Cisco Nexus Switch vs Catalyst Switch: Choosing the Right Switch Line

Quick Answer: Cisco Nexus and Catalyst switches are both great network options, but each serves its own purpose. Nexus switches are intended for data centers and provide more advanced functionality, while Catalyst switches are better for typical corporate network use.

You can’t have a network without network devices such as switches and routers, but with so many devices on the market, it's easy to get overwhelmed with the options. In this article, we'll compare and contrast two well-known models: the Cisco Nexus switch and the Cisco Catalyst switch. 

We'll discuss cost, performance, scalability, and features. After all, you don’t want to spend money on a product that doesn’t best suit your needs.  Additionally, we’ll evaluate each switch's functionality, as they both offer a wide array of features, from security to automation. Let’s begin with each switch’s purpose.

What are Nexus Switches, and What Environments Are They Designed For?

The Nexus switch is best suited for data centers and similar environments. It is intended for professional use and has flexible networking capabilities to support fiber, Ethernet, and FCoE (Fiber Channel over Ethernet). 

Nexus switches run on the NX-OS, which provides more features in exchange for being more complex to configure than the Catalyst’s IOS operating system. Unlike Cisco Catalysts, Nexus switches only support the Link Aggregation Control Protocol. 

What are Catalyst Switches, and Where are They Typically Used?

On the other hand, Cisco Catalyst switches are great for enterprise networking, where you might expect to support a sizable number of users across a large network. Think of public spaces such as offices and university campuses. 

Cisco Catalyst switches run on the IOS operating system (different from the Apple iOS operating system) and support both LACP (Link Aggregation Control Protocol) and PAGP (Port Aggregation Control Protocol), which are open-source and proprietary protocols, respectively.

Nexus and Catalyst Switches: Performance and Scalability

Due to their intended use in data centers, Nexus switches outclass Catalyst switches in both performance and scalability. Nexus switches can be upgraded while maintaining uptime and support the same network quality when the on-site is down. That performance comes at the cost of ease of use, though, as switch management can be more complicated with Nexus models than with Catalysts. 

The Cisco Catalyst models don’t pigeonhole themselves into a primary use case, making them more versatile than the Nexus models. These switches are easier to manage and support a wide array of security features.

Nexus and Catalyst Switches: Virtualization

Virtualization is an important consideration when evaluating whether your organization should choose a Cisco Nexus switch or a Cisco Catalyst switch. While both models support virtualization, their capabilities differ. 

The Cisco Nexus line of switches provides the ability to divide physical resources into virtual devices and networks. This capability further provides access to features like NetFlow (traffic visibility used for monitoring performance), Virtual Device Contexts (VDCs), and policy-based virtual machine connectivity, which simplifies the application of networking rules to future virtual machine deployments. 

The Cisco Catalyst line of switches also has some more basic virtualization features like resource sharing and flexible deployment options, but not to the extent of the Nexus line of switches.

Nexus and Catalyst Switches: Key Security Features 

While both switches offer security capabilities, each shines in its own way. The Cisco Nexus line of switches excels at network segmentation and policy enforcement in multi-tenancy environments. 

The Cisco Catalyst line of switches hosts many security features, but the main features include Access Control Lists (ACLs), port security, and DHCP Snooping. Access Control Lists can help keep individual devices and entire network segments secure by restricting traffic to and from other devices and segments, which can also help improve performance. Port security helps mitigate the risk of unauthorized devices gaining access to the network. Finally, DHCP Snooping (Dynamic Host Configuration Protocol) works by filtering out and rate-limiting DHCP traffic from untrusted devices to mitigate being flooded by DHCP packets as part of an attack.

How do Nexus and Catalyst Switches Handle Network Convergence?

Since the Cisco Nexus line of switches is intentionally designed for data centers, they handle convergence utilizing Spanning Tree Protocol (STP) implementations like Rapid PVST+. Nexus switches also use features like Virtual Port Channels (vPC) for high availability.

Catalyst switches focus on more general network convergence, supporting converged wired and wireless access on a single platform and utilizing Spanning Tree Protocol to ensure efficient loop detection and recovery across different network segments. 

Both lines of switches utilize the Spanning Tree Protocol to quickly adapt to changing network topologies. However, the Cisco Catalyst line of switches is aimed toward a more generalized market of users. In contrast, the Nexus line of switches is tailored almost exclusively to meet the needs of data center operations.

Can Nexus and Catalyst Switches be Managed Using Automation Tools?

Automation is a critical factor to consider when evaluating which switch to deploy within your network, and both the Nexus and Catalyst models offer different capabilities to help optimize network activities. The Nexus switch runs on NX-OS, which is based on the Linux kernel and natively supports the Python programming language. Using APIs and other DevOps integrations should be relatively simple with the Cisco Nexus. 

Cisco Catalyst switches also offer automation through API integration and the use of the Cisco Catalyst Center. The Cisco Catalyst Center is a user interface from which administrators can take advantage of several automation features, such as auto-discovery, automated configurations, and zero-touch provisioning. 

What are the Power-Over-Ethernet (PoE) Capabilities of Nexus and Catalyst Switches?

Technology often requires a lot of cabling. One way to cut down on some of that is through the use of PoE, or power-over-Ethernet. It’s exactly what it sounds like in that one cable will deliver both data and power to a device, often smaller devices like phones,  access points, and other IoT devices. It may seem trivial, but it can scale quickly and make a difference. While both the Nexus and Catalyst models offer PoE capabilities, the Nexus model offers it with a caveat. Not all Nexus models provide PoE, so if that’s important to you, make sure you’re looking at the right Nexus switches. 

Catalyst models, on the other hand, offer extensive support for PoE and something called PoE+, which increases the amount of power distributed via Ethernet, expanding the range of devices you can plug into a switch without worrying about an accompanying power cable. 

Pricing and Cost of Ownership Comparison 

Cost is an obvious consideration when purchasing technical equipment, so which switch provides a better return on investment? The Cisco Nexus switch has a higher initial cost due to its more advanced functionality, but it lasts a long while, so you should be able to get plenty of value out of each unit. Catalyst switches have a lower initial cost, but there may be additional costs based on what exactly you’re looking for. Licensing for some features and support should be considered when evaluating the total cost of ownership for these switches.

Can I Use Nexus and Catalyst Switches Together in the Same Network?

Both switches are compatible with each other. If your environment needs it, you can combine Nexus and Catalyst switches to the same network. One example of how you could use these together would be to use a Nexus switch as a top-of-rack (TOR) switch to connect devices within the same server rack, as well as aggregate switches like the Cisco Catalyst line of switches. Together, these switches can create a powerful, capable, and extensive network.

Final Thoughts 

If you’re in the market for new switches, both the Cisco Nexus and Cisco Catalyst are great options and almost certainly have the features you’re looking for, depending on your needs. 

While they’re both great and offer many similar capabilities, each has its strengths. The Nexus line of switches is powerful and intended for operations in data centers. It only supports LACP, whereas the Catalyst line of switches supports LACP and PACP. The Nexus switch runs on NX-OS, which is based on the Linux kernel, while Cisco Catalysts run on Cisco IOS. As far as cost is concerned, Nexus switches have a higher upfront cost, while Catalyst switches are more sparing on a budget in comparison. 

Want to learn more about Cisco switches? This CBT Nuggets Data Center Networking with Cisco Nexus Switches Online Training course is a great place to start.