It's a confusing wireless world out there. We sort through the protocols that are gaining momentum.
- By Bill Heldman
- February 01, 2003
Suppose that you have a group of users who'd really benefit from being
able to take their laptop, PDA or tablet PC with them and wirelessly connect
with the network from any location. Really cool idea, right? But exactly
how do you go about accomplishing this lofty goal?
There are several different wireless methodologies that are loose in
the world—some more popular than others but not necessarily technologically
superior. In this article, we'll look at the technologies that are making
headway onto corporate networks and look at the design decisions that
may affect you as you try to keep those roaming users connected.
Bluetooth (see www.bluetooth.com)
is fairly new—in fact, the specifications for it are not yet fully
developed. It allows for low-powered Bluetooth-compatible devices to communicate
with one another in the unlicensed 2.4 GHz radio frequency range. This
band was originally intended for industrial, scientific and medical (ISM)
applications but is now being leveraged for wireless networking activities,
not just by Bluebooth but also by other standards.
Bluetooth uses a spread spectrum, frequency hopping, full-duplex signal
that is able to hop from one frequency to the other at up to 1,600 hops
per second. There are 79 frequencies 1 MHz apart from one another that
can be used by Bluetooth. This frequency hopping characteristic sets up
a good secure environment for the Bluetooth users.
You must have at least two Bluetooth-compatible devices in order to be
able to set up a Bluetooth wireless network. Bluetooth technology is designed
with the "Personal Area Network" (PAN) in mind—not the stuff you
need for large networks. You can't run a backbone or LAN off a Bluetooth
environment. In fact, you're limited to eight devices within a single
Bluetooth PAN—called a Piconet. Additionally, you're limited to a
30-foot distance between devices. I wanted to set up a Bluetooth network
between a USB Bluetooth device I purchased for my wife's computer and
her Bluetooth-equipped Compaq iPAQ so that she could access information
on her PDA while sitting out on our deck. But I couldn't accomplish my
mission because her PC is farther away from our deck than the 30-foot
Bluetooth distance limit. (Note that Bluetooth does not require
the two devices to point directly to one another as infrared [IR] devices
You can use Bluetooth to connect a Bluetooth-supported PC to a cell phone,
PDA and perhaps a printer in a PAN so that you eliminate the personal
workspace cable mess. The devices participating in the PAN are said to
be in the "Bluetooth neighborhood" which shows up in the Bluetooth software
that comes with the devices. If a person in your office needs to make
use of this kind of close-quarters networking, then Bluetooth is a great
Bluetooth has a huge shortfall, though. Its newness produces large technology
gaps, holes that you might clamor to have filled. In my wife's case, for
example, she had three basic requirements:
- Surf the Internet from her iPAQ.
- Send and receive e-mail.
- Send and receive files.
A Sad Story
The Bluetooth USB adapter we purchased for her PC installed just
fine, as did its supporting software. Upon pointing the iPAQ at it, it
was exciting to see both devices show up in the Bluetooth neighborhood!
However, functionality was very limited and I was disturbed to find out
that she was not going to be able to surf the Web or send/receive e-mail
via her PDA. She could send/receive file or cached Web pages
that her Active Synch software had cached for her at the PC, but couldn't
actively utilize the Internet.
In a reply from an e-mail I sent to "The New HP's" help-desk I was informed
that I needed to purchase a Bluetooth backpack for the iPAQ—even
though it already had an on-board Bluetooth chip. Turned out that this
was bad help-desk advice and I really didn't need the $189 device. The
Bluetooth USB adapter vendor said that that I couldn't accomplish my mission
with the materials I currently had.
Turns out that in order for Bluetooth to be a viable Internet option,
it has to "see" an ISP that supports Bluetooth. For example, if I had
had a Bluetooth cell phone that had an Internet connection, then I'd be
able to accomplish my goal. But my non-Bluetooth-aware AT&T Broadband
account wouldn't be able to cut the Bluetooth mustard.
So, here's the long and short of Bluetooth: I'm not sure it's ready for
prime time, especially in the business arena. But stay tuned because the
members of the Bluetooth SIG (Compaq…er… "The New HP" among them) are
hot to utilize this new technology. It has worldwide governmental standardization
and folks are working hard to find a niche for this nifty technology.
Things to Think About with Bluetooth
Because Bluetooth uses the same 2.4 GHz spectrum that 802.11b (Wi-Fi)
uses (more on this later), I wonder if you might get some interesting
radio interference if you put Wi-Fi and Bluetooth devices near one another?
Blackberry is a wireless e-mail technology developed by Research
in Motion (Rim) Corporation (see www.blackberry.net
or www.rim.com for more information).
The technology requires a Blackberry-equipped device and either a subscription
to a Blackberry service such as those provided by AT&T Wireless, Cingular
and others, or through a Blackberry Enterprise server.
Blackberry solutions have been developed for enterprise-class e-mail
server software such as Microsoft Exchange and Lotus Domino Server. Blackberry
devices of varying ranges of sophistication can be obtained—everything
from simple e-mail transfers to support for voice, e-mail attachments,
data transfer, paging and other elements.
Blackberry operates in three different frequencies: 800 MHz, 900 MHz
or 1900 MHz. There have been some questions as to whether Blackberry devices
might interfere with formal radio systems (such as police radios) operating
close by in the same range.
Blackberry might be a great choice for environments in which you need
to get simple messages to a variety of geographically separated people.
A uniform-delivery service, for example, operating trucks in a metropolitan
area might be able to make good use of Blackberry.
However, security and potential interference with other radio systems
in the same area—800 and 900 MHz systems are the bread and butter
of most radio networks—need to be elements that are on the forefront
of a wireless network designer's mind when considering a Blackberry deployment.
Now, here's the really interesting wireless science—the one
that you'll most probably consider deploying in your enterprise. This
technology is called "Wi-Fi"—short for Wireless Fidelity—in
an effort by a group of manufacturers and others interested in the technology
and www.802.11-planet.com for
more info) to bring brand and class identification to the field. When
we talk about Wi-Fi, we could be referring to one of two different types
of the IEEE 80211 specification:
- 802.11b—In this, the most commonly used of the two 802.11
specifications, you're dealing with 2.4 GHz, the same spectrum that
Bluetooth and microwave ovens operate in. There is a veritable plethora
of 802.11 devices available and ready for use today to equip everything
from the home network to the enterprise-level WAN or ISP base.
- 802.11a—This specification provides for wireless connectivity
in the 5 GHz spectrum, thus eliminating today's problem of Bluetooth
and other company's 802.11 devices potentially crowding out the frequencies
you're operating in.
The 802.11 standard can support a couple of different architectures for
wirelessly-equipped devices to connect to the network:
Suppose that you have several laptop computers, all equipped with
802.11 devices and these laptops need to connect to one another without
benefit of any cabling. In this case an algorithm called Spokesman Election
Algorithm (SEA) can be utilized in an 802.11 environment. SEA and others
like it call for one master base station to be elected so that all laptops
can communicate with one another.
The more common wireless connection environment is one that utilizes
Wireless Access Points (WAPs). A WAP is a hardware device that connects
to the LAN and provides radio connectivity (as both a transmitter and
receive—a transceiver) to the network for wireless devices.
You can purchase Small Office Home Office (SOHO), Small- to Mid-sized
Business (SMB), or enterprise-class WAPs, depending on the size of your
organization, for connectivity to the LAN. The New HP, for example, sells
the WL310 Home Office Gateway, the WL410 Small Business Access Point and
the WL510 Wireless Enterprise Access Point, all Compaq devices. Cisco
Corporation and others also offer a wide variety of enterprise-scale WAP
Interested in setting up an 802.11 wireless network at work? You just
need a few parts:
- A WAP
- Wireless PC cards or NICs for your computers and PDAs
- If you're interested in letting your users access their e-mail and
calendars from wirelessly-equipped devices you'll also need to have
Microsoft Mobile Information Server 2003 installed and configured. (Noting
that this also requires that you have Windows 2000 Active Directory
and Exchange 2000 up and operational as well).
Things to Think About with 802.11
Three words: Security, security, security. Hackers have a new game
they play called "warchalking."
Unlike artists who like to use public sidewalks for their canvas, warchalking
hackers roam city corridors with an 802.11 device looking for entry onto
corporate wireless networks. Once they find a connection, they chalk the
building or the sidewalk to denote that they've gotten in.
Many enterprise-class 802.11 devices come with a firewall that helps
you manage rogue intrusion into the network—but still and all rigorous
management of your DHCP scopes and monitoring of your wireless traffic
are in order when considering the widespread use of a wireless network.
While WAPs provide a way for your wireless users to connect to the network,
you'll want to set up wireless encryption in such a way that you meet
your security policies. Maintaining security in a wireless LAN (called
a WLAN) can create significant difficulties for administrators.
supplies wireless connectivity to the Internet using a proprietary protocol
and associated hardware. Today Ricochet has live deployments in Denver
and San Diego, with one planned for Dallas/Fort Worth.
Because of Ricochet's Metropolitan Area Network (MAN)-based technology,
this is a good choice for companies in these cities to take into consideration.
Getting Wired Up with Wireless
Your selection of an appropriate wireless environment will depend
in large part on the type of geographic distances your wireless users
will be connecting from (across the hall; across the campus; across the
city; across the country; across the world). An 802.11 WLAN won't be helpful
if you're in Detroit and an executive wanting to wirelessly connect needs
to do so from Beijing. (In such a case, a Blackberry subscription and
Blackberry-supported device for this user would be the logical choice).
Apart from this rarity, the majority of uses you'll be able to envision
for your wireless network center on users connecting in some sort of metropolitan
environment (or closer). In most cases, 802.11 will be the network of
choice because it's easy to deploy, standardized, there's a wide variety
of equipment available and it's well-understood (i.e. training and books
are readily available).
If I were simply considering users who only wanted access to the Internet
and their e-mail—who did not require VPN connections for access to
applications, files or the intranet/portal—then I'd probably choose
a 802.11 network over the Blackberry Enterprise server to hook into my
network. Blackberry services are costly, as are Blackberry devices.
In all cases, the client configuration characteristics with regard to
their security settings will be of high importance. You'll want to make
sure that your users utilizing wireless technologies can't be hacked and
that hackers can't gain entry to your wireless network. (To find out more
about security, check out Roberta
Bragg's column this month.)
Note that wireless networks are not performers, in terms of speed.
The 802.11 speeds vary depending on the distance the remote device is
away from its base, as well as various building characteristics (concrete
vs. drywall, etc.) Plan on a whopping maximum 11 MB/s out of 802.11 network,
but be pleasantly surprised if you get anywhere close. Bluetooth operates
at the 1 MB range. Users of any of the wireless networks will find much
slower performance than they're accustomed to at the local desktop.
Your customer care operations will need to be aware of the differences
involved in a wireless user connecting as opposed to a normal LAN-cabled
user. Plan on help-desk calls coming from wireless users—calls that
may bewilder your staff if they've not had a chance to experiment with
this new technology.