Home Networks
Technology experts have been predicting for some time that, in the future, we will be
living in completely computerized “smart” or “intelligent” homes with a central computer
controlling all sections of the residence: lights, doors, environmental control system
(heating/air-conditioning), audio, and video. In recent years, this “home of the future”
has come closer to being a reality. It is now possible to connect a personal computer to a
laptop, a handheld organizer, a family car, a TV, a DVD player, a stereo, a digital
camera, and even a security system. Interest in taking the next step, the creation of home
networks, is growing. A recent study performed by the Yankee Group found that a third
of U.S. households with personal computers are interested in creating home networks.
The home network today is centered on the personal computer. Home networks
emphasize application and technology sharing, including the ability to share printers,
storage devices, and Internet connections. They are sometimes marketed for their ability
to enable family members to play online games. In a typical home network configuration,
the Internet service provider (ISP) supplies a high-speed line via a cable modem or a
digital subscriber line (DSL) modem. That line is plugged into an Internet gateway
device, which splits the signal to send it to different devices. With wired networks, that
gateway is a small box with several cables connected into it. With wireless networks, the
gateway is an antenna that can transmit data through the walls as far as 1,500 feet and at
speeds ranging from 11 mbps to 54 mbps. The signal can be picked up by any device in
the home equipped with an appropriate PCMCIA (PC) network adapter card.
The Consumer Electronics Association, which represents the diverse products involved in
a home network, has identified three major home network configurations: a cluster, a
multiroom, and a whole-home network. A cluster network is a group of devices
interconnected to one another. The network is self-sufficient and can perform its basic
functions without having to communicate with other networks. Home theatre systems fall
into this category by virtue of interconnecting a big-screen TV, a DVD playeror a VCR,
and audio devices.
A multiroom network connects two cluster networks or extends a single cluster into a
second room. It is more complex than a cluster network because the devices must know
something about each other, such as network address, location and capabilities. For
example, if there are two DVD players in the house, it is necessary to differentiate the
one in the living room from the one in the bedroom.
Finally, a whole-home network involves multiple kinds of cluster networks connected to
each other through gateways. For example, a house could have several clusters: one for
the audio/video system, lighting controls, heating, security, and telephony. If the security
cluster detects a break-in, it can alert the video camera to send a video stream to a data
storage cluster and store it in a hard disk. Then, it can call the home owner to a cellular
phone or send an e-mail with a video stream attachment, so the home owner can decide
whether to call the police.
One of the problems for home networks has been how to connect each device. However,
wireless technology has emerged in the past 2 years to bring us a big step closer to the
vision of a fully connected home. Two standards are currently in use for wireless
networks: IEEE 802.11a and 802.11b. The most common standard is the 802.11b. Some
802.11b networks are also known as “Wi-Fi” for wireless fidelity. It has been installed in
businesses, schools, airports, shopping centers and Starbucks coffee shops throughout the
United States. The new 802.11a, known as “Wi-Fi5,” provides up to 54 Mbps in the 5GHz band; Wi-Fi provides up to 11 mbps in the 2.4-GHz band. Although Wi-Fi5 is
faster than Wi-Fi, it operates in a shorter range.
Several companies, from cable and media giants like AOL Time Warner to unknown
startups, are trying to connect existing electronic devices to the home computer network.
More than 240 devices have been already certified for Wi-Fi. For example, IBM has
tested a special device inside a car that is capable of receiving a library of music beamed
wirelessly from an Internet set-top box connected to a TV. In addition, Siemens has
introduced a Voice Data Gateway wireless system that connects computers and cordless
phones to one wireless gateway that enables users to access voice and PC–data services
from anywhere in the house.
Another wireless standard, IEEE 1394, will make multimedia home networking a reality.
IEEE 1394 provides high-bandwidth and real-time data transfer in a peer-to-peer
network, but maximum distance allowed between nodes limits the effective range of a
1394-enabled network to a single room. However, in a whole-home network it is possible
to define audio/video clusters running with the 1394 standard and connect them to the
rest of the house through Wi-Fi.
An issue that also needs to be solved is security. Unlike a wired network, wireless
networks spread their signal beyond the boundaries of a typical home. Thus, in densely
populated neighborhoods, potential hackers can scan for available networks and gain
access to them. There is also the issue of interference. Wi-Fi uses radio spectrum that is
unregulated, and therefore all kinds of products, from microwaves to mobile phones,
could interfere with a signal.