No More ROS Master)

ROS 2 uses the Data Distribution Service (DDS) protocol for inter-process communication. DDS is decentralized, so there’s no need for a master node. Nodes can come and go freely, discover each other dynamically, and communicate peer-to-peer.

This enables:

• Distributed multi-robot systems with zero configuration.
• Fault tolerance—if a node dies, the system doesn’t collapse.
• Scalability across networks, platforms, and locations.

Real-Time Support

Unlike ROS 1, ROS 2 supports real-time execution. You can now:

• Run control loops with deterministic timing.
• Assign thread priorities and memory bounds.
• Interface directly with real-time operating systems (RTOS).

This makes ROS 2 viable for hard real-time applications like industrial robot arms, autonomous vehicles, and flight controllers.

Quality of Service (QoS)

DDS allows developers to fine-tune how messages are delivered with QoS profiles. You can configure:

• Reliability (best effort vs guaranteed delivery)
• Durability (do new subscribers get old messages?)
• Latency budgets
• Liveliness detection (detecting dead publishers)

This gives developers precise control over how nodes interact, especially in lossy or high-throughput networks.

Security Built-In

Security was an afterthought in ROS 1. In ROS 2, it’s a first-class citizen. It includes:

• Encryption of messages in transit
• Authentication of nodes
• Access control policies to restrict who can publish/subscribe

Security is crucial for commercial robotics, especially in fields like healthcare, defense, and autonomous transport.

Improved Node Lifecycle Management

ROS 2 introduces managed lifecycles for nodes. A node can be explicitly initialized, activated, deactivated, and shut down. This allows:

• Cleaner startup and shutdown sequences
• Better error handling
• Easier introspection and supervision

This is particularly useful in systems that require staged initialization or watchdog monitoring.

Cross-Platform & Embedded Ready

ROS 2 is designed to work across platforms:

• Native support for Linux, Windows, and macOS (though Windows and macOS are not considered production-grade for most robotics deployments)
• Builds on ARM and embedded Linux devices
• Supports cross-compilation for real-time microcontrollers

This means you can build a system with a Jetson for perception, a Raspberry Pi for control, and a desktop for planning—ROS 2 will tie it all together.

ROS 1 Doesn’t Stop Overnight

The end of official support doesn’t mean that ROS 1 systems will suddenly break. Existing applications and research projects built on ROS 1 will continue to run. But the risks will grow over time:

• No new bug fixes or security patches
• Incompatibility with newer operating systems and compilers
• Reduced community activity and package maintenance
• No support for evolving hardware or standards

For small-scale projects, this may not matter. But for production environments, long-term maintenance, and scalable deployments—ROS 2 is the way forward.

Final Thoughts

ROS 2 isn’t just a newer version of ROS—it’s a complete rethink, engineered for where robotics is headed. Real-time control, secure communication, decentralized systems, and embedded readiness are no longer optional—they’re essential.

Yes, migrating to ROS 2 can be a non-trivial effort. APIs are different. Not all ROS 1 packages have 1-to-1 equivalents. But the foundational improvements are worth it—and necessary.

If you’re starting a new robotics project in 2025, choosing ROS 1 now would be like choosing Python 2 for a new web app. It might work, but you’re building on borrowed time.

So—what changed? Everything. And that’s why it matters.