Title: The Who, What, Where, When, Why of HTTP/2 – Instart Logic
1THE WHO, WHAT, WHERE, WHEN, WHY OF HTTP/2
BY DAWN PARZYCH
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3It is hard to believe that HTTP has been getting
used for 25 years and we are now only on the
second version while Chrome has only been in
existence for seven years yet is on version 45.
This is a first in a series of blog posts
designed to give you all the information you need
to know about HTTP/2 - what it is, why it
matters, what you need to do, if you have to
re-design your website and when should you start
planning.
WHAT EXACTLY IS HTTP/2 ?
HTTP/2 is a replacement for how data is
transferred on the web. It maintains all the
semantics of HTTP but eliminates the
inefficiencies improving performance for end
users. The main features of HTTP/2 (which will be
covered in detail in the next blog post) include
header compression, connection multiplexing,
server push, and request prioritization. These
features make the protocol less sensitive to
round trip times (RTT), resolves pipelining and
head of line blocking, and reduces TCP overhead
by eliminating the need for multiple connections
to a single host.
WHY CHANGE HTTP?
The internet has continued to evolve over the
last 20 years but the standard has not. The
timeline below illustrates just a few of the
major events in HTTPs lifetime. There is a huge
gap in the evolution of the standard, but during
this time frame many key events happened, such as
the ability to access the internet from your
phone and make a phone call from your computer.
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5As a result of the increased demands placed on
web applications, developers created work arounds
such as spriting data, sharding domains, and
concatenation to try and improve the performance
of their applications, but these workarounds
could be time consuming and did not work for all
sites. A universal easy solution was needed. In
2009 Google took the first step towards a new
solution with the creation of SPDY, which set the
ball rolling for the HTTP/2 specification. For
those of you that saw the image of the dancing
baby and must see the video again (or for the
first time) here it is.
WHO WAS INVOLVED IN MAKING THE CHANGE?
In 2012 the Httpbis working group at the IETF was
tasked with drafting the new HTTP specification.
As SPDY started to gain momentum the Httpbis
working group took on the project of drafting a
new standard. The working group consists of
industry experts and people passionate about HTTP
from companies such as Firefox, Microsoft,
Chrome, and Twitter. As the specification
progressed through various stages many
organizations created implementations to test
interoperability and validate functionality. A
list of current implementations is available on
the HTTP/2 Github site and includes browsers,
servers and proxies.
6WHEN CAN I START USING HTTP/2?
In May 2015 RFC 7540 was submitted to the IETF as
a proposed standard to replace HTTP/1.1 and make
the web faster. Browsers and applications have
begun to support HTTP/2 in conjunction with
HTTP/1.1 and more will be following in the coming
months. The chart below from CanIUse shows the
current browser support for HTTP/2 as of
September 2015 with global browser support at 59
.
7Browser support is only half of the equation,
your application delivery infrastructure also has
to support HTTP/2. This could mean web servers,
application delivery controllers or your CDN.
While 59 of browsers support HTTP/2 as of
September 2015, only 1.2 of web sites use the
protocol, according to W3Techs. You might be
thinking that 1.2 is a very small percentage,
but remember that the standard only became a
proposed RFC in May, which means in four short
months 1.2 of web sites have implemented the
standard, and out of the two most popular servers
Nginx released initial support yesterday
(September 16) and Apache has not yet released
support. Expect to see this number rise rapidly
in coming months as the servers, proxies and CDNs
that previously implemented SPDY roll out HTTP/2
support. Instart Logic supports SPDY today and
we are currently testing HTTP/2 internally.
Production support will be rolling out in coming
months, stay tuned for more information on this
exciting development. With Nginx releasing
initial support, and production support planned
for a later date, the other notable HTTP/2
release to look out for is Apache. The Apache
module mod_h2 is currently in development and is
listed as not hardened enough for production use
as of September 2015.
8WHERE CAN I FIND MORE INFORMATION?
- RFC 7540 specification
- HTTP/2 on Github
- HTTP/2 Explained by Daniel Stenberg
- In the next post I will dig into the technical
details of the specification and how it
compares/differs from HTTP/1.1
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