Converged Network Adapter (CNA): Maximize Network Efficiency

A converged network adapter, or CNA, is a device that plays a crucial role in modern data center environments. It combines network, storage, and data traffic functionality into a single adapter card, offering a more streamlined and efficient solution for connectivity.

In this article, we will explore the concept of converged network adapters, their importance, use cases, key features, and factors to consider when selecting your network's correct circuit adapter, such as a circuit board.

Key takeaways

  • Converged network adapters (CNAs) combine storage, data, and networking functionality into a single device, simplifying infrastructure and enhancing efficiency.
  • CNAs emerged from the need to unify Fiber Channel and Ethernet traffic onto one adapter instead of separate cards for storage and networking.
  • CNAs reduce costs, improve performance, provide flexibility, and make it easier to scale networks as needs change.
  • When selecting a CNA, key considerations are compatibility, speed, protocol support, vendor reputation, and cost.
  • With the ability to optimize and future-proof networks, CNAs play an increasingly vital role as data centers leverage technologies like AI and 5G.

Converged Network Adapter (CNA)

What is a Converged Network Adapter?

A Converged Network Adapter (CNA), also known as a converged network interface controller (C-NIC), is a device that provides access to both storage and Ethernet from a single card. It can handle the TCP/IP and the storage protocol stack, such as Fiber Channel over Ethernet (FCoE) or iSCSI.

In other words, a CNA "converges" access to a storage area network and a general-purpose computer network. This convergence of networking and storage functionality onto one device simplifies the infrastructure and can lead to cost savings and increased efficiency.

It's like having a multi-talented performer in a play who can act, sing, dance, and handle networking and storage tasks all in one!

The history of a Converged Network Adapter

The history of the Converged Network Adapter (CNA) is a fascinating journey that reflects the evolution of networking technology. It all began with the advent of Ethernet and Fiber Channel Host Bus Adapters (FC HBA), two distinct technologies that served different purposes. Ethernet was primarily used for data, while FC HBA was designed for storage networking in SAN environments.

In the early days, Ethernet was a lossy network, allowing some data packets to be dropped. FC HBA provided lossless Ethernet, ensuring high standards of data integrity, which was crucial for storage. The functionality of a Network Interface Card (NIC) was limited to handling Ethernet data packets, while FC HBA handled Fiber Channel data packets.

As technology advanced, the need for a unified solution became apparent. This led to the development of the Ethernet Converged Network Adapter. The CNA combined the functionality of a NIC and FC HBA into a single device capable of handling both Ethernet and Fiber Channel data packets. This was a significant milestone in networking technology, as it allowed for the convergence of data and storage networks.

High Speed Ethernet CNA

The introduction of Gigabit Ethernet further enhanced the capabilities of CNAs. With the ability to transmit data at 1 gigabit per second, CNAs became an integral part of high-speed networks. 10Gig Ethernet increased this by tenfold, and then 100GB increased this by 100.

In the United States, the adoption of CNAs increased rapidly. The number of adapters grew exponentially as businesses recognized the benefits of a converged adapter solution. Soon, dual-port adapters with redundancy and increased throughput were introduced, providing an additional layer of reliability.

The Active Health System was another significant development in the history of CNAs. This system continuously monitors the network, detecting potential issues before they become critical. This proactive approach to health has been instrumental in maintaining the high standards of data integrity that CNAs are known for.

Converged Network Adapters Features Use cases

Importance and use cases

Converged network adapters play a vital role in data center environments. They reduce operational costs and complexity by enabling a single adapter to handle network, storage, and data traffic. Everyday use cases of converged adapters include server adapters, storage area networks, and ethernet traffic, all of which benefit from the simplification of administration and enhanced system performance.

Key features of a CNA?

A Converged Network Adapter (CNA) offers unified networking by combining Ethernet and storage functionalities. It supports high-speed performance and protocols like iSCSI and FCoE and is compatible with multiple systems. It's cost-efficient, scalable, and enhances management, making it a vital component in modern networking.

How does a Converged Network Adapter improve connectivity?

A Converged Network Adapter (CNA) enhances connectivity by unifying data and storage networking. This simplifies infrastructure, reduces costs, and improves performance. CNAs offer scalability and flexibility, accommodating growth and changing network needs, making them a cost-effective solution for modern environments.

Unified Infrastructure: A CNA combines the functionality of a traditional Ethernet network interface card (NIC) and a host bus adapter (HBA), which is used for storage networking. This means you can handle Ethernet data and storage networking (iSCSI or FCoE) over a single piece of hardware.

This simplifies the infrastructure, reducing the number of adapters, cables, and switch ports needed, resulting in fewer adapter cards, cables, switch ports, PCIe slots, and a converged switch that can handle both types of traffic required, such as Converged Enhanced Ethernet (CEE).

The CNA connects to the server via a PCI Express (PCIe) interface. The server sends FC SAN and LAN traffic to an Ethernet port on a converged switch using the Fiber Channel over Ethernet (FCoE) protocol for the FC SAN data and the Ethernet protocol for LAN data. The converged switch converts the FCoE traffic to FC and sends it to the FC SAN.

Cost Efficiency: By converging data and storage, a CNA can lead to cost savings. You can reduce capital expenditure on separate adapters for data and storage networking and lower operational costs due to simplified management and lower power consumption.

Performance: CNAs often come with advanced features like high-speed Ethernet support (10GbE and above), offload capabilities for storage protocols, and Quality of Service (QoS) features. These can lead to improved performance and efficiency.

Scalability: As your network grows, managing separate data and storage networks can become increasingly complex. With a CNA, you can scale more efficiently, as you only need to add more of the same type of adapter rather than different adapters for data and storage.

Flexibility: A CNA provides the flexibility to use either Ethernet storage networking or both simultaneously. This can be particularly useful when the data and storage mix may change over time.

Role of CNA in Ecosystem

5 things to consider when selecting a right CNA?

Selecting the right Converged Network Adapter (CNA) involves considering several factors:

  1. Compatibility: Ensure the CNA is compatible with your server's hardware and software. Check the operating systems and hypervisors it supports and whether it fits into your server's form factor (PCIe slot).
  2. Performance: Look at the data rate the CNA supports. If you have high-performance needs, you might need a CNA that supports 10GbE, 25GbE, or even 100GbE. Also, consider the offload capabilities of the CNA for storage protocols like iSCSI and FCoE.
  3. Protocol Support: Depending on your storage needs, you might need a CNA that supports specific protocols. For instance, if you're using Fibre Channel storage, you'll need a CNA that supports Fibre Channel over Ethernet (FCoE).
  4. Vendor Support and Reputation: Consider the reputation of the CNA's manufacturer. Look at their support policies, the availability of firmware updates, and the responsiveness of their customer service.
  5. Cost: Finally, consider the cost of the CNA. This includes not just the upfront cost of the adapter but also the ongoing costs of management and power consumption.

Remember, the right CNA for you depends on your needs and circumstances. It's always a good idea to consult with a professional or a trusted vendor before deciding.


In conclusion, converged network adapters deliver immense value in modern data centers by converging storage and networking functionality into a single device. CNAs simplify infrastructure, reduce costs, enhance efficiency, and provide a flexible, scalable solution to meet evolving connectivity needs.

The development of CNAs has been driven by the need for unified networking that converges Fiber Channel and Ethernet traffic. CNAs eliminate the need for multiple adapters and switch ports by combining storage and data capabilities.

When selecting a CNA, key factors include compatibility, performance, protocol support, vendor reputation, and cost efficiency. As data centers handle growing volumes of data, the role of CNAs will become increasingly vital. Their ability to optimize while cutting costs makes CNAs a strategic investment for future-proofing infrastructure.

With their versatility and next-generation capabilities, converged network adapters represent the future of connectivity. As businesses modernize their data centers to capitalize on emerging technologies like IoT, AI, and 5G, CNAs will be at the core of unlocking efficiency and innovation.

When looking for networking devices to connect to your CNA, keep RUCKUS in mind.


What is the difference between CNA and Ethernet?

CNA (Converged Network Adapter) and Ethernet are both networking technologies. Ethernet is a standard communication protocol embedded in software and hardware devices used for building a local area network (LAN). CNA, on the other hand, is a single networking interface card that combines Ethernet and storage capabilities, simplifying management and reducing costs.

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