HTTP/3(QUIC)

# nginx.conf (HTTP/3를 지원하게 빌드된 nginx 1.25 이상)
server {
    listen 443 quic reuseport;     # UDP 443: HTTP/3
    listen 443 ssl;                # TCP 443: HTTP/2, HTTP/1.1 (대비용)
    http2 on;                      # nginx 1.25.1 이상
    http3 on;

    ssl_certificate     /etc/ssl/example.crt;
    ssl_certificate_key /etc/ssl/example.key;

    add_header Alt-Svc 'h3=":443"; ma=86400';
}

# 확인: Alt-Svc 헤더와 HTTP/3 응답
curl -sI https://www.example.com/ | grep -i alt-svc
curl --http3-only -I https://www.example.com/

RTT = 50                       # 왕복 시간 (ms)

def first_response(handshake_rtts):
    # 핸드셰이크 왕복 수 + 요청 · 응답 1왕복
    return (handshake_rtts + 1) * RTT

print(first_response(2))      # TCP 1 + TLS 1.3 1  -> 150
print(first_response(1))      # QUIC (TLS 1.3 통합)  -> 100
print(first_response(0))      # QUIC 0-RTT 재연결   -> 50

WIRE = [(s, n) for n in range(1, 4) for s in "ABC"]   # A1 B1 C1 A2 ...
received = set(WIRE) - {("A", 2)}                  # A2가 유실됨

def deliver_tcp(received):
    out = []
    for pkt in WIRE:                 # 연결 전체의 순서를 지킴
        if pkt not in received:
            break
        out.append(pkt)
    return out

def deliver_quic(received):
    out = []
    for s in "ABC":                  # 스트림마다 순서를 지킴
        n = 1
        while (s, n) in received:
            out.append((s, n))
            n += 1
    return out

print(len(deliver_tcp(received)), len(deliver_quic(received)))   # 3 7