Home Sweet LAN
The employees of OK Cable had never seen Willy so angry. At least not
since one of the ex-employees crimped an entire building's worth of
solid Category 5 UTP cable with RJ-45 plugs meant for stranded cable.
Something different had set Willy steaming this time. Whatever it was
happened as he opened the mail. Employees tip-toed past his office door
as he muttered, mumbled, searched his bookshelf, and started Internet
searches that never finished.
After an hour of this, Willy called in his three lead installers from
the field. It was late in the day when they gathered and he asked, “What
do you guys know about power line networking and who have you told?”
His question drew two blank stares, but it caused one face to flash
wide-eyed panic. “Stewart,” Willy asked the guilty face, “who
did you talk to at Direct Data?”
“Uh, I met Sharon at the post office and we talked for a while.
I think she asked me if I knew anything about using the power lines
in a house for a network.”
“Let me guess,” Willy said. “You really didn't
know what to tell her so you made it up as you went along in order to
be able to talk to her for a while, right?”
“Uhhh, well” Stew said.
"And somehow she got the idea that power line networking was a
good idea? Willy asked. “Let me tell you how I know. This is an RFP
we got from Direct Data. They want somebody to help their 200 work-at-home
employees to set up home networks. This is a great idea. It could be
a start on a whole new line of business for us. But the RFP gives preference
to what it calls 'easily installed' alternatives such as wireless and
power line networking. A nice note from Janet clipped to this copy of
the RFP thanks me for the help my guys provided.”
“Well, I set up one of those power line networking things for
my sister and it worked.” Stew replied.
Willy pushed back from his desk and started to pace. As he walked
across the tile in front of his desk, he said, “Well, that's a
big part of the problem. Often it does work, but often it has problems.
Power line networking pushes radio waves over copper power wires.
But the power wires are a radio nightmare. Any high-current motor,
a sparking hair dryer, an elevator motor, or other electrical device
can raise the noise level and reduce performance. But you never know
where or when it will happen. Tech support would be a nightmare. I
don't want a thing to do with this.”
“Well, what can we do, Willy?” Stew asked.
“Research!” Willy replied without hesitation. “I'm
going to work with you, and we are going to reply to the RFP with
research. There's nothing better than good data-grade cable for any network,
and we're going to prove it.”
Their work paid off two months later. It was a similar meeting with
a happier group. “Well,” Willy began, “we have
a challenge in front of us. We have two weeks to figure out how to
help the first group of Direct Data employees with their home networks.
It's time for more research.”
Home Networks—once a badge of honor for the truly nerdish—are now
a mainstream item. Walk into any computer superstore and you'll likely find
an aisle devoted to home networking kits. As the price of PCs has
come crashing down, many users have discovered that it's often cheaper
to buy a new PC than it is to upgrade an old one. When people buy
new PCs, they often give the old one to the kids or keep it as a
second PC. It doesn't take multi-PC home users long to figure out
that they need a network. Just as in the office, home networks allow
users to share files, printers, and—most importantly—an
Internet connection among two or more PCs. A new generation of multi-player
games—with each player on his or her own PC—has also
increased the demand for home LANs.
Since home users are doing many of the same things with their
LANs as their office counterparts, it seems logical that they'd use the
same networking technologies—although on a smaller scale—as
office LANs. But aesthetics are much more important in a home environment
than in the office. Most companies won't hesitate to drill holes
or install in-the-wall wiring when needed, but home users aren't
as willing to pick up the drill and punch a hole in the wall or
floor. It may be perfectly acceptable to have a tangle of wires
under your office desk, but that high-tech look is out of place
in your den.
If all of your PCs reside in the same room, you can easily
install an ethernet LAN using many of the same techniques we've described
for office LANs. But if you want to scatter your home PCs around
the house, you'll need to consider several alternatives. We'll examine
the ethernet options first, since they're the least expensive and
offer the highest performance. If ethernet cabling isn't an option
in your home, we'll also discuss ways to connect your PCs using
phone lines, radio waves, and even the AC power wiring.
Do a quick survey of mail-order and computer superstore
catalogs, and you'll find 10/100 ethernet starter kits for about
$99. These kits—from well-known vendors like 3Com, Intel,
D-Link, and Linksys—typically include two ethernet network
interface cards (NICs), a small 4- or 5-port hub, and two 25-foot
ethernet cables.
Ethernet offers the best performance (up to 100Mbps) at the lowest cost
of any of the home networking alternatives. Other home networking technologies
are limited to speeds of about 2Mbps. While 2Mbps is fast enough for casual
file and printer sharing, it may not be fast enough if you have a high-speed
Internet access device like a cable or DSL modem. Figure
9.1 shows an example of how an ethernet network might be used to share
several computers, printers and a modem in your home.
As with office PCs, you'll need to open the case of the PC to
install the NIC cards. Most of the ethernet vendors provide excellent
installation instructions and self-installing driver software, but
there's always a risk of messing something up when you install a
new card in a PC—especially in today's resource-crowded multimedia
PCs.
We prefer PCI network cards because they offer higher performance
and easier installation than the older ISA cards. We also prefer 100Mbps
Fast ethernet to the older, slower 10Mbps standard ethernet because
it offers ten times the speed for only a nominal increase in cost.
Most of the hubs provided with home networking kits have four or
five ports, and are switchable between 10 and 100Mbps. It's important
to note that when you use a switchable hub, all the devices on the
LAN must operate at the same speed. In most home environments, you'll
simply set the hub to operate at 100Mbps and forget about it. But
if you ever need to connect a 10Mbps device (like an older laptop
with a 10Mbps ethernet card) to the LAN, you'll need to slow the
entire LAN down to 10Mbps. A few hubs offer 10/100 auto-switching
operation, which allows each port to operate at either speed, independently
of the other ports. These hubs are often more expensive than switchable
hubs, but they provide more flexibility.
The most obvious shortcoming of ethernet home networking kits is
the cable itself. Most networking kits include two 25- to 30-foot CAT
5 cables, with connectors already attached. If your PCs are in the
same room, you can usually hide the cable along the baseboard or
under the carpet. But some kits include bright yellow or blue cable
that sticks out like a sore thumb, so you'd be wise to check the
color of the cable when shopping for a network kit.
Figure 9.2 shows
a typical ethernet kit (also commonly called “a network in a box”).
If your computers aren't in the same room, you'll need to run
ethernet cable from the hub location to each PC on your home LAN. Unless
you live in a very small house, the 25-foot cables provided with
most network kits probably won't be long enough. You can buy ready-made
50- and 100-foot ethernet cables with the connectors already attached,
but they're usually expensive, and the pre-attached connectors make
it difficult to pull the cable through tight spaces. Thanks to the
popularity of home LANs, many residential electrical and alarm contractors
are ethernet-savvy, so you may want to consider farming out the
cable-pulling to a professional.
No matter how you run the cable, you'll want as neat an installation
as possible. While it's tempting to simply pull a cable to each PC
and attach a connector, you may want to consider using one of the modular
wall outlet systems we mentioned in Chapter
8, “From the Wall to the Desktop.” These outlet
systems let you mix and match several ethernet, telephone, and cable
TV connectors on a single wall plate. If you already have a TV or
phone outlet, you can usually pull an ethernet cable to the same
outlet and then use a modular connector plate to neatly connect
your PC, phone, and TV.
While ethernet
offers the best bang for the buck, there are circumstances where
it's too difficult or even impossible to run ethernet cabling. Fortunately,
there are three “no new wires” networking technologies
that allow you to connect two or more PCs into a LAN without running
an inch of wire.
True wireless systems use two-way radio signals—mounted on
an ISA, PCI, or PC Card—to transmit data among the PCs on a LAN.
These systems offer 2Mbps of throughput at a reasonable cost. 11Mbps
wireless systems are also available, but they are much more expensive
and are targeted at business users. See Chapter
12, “Wireless Communications,” for more information
on business wireless systems.
Phone line networking products like Intel's AnyPoint
use your home's existing phone wiring to carry data at 1 or 10Mbps.
These systems typically connect to your PC via the parallel port,
so they have the added benefit of being simple to install. The downside
is that they require a telephone outlet near the PC.
Power line networking systems
are similar to phone line networking, but they use your home's existing
AC power wiring to carry data that is modulated onto a weak radio
signal carried over the wires. Most power line products also connect
via the parallel port, but power line LANs run significantly slower
than phone line LANs. Most homes have several power outlets in each
room, so they're slightly more flexible than phone line systems.
Unfortunately, our experience with power line systems has been erratic
at best.
Wireless systems
offer the best flexibility of the three ethernet alternatives for home
networking. Unfortunately, they're also the most expensive of the three,
weighing in at about $200 to $400 per PC. Wireless networks are most appropriate
for notebook PCs, because they allow you to stay connected to the network
while you move your notebook around the house. Some wireless systems also
are well-suited for medium-speed Internet sharing and multi-player game
duty in multi-story homes, apartment buildings and college dorms (see
Figure 9.3).
A typical wireless network consists of one or more desktop PCs
with a wireless network card installed, and one or more notebook PCs
with a wireless PC Card. Desktop wireless cards come in ISA and
PCI formats, so you'll need to purchase the appropriate type for
your PC. Most desktop wireless cards include an external antenna
with 6 to 8 feet of cable. Although it's tempting to hide the
antenna in that tangle of wires behind your PC, you'll experience
better range and more reliable connections if you position the antenna
clear of other objects and as high up as possible.
Notebook wireless cards usually have a built-in antenna
contained in a small plastic cover that is permanently attached to the end
of the PC Card (see Figure
9.4). The antenna sticks out of the PC Card socket by an
inch or so. Software installation for both the desktop and PC
Cards is similar to conventional ethernet cards.
Range is always an issue with wireless systems. Most vendors
claim an effective indoor range of 150 feet between units, but we've
found that figure to be wildly optimistic. Radio waves don't carry
well through metal-reinforced walls and floors. The radio signals
used by these systems are extremely low in power, so it doesn't
take much of an obstacle to completely block the signal. Fortunately,
moving one of the antennas an inch or two usually cures any signal
blockage problems. Most wireless vendors provide a signal-level
checking program that lets you see the strength of the radio signal;
this is especially useful on portable PCs.
Virtually all wireless LAN systems offer security features to
keep unauthorized users from connecting to your wireless LAN. In most
cases, one PC is designated as the security master, and other
PCs can't connect to the LAN until the security master verifies
their identity. Given the short range of most wireless LANs, it's
highly unlikely that anyone will try to access your LAN, but security
can be a problem in multi-unit homes and apartment buildings.
We recommend that you use whatever security features
your wireless LAN offers.
Second on our
list of ethernet alternatives, phone line networks offer adequate performance
at a much lower cost than wireless systems. Phone line adapters cost about
$75 to $100 per PC, but there's no hub or wiring costs as with ethernet
products. The current standard for phone line networking provides 1Mbps
of throughput, but a faster version is on the drawing boards. Figure
9.5 shows a typical phone line network.
While phone line LANs use your existing phone wiring, they do
not interfere with normal operation of the phone. The LAN and telephone
signals travel over the same copper pair, but they are electrically
distinct and completely invisible to each other.
Phone line LAN adapters come in internal (ISA and PCI) and
external (parallel) versions. The parallel units don't require you to open
your PC, and most provide a printer pass-through port that allows
your PC's parallel port to connect to the LAN adapter and printer
at the same time.
Figure 9.6
shows a typical phone line network adapter.
The big advantage of phone line LANs is that you can network
two or more PCs located anywhere there is a phone jack—with one
important caveat: Each PC on a phone line network must be connected
to the same phone line. If you have multiple phone lines in your
home, you'll need to connect all of your network adapters to the
same phone line.
We like phone line networks for their simplicity and ease of
use, and they're fine if you already have phone jacks in every room.
But if you don't have phone jacks and are going to run new cable,
you may as well install ethernet and get 100 times the speed for less money.
As you can tell
from our story at the beginning of the chapter, Willy doesn't
like power line networks, and we don't either. The power line
products we've tested offer barely acceptable performance of 350Kbps
when they work properly—which isn't all that often.
At first glance, power line networking products appear to be
very similar to phone line networks. Both typically attach to your PC
through the parallel port, and both use existing wiring to carry
networking data around the house.
Unfortunately, power wiring makes a less-than-ideal carrier for
network data. The weak radio signal used to carry data over the wiring
is easily overwhelmed by interference from a variety of sources
including elevators, washing machines, and even vacuum cleaners.
This means that your power line network may work fine one moment,
then inexplicably slow down or even stop working a few seconds
later.
To further complicate matters, the signal from power line
networks can't pass through transformers. This can be a problem in modern
homes that are wired for 220-volt service. The power company delivers
220 volts to residential customers by providing two 110-volt feeds
from the neighborhood step-down transformer. Some of the outlets
will be fed by one of the 110-volt lines, and the rest by the
other. But the two 110-volt lines aren't electrically connected
to one another, so there's no path for the power line LAN to follow.
The end result is that power line LANs may not work in every room
if you have 220-volt service.
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