HTTP/3

The announcement of HTTP/3 at the start of November 2018 may have come as a surprise for a lot of us.

Indeed, compared to the 18 years that separated HTTP/1.1 et HTTP/2, this announcement comes only 4 years after the release of HTTP/2.

But the biggest surprise is under the hood, with a replacement of the transport layer.

In this talk, we will explain why this version 3 of the HTTP protocol has been designed, especially around the latency topic.

We will cover as well how technically this version works, and what it will bring to our applications, and what are the challenges, that us, DevOps, we will need to address, in order to fully benefit from this version.

Transcript

1. HTTP/3
   HTTP/3
   It's All About The Transport!
   It's All About The Transport!
   Benoit Jacquemont
   Benoit Jacquemont
   @bjacquemont
   @bjacquemont
   

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2. But HTTP/2 Just Came
   Out!?
   HTTP/1.1: 1997 - HTTP/2: 2015 - HTTP/3: 2018 (announcement)
   

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3. HTTP/3
   =
   HTTP/2 Over QUIC
   Kwiiiick!
   

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4. HTTP/2 = TCP
   Application
   Transport
   HTTP/3 =
   QUIC
   

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5. What's The
   Problem With
   TCP?
   

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17. Hey, but latency sums up!
    

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18. Network Performance
    Latency &
    Bandwidth
    

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20. Chappe Telegraph
    A B C D E F
    Volume of data: 7 bit (92 symbols)
    Transport: light
    Speed: 3 symbols per minute
    

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23. Chappe Telegraph Performances
    Latency: 0.003 ms (light delay over 10km)
    Bandwidth: 0.4 bit/s
    

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24. Truck Full Of SSD
    Transport: 15 TB SSD in a container
    Volume of data: 3 exabyte, aka 3 millions of TB
    (200k disks)
    

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27. SSD Truck Performances
    Latency: 40 minutes (30 km at 50 km/h average)
    Bandwidth: 10 Petabit/s (or 10.000 Tb/s)
    

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28. Bandwidth Latency
    Chappe Telegraph 0.4 bit/s 0.003 ms
    SSD Truck 10 Pbit/s 40 minutes
    

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29. Bandwidth And Latency Evolution
    Medium Bandwidth Latency
    56k modem 40 Kbit/s 150ms
    ADSL 18 Mbit/s 50ms
    Optical Fiber 200 Mbit/s 10ms
    Bandwidth: 5000x Better
    Latency: 15x Better
    

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31. Should I Care About Latency?
    The 3 Important Time Limits In UX
    Source: Jakob Nielsen, "Usability Engineering" 1993; Miller 1968
    0.1s: instantaneous feeling limit
    1s: ow of thought limit
    10s: user attention limit
    Latency Is The #1 Enemy
    Of Web UX!
    

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32. HTTP: A History Of
    Battle Against Latency
    

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46. Hey, It Gets Worse!
    

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47. The TLS Handshake
    

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48. Initiator Receiver
    SYN
    ACK
    SYN-ACK
    Client Hello
    Server Hello
    Client Key Exchange
    Server Finished
    Client Finished
    HTTP Request
    HTTP Response
    TCP
    TLS
    HTTP
    Time
    

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49. Introducing QUIC
    Previously Known As
    Quick UDP Internet Connections
    

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50. QUIC Handshake
    Initiator Receiver
    QUIC HELLO
    QUIC TOKEN
    QUIC HELLO + TOKEN
    

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51. QUIC
    =
    Transport And Encryption
    

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52. TCP/TLS Vs QUIC
    

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53. But Isn't UDP Unreliable?
    What Was The Point Of TCP, Again?
    

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70. But With
    UDP...
    

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71. my
    important
    message
    1 2 3 4 2 1 4
    But With
    UDP...
    

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72. QUIC Takes Care Of The
    Packets...
    ...At The Browser/Server
    Level
    

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85. TCP Is Strongly Coupled
    To The Network
    Connection
    

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95. QUIC Is Loosely Coupled
    To The Network
    Connection
    

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96. TCP And Head Of Line
    Blocking
    

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115. With Bad Connectivity, HTTP/2
     Streams Can Be Worse Than
     HTTP/1.1 Parallel Connections!
     

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136. QUIC Streams Are
     Independent From Each
     Other.
     No HOL Blocking
     

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137. HTTP/3: What's In It For Me?
     HTTP/3 =
     QUIC
     HTTP/3 doesn't change HTTP/2 semantics
     HTTP/3 is mostly a drop-in replacement for HTTP/2
     Main (only?) change for web dev: streams priority
     Code for HTTP/2
     and bene t from HTTP/3 when it's out!
     

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138. QUIC
     Challenges
     

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165. QUIC Maturity
     Enabled by default in Chromium since 2013
     Enabled on Chrome for Google web servers
     Ongoing standardisation by IETF
     7 November 2018: rst interop connection between
     LiteSpeed and Facebook
     tools.ietf.org/html/draft-ietf-quic-http-24
     

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166. HTTP/3 Key Takeaways
     QUIC latency is far better than TCP+TLS
     HTTP/3 allows HTTP/2 to meet its full potential
     Final HTTP/3 release date not yet de ned...
     ... but already battle tested
     Still a lot of work to make it happen
     

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167. Thank You!
     Questions?
     For more information:
     @bjacquemont
     daniel.haxx.se/http3-explained/
     www.chromium.org/quic/
     

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