Page 100 - DCAP311_DCAP607_WIRELESS_NETWORKS

Wireless Networks

Notes When first widely deployed in the 1980s, Ethernet supported a maximum theoretical data rate
of 10 megabits per second (Mbps). Later, so-called “Fast Ethernet” standards increased this
maximum data rate to 100 Mbps. Today, Gigabit Ethernet technology further extends peak
performance up to 1000 Mbps.
Higher level network protocols like Internet Protocol (IP) use Ethernet as their transmission
medium. Data travels over Ethernet inside protocol units called frames.
The run length of individual Ethernet cables is limited to roughly 100 meters, but Ethernet
networks can be easily extended to link entire schools or office buildings using network bridge
devices.

6.3.2 Phone Line

Phone-line networking is one of several ways to connect the computers in your home. If your
computers are in different rooms, then phone-line networking could be a good solution for you.
Phone-line networking is easy to install, inexpensive and fast, and it doesn’t require any
additional wiring.
Phone-line networking, most commonly referred to as HomePNA, is based on the specifications
developed by the Home Phone Networking Alliance (HPNA). The HPNA is a consortium of
key networking technology companies that created a phone-line standard for the networking
industry. HPNA 1.0, the original version of the standard, operated at a rather slow 1 megabit
per second (Mbps). The current specification, HPNA 3.0, is based on technology developed by
Broadcom and Copper Solutions. It operates at 128 Mbps.
HomePNA has several distinct advantages:

z z It’s easy to install.
z z It’s inexpensive.
z z It’s standardized.
z z It’s reliable.

z z It operates at a constant 128 Mbps, even when the phone is in use.
z z It requires no additional networking equipment (such as hubs or routers).
z z It supports up to 50 devices.
z z It is fast enough for bandwidth-intensive applications, such as video.

z z It is compatible with other networking technologies.
z z It works on Macs and older PCs (in addition to Windows and Linux systems).
HomePNA does have some drawbacks, though. You need a phone jack close to each computer.
Otherwise, you will have to run phone extension cords or install new wiring. There is a physical
limit of 1,000 feet (304.8 m) of wiring between devices, and the overall area of coverage should
not exceed 10,000 square feet (929 m2). Rarely (in fewer than 1 percent of U.S. homes), HomePNA
will not work on the existing wiring. And while this author did not notice any interference with
voice use, there have been reports of voices sounding “funny” or of a lot of noise on the phone
once HomePNA is installed.

6.3.3 Wireless

Wireless is a term used to describe telecommunications in which electromagnetic waves (rather
than some form of wire) carry the signal over part or all of the communication path. Some

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