Difference Between Cisco NX-OS and Cisco IOS

Difference Between Cisco NX OS and Cisco IOS

Since the company’s inception, Cisco has been a forerunner in the networking software business. It has created and implemented a number of systems that combine cutting-edge technology with extensive hardware system support. Cisco NX-OS and Cisco IOS are two such systems that are widely appreciated and used by a large number of people.

Cisco NX-OS Vs. Cisco IOS

Cisco NX-OS and Cisco IOS differ in that Cisco NX-OS processes function in memory spaces that are independent of one another, but Cisco IOS processes share a single memory space. This means that a failure in any process would have little impact on Cisco NX-OS, but would cause chaos with other router functions in Cisco IOS.

Cisco NX-OS is a network operating system created exclusively for Cisco Nexus Ethernet switches and MDS Fibre Channel storage area network devices. It’s an improved version of Cisco’s SAN-OS operating system, which was designed specifically for MDS switches. The system is based on the Linux kernel and comes with a number of high-availability capabilities.

Cisco IOS is a previous version of Cisco’s operating system that predates Cisco NX-OS. It can be thought of as a software family that runs on most Cisco System routers and current Cisco network switches. Its code base features a cooperative multitasking kernel; nonetheless, when compared to Cisco NX-OS, it has numerous architectural restrictions.

What is Cisco NX-OS?

Cisco NX-OS is a network operating system with high scalability and application availability. It originated from Cisco SAN-OS, an industry-proven system designed for MDS switches. Cisco NX-OS has been enhanced to work with Nexus Ethernet switches. It includes IPv4 and IPv6 routing, as well as multicast capabilities. It included a centralized data centre with comprehensive serviceability and security. The system’s code was written in the Python programming language.

A virtual device context, virtual port channels, and continuous system operation are some of Cisco NX-important OS’s features. Layer 2 extension between distant data centres over any Layer 3 transport network is possible with this architecture. It provides a lightweight and effective persistent storage solution for maintaining a runtime information state. This allows software components to save their internal state and restart without causing any disruptions.

Even without a licence, Cisco NX-OS allows users to test, configure, and operate a feature. When a consumer wants to try a feature before purchasing an operating system, this comes in handy. Nexus 7000, Nexus 5000, Nexus 2000, Nexus 1000V, Nexus 4000, Cisco MDS 9000, and Cisco Unified Computing System are among the platforms supported by the system.

What is Cisco IOS?

Cisco IOS is an internetwork operating system that may be found on a variety of Cisco routers and switches. The system’s main goal is to make data exchange between two or more network nodes easier. It comes with a slew of features and services that help users boost the speed and security of their network traffic. It was coded in the C programming language.

Authentication, encryption, policy enforcement, firewall capabilities, quality of service, intelligent routing, deep pocket inspection, and even proxy capabilities are some of the most significant characteristics of Cisco IOS. Call processing and unified data transmission services are also supported by the system. It allows for preemptive multitasking, which prioritises high-priority processes above low-priority activities. It does, however, have some drawbacks, such as the fact that it does not enable symmetric multiprocessing. Furthermore, it can only execute on shared memory.

To address these flaws, new versions of the system were released. Cisco IOS-XE and Cisco IOS-XR are two of the new platforms. Cisco IOS-XE works on top of the Linux kernel. It has a lot of code in common with Cisco IOS-XR, however the latter is built on QNX, which is similar to a Unix real-time system. As a result, it may support software-defined networking while also embedding the systems market.

Difference Between Cisco NX-OS and Cisco IOS

  • NX-OS provides numerous architectural advancements over Cisco IOS, however Cisco IOS has many operational constraints.
  • Cisco NX-OS processes run in their own memory spaces, whereas Cisco IOS processes use a single memory space.
  • Symmetric multiprocessing is supported by Cisco NX-OS but not by Cisco IOS.
  • Cisco NX-OS was developed using Python code, whereas Cisco IOS was developed using C code.
  • Cisco NX-OS can use slash notation to enter the subnet, but Cisco IOS uses dotted decimal notation.
  • Cisco NX-OS is a SAN-OS upgrade, whereas Cisco IOS is an older version of Cisco IOS-XE and IOS-XR.


Cisco NX-OS and Cisco IOS are two network operating systems that millions of people use throughout the world. Cisco NX-OS is a recent update that includes various design enhancements as well as a slew of new capabilities. Cisco NX-OS can operate its processes in their own memory spaces, but Cisco IOS uses a pooled memory space for all of its processes.

In addition, whereas Cisco NX-OS allows for symmetric multiprocessing, Cisco IOS does not. This indicates that Cisco NX-OS is far more user-friendly and helpful than Cisco IOS. Cisco IOS includes upgrade versions, such as Cisco IOS-XE and Cisco IOS-XR that address these issues. As a result, users now have a wide range of possibilities from which to choose.