Life on the Edge
Edge delivery. Virtually unheard of less than a year ago,
this buzzword has become one of the hottest in the
Internet economy. Companies providing edge delivery
(also known as "content delivery" or "Internet caching")
services are pulling off skyrocket IPOs and becoming
major names, seemingly overnight. Their founders, who
responded to the problems created by growing
congestion on the Internet as well as sudden,
unpredictable spikes in Internet traffic owe a big thanks to
an oversight on the part of the Internet's builders.
The companies and institutions that make up the Internet
infrastructure may have built the most advanced series of
high-speed networks ever, but they didnıt do a very good
job of buttressing the points at which these networks
come together. These network access points (NAPs) are
the nodes at which ISPs can connect with each other.
The two major ones are Metropolitan Area Ethernet (MAE)
East in Washington, D.C., and MAE West, in Silicon Valley.
The system still breaks down in these hot spots, where
the private networks converge and much of the content
on the Web must pass through in order to eventually
make it to a user's computer.
"It's a lot like the highways," says John Katsaros,
president of the Internet Research Group, a private
consulting firm. "The packets [of information] get on paths
to go to their destinations, and there are major
intersections where the traffic meets. At those
intersections, there are congestion problems when things
get busy."
This is where content delivery service providers, with
names like Akamai Technologies and Sandpiper
Networks, have stepped in. They are finding ways
around those points by taking content to the "edge" of the
Internet.
Internet caching technology comes in a number of forms:
software, hardware, services, or a combination of these.
No matter what form it takes, it is essentially designed to
do the same thing: to speed up access to frequently
requested Web pages by storing a temporary copy of the
content on a nearby or better-performing server.
Caching on to the benefits
"What caching is about is trying to deliver a better
experience to the ultimate consumer of content," says
Brendan Hannigan, an analyst at Forrester Research.
"What these [content delivery] providers do is deliver a
turnkey caching service so that content providers can
subscribe to the service, and their content is blasted out
to hundreds and hundreds of caches that these
companies have located all over the world."
These services can provide three benefits if correctly
implemented, according to Hannigan. First, the user
experiences better download times. Second, the site isn't
bombarded with constant hits from lots of users, so
performance bottlenecks at the central source of content
are alleviated. Third, when there are unusual spikes in
demand for content, the providers can reroute the traffic.
"Because they have such a distributed network of
caches, they can load-balance those sites across their
network of caches," says Hannigan.
Sandpiper Networks, now part of San Francisco's Digital
Island, claims to have the longest-running content delivery
network. They've been in business all of 24 months.
To do a good job, a content delivery network must do at
least two things, according to Pat Greer, the company's
director of streaming services. "One is that it distributes
the content out toward the edges of the Internet so that
people can perceive better performance from the Web
site," he says. "The other is that it directs the users to the
best server for them--not necessarily the best
geographic server, but the best-connected server."
Greer emphasizes the need to look at factors like Internet
topology, connectivity, and congestion, rather than just
concentrating on the geography of the server when
choosing the best place to send a user to retrieve
content. This, he says, is what gives Digital Islandıs
Footprint technology the edge over regular caching
services.
"We look at the Internet on a minute-by-minute basis. We
look at congestion and connectivity to different places,"
says Greer. "So, we might take your request and look
and say, geographically, the closest server is Chicago
but connection-wise and [for] speed of response, the
best place to send you is Atlanta."
Caching in on currency
Akamai Technologies takes an approach similar to
Sandpiper's but offers a larger network of servers and
its own FreeFlow technology. FreeFlow allows sites to
use caching to store static information--logos and
graphics, for example--on one of its more than 2,000
servers in 100 networks in 40 countries, according to
Andrew Lickley, an Akamai product manager.
Lickley is quick to point out that although Akamai uses
caching as part of its services, the company is different
from a traditional cache server. "The chief difference is
that we're designed as a system [built from the] ground
up for delivering Internet content. Our customers are the
content providers, the actual Web properties," he
explains. "Caching servers were originally designed to
alleviate bandwidth at ISPs, and they're very good
solutions for that." But they're not the best for providing
the new content, according to Lickley, because cached
content--especially things like news stories and weather
reports--can get old fast. "We do cache content on our
servers. However, weıre constantly checking for
popularity and freshness," says Lickley. "It's built into the
ARL."
The ARL is the Akamai Resource Locator, which is
placed in front of the URL on those items that have been
"Akamaized." When an end user requests a page from an
Akamaized Web site, the components with ARLs are
pulled together from the most efficient servers. An
example of this is Yahoo's navigation banner; it stretches
across the top of the page, as do 90 percent of AOL's
ads, and all are Akamaized, according to the company.
This can speed up a site's performance anywhere from
two to 10 times, according to Lickley. "What we offload is
the heavy part of the Web page," he says. "By offloading
that content onto our network, we allow Yahoo to
concentrate on what they do well, which is creating
content. We also allow Web sites to handle more
transactions. The hidden benefit is their Web sites' not
processing 70 to 80 percent of the Web page any longer,
so they're free to handle more users and, thus, more
transactions."
Caching the next wave
Lickley believes that it is only the tip of the iceberg for
content delivery service providers and others interested
in caching services. "Itıs a lot like the Gold Rush," says
Lickley. "What we're doing is providing the picks and
shovels. The more popular the Web becomes, the more
properties there are, the more congested it becomes, the
better it is for us. The more dot-coms that spring out of
nowhere, the more customers there are for us."
Eventually, more and more sites will turn to caching or
some other form of delivery, says Forrester's Hannigan.
"Any major site would be bonkers over time not to be
putting some of their content on to somebody elseıs
server utilizing some of these services."
By Liz Garone