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Martha Kelly (@marthakelly) explains what SPDY is and how it makes the Web faster.

From a talk Martha gave at Nashville Code Co-op Talk Day, March 30, 2013.

Jason Orendorff

March 30, 2013

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  1. WAT is SPDY? Networking Protocol Session layer on top of

    HTTP Transports web content Reduces latency
  2. LMAO HTTP! HTTP was proposed in 1991 Single request per

    connection FIFO queues Only client initiated requests Uncompressed headers Redundant Headers
  3. OMG HEADERS! Request headers can be 2KB (cookies, user agents

    expand features) HTTP sends redundant headers Host User Agent Accept* headers are static
  4. How does SPDY work? It works “on top” of HTTP/TCP

    SPDY is delivered via SSL Introduces new framing layer Reduces latency with Compression Multiplexing Prioritization
  5. SPDY sauce Multiple (unlimited) simultaneously multiplexed requests over a single

    TCP connection Fewer, but more densely packed packets are issued Connection is bi-directional, servers can push data to clients Server Hints
  6. MEH, CAVEATS SPDY only works per domain It doesn't prevent

    scripts from blocking other resources SSL latency penalty
  7. YAY!!1 SPDY! Domain sharding could now be obsolete More wide

    usage of SSL increases security for everyone Packet loss penalty reduced 48% speedup at 2% (IRL packet loss rates are typically 1-2%) TCP++