Cache buys better Web dynamics

The well-known shortcoming of the World Wide Web is the fact that it takes

time — "forever" as many people like to put it — to move information from

a server to a user's desktop, no matter if that server is on the other side

of the globe or down the street.

There are many reasons why Web pages can take a long time to download,

but two of the most common causes are slow Internet connections and overburdened

Web servers pushed to their limits.

Federal users from the U.S. Army to the Food and Drug Administration are

discovering that Web caches can solve both problems and provide an additional

layer of defense against hackers to boot. Plus, deploying cache can help

agencies postpone expensive network upgrades that were meant to improve

Internet access time.

The concept behind Web caches is not new. Web browsers have long used

cache to retain recently downloaded Web pages so that if the user returns

to those sites, the browser only needs to reload those components on the

page that have changed. The user sees the page almost instantly, and traffic

over the often-limited Internet connection is reduced.

Web caching servers expand on this model, putting a depot for frequently

visited sites between an agency's server and the Internet. Such caches can

work two ways:

* They can hold all of the most recently accessed Web pages for everyone

on the server. For example, after a user visits the National Weather Service

site to check on the progress of a hurricane, and calls to a colleague to

take a look for himself, this second user will get to see the satellite

picture almost instantly. That is because the computer retrieves the image

from the local Web cache, rather than from the NWS server.

* Alternatively, if a Web site operator, such as the National Weather

Service, needs to accelerate response time because a lot of users are hitting

its site, a cache containing the most-downloaded information can speed pictures

to users without bogging down the server with constant requests for the

same information.

In fact, 54 percent of information on Web sites is suitable for caching,

according to a survey by The HTRC Group LLC, San Andreas, Calif. "That means

they can use Web caching to increase performance for a significant amount

of their Web site," said Greg Howard, an analyst for HTRC.

In a survey of Web sites last year, the time to load pages was quite

slow, said Peter Christy, research director for Jupiter Communications Inc.

"Page fetch times were about eight seconds," he said. "People realized that

you want something much faster. Under one second is the right goal."

Average time to load pages has fallen as Web caches have gained popularity,

said Christy. "Much of the improvement is due to the deployment of caching."

"Sooner or later, Web caches will be a standard part of the network architecture,

like a router or a firewall," said Dan Brigati, director of federal sales

for CacheFlow Inc. "When you go from a T-1 connection to a T-3, you certainly

are not getting 35 times the performance. The Internet isn't strategic,

but the intranet certainly is."

That may have been true in the recent past, but not anymore, said Walter

Henderson, federal sales manager for Network Appliance Inc. "A lot of employees

need to get to the Internet as part of their job," he said. "It is not just

a plaything."

"You use a cache when you are looking to lower Internet access costs or

to at least delay your network's increase in bandwidth," said Alex Benik,

an analyst for The Yankee Group, Boston. "It is a pretty compelling cost

story."

"We think the use of caching is very cost effective, by a factor of

ten, over network improvements," Christy said.

Such effectiveness is driving rapid growth in Web caching server sales.

"We see the market growing 100 percent in 2000, over 1999 [figures]," Benik

said.

Web caching server prices start at about $2,500 and go as high as $80,000,

depending on the configuration and brand. The investment can produce many

benefits for agencies:

* A cache may let agencies forego network upgrades. "I would put it

on the gateway to the Internet to reduce the need for bandwidth," said Peter

Firstbrook, a research analyst for Meta Group Inc., Stamford, Conn. "It

may mean the difference between needing a T-1 and needing a [much more expensive]

T-3 connection."

* Small Web caching servers can help small field offices get better

performance from their dial-up connections, said Roy Wells, director of

product marketing for Ramp Networks Inc. That is because the server not

only accelerates access speed, it also can double bandwidth available from

dial-up connections by coordinating two modems. "It allows modem pooling,

which looks like a single connection to users," he said.

* A cache can increase security by acting as a buffer between a Web

server and the rest of the Internet as the server handles all incoming requests

for information. This way intrusive requests from hackers trying to break

into a server never actually reach the server. They only talk to the Web

cache, which runs a specialized operating system that has fewer potential

entrances for hackers than a more general-purpose operating system.

"It reduces vulnerability because our product has fewer points of entry

than most network devices," said Greg Govatos, director of marketing for

CacheFlow.

"Putting a cache in front of a Web server tends to improve security

because it doesn't have as many means of entry," Christy said.

And even if a cached Web site got hacked, it would soon be updated with

the correct information when it refreshed its content, Firstbrook said.

"It is like graffiti on a wall. If you paint over it every morning, it becomes

uninteresting to paint it in the night."

* Web caching servers are also a good location for tools such as filters

used to screen undesirable sites. "Web caches give you the opportunity to

put Playboy.com out there and block it," said Jay Mulkerin, local-area

network campus architect for Nortel Networks.

Another security tool that can be deployed on the cache is a filter

to protect against denial-of-service attacks that flood sites with false

requests for information. "It is an easy place to put the tools to defend

against that," Christy said.

An alternative to a dedicated Web caching server is to run software on the

Web server that provides caching functions. Microsoft Corp., Netscape Communications

Corp. and Novell Inc. all offer caching tools for their software, but the

dedicated appliances are easier to install and manage. "We definitely like

the appliances better," said Firstbrook. "They are plug and play, they are

secure and they don't use a well-known operating system [so they are less

vulnerable to attack]," he said. "They are optimized for what they do."

"You just plug it in and you don't have to do anything," said Mulkerin.

"It will intercept the addresses automatically. You plug it in and away

you go."

— Carney is a freelance writer based in Herndon, Va.