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

116 CHAPTER 7 Wide Area Networking
Satellite (MEO)
Satellite (LEO)
User
PDA
User with PDA and Antenna
FIGURE 7.2
A satellite-based network
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GEOs are located at about 22,000 to 23,000 miles above Earth.
Wireless systems and satellites are commonly used in geographical areas
that are far from a CO or when extreme flexibility is needed.
Summary of Exam Objectives
In this chapter, we covered the Network+ exam objectives based around wide
area networking technologies such as packet switching, which is an “always on”
network type, and circuit switching, which is an “on demand” network type.
We also covered the fundamentals of ISDN, which is a digital method of transmitting
data across copper telephone lines, using SPIDs to connect the network
(circuit switched) for the sending and receiving of data. We covered the fundamentals
of Frame Relay, MPLS, X.25, and SONET, as well as T- and E-level carrier
lines.
We discussed the primary ways to get Internet access, such as with DSL. DSL is
a digital method of transmitting data over preexisting copper telephone lines.
ADSL is a technology that allows for faster download speeds. DSL speeds also
vary depending on how far from the CO you are. Cable-based ISPs were also
covered, which is generally faster than DSL but can also become congested if
too many subscribers use the shared media all at once. Both are far better when
it comes to speed and use than POTS or PSTN. The dial-up method of access
using a standard modem is the slowest method of access. Satellite and WWAN
technologies were also discussed; they afford you the flexibility of use over speed
and security.