Most networked applications spend a significant amount of time on communication, and the software libraries and hardware used for communication often determines their performance (both throughput and latency), and their resource requirements. In the past decade, we have seen several efforts to improve communication performance and efficiency at the end-host. These include kernel bypass libraries such as DPDK, new kernel interfaces such as io_uring, in-kernel network offloads provided by XDP and eBPF, and SmartNICs of a variety of types. Each of these approaches makes trade-offs in terms of their performance, how easily they can be deployed (in private clusters and multi-tenant environments), their resource requirement, the reliability they provide, and how easy it is for programmers to use them when building networked applications. We are organizing this Dagstuhl Seminar to bring together people who work on systems, networking, programming languages, compilers, computer architecture, and distributed systems to work together to articulate and understand these trade-offs, and collectively propose approaches to improve usability, reliability, deployability, and analysis of high-performance networking software and hardware.