> For the complete documentation index, see [llms.txt](https://http3-explained.haxx.se/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://http3-explained.haxx.se/ko/the-protocol/feature-handshakes.md).

# 빠른 핸드쉐이크

QUIC은 0-RTT와 1-RTT 연결 설정을 둘 다 지원한다. 즉, 최선의 상황에서는 새로운 연결을 설정할 때 추가적인 라운드 트립이 전혀 필요치 않는다. 둘 중 가장 빠른 0-RTT 핸드쉐이크는 호스트에 이미 이전 연결이 구성되어 있고 해당 연결의 시크릿이 캐시 되어 있을 때만 동작한다.

## 초기 데이터

QUIC은 클라이언트가 이미 0-RTT 핸드쉐이크에 데이터를 넣을 수 있다. 이 기능으로 데이터를 피어에 최대한 빨리 전달할 수 있으므로 서버가 더 빨리 응답하고 데이터를 돌려줄 수 있다.


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