Ultra-low latency network interface card High port density Dual QSFP+ ports in a half-height form factor provide eight 10GbE interfaces. The Cisco Nexus® X40 SmartNIC (K35-Q) is a 10/40Gbps interface card specifically optimized for low-latency environments. It can connect to eight SFP+ ports QSFP+ breakout cables and/or Layer 1 switches. This enables a range of high-performance applications such as packet capture across multiple connections, or market data line arbitration across many different feeds. Easy to use In addition to a standard Linux driver, a transparent TCP and UDP acceleration library is included, as well as a library for low-level access. A transparent socket acceleration library allows applications to benefit from the low latency of a kernel bypass, in most cases without modifications to the applications. For the most latency sensitive applications, a library called "libexanic" allows direct low-level access to the Cisco Nexus X40 SmartNIC (K35-Q) hardware and includes simple functions for sending and receiving Ethernet frames. With the optional firmware development kit, it is even possible to extend the SmartNIC firmware and add your own logic to the onboard Field Programmable Gate Array (FPGA). Advanced capture Flow steering delivers packets to the right application's receive buffer. Filters can be defined over Ethernet frame components such as SRC/DST MAC, SRC/DST IP, etc., and a receive buffer associated with that filter. As packets come off the wire, the Cisco Nexus X40 SmartNIC (K35-Q) will analyze the traffic and deliver packets that the match filters directly to the correct receive buffer. Nonmatched packets are delivered to the default buffer. This flow steering is done inline at line rate, adding no additional latency. Flow hashing distributes packets evenly across multiple buffers, allowing CPU load to be spread for demanding capture and analysis applications. Timestamping Built-in timestamping functionality records each frame's arrival time to within 6.2ns. These timestamps are available through a direct API and through Exact Capture, our free and open-source, high-rate capture system. Exact Capture can write tcpdump-compatible captures at line-rate to disk. Additionally, the Cisco Nexus X40 SmartNIC (K35-Q) features Pulse-Per-Second (PPS) input and output and supports hardware accelerated PTP. These can be used to synchronize the SmartNIC clock to external time references (such as a GPS receivers), allowing users to meaningfully compare captured timestamps across multiple servers and geographic locations.