SPDY or maybe HTTP2.0

An introduction to the SPDY protocol

Transcript

1. Or  maybe  HTTP2.0   [SPeeDY]   Andreas Bjärlestam! 2012-02-23!
2. SPDY  quick  overview   •  An  evolu?on  of  HTTP   •  Developed  by  Google  since  2009   •  Proprietary   •  But  open  
3. Why  the  hell  would  you  want  to   replace  HTTP?  
4. HTTP  is  fantas?c   it  has  totally  changed  the  world  
5. but…  
6. HTTP  1.1  is  12  years  old  
7. Webpages  in  1999  
9. Webpages  in  2012  
11. Mobile    internet  usage   source:  svenskarna  och  internet  2011  hPps://www.iis.se/docs/SOI2011.pdf  
12. This  is  how  more  and  more  of  us   consume  the  web…  
13. OSen  it  feels  a  lot  like…  
14. People  no  longer  have  pa?ence  to   wait  for  slow  pages  
15. Web  pages  February  2012   •  www.facebook.com  -­‐  ca  100  hPp  requests   •  www.bostonglobe.com  -­‐  ca  100  hPp  requests   •  www.svtplay.se  -­‐  ca  90  hPp  requests   •  www.aSonbladet.se  -­‐  ca  350  hPp  requests   source:  hPp://hPparchive.org/    
16. What  does  it  look  like  over  the   network  fetching  100  resources?  
18. Can  you  spot  the  problem?  
19. Its  all  synchronous  
20. How  come  an  advanced  page  like   facebook.com  loads  in  under  4   seconds  when  its  all  synchronous?  
21. Hacky  op?miza?ons   CSS  sprites   base64  images  in  data-­‐urls   CSS  concatena?on   JavaScript  concatena?on  
22. HTTP/TCP   HTTP/TCP   HTTP/TCP   HTTP/TCP   HTTP/TCP   HTTP/TCP   6  x  HTTP  connec?ons  
23. What  is  the  problem  with  this?  Why   not  even  more?  
24. TCP  Conges?on  control  
25. Maximize  throughput   and   Share  network  equally   among  sessions  
26. 2  connec?ons  per  host  recommended   by  HTTP  1.1  spec   6  connec?ons  in  most  browsers    
27. Domain  sharding   •  www.bostonglobe.com  -­‐  59  connec?ons   •  www.svtplay.se  -­‐  22  connec?ons   •  www.aSonbladet.se  -­‐  118  connec?ons   source:    hPp://www.webpagetest.org  
28. We  kind  of  abuse  TCP   when  we  open  more   connec?ons  
29. and…  
30. New  TCP  connec?ons  are  slow  
31. 3  way  handshake  
32. On  my  macbook   Ping  20ms  ≈  30ms  to  set  up  a   connec?on   On  my  mobile  (3G)   Ping  300ms  ≈  450ms  to  set  up  a   connec?on  
33. HTTP/TCP   HTTP/TCP   HTTP/TCP   HTTP/TCP   HTTP/TCP   TCP  Slow  start   HTTP/TCP  
34. It  turns  out  that  page  load  ?me  for  a  moderately   complex  site  is  almost  no  faster  over  20mbits/ sec  than  over  2mbits/sec  
35. So…  we  need  to  u?lize  our  TCP   connec?ons  bePer  
36. Enter  
37. Don’t  we  break  the  web  if  we  replace   HTTP?  
38. Nope  
39. The  seman?cs  of  HTTP  is  kept  
40. Spdy  implements  HPpApi  
41. You  can  switch  to  SPDY  with  no   changes  to  your  web  applica?on  
42. HTTP  -­‐>  SPDY   GET   PUT   POST   …   HEADERS   Use  of  URIs   Use  of  TCP   GET   PUT   POST   …   HEADERS   Use  of  URIs   Use  of  TCP  
43. SPDY  runs  over  TCP  and  will  not   require  upgraded  network   equipment  
44. HTTP  -­‐>  SPDY   TCP/IP   TLS/SSL   HTTP   TCP/IP   TLS/SSL   SPDY   HTTP  
45. Designed  with   speed  as   primary  goal  
46. 1  TCP  connec?on   HTTP/TCP  
47. HTTP/TCP   But  it  will  be  on  fire!  
48. SPDY  is  mul?plexed  
49. This  is  a  typical  HTTP  session   GET   GET   GET   200  OK   200  OK   200  OK  
50. Mul?plexing   GET  1   GET  2   GET  3   200  OK  2   200  OK  3   200  OK  1  
51. Stream  priori?es  
52. SPDY  is  binary  
53. Will  be  difficult  to  just  fire  up  telnet   and  hack  away  
54. Every  decent  site  will  be  encrypted   and  gzipped    anyways  
55. TLS/SSL  is  mandatory  
56. Communica?on  should  be   secure  by  default     Users  should  not   have  to  care  
58. Using  SSL  ensures  that   communica?on  over  exis?ng   proxies  is  not  broken  
59. ..but  you  will  not  be  able  to   use  proxies  for  caching  etc  
60. Headers  are  compressed  
61. A  SPDY  conversa?on  
62. How  will  the  client  know  that  it  can   use  SPDY  towards  a  server?  
63. NPN   TLS  Next  Protocol  Nego?a?on  
64. Server  Push  
65. Server  Push  
66. So  is  it  worth  it?  
67. Google  tested  25  of  the   “top  100”  sites  
68. Average  speedup   39%  -­‐  55%  
69. SPDY  could  make  your  life  easier   •  Less  important  to  concatenate  JavaScripts   •  Less  important  to  concatenate  CSS  files   •  Less  need  for  CSS  sprites   •  No  need  for  domain  sharding  
70. Should  I  add  SPDY  support  to  my   servers  on  Monday?  
71. Probably  not…  
72. Implementa?ons   •  mod_spdy   •  Nginx  –  in  roadmap   •  node_spdy  –  with  special  openssl  build  etc   •  express_spdy  –    with  node  0.7  etc   •  nePy   •  more…  
73. Browsers   •  Chrome  (since  version  6)   •  Firefox  11  (turned  off  by  default)   •  (Amazon  silk)  
74. CDNs   •  Strangeloop   •  Contendo  
75. CDNs   SPDY   Gateway   Your  web   server   Browser  
76. Google   •  Support  SPDY  on  most  of  their  services   •  90%  of  their  SSL  traffic  is  over  SPDY  
77. Amazon  silk   Silk   Browser   SPDY   Gateway   The   Internet   SPDY   HTTP  
78. The  spec   •  DraS  spec,  version  3   •  Plan  is  to  submit  it  to  IETF  as  input  to  HTTP2.0   •  IETF  HTTPbis  WG  chair  recently  proposed  to   start  work  on  HTTP2.0  
79. Cri?cism   •  Going  over  SSL  means  no  proxies   •  More  difficult  to  debug  since  it  is  binary  and   compressed  
80. Alterna?ves  
81. HTTP  Pipelining   •  Not  as  effec?ve  as  mul?plexing   •  Hard  to  implement  in  browser   •  Opera  is  the  only  desktop  browser  that  has  a   full  implementa?on  enabled  by  default   •  Android,  IOS5  and  Opera  mobile  browsers  do   some  amount  of  pipelining   •  Not  used  by  most  proxies  
82. Pipelining   GET  1   GET  2   GET  3   200  OK  1   200  OK  2   200  OK  3   GET  1   GET  2   GET  3   200  OK  2   200  OK  3   200  OK  1   Mul?plexing   GET   GET   GET   200  OK   200  OK   200  OK   Synchronous  
83. Alterna?ve  transport  protocols   •  SCTP   •  BEEP  
84. Roundup   •  ~  50%  Faster  page  loads  than  HTTP   •  Backwards  compa?ble  with  HTTP   •  BePer  u?liza?on  of  TCP   •  Secured  by  default   •  Binary  +  compressed   •  Will  likely  be  the  base  for  HTTP2.0  
85. APribu?ons   •  hPp://en.wikipedia.org/wiki/ File:US_Robo?cs_56K_Modem_Front.JPG   •  hPps://www.iis.se/docs/SOI2011.pdf   •  hPp://www.flickr.com/photos/howi/6366423373/   •  hPp://www.flickr.com/photos/wwarby/5110037138/   •  hPp://www.flickr.com/photos/alicetragedy/ 4977295298/   •  hPp://www.flickr.com/photos/koltregaskes/ 624914973/in/photostream/