HTTP/3 explained
  • README
  • English
    • Why QUIC
      • Remember HTTP/2
      • TCP head of line blocking
      • TCP or UDP
      • Ossification
      • Secure
      • Reduced latency
    • Process
      • IETF
      • Experience from HTTP/2
      • Status
    • Protocol features
      • UDP
      • Reliable
      • Streams
      • In Order
      • Fast handshakes
      • TLS 1.3
      • Transport and application
      • HTTP/3 over QUIC
      • Non-HTTP over QUIC
    • How QUIC works
      • Connections
      • Connections use TLS
      • Streams
      • 0-RTT
      • Spin Bit
      • User space
      • API
    • HTTP/3
      • HTTPS:// URLs
      • Bootstrap with Alt-svc
      • QUIC streams and HTTP/3
      • Prioritization
      • Server push
      • Comparison with HTTP/2
    • Common criticism
    • The specifications
    • QUIC future
  • Español
    • Por qué QUIC
      • ¿Te acuerdas de HTTP/2?
      • Bloqueo de cabeza de línea TCP
      • TCP o UDP
      • Osificación
      • Seguro
      • Datos tempranos
    • Proceso
      • IETF
      • La experiencia de HTTP/2
      • Estado
    • Características del protocolo
      • UDP
      • Transferencias de datos fiables
      • Flujos múltiples
      • Entrega en orden
      • Rápido establecimiento de comunicación
      • TLS 1.3
      • Nivel de transporte y aplicación
      • HTTP/3 sobre QUIC
      • No-HTTP sobre QUIC
    • Cómo funciona QUIC
      • Conexiones
      • TLS
      • Flujos
      • 0-RTT
      • Spin Bit
      • Espacio de usuario
      • API
    • HTTP/3
      • HTTPS:// URLs
      • Alt-svc
      • Flujos de QUIC y HTTP/3
      • Priorización
      • Push del servidor
      • Comparación con HTTP/2
    • Críticas habituales
    • Especificaciones
    • QUIC v2
  • Deutsch
    • Warum QUIC
      • Erinnerst du dich an HTTP/2?
      • TCP Head-of-line blocking
      • TCP oder UDP
      • Ossifikation
      • Sicherheit
      • Reduzierte Latenz
    • Prozess
      • IETF
      • Erfahrungen von HTTP/2
      • Status
    • Eigenschaften des Protokolls
      • UDP
      • Zuverlässige Datenübertragung
      • Streams
      • In-Order Ausliefung
      • Schnelle Handshakes
      • TLS 1.3
      • Transport und Anwendung
      • HTTP/3 über QUIC
      • Nicht-HTTP über QUIC
    • Wie QUIC funktioniert
      • Verbindungen
      • Verbindungen verwenden TLS
      • Streams
      • 0-RTT
      • Spin Bit
      • User-space
      • API
  • فارسی
    • چرا QUIC
      • آیا HTTP/2 را به یاد دارید؟
      • مسدود کننده سرِ صف TCP
      • TCP یا UDP
      • استخوان‌سازی (fa/Ossification)
      • امن
      • تأخیرِ کاهش یافته
    • پردازش
      • کارگروه مهندسی اینترنت (fa/IETF)
      • تجربه از HTTP/2
      • وضعیت
    • ویژگی‌های پروتکل
      • UDP
      • مطمئن
      • جریان‌ها
      • منظم
      • دست‌دهی‌های سریع
      • TLS 1.3
      • انتقال و کاربرد
      • پروتکل HTTP/3 بر روی QUIC
      • غیر HTTP بر روی QUIC
    • پروتکل QUIC چطور کار می‌کند
      • اتصال‌ها
      • اتصال‌ها از TLS استفاده می‌کنند
      • جریان‌ها
      • زمان تأخیر چرخشی صفر (fa/0-RTT)
      • بیت چرخشی
      • فضای کاربر
      • رابط برنامه‌نویسی کاربردی (fa/API)
    • پروتکل انتقال ابرمتن نگارش ۳ (fa/HTTP/3)
      • نشانی وب‌های HTTPS://
      • بوت اِسترپ با سرایندِ Alt-svc
      • جریان‌های QUIC و HTTP/3
      • اولویت بندی
      • فشارِ سرور
      • مقایسه با HTTP/2
    • نقدگریِ مرسوم
    • مشخصات
    • پروتکل QUIC نسخه ۲
  • Français
    • Pourquoi QUIC
      • Souvenez-vous de HTTP/2 ?
      • Blocage de tête de ligne TCP
      • TCP ou UDP
      • Ossification
      • Sécurisé
      • Latence réduite
    • La procédure
      • IETF
      • Expérience depuis HTTP/2
      • Statut
    • Caractéristiques du protocole
      • UDP
      • Fiable
      • Flux
      • Dans l'ordre
      • Handshakes rapides
      • TLS 1.3
      • Transport et application
      • HTTP/3 sur QUIC
      • Non-HTTP sur QUIC
    • Comment QUIC fonctionne
      • Connexions
      • Les connexions utilisent TLS
      • Flux
      • 0-RTT
      • Spin Bit
      • Espace utilisateur
      • API
    • HTTP/3
      • URLs HTTPS://
      • Amorçage avec Alt-svc
      • Flux QUIC et HTTP/3
      • Priorisation
      • Push serveur
      • Comparaison avec HTTP/2
    • Critique générale
    • Les spécifications
    • QUIC v2
  • Italiano
    • Perché QUIC
      • Ricordi HTTP/2 ?
      • Blocco ad inizio linea, "TCP head of line blocking"
      • TCP o UDP
      • Ossificazione
      • Sicuro
      • Latenza ridotta
    • Evoluzione
      • IETF
      • Esperienza da HTTP/2
      • Status
    • Caratteristiche del protocollo
      • UDP
      • Affidabile
      • Streams
      • Ordinato
      • Negoziazioni veloci
      • TLS 1.3
      • Trasporto e applicazione
      • HTTP over QUIC
      • Non-HTTP over QUIC
    • Come funziona QUIC
      • Connessioni
      • Connessioni su TLS
      • Streams
      • 0-RTT
      • Bit Rotante
      • User space
      • API
    • HTTP/3
      • URLs in HTTPS://
      • Bootstrap via Alt-svc
      • Gli streams QUIC e HTTP/3
      • Prioritizzazione
      • Server push
      • Paragone con HTTP/2
    • Critiche comuni
    • Le specifiche
    • QUIC v2
  • 日本語
    • なぜ QUIC なのか
      • HTTP/2、覚えていますか?
      • TCP head-of-line ブロッキング
      • TCP か UDP か
      • 硬直化
      • セキュア
      • レイテンシの軽減
    • これまでの歩み
      • IETF
      • HTTP/2 からの経験
      • 現在の状況
    • プロトコルの機能
      • UDP 上の転送プロトコル
      • 高信頼性のデータ転送
      • コネクションは複数のストリームを扱う
      • 到着順序の保証
      • 素早いハンドシェイク
      • TLS 1.3
      • トランスポートとアプリケーションレベル
      • HTTP/3 over QUIC
      • Non-HTTP over QUIC
    • QUIC の仕組み
      • コネクション
      • 接続で TLS を使う
      • ストリーム
      • 0-RTT
      • Spin Bit
      • ユーザー空間
      • API
    • HTTP/3
      • HTTPS:// の URL
      • Alt-svc を使ったブートストラップ
      • QUIC ストリームと HTTP/3
      • プライオリティ制御
      • Server push
      • HTTP/2 と比較した HTTP/3
    • よくある疑問点
    • The specifications (ja/仕様)
    • QUIC v2
  • 한국어
    • 왜 QUIC인가
      • HTTP/2를 기억하는가?
      • TCP HOL(ko/head of line) 블로킹
      • TCP or UDP
      • 고착화(ko/Ossification)
      • 안전
      • 감소된 지연시간
    • 과정
      • IETF
      • HTTP/2에서의 경험
      • 상태
    • 프로토콜 기능
      • UDP
      • 신뢰성
      • 스트림
      • 순서에 맞는 전송
      • 빠른 핸드쉐이크
      • TLS 1.3
      • 전송 계층과 애플리케이션 계층
      • QUIC을 통한 HTTP/3
      • QUIC을 통한 HTTP가 아닌 프로토콜
    • QUIC의 동작 방식
      • 연결
      • TLS을 사용하는 연결
      • 스트림
      • 0-RTT
      • 스핀 비트
      • 사용자 영역
      • API
    • HTTP/3
      • HTTPS:// URL
      • Alt-svc로 부트스트랩하기
      • QUIC 스트림과 HTTP/3
      • 우선순위 정하기
      • 서버 푸시
      • HTTP/3과 HTTP/2의 비교
    • 일반적인 비판
    • 명세
    • QUIC v2
  • Română
    • De ce QUIC
      • Vă mai aduceți aminte de HTTP/2?
      • Blocarea vârfului stivei în TCP
      • TCP sau UDP
      • Osificarea
      • Securitate
      • Timp de așteptare redus
    • Procesul
      • IETF
      • Experiența acumulată cu HTTP/2
      • Starea curentă
    • Funcționalitățile protocolului
      • UDP
      • Fiabilitate
      • Fluxuri
      • În aceeași ordine
      • Handshakes rapide
      • TLS 1.3
      • Nivelurile de aplicație și de transfer
      • HTTP/3 peste QUIC
      • Non-HTTP peste QUIC
    • Cum funcționează QUIC
      • Conexiuni
      • Conexiunile folosesc TLS
      • Fluxuri
      • 0-RTT
      • Spin Bit
      • User space
      • API
    • HTTP/3
      • Adresele HTTPS://
      • Bootstrap cu Alt-svc
      • Fluxurile QUIC și HTTP/3
      • Prioritizare
      • Server push
      • Comparația cu HTTP/2
    • Critici comune
    • Specificația
    • QUIC v2
  • 简体中文
    • 导言
    • 为什么需要QUIC
      • 回顾HTTP/2
      • TCP队头阻塞
      • 用TCP还是UDP
      • 协议僵化
      • 安全性
      • 减少延迟
    • 协议进展
      • IETF
      • HTTP/2的经验
      • 标准化进展情况
    • 协议特点
      • 基于UDP
      • 可靠性
      • 数据流
      • 有序交付
      • 快速握手
      • TLS 1.3
      • 传输层与应用层协议
      • QUIC之上的HTTP协议
      • QUIC之上的非HTTP协议
    • QUIC工作原理
      • 连接
      • 使用TLS的连接
      • 数据流
      • 0-RTT
      • 旋转比特位
      • 用户空间实现
      • API
    • HTTP/3
      • HTTPS:// URL
      • 使用Alt-svc自举
      • QUIC流与HTTP/3
      • 优先度
      • 服务器推送
      • 与HTTP/2的比较
    • 常见批评
    • 技术标准
    • QUIC v2
  • 繁體中文
    • 導言
    • 為什麼是QUIC
      • 回顧HTTP/2
      • TCP隊頭阻塞
      • TCP還是UDP
      • 協定僵化
      • 安全性
      • 減少延遲
    • 協定的進展
      • IETF
      • 從HTTP/2得到的經驗
      • 目前的狀況
    • 協定的功能
      • 基於UDP的傳輸層協定
      • 高度可靠的傳輸
      • 串流
      • 有序交付
      • 快速交握
      • TLS 1.3
      • 傳輸層與應用層協定
      • HTTP/3 over QUIC
      • Non-HTTP over QUIC
    • QUIC運作原理
      • 連接
      • 使用TLS的連接
      • QUIC串流
      • 0-RTT
      • Spin Bit
      • 用户空間
      • API
    • HTTP/3
      • HTTPS:// URL
      • 使用Alt-svc進行引導
      • QUIC串流與HTTP/3
      • 優先次序
      • 伺服器推送
      • 與HTTP/2的比較
    • 常見的錯誤批評
    • 技術標準
    • QUIC v2
Powered by GitBook
On this page
  • TCP or UDP
  • Why not SCTP-over-UDP

Was this helpful?

Export as PDF
  1. English
  2. Why QUIC

TCP or UDP

PreviousTCP head of line blockingNextOssification

Last updated 5 years ago

Was this helpful?

TCP or UDP

If we can't fix head-of-line blocking within TCP, then in theory we should be able to make a new transport protocol next to UDP and TCP in the network stack. Or perhaps even use which is a transport protocol standardized by the IETF in with several of the desired characteristics.

However, in recent years efforts to create new transport protocols have almost entirely been halted because of the difficulties in deploying them on the Internet. Deployment of new protocols is hampered by many firewalls, NATs, routers and other middle-boxes that only allow TCP or UDP are deployed between users and the servers they need to reach. Introducing another transport protocol makes N% of the connections fail because they are being blocked by boxes that see it not being UDP or TCP and thus evil or wrong somehow. The N% failure rate is often deemed too high to be worth the effort.

Additionally, changing things in the transport protocol layer of the network stack typically means protocols implemented by operating system kernels. Updating and deploying new operating system kernels is a slow process that requires significant effort. Many TCP improvements standardized by the IETF are not widely deployed or used because they are not broadly supported.

Why not SCTP-over-UDP

SCTP is a reliable transport protocol with streams, and for WebRTC there are even existing implementations using it over UDP.

This was not deemed good enough as a QUIC alternative due to several reasons, including:

  • SCTP does not fix the head-of-line-blocking problem for streams

  • SCTP requires the number of streams to be decided at connection setup

  • SCTP does not have a solid TLS/security story

  • SCTP has a 4-way handshake, QUIC offers 0-RTT

  • QUIC is a bytestream like TCP, SCTP is message-based

  • QUIC connections can migrate between IP addresses but SCTP cannot

For more details on the differences, see .

SCTP
RFC 4960
A Comparison between SCTP and QUIC