ServersHTTP Compression Speeds up the Web

HTTP Compression Speeds up the Web




A longer version of this appeared on WebReference.

by Peter Cranstone

The volume on the Web is forecasted to more than triple over the next three years and the category expecting the fastest growth is data. The solution: compression.

The volume on the Web is forecasted to more
than triple over the next three years and the category expecting the fastest
growth is data. Data and content will
remain the largest percentage of Web traffic and the majority of this
information is dynamic so it does not lend itself to conventional caching technologies. Issues range from Business to Consumer
response and order confirmation times, to the time required to deliver business
information to a road warrior using a wireless device, to the download time for
rich media such as music or video. Not surprisingly, the number one complaint among Web users is lack of speed. That’s
where compression can help, by using mod_gzip.

The Solution: Compression

The idea is to compress data
being sent out from your Web server, and have the browser decompress this data
on the fly, thus reducing the amount of data sent and increasing the page
display speed. There are two ways to compress data coming from a Web server,
dynamically, and pre-compressed. Dynamic Content Acceleration compresses the data transmission data on
the fly (useful for e-commerce apps, database-driven sites, etc.).
Pre-compressed text based data is generated beforehand and stored on the server
(.html.gz files etc).

The goal is to send less
data. To do this the data must be
analyzed and compressed in real time and be decompressed with no user
interaction at the other end. Since
smaller amounts of data (less packets) are being sent, they consume less
bandwidth and arrive significantly faster. The network acceleration solutions
need to be focused on the formats utilized for data and content including HTML,
XML, SQL, Java, WML and all other text based languages. Both types of
compression utilize HTTP compression and compress HTML files fully three times
smaller.

To get an idea of the improvement in speed involved, here’s a live demonstration:

Real time Web server content acceleration test:

Why Compress HTML?

HTML is used in most Web pages,
and forms the framework where the rest of the page appears (images, objects,
etc). Unlike images (GIF, JPEG, PNG) which are already compressed, HTML is just
ASCII text, which is highly compressible. Compressing HTML can have a major
impact on the performance of HTTP especially as PPP lines are being filled up
with data and the only way to obtain higher performance is to reduce the number
of bytes transmitted. A compressed HTML page appears to pop onto the screen,
especially over slower modems.

The Last Mile Problem

The Web is as
strong as its weakest link. This has and always will be the last mile to the
consumer’s desktop. Even with the rapid
growth of residential broadband solutions the growth of narrowband users and
data far exceeds its limited reach. According to Jakob Nielsen he expects the standard data transmission
speed to remain at 56K until at least 2003 so there is a distinct need to do
something to reduce download times. Caching data has its benefits, but only content reduction can make a
significant difference in response time. It’s always going to be faster to
download a smaller file than a larger one.

Is Compression Built into the Browser?

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