Syngress - Eleventh Hour Network+ Exam N10-004 Study Guide (11 ...

Internet Access Methods 115
Wireless
WISPs provide Internet access anywhere that it has coverage. Many locations that
have very little access to a good last mile source utilize this technology to connect
to the Internet. Homes also use this very often to get Internet access. You can
access the Internet from an antenna in your local PC, no matter where you are,
as long as you can access an antenna and have a clear shot to the antenna you
want to connect with.
■ Wireless wide area network (WWAN) WWANs are network traffic encapsulated
in mobile communications technology such as Worldwide Interoperability
for Microwave Access (WIMAX), Universal Mobile Telecom System
(UMTS), code division multiple access (CDMA) 2000, Global System for
Mobile (GSM), or 3G networks to name just a few. The mobile telecommunication
cellular network allows users with WWAN cards or built-in cellular
radios (GSM/CDMA) to surf the Web, send, and receive e-mail and in general
perform any networking function as if physically connected to a WAN.
Its characteristics are as follows:
■ Transmission rates are greatly reduced when compared with physical
connections.
■ WIMAX is based on Institute of Electrical and Electronics Engineers, Inc.
(IEEE) 802.16 standards or Broadband Wireless Access.
■ An acceptable rule of thumb is that WIMAX will sustain 70 Mbps
transmission rates at approximately 30 miles.
■ As distance increases, throughput decreases and vice versa.
■ Competition for access point connectivity is reduced through scheduling
such that once the WIMAX device connects to the access point,
it is assigned a set time to communicate with the access point from
then on.
■ Satellite Satellite dishes are starting to gain popularity as a way to access
the Internet. Many times (as is the case with cable), your carrier or ISP will
provide you with television service or some other form of service, so you
can use the satellite dish for multiple purposes. In addition, the dish is
less intrusive into your home because it’s mounted with very little need
for wires or a run to a CO. A typical satellite-based network is shown in
Figure 7.2. Characteristics of satellite are as follows:
■ A satellite is used to allow a user with a laptop, personal digital assistant
(PDA), or PC with wireless satellite capabilities to connect to the Internet
from anywhere within the coverage area.
■ It includes usage of low Earth orbit (LEO) and medium Earth orbit
(MEO) satellites.
■ LEOs are primarily used with Internet-based satellite communications
and are typically located at about 1,800 to 2,000 miles above Earth.
■ MEOs are located at about 9,000 to 10,000 miles above Earth.
■ There are also geosynchronous Earth orbits (GEOs), which are typically
used for the carrier’s or ISP’s trunk lines.