Onward, Through the Fog

Onward, Through the Fog!

Once you've assessed your readiness, undertaken the right background studies, obtained the hands-on experience that will help you understand the technologies at work, and reviewed the many sources of information to help you prepare for a test, you'll be ready to take a round of practice tests. When your scores come back positive enough to get you through the exam, you're ready to go after the real thing. If you follow our assessment regime , you'll not only know what you need to study, but also when you're ready to make a test date at Prometric or VUE.

Good luck!

Chapter 1. Introduction to Networking

Objectives

1.1 Recognize the following logical or physical network topologies given a diagram, schematic, or description:

• Star

• Bus

• Mesh

• Ring

• Wireless

1.2 Specify the main features of 802.2 (Logical Link Control), 802.3 (Ethernet), 802.5 (token ring), 802.11 (wireless), and FDDI (Fiber Distributed Data Interface) networking technologies, including

• Speed

• Access method (CSMA/CA (Carrier Sense Multiple Access/Collision Avoidance) and CSMA/CD(Carrier Sense Multiple Access/Collision Detection))

• Topology

• Media

1.7 Specify the general characteristics (for example, carrier speed, frequency, transmission type, and topology) of the following wireless technologies:

• 802.11 (Frequency hopping spread spectrum)

• 802.11 x (Direct sequence spread spectrum)

• Infrared

• Bluetooth

1.8 Identify factors that affect the range and speed of wireless service (for example, interference, antenna type, and environmental factors)

What you need to know

• Understand the differences between local area networks (LANs), wide area networks (WANs), and personal area networks (PANs)

• Identify the characteristics between peer-to-peer and client/server networking

• Identify the characteristics of various network topologies

• Understand the characteristics of the following IEEE standards: 802.2, 802.3, 802.5, and 802.11

• Identify the characteristics of Fiber Distributed Data Interface (FDDI)

• Understand the impact of interference on Wireless communications

Introduction

There are a variety of physical and logical network layouts in use today. As a network administrator, you might find yourself working on these different network layouts or topologies and, as such, will require knowledge of how they are designed to function.

This chapter reviews general network considerations such as the various topologies used on today's networks, LANs, PANs, and WANs, and the IEEE standards.

LANs, WANs, and PANs

Networks are classified according to their geographical coverage and size . The two most common network classifications are local area networks (LANs) and wide area networks (WANs).

LANs

A LAN is a data network that is restricted to a single geographical location and typically encompasses a relatively small area such as an office building or school. The function of the LAN is to interconnect workstation computers for the purposes of sharing files and resources. Because of its localized nature, the LAN is typically high speed and cheaper to set up than a WAN. Figure 1.1 shows an example of a LAN.

WANs

A WAN is a network that spans more than one geographical location often connecting separated LANs. WANs are slower than LANs and often require additional and costly hardware such as routers, dedicated leased lines, and complicated implementation procedures. Figure 1.2 shows an example of a WAN.

Figure 1.2. Wide area network.

PANs

Wireless technologies have introduced a new termWireless Personal Area Networks (WPAN). WPAN refers to the technologies involved in connecting devices in very close proximity to exchange data or resources. An example of this can be seen through connecting a laptop with a PDA to synchronize an address book. Because of their small size and the nature of the data exchange, WPAN devices lend themselves well to ad hoc networking. Ad hoc networks are those that have devices connect directly to each other and not through a wireless access point. Ad hoc wireless networks are discussed later in this chapter.

Because of the close proximity of WPAN networking, short-range wireless technologies are typically used. This includes Bluetooth and Infrared. The key WPAN technology supported in Windows XP Professional, for example, is Infrared Data Association (IrDA). In addition, the IEEE wireless standards, including 802.11b/g, can be used to create a WPAN.