Towards a Scalable Modular QUIC Server

QUIC has been recently proposed as an alternative transport protocol for web services requiring both low latency and end-to-end encryption. In a different direction, recent kernel-bypass techniques enabling high-speed packet I/O have fostered the development of scalable middleboxes and servers with the introduction of user-space network stacks. Attempting to join the best of both solutions, we introduce in this paper a modular L2--L7 network stack in user space based on QUIC. Our modular and scalable QUIC transport protocol called cQUIC is implemented in Click and uses Intel® DPDK for high-speed packet I/O. We prototype cQUIC and show at least an order of magnitude improvement over the Google QUIC server. We also show that cQUIC scalability is CPU (and not I/O) bounded due to the high cost of cryptographic operations. From real-world traffic traces, we observe that up to 18% of QUIC connections are established using the expensive 2-RTT handshake, limiting scalability further.