Ericsson Ericsson Arm Cloudflare In situations where direct connectivity is not available or desired, proxies in the network are used to forward and potentially translate traffic. TCP is often used as a proxying or tunneling protocol. QUIC is a new, emerging transport protocol and there is a similar expectation that it too will be used as a substrate once it is widely deployed. Using QUIC instead of TCP in existing scenarios will allow proxying and tunneling services to maintain the benefits of QUIC natively, without degrading the performance and security characteristics. QUIC also opens up new opportunities for these services to have lower latency and better multistreaming support. This document summarizes current and future usage scenarios to derive requirements for QUIC as a substrate and to provide additional considerations for proxy signaling and control protocol as proposed by MASQUE.