What makes a Smart NIC smart?

What makes a Smart NIC smart?

May 04, 2021


You may have noticed the term “Smart NIC” while searching around for Ethernet cards. If you wonder what a Smart NIC is, it’s any network interface card with an Ethernet Controller chip that can handle operations that a CPU (central processing unit) would normally have to handle. While that sounds interesting, it doesn’t explain what makes it smart and why the distinction is important.

To get to the crux of that issue you have to keep in mind one very important factor: overhead. Forever the bane of network engineers across the world trying to share storage over Ethernet, overhead is any combination of CPU or other system resources needed to perform a specific task. This is why the actual speed of a NIC is never what it says on the box; almost half of the bandwidth of a non-smart NIC is consumed by overhead.

When the Ethernet protocol was designed in the 1970s for scientists to share data globally, they didn’t plan for large, highly intensive streaming storage applications like we see today. This is why for many years storage architects turned to other protocols like Fibre Channel to maximize bandwidth.

Over the years, many technologies have been implemented specifically to reduce or virtually eliminate Ethernet overhead by alleviating system resources. These technologies are the smart part of a Smart NIC. They include offloads which are highly complex algorithms like the TCP offload engine in ATTO Advanced Data Streaming™ (ADS) technology found inside our 10/25/40/50/100GbE FastFrame™ Smart NICs.

We also have unique offloads that create cache buffers taking advantage of the power inside our FastFrame cards like Large Receive Offload (LRO) and TCP segmentation offload (TSO). Both LRO and TSO have been utilized recently along with other system tweaks inside our ATTO 360 application’s tuning profiles to reduce overhead by over 50 percent!

More recently RDMA, which stands for remote direct memory access, has been added to FastFrame allowing our Smart NIC’s controller chip to access system memory directly. Doing this eliminates the CPU’s task completely and virtually eliminates overhead. RDMA uses Fibre Channel methods like direct memory access and zero copy which we exploit to achieve near line-rate transfers.

The downside to RDMA is that it can be hard to implement as there are a lot of dependencies and, because it’s not a TCP technology, system administrators might not know what to do with it. This is why ATTO has decided to add RDMA support in the next release of our groundbreaking ATTO 360™ Tuning, Monitoring and Analytics Software.

With the next version of ATTO 360 not only will you be able to apply our customized TCP tuning profiles that significantly reduce overhead on normal TCP transfers, but we have all new RDMA profiles and diagnostics. 360 all but eliminates downtime by instantly setting up and configuring ATTO NICs for any type of environment and the diagnostic engine will automatically alert you when it discovers any issue that could cause bottlenecks.

Whether it’s a small, medium, or enterprise storage network using the tried and true Ethernet standards or latest Smart technologies, ATTO FastFrame Smart NICs are engineered to get the job done. With built-in intelligence and features like ATTO 360 Tuning Software, FastFrame is the high-performance end-to-end Ethernet solution for any architecture.

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