Cloud, Datacenter, Networking

Xilinx Unleashes the Power of the Smart NIC

Network Interface Cards, or NICs, are like car tires: they rarely get any attention, but they’re absolutely essential for operation. It’s easy to even forget they’re attached, since they’re so fundamentally basic—until something goes wrong. When that happens with your tires, your car stops. So does your network when it happens to the NIC.

Thus the humble NIC, like so much else in IT, has had to grow and adapt to the current era of virtualization, cloud computing, containers and Kubernetes, the Internet of Things, cloud-native development… you get the idea.

Since NICs are so unsexy, it’s easy to overlook how much they’ve evolved over the years. They started out as simple devices—their role was to move packets in and out of servers from the network to the storage and back again.

But CPUs can’t keep up with the traffic onslaught anymore—with Ethernet pushing speeds of 100 Gigabits (and beyond), and the explosion of data brought about by digital transformation, CPUs are becoming a primary bottleneck.

Because of this, the NICs that used to do nothing more than shuttle packets to and fro evolved into “smart” NICs that can do a lot of the packet processing and other duties, offloading the work from the CPU and increasing network performance, efficiency, and security.

One of the pioneers of smart NICs is Xilinx, which is most famous for the invention of the field programmable gate array (FPGA). Xilinx discussed its latest smart NIC, the Alveo U25N, at Tech Field Day 24, and how it can help enterprises. The U25N is a dual-25 Gigabit, half-height, half-length NIC that Xilinx touts as a solution for tier-2 cloud service providers (CSPs), telcos, and enterprises. See Figure 1.

Figure 1. Architectural overview of the Xilinx Alveo U25N.

The purpose of offloading, like that done by the U25N, is to avoid sending packets to the host (specifically, the host’s CPU). The NIC’s hardware can handle all of the packets, without losing any of the compatibility and configurability that a standard software control plane offers.

Sanjay Manney, Director of Product Planning and Product Management for Xilinx, talked about why that’s important. “Offloading gives you the benefits of relieving the CPU, [resulting in] lower power, lower cost, higher performance. You can get line rate [speeds] without compromising any of the adaptability, programmability, or compliance with standard software modules.”

In current IT environments, un-burdening the CPU is crucial. Pradeep Nallimelli, Datacenter Network and Security Architect for Xilinx, gave an illustration demonstrating the scope of the issue. He explained that on a typical 25 Gigabit line, the network may handle 37 million packets per second.

That’s a lot. And when something like IPsec is enabled, a bunch of operations need to happen on each packet, including:

  • Examining the packet
  • Applying crypto-processing
  • Overlay processing, such as adding or stripping headers
  • Sending the packet toward its ultimate destination

If this is done by the CPU, it could be easily overwhelmed, even 8- and 12-core CPUs. “By contrast, the U25N takes on the entire burden of IPsec processing. It also does the switching, relieving both the CPU and the host,” Nallimelli said. See Figure 2.

Figure 2. How the Xilinx U25N offloads IPsec processing from the CPU.

That’s just one example of the U25N’s power. Others provided during the presentation were open virtual switch (OVS) acceleration; Layer-4 firewall acceleration; and Quality of Service (QoS) operations.

Given the extreme needs of enterprises for moving and securing data in both the physical and virtual realms, the usefulness of a smart NIC becomes instantly clear and compelling. Ethernet speeds are likely to keep increasing, and data creation certainly shows no signs of slowing. As these twin trends roll on, the CPU’s ability to handle all that, along with everything else it does, will fall further and further behind.

That will eventually bring your network to a grinding halt. On the other hand, using a smart NIC like the U25N can free up CPU resources. This could mean better performance for line-of-business (LOB) applications, for example, as well as increased server utilization.

So, as you look at upgrading your IT infrastructure, don’t forget the unassuming NIC. It can do a lot more than you think.