Improved performance and a proven
deployment strategy make SPDY a potential
successor to HTTP.
bY bRYce thomas, RaJa JuRDaK, anD ian atKinson
todaY’s WeB Bears little resemblance to the Web
of a decade ago. A Web page today encapsulates
tens to hundreds of resources pulled from multiple
applications, not a tool for frivolous animation.
Users access the Web from diverse device form factors,
while browsers have improved dramatically. A constant
throughout this evolution is the underlying application-layer protocol—HTTP—providing fertile ground
for Web growth and evolution but was designed at a
time of far less page complexity. Moreover, HTTP is
not optimal, with pages taking longer to load. Studies
over the past five years suggest even 100 milliseconds
additional delay can have a quantifi-ably negative effect on Web use, 9 spurring interest in improving Web performance. One such effort is SPDY, a
potential successor to HTTP championed by Google that requires both client and server changes, a formidable
hurdle to widespread adoption. However, early client support from major
browsers Chrome and Firefox suggests
SPDY is a protocol being taken seriously. Though server support for SPDY
is growing through projects like mod_
spdy12 truly widespread server adoption is likely to take time. In the interim, SPDY gateways are emerging as a
compelling transition strategy, promising to accelerate SPDY adoption by
functioning as a translator between
SPDY-enabled clients and non-SPDY-enabled servers (see Figure 1). A variety
of incentives motivate organizations to
deploy and users to adopt SPDY gateways, as described here.
SPDY (pronounced SPeeDY) is an
experimental low-latency application-layer protocol27 designed by Google
and introduced in 2009 as a drop-in
replacement for HTTP on clients and
servers. SPDY retains the semantics
of HTTP, allowing content to remain
unchanged on servers while adding request multiplexing and prioritization,
header compression, and server push
of resources. Since 2009, SPDY has undergone metamorphosis from press release written and distributed by Google
to production protocol implemented
by some of the highest-profile players
on the Web.
Figure 2 is a timeline of SPDY milestones, first appearing publicly in a
sPDY seeks to improve Web page
load times by making fewer round trips
to the server.
client-side browser support for sPDY
has grown rapidly since 2009, and sPDY
gateways offer a transition strategy that
does not rely on server-side support.
open sPDY gateways are an opportunity
for organizations to capitalize on the
behavioral browsing data they produce.