什麼是 SPDY?

SPDY 的說明文件如下述:

• SPDY - The Chromium Projects
• SPDY: An experimental protocol for a faster web
• draft-ietf-httpbis-http2-00 - SPDY Protocol

什麼是 SPDY? SPDY 作什麼事情?

SPDY 主要是希望可以讓現在 HTTP 加速, 加強 HTTP 的部份摘錄如下述: (取自上述官方文件)

SPDY is not the only research to make HTTP faster. There have been other proposed solutions to web latency, mostly at the level of the transport or session layer:

• Stream Control Transmission Protocol (SCTP) -- a transport-layer protocol to replace TCP, which provides multiplexed streams and stream-aware congestion control.
• HTTP over SCTP -- a proposal for running HTTP over SCTP. Comparison of HTTP Over SCTP and TCP in High Delay Networks describes a research study comparing the performance over both transport protocols.
• Structured Stream Transport (SST) -- a protocol which invents "structured streams": lightweight, independent streams to be carried over a common transport. It replaces TCP or runs on top of UDP.
• MUX and SMUX -- intermediate-layer protocols (in between the transport and application layers) that provide multiplexing of streams. They were proposed years ago at the same time as HTTP/1.1.

SPDY 可以幫 HTTP/HTTPS 速度提昇的數據 (摘錄自上述官方文件)

• The results show a speedup over HTTP of 27% - 60% in page load time over plain TCP (without SSL), and 39% - 55% over SSL.

關於 SPDY 的相關套件與模組

• mod-spdy - Apache SPDY module
• spedye: A reverse proxy for the HTTPS and SPDY protocols

關於 SPDY 的相關文章、投影片介紹

• SPDY -WikiPedia
• Making the Web Faster with HTTP 2 Protocol
• Making the web speedier and safer with SPDY
• SPDY of the Future Might Blow Your Mind Today « Mike's Lookout, 下述摘錄自此文
  

  What is SPDY?
  SPDY is a protocol created by Google researchers. Announced first in 2009, it brings some of the original goals proposed by the HTTP-NG group in 1998.

• Google 的 SPDY 將可能包含在下一代 HTTP 標準中, 下述摘錄自此文:
  

  SPDY設計目標在減少 Client 和 Server 之間的延遲。
  當資料經過 TCP 連接傳輸，發送端必須先等待接收方確認之後才能發送資料。
  接受和確認所需的時間是由往返時間(Round-Trip Time)控制。
  Client 和 Server 可能要將大部分時間花在確認上，而不是資料傳輸上。
  通過 HTTP Header 壓縮、包優先權 和 reuse 等，SPDY能減少網頁載入時間。
  HTTP 工作組 的 主席Mark Nottingham呼籲應該將SPDY包含在下一代HTTP/2.0標準中。

• Firefox 將支持 SPDY 協議, 下述摘錄自此文:
  

  舊的 HTTP 和 TCP Protocol 不能充分利用頻寬，Google 的 SPDY Protocol 是基於TCP的應用層協議，一次會話能復用傳輸多個文件，降低頁面載入時間。

投影片: You Ain't SPDY (Ruby Nation), 下述為此投影片的一些重點摘錄:

• SPDY is a replacement for HTTP
• SPDY is backwards compatible with HTTP
• SPDY still does HTTP-like things
• SPDY is optimized for page load times
• SPDY
  

  Built on SSL
  Binary
  Don't send redundant header information
  Aggressively compress stuff
  Use a single(!) tube
  Only pay the warm-up penalty once
  Just like downloading an Ubuntu ISO!

• SPDY
  

  SYN_STREAM
  SYN_REPLY
  RST_STREAM
  SETTINGS
  HEADERS
  PING
  GOAWAY
  WINDOW_UPDATE
  DATA

相關網頁

• Y U No Support SPDY Yet?
• Google SPDY初探：HTTP 1.1之外的世界
• What is SPDY? Deployment Recommendations
• HTTP 2.0 First Draft Published - HTTP 2.0 有把 SPDY 列入

作者: Tsung

對新奇的事物都很有興趣, 喜歡簡單的東西, 過簡單的生活. 檢視「Tsung」的全部文章