Wireless Network Installation

Wireless Network Installation
Now that you understand the basic components involved in a wireless network, it’s time to learn about their actual installation. Although we’ve stated earlier that wireless networks contain
fewer components and are less complex, there are several major factors that figure into a wireless network installation:

• Wireless LAN standards
• Installation type
• Signal degradation (Site Survey)

Wireless LAN Standards
Although wireless LANs have been around for only a relatively short time (in networking terms), there are many standards that have been ratified that deal with them. The majority of the technology in use today for wireless LANs is based on the IEEE 802.11 series of standards, although a slightly misaligned niche market exists for infrared and Bluetooth networking as
well. More suited to LAN networking than infrared, Bluetooth, and the original 802.11 standard, the three most commonly used 802.11 standards today are as follows:

 IEEE 802.11a
IEEE 802.11b

IEEE 802.11g

NOTE:

All three of these wireless versions are technically subgroups of the 802.11 working group. Even though they are in the same group, they are fundamentally different, as you will see.

Infrared Networking
One type of wireless networking that doesn’t receive much attention is infrared wireless. Infrared wireless uses the same basic transmission method as many television remote controls, infrared
technology. Infrared is used primarily for short distance, point-to-point communications, like those between a peripheral and a PC. The largest use of infrared wireless is for peripherals using
the IrDA standard. 

NOTE:
A little-known fact about infrared is that the original IEEE 802.11 wireless standard specified a somewhat limited baseband infrared medium in addition to the more common Direct Sequence Spread Spectrum (DSSS) and Frequency Hopping Spread Spectrum (FHSS) modulation techniques.

IrDA stands for Infrared Data Association, which is the standards body that develops the IrDA standard for point-to-point, peer-to-peer communications over infrared radiation. Infrared
equipment that uses the IrDA standard can be found in many places, including cell phones, handheld PDAs and computers, keyboards, and so on. The standard specifies a data transmission rate of 16Mbps (that will soon be increased to over 100Mbps with updates to the standard) and a maximum range of about 1 meter (1m). As you can see, although it possesses significant throughput, the range is lacking for a wireless LAN standard for large LANs.

Bluetooth Networking
One of the newest wireless standards is the wireless networking standard known as Bluetooth. It was designed to replace the myriad cords on an average computer user’s desk. Cords for
things like keyboards, mice, and headphones can all be eliminated. The standard allows for these many different types of peripherals to all be able to communicate wirelessly with a host device, like a computer. For example, a popular Bluetooth accessory is the wireless headset for cellular phones. It’s battery powered and will communicate directly with the phone wirelessly. Bluetooth has a total maximum throughput of 1Mbps. It isn’t a speed demon as far as throughput is concerned, but it is still more than enough for peripheral communications like mice, keyboards, and headphones, and it is possible for two Bluetooth devices to network to
each other in a peer-to-peer fashion. But, as with infrared, it is impractical to build an entire multistation wireless LAN using the Bluetooth technology.

802.11
The original 802.11 standard specified a somewhat impractical recommendation, in terms of data rates, with regard to the bandwidth-hungry mentality of its contemporary LANs. In 1997, IEEE specified what is now referred to as 802.11-1997, a wireless LAN standard with a bandwidth of 2Mbps (with the ability to fall back to 1Mbps in noisy environments) when using DSSS modulation and a bandwidth of 1Mbps when using FHSS modulation. Even when using FHSS, the standard allows for possible 2Mbps operation in environments in which the noise level is below an acceptable threshold. Both the DSSS and FHSS methods operate in the unlicensed 2.4GHz frequency
range. 802.11-1997 has since been updated by 802.11-1999, the supplements to which have given rise to the newer, more common standards of 802.11a, 802.11b, and 802.11g.

802.11a
The IEEE 802.11a standard is an extension to the IEEE 802.11 standard that specifies a wirelessradio frequency LAN technology that provides for up to 54Mbps of available throughput.It
uses the 5GHz radio frequencies (regulated) and OFDM for data encoding. It has a maximum range of 250ft (76m) indoors and approximately 1000ft (305m) outdoors.

Wireless LAN Modulation Techniques
While a complete discussion of the technical workings of the wireless modulation techniques is beyond the scope of the objectives of the Network + exam and of this Study Guide, it is still important that you are aware of the mating of these techniques with their corresponding 802.11 standards.

DSSS
DSSS is one of the modulation techniques specified by the original IEEE 802.11 standard and the one chosen for use in the widely accepted IEEE 802.11b standard. IEEE 802.11 uses Differential
Binary Phase Shift Keying (DBPSK) for 1Mbps DSSS and Differential Quadrature Phase Shift Keying (DQPSK) for 2Mbps DSSS. The DSSS defined in IEEE 802.11b uses the Complementary Code Keying (CCK) modulation technique, making 5.5Mbps and 11Mbps data rates. All three modulation schemes are compatible and can coexist by using 802.11-standardized rate-switching procedures. DSSS creates a redundant bit pattern for each bit that is transmitted, increasing DSSS’s resistance to interference. The benefit is that if one or more bits in the bit pattern are damaged

in transmission, the original data might be recoverable from the redundant bits.

FHSS
Although it’s the original modulation technique specified by the IEEE 802.11 standard, FHSS is not the modulation of choice for vendors or the 802.11 working group. As very few vendors
support FHSS in 802.11 products, it seems DSSS has become the preferred modulation standard. Continued developments within 802.11 favor DSSS. FHSS modulates the data signal with
a carrier signal that changes (hops) in a random yet predictable sequence of frequencies, over time These changes also occur over a wide frequency band. A spreading, or hopping, code determines the transmission frequencies. The receiver is set to the same code, allowing it to listen to the incoming signal at the right time and frequency to properly receive the signal. Manufacturers
use 75 or more frequencies per transmission channel. The maximum dwell time, or time spent during a hop at a particular frequency, has been established by the FCC at 400ms.

OFDM
802.11a uses Orthogonal Frequency Division Multiplexing (OFDM), with a system of 52 carriers (sometimes referred to as “subcarriers”)modulated by BPSK or QPSK. OFDM’s spread spectrum technique distributes the data over these 52 carriers, which are spaced apart at precise frequencies. This spacing helps prevent demodulators from seeing frequencies other than their
own. OFDM is resistant to RF interference, exhibiting lower multipath distortion. For more information on OFDM, check out the OFDM Forum’s website at www.ofdm-forum.com.

The IEEE 802.11a standard was released at approximately the same time as 802.11b. However, 802.11b received more attention because 802.11a equipment was released approximately
two years after the introduction of the 802.11b equipment and because of 802.11b’s lower equipment cost. Plus, 802.11a has shorter range due to its higher frequency (higher frequencies

attenuate sooner), and also due to the higher frequency, its signal is interfered with more easily. But, on the plus side, because it uses regulated frequencies, there is less chance of standard
devices like microwaves and such interfering with the wireless signal.

802.11b
The IEEE 802.11b standard has been given credit for the explosion of wireless networking. The equipment is cheap (and getting cheaper) and provides for decent network access speeds. It’s
easy to set up and use and is readily available. 802.11a and 802.11b were created at approximately the same time, but the 11b standard got the spotlight as the preferred LAN standard (primarily
because of cost and the late introduction of 11a equipment).
The IEEE 802.11b standard specifies a wireless radio frequency LAN technology that provides for up to 11Mbps of available throughput. It uses the 2.4GHz radio frequencies (unregulated)
and Direct Sequence Spread Spectrum (DSSS) for data encoding. It has a maximum range of 300ft (91m) indoors and about 1500ft (457m) outdoors.

NOTE:
Even though they are subsets of the same standard, IEEE 802.11a and 802.11b are incompatible.

So What Is Wi-Fi?
You may have seen products that are 802.11b compliant with a small sticker on them that says “Wi-Fi.” You might be able to guess that this rather odd phrase stands for Wireless Fidelity, but
you may not know what its implications are. Simply put, that sticker indicates that the product in question has passed certification testing for 802.11b interoperability by the Wi-Fi Alliance.
This nonprofit group was formed to ensure that all 802.11b wireless devices would communicate seamlessly. So, Wi-Fi is a good thing.

802.11g
The most recent player in the 802.11 standards game is the IEEE 802.11g standard. It is kind of a “best of both worlds” standard. It includes the high data rate (54Mbps) of 802.11a with
the stability and wide product base of 802.11b. Plus, it is backward compatible with 802.11b (alas, not so with 802.11a).
The IEEE 802.11g standard specifies a wireless radio frequency LAN technology that provides for up to 54Mbps of available throughput. It uses the 2.4GHz radio frequencies (unregulated)
and both DSSS and OFDM for data encoding. It has a maximum range of 300ft (91m) indoors and about 1500ft (457m) outdoors

NOTE:

It is important to note that most 802.11g devices are compatible with 802.11b devices. For example, a 802.11b NIC will work with an 802.11g access point (at the lower, 802.11b speed, of course) and vice versa.

Table 6.2 summarizes these IEEE 802.11 wireless LAN standards in comparison to Bluetooth, a possible interferer.

TABLE 6 . 2 Bluetooth and Wireless LAN Standards

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Wireless Network Components

Wireless Network Components
Wireless networks are a little less complex than their wired counterparts. They require fewer components to operate properly. There are two main devices that can be found in a small wireless
network: a wireless access point and a wireless NIC. In order to understand proper wireless network installation, you should understand the basics of these two components.

Wireless Access Points (WAPs)
For a majority of wired networks, there is a central component, like a hub or a switch, that connects the nodes together and allows them to communicate. Wireless networks are similar in that they have a component that connects all wireless devices together. That device is known as a wireless access point (WAP). Its function is to operate as a hub of sorts for the wireless devices.
It has at least one antenna (sometimes two for better reception) and a port to connect the wireless AP to a wired network. Figure 6.4 shows an example of a wireless access point.

FIGURE 6 . 4 A wireless access point

One way of thinking of a WAP is as a bridge between the wireless clients and the wired network. In fact, an WAP can be used as a wireless bridge (depending on the settings) to bridge two

wired network segments together.

NOTE:

In addition to the stand-alone WAP, there is a WAP that includes a built-in router that can be used to connect both wired and wireless clients to the Internet. This device is usually known as a wireless router. Wireless routers usually act as Network Address Translation (NAT) servers by using the one ISP-provided global IP address to multiplex multiple local IP addresses (often handed out to inside clients by the wireless router from a pool in the 192.168.x.x range). Therefore, the subscriber need not change their service with the ISP in order to increase the number of devices that can simultaneously access the Internet.

Wireless NIC
Every station that wants to connect to a wireless network will need a wireless network interface card (NIC). In most respects, a wireless NIC does the same job as a traditional NIC, but instead
of having a socket to plug some cable into, the wireless NIC will have a radio antenna. In addition to the different types of wireless networking (discussed in the next section), wireless NICs
(like other NICs) can also differ in which type of connection they use to connect to the host computer. Figure 6.5 shows an example of a wireless NIC.

FIGURE 6 . 5 A wireless NIC

NOTE:

There are wireless adapters that are not NICs. For example, Linksys makes an external USB wireless adapter for notebooks. It is not a NIC because it isn’t an expansion card (the C in NIC), so they are generally referred to as “adapters.” Additionally, NICs also come in the form of PC cards, generally for laptops, notjust conventional expansion cards.

Wireless Antenna Characteristics
Wireless antennas act as both transmitters and receivers. There are two broad classes of antennas on the market, omni directional (Omni, or point-to-multipoint) and directional (Yagi or point-topoint). As a general rule, Yagi antennas have greater range than Omni antennas of equivalent gain because Yagis focus all their power in a single direction whereas Omnis must disperse the same
power in all directions at once. The drawback of using a directional antenna, though, is that more care must be taken to align communication points, generally making Yagi a good choice only for point-to-point bridging of access points. Most WAPs use Omnis because clients and other APs could be in any direction at any given moment. A non-networking example of an Omni antenna
is the FM antenna on your automobile. The orientation of your car does not affect the reception of the signal. The television aerials that some of us are old enough to remember rotating into a specific
direction for a certain channel (how many of you labeled your set-top antenna dial for the actual TV stations you could receive?) are examples of Yagi antennas. Omnis and Yagis are both rated according to their signal gain with respect to an actual or theoretical
laboratory reference antenna. These ratings are relative indicators of the corresponding production antenna’s range. Range is also affected by the bit rate of the underlying technology, 
with higher bit rates extending shorter distances. Remember, a Yagi will always have a longer range than an equivalently rated Omni, but the straight-line Yagi will be limited in coverage area.
Manufacturers rate these antennas in units of decibel isotropic (dBi) or decibel dipole (dBd), based on the type of reference antenna (isotropic or dipole) of equivalent frequency operation
used to rate the production antenna. A positive value for either unit of measure represents a gain in signal strength with respect to the reference antenna. Webster’s defines isotropic as “exhibiting
properties (as velocity of light transmission) with the same values when measured along axes in all directions.” Isotropic antennas are not able to be produced in reality, but their properties
can be engineered from antenna theory for reference purposes.
As a practical example, consider Cisco Systems’s series of Aironet Access Point (indoor) and Bridge (outdoor) antennas. Table 6.1 illustrates the effect gain ratings and attempted bit rates

have on range limitations.

TABLE 6 . 1 Wireless Antenna Types and Ranges

  The rule of thumb is that antennas operating with frequencies below 1GHz are measured in dBd while those operating above 1GHz are measured in dBi. As this is not always the case, you

may find the need to compare the strength of one antenna, measured in dBd, with another, measured in numerically equivalent dBi, in order to determine which is stronger. That’s why it’s

important to know that a particular numerical magnitude of dBd is more powerful than the same numerical magnitude of dBi. The good news is that the relationship between the two is linear,

making the conversion quite simple. At the same operating frequency, a dipole antenna has about 2.2dB gain over a 0dBi theoretical isotropic antenna. Therefore, you can easily convert

from dBd to dBi by adding 2.2 to the dBd rating. Conversely, subtract 2.2 from the dBi rating to produce the equivalent dBd rating. Taking into account what you’ve learned about the difference between Omni and Yagi antennas and the difference between dBd and dBi gain ratings, you should be able to compare the relative range of transmission of one antenna with respect to another based on a combination of these characteristics. By way of example, the following four antenna ratings are given in relative order from greatest to least range:

7dBd Yagi (equivalent to a 9.2dBi Yagi)
7dBi Yagi (longer range than 7dBi Omni)
4.8dBd Omni (equivalent to a 7dBi Omni)

4.8dBi Omni (equivalent to a 2.6dBd Omni)

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Wireless Networking "Network + Chapter 6"

Wireless Networking

Wireless networks have become widespread and are found in both public and commercial settings. As a matter of fact, it is now possible to find wireless networks in many public spaces like
coffee shops, malls, airports, and hotels. To that end, the entry level technician should know about the various wireless network components and their installation factors.

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Other Documentation

Other Documentation

You have at your disposal three more resources that can be of value before, during, and after upgrading or installing new hardware or software:

• README files
• The manufacturer’s technical support CD-ROM
• The manufacturer’s technical support website

We discuss all of these in detail in Chapter 10.

NOTE:
All three of these resources can come in handy when you are unable to get through to technical support phone numbers. But some people feel that talking with a human is worth the effort it sometimes takes. Be aware that this is not necessarily free. See Chapter 10 for more information.

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Current Configuration and Baselines

Current Configuration and Baselines
Of particular value when you are upgrading a network or installing new hardware or software are the server and client configuration documents. If these have been properly maintained, they
include information about the current hardware configuration (including I/O address, IRQ, DMA, and memory address), the installed software, any patches, and any special settings.
Configuration documentation should also include cable maps that indicate each network cable’s source (workstation/server) and destination (typically, a port in a hub), as well as where
each network cable runs. (We’ll discuss cabling in detail in Chapter 10.)
Baseline documentation indicates how the network normally runs. It includes network traffic statistics, server utilization trends, and processor performance statistics. Baselines indicate how
things currently are, not how they should be. Creating and maintaining these types of documents provides a valuable reference point should a client or server fail or malfunction after an upgrade.

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Error Messages and Log Files

Error Messages and Log Files

A careful perusal of error messages and log files can give you a good sense of the health of a network. This is important because you may not want to add a new network device to a network
that is experiencing problems. Log files record every action that occurs on a computer. For example, a log file can contain a record of who logged in to the network when, from which machine, and at what time. Figure 6.3 shows a sample log file.
     Each network operating system includes special tools for creating and maintaining log files. In Windows NT and later, for example, you use Event Viewer (as shown in Figure 6.3) to display
System Logs, Security Logs, and Application Logs. NetWare tracks events in the ABEND.LOG, SYS$LOG.ERR, and CONSOLE.LOG files. In Chapter 10, “Network Troubleshooting,” we’ll look at log files and error messages in detail.

FIGURE 6 . 3 A sample log file from the Windows NT Event Viewer

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Environmental Issues

Environmental Issues
Environmental conditions, as they relate to installing or upgrading a network and its components, are important. Just like human beings, computers require a proper environment in order to function correctly. If the environment is harsh, the device will not function at peak efficiency. Surprisingly, environmental conditions and their consequences may be the most overlooked topic in the entire industry of networking. Often problems that seem to appear out of nowhere and appear to make no sense are caused by environmental conditions. Let’s examine the frequently elusive challenges that we all face at one time or another:

• Power problems
• ESD problems
• EMI problems
• RFI problems
• Climate problems

Power Problems

Alternating current (AC), which is “food” to PCs and other network devices, is normally 110 volts and changes polarity 60 times a second (or 60 Hertz). These values are referred to as line

voltage. Any deviation from these values can create problems for a PC or other network device. Power problems fall into three categories:

• Overage
• Underage
• Quality

Power Overage Problems

During a power overage, too much power is coming into the computer. Power overage can take two forms:

• A power spike occurs when the power level rises above normal levels and then drops back to normal in less than one second.
• A power surge occurs when the power level rises above normal levels and stays there for

more than one or two seconds.

FIGURE 6 . 1 Comparing a power spike and a power surge

Typically, power surges last longer than a second or two, and they may last for several minutes.

For this reason, surges are usually more damaging than spikes (although a very large spike can damage a computer’s power supply just as much as a surge). Figure 6.1 shows the difference

between a spike and a surge. Two types of devices are used to protect computers and other network devices from power

overage problems:

• Surge protectors  
• Line conditioners

A surge protector contains a special electronic circuit that monitors the incoming voltage level and trips a circuit breaker when the overvoltage reaches a certain level (called the overvoltage threshold). The problem with surge protectors is that the threshold is set too high to be safe. By the time the circuit breaker trips, some overvoltage has gotten to the power supply of the computer, possibly damaging it. Nor does a surge protector protect against power surges and spikes that are lower than the threshold. For the most part, a surge protector is better than nothing, but not by much. It is really only a multiple-outlet strip and should not be considered

anything more.

TIP:

Surge protectors with a very low overvoltage threshold cost upward of $50. They sacrifice themselves in the event of any significant overvoltage but are smart enough not to trip for just a small amount over the standard power levels. Additionally, most of these protectors contain electronic circuits that can “shave off” any overvoltage and ensure that the powered devices receive only

the voltage they need.

Line conditioners are a much better choice for protecting against surges and spikes. Line conditioners use several electronic methods to “clean” all power coming into them. The best models

can be prohibitively expensive, but there is a way to get a kind of “natural” line conditioner. An Uninterruptible Power Supply (UPS) uses a battery and power inverter to run the computer

equipment that plugs into it. A battery charger continuously charges the battery. The battery charger is the only thing that runs off line voltage. The computer itself runs off steady voltage

supplied by the UPS. When power problems occur, the battery charger stops operating and the equipment continues to run off the battery. The power coming from the UPS is always a continuous

110 volts, 60 Hertz. Because the AC power from the wall never crosses over the battery charger to run the computer components, it’s considered a “natural” line conditioner. As you

will see, the UPS is the solution for a number of power problems.

Power Underage Problems

Power underages occur when power levels drop below the standard, and they are almost as common as power overages. There are three types of power underages:

• A sag is an inverted spike. Sags occur when power levels drop below normal and rise back to normal within a brief period of time (usually less than one second). It is doubtful that you would be aware of sags (you might see a light flicker off and then on), although your computer might reboot.
• A brownout, on the other hand, occurs when power drops below normal levels for several seconds or longer. In other words, a brownout is an inverted surge. The lights in the room will dim for a short period of time and then come back to full brightness. 

    A blackout is a total loss of power for several seconds, several minutes, or several hours.

Any one of these problems will cause your computers and other network devices to malfunction. Figure 6.2 contrasts these power problems. 

    To ward off power underage problems, you need only one device: a UPS, which allows network devices to continue to function even in the complete absence of power. Some are intelligent and can shut down your computer in the case of a blackout.

FIGURE 6 . 2 Comparing power underage problems

Power Quality Problems

Power quality problems generally indicate that stray frequencies have entered the power supply through the power cord. Stray frequencies can cause strange problems (such as intermittent

reboots or hangs) and can damage a device’s power supply. You can detect problems in power quality only with an oscilloscope. If you’re having power quality problems, you need either a

UPS or a line conditioner.

Electrostatic Discharge (ESD) Problems

ESD occurs when two items with dissimilar static electrical charges are brought together. Nature doesn’t like things to be unequal, so static electrical charges will “jump” from the item with more electrons. This jump is seen as an electrical spark and thus is called an electrostatic discharge. ESD can damage electronic components because the several thousand electrons moving through delicate circuit junctions of silicon chips render the chips useless.

    Static can be damaging to equipment and uncomfortable for users at the same time. For example, one worker had the habit of walking around the office without shoes. Walking across a nylon carpet in cotton socks created an immense static charge. When he got within 15 centimeters (not a typo) of the keyboard, the static charge jumped from his fingers to the keyboard. This not only caused him considerable pain, but it also burned out one of the horizontal scan rows on the keyboard, destroying it forever. Fortunately, the computer was properly grounded; otherwise, much more damage could have been done.

TIP:

Properly grounding equipment can prevent static, as can maintaining room humidity in the 40–60 percent range.

Electromagnetic Interference (EMI) Problems
EMI occurs when magnetic fields intersect network or computer cables, causing interference in the cables. Motors and transformers, which are ubiquitous in an office (in air conditioners, heaters,
and so on), are a typical source of EMI. A common mistake is to run network cable through an elevator shaft or through a ceiling that hides a bank of transformers in fluorescent lights.
Finding the source of EMI can be a challenge. The best approach is to follow a cable with an inexpensive compass, noting strong, odd needle movement. When you find the source of the EMI, you can protect the cable against it by either replacing the cable with a shielded cable (or fiber-optic cable, which is immune to both EMI and RFI) or by moving the cable far away from the source of the EMI.

Radio Frequency Interference (RFI) Problems
RFI occurs when radio signals interfere with the normal operation of electronic circuits (computers in particular). Everyday sources of RFI include television and radio transmitters, which by nature create a specific radio frequency as part of the transmission process. Other sources are two-way radios and cellular phones.
The only way to protect against both EMI and RFI is to use shielded network cables. Shielded cable, as used in shielded twisted-pair (STP) and coaxial cable, can reduce the effects of RFI.
You could also use fiber-optic cable, which is immune to EMI and RFI, throughout your entire network, although this option can get a little pricey.

Real World Scenario  
“Let’s Be Careful Out There!”

In one of the strangest cases of RFI I have ever seen, a server was resetting almost every night, right about 3 AM, while doing a tape backup. Changing the tape drive, the power supply, and other components were of no avail. The log files showed that the tape drive was operating normally and that the server would simply go down and restart, returning to normal operation. Frustrated with dead ends, an engineer was on-site at 3 AM to observe the failure. He noticed that a police patrol car was parked nearby, radioing in status reports. Separated only by a wall, the server didn’t have a chance with 25 watts of VHF radio signal being transmitted from only a few meters away. The radio signal was resetting the server, and once the policeman was done filing reports, the RFI was gone and the server restarted.

Climate Problems
Network devices (including computers and servers) are very sensitive to temperature extremes and can fail prematurely if subjected to them. The environment for network devices should be
roughly the same as that for human beings. Keep the temperature consistently at 70 degrees Fahrenheit, and keep the relative humidity between 40 and 60 percent. Maintaining consistent
temperature and humidity can be a challenge because every computer constantly generates heat. Larger companies usually place network equipment in a special room that is climate controlled.

TIP:
Even if your company can’t provide a climate-controlled server room, you can do at least one thing to avoid climate problems: never put servers in a network closet without ventilation. It is better to put servers out in the open, locked to a desk, than to lock them up in an unventilated closet. Also, never put an electronic
device of any kind directly in front of a heat source, such as a space
heater. This can cause the components to fail prematurely because excessive heat can damage electronic components.

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Standard Operating Procedures

Standard Operating Procedures
Standard operating procedures (SOPs) are part of company policy and typically cover everything from sick-day accrual to how the computer systems are used. In particular, network administrators need to be aware of company policies regarding the following:

• Internet access
• Printing
• Storage allocation
• E-mail usage
• User administration

Policies about these issues will be reflected in the network’s naming conventions, protocol standards, and workstation configuration and will affect the location of network devices.

Naming Conventions

Naming conventions specify how network entities are named within the guidelines of the network operating system being used. Each entity name must be unique on the network, including the names you give to the following:

• Servers
• Printers
• User accounts
• Group accounts
• Test and service accounts

Naming Servers

In general, you name servers according to their location or function; sometimes it makes sense to use a combination. For example, a server located in Seattle might be named SEATTLE, or a server in the sales department might be named SALES. Or you might name a server that stores data DATA1, a server that stores applications APPS1, a server that stores a database DB1, and so on.

Another common practice is to name file servers FS followed by a number, such as FS1, FS2, FS3, and so on. Unfortunately, this naming convention doesn’t provide the user with any information

about what the server stores. The most common naming convention in use today is a combination of location and function. Using this approach, you might specify that the first four characters of the name identify the server’s location; the next two, the server’s function; and the last two, the server’s rank for

that type of server. For example, the FRGOFS02 server is located in Fargo, it’s a file server, and it is the second server of that type in Fargo.

Naming Printers

As with server names, printer names are often derived from their function, location, or both. Naming a printer after its function or location makes the printer easier to locate for the users.

If, for example, your dot-matrix printer is used to print multiple-part forms, you might name it Forms. If you have more than one forms printer, you might need to use two-word names, such

as Forms-Ship or Forms-Finance. You might name high-quality printers Laser or Laser-Legal, indicating that this printer is always loaded with legal-size paper.

NOTE:

This is not intended to reflect a right or a wrong way to address naming conventions. There is only one right way for any organization—the method it follows.

The X.500 Standard 

As an aside, it may interest you to understand where the directory services that you use today come from. Novell Directory Services (NDS) and Active Directory (included with Windows 2000
Server) are modeled after a standard known as X.500. X.500 is a type of global phone book. The period (.) is the delimiter for NDS, Active Directory, and X.500 entries. Suppose, for example,
a user’s name is Bob. Bob works in the accounts department of the finance division at a company known as YourCo.
 His full address would be Bob.Accounts.Finance.YourCo.

In NDS and Active Directory, each name is known as an
object.
A graphical tree displays each object. Thus, it is efficient to begin at a higher level and administer policies to an entire network,
for example, at YourCo. Furthermore, it is possible to drill down and work on a smaller unit
level. Additional policy information can be applied to the Finance level.

Using periods as the delimiter, NDS and Active Directory look similar to DNS, or the Domain Name Service.

DNS is an Internet standard. This standard is like NDS in that it is based on X.500 and the period is used as a delimiter. But it’s time to put one misconception to rest here and now: Not all Internet
addresses need www. Try http://research.Microsoft.com
to prove this to yourself.

Another point needs to be made about DNS entries. All URLs don’t end with .com , .org , or .edu. Country codes are common final entries in a URL. Here are some of them:

• .tw (Taiwan)
• .tz (Tanzania)
• .ua (Ukraine)
• .ug (Uganda)
• .uk (United Kingdom)
• .um (U.S. Minor Outlying Islands)
• .us (United States of America)
• .uy (Uruguay)
• .uz (Uzbekistan)
• .va (Vatican City State)

As you use the Internet, NDS, and Active Directory, notice the commonalities between them. When you do, you will see how their common lineage ties them together.

Naming User Accounts

Generally speaking, the simplest username is the user’s first name. This method works well in a company with only a few users and fits the informality often found in a small office. It is fairly insecure, however, because hackers could easily guess a username. It also won’t work in a larger organization that could easily include two people with the same first name. The user-naming convention you use should allow for unique IDs and ensure that there are no

duplicates. Larger firms typically use a first initial followed by part of or the entire last name. For example, Rebecca Messersmitt-Kazlowski would be RMessersmittKazlowski. This is still a long

username and might even cause a problem with maximum character lengths allowed in some operating systems. In this example, Rmesser might be used as a short, yet unique, login name.

Naming Groups
Groups are network entities that logically associate users by function. They are designed to make network administration easier: You can assign rights to a group of users all at once rather
than to each individual. Because the group of users is organized by function, it would stand to reason that groups should be named by function. Additionally, the names should be short, fewer
than 15 characters if possible. For example, if you have a group of users from the sales department that all use the same printer, you might name the group SALES_PRN. On the other hand,
if you just want a general group for security and rights assignment purposes, you might name that group of users SALES.

NOTE:

We’ll discuss groups in detail in Chapter 8, “Network Access and Security.”

Naming Test and Service Accounts
When you install new services on the network, such as printers, applications, and so on, it is always a good idea to test their functionality first. It is not good practice to do this testing while
logged in using an administrative account because administrative accounts usually have all encompassing rights to the network. Thus, problems related to accessing the service are more likely to occur when an administrative account is not used for testing. It is better to use a user account that is equivalent to one who will be using the service. For this reason, it makes sense to create
test accounts that you can use to test access to and the functionality of new services. Service accounts, on the other hand, give outside network maintenance personnel the ability to perform administrator-level functions on your network. This is necessary whenever you must call in outside personnel. The naming conventions document should also specify naming conventions for these accounts and define their security rights.

Protocol Standards
You have already learned that protocols have different properties. If your firm has nothing but NetWare servers that are either version 3.xor 4.x, using Internet Packet eXchange (IPX) as the standard protocol would make sense. Alternatively, suppose there is a small group called New Product Development. Because of the sensitive nature of this group’s work and because data

should not leave the department, a routable protocol might be forbidden. In this case, NetBIOS Enhanced User Interface (NetBEUI) would be a wise choice because it cannot be routed and
serves a small group without much maintenance. Today, because of its prevalence and to reduce training and operational expenses, a great number of companies are standardizing on Transmission
Control Protocol/Internet Protocol (TCP/IP).
Regardless of the protocol you choose, you must obtain all network addresses before installing or upgrading a network device. This brings its own set of considerations. As you saw in
Chapter 4, “TCP/IP Utilities,” using TCP/IP as an example, each IP address must be unique, and just guessing at one is bound to create havoc. Clearly, you need a well-documented IP address
and associated parameters, such as where the IP address comes from. Your SOPs should specify how network addresses are to be formatted and distributed.

Workstation Configuration

A standardized workstation configuration serves a company well for a couple of reasons:

You can narrow the scope of problems at a client station.

You can more easily troubleshoot if everyone uses the same operating system, network client, and productivity software.
This is not to say that everyone in the office has to have the exact same software. The engineering group would most likely need a computer-aided design (CAD) program, along with the
appropriate horsepower and RAM. Giving everyone in the company a CAD program, however, would waste resources, and it would be difficult for the accounting department to use a CAD
program to create a paycheck for each employee. Therefore, a standard for workstation configuration is usually mandated by a group’s function. However, once an application is chosen,
only that application (preferably the same version) should be used by anyone who requires access to that type of program. Which applications and which versions of each application can
be used on the network should be documented in your SOPs.

TIP:

Some network management applications simplify the process of distributing unique applications to those users who need them while maintaining the same
basic workstation software configuration. Examples of these include Microsoft’s Systems Management Server (SMS) and Novell’s ZENworks.

It is also important to define minimum workstation hardware standards. Typically, the minimum requirement is one or two generations behind what is considered the hottest, fastest new
system. A standards document might specify the following:

• Type, brand, and speed of CPU
• Minimum RAM
• Minimum hard-disk size
• Type and brand of NIC
• Minimum monitor size (14˝, 15˝, or 17˝)

Network Device Placement

The network SOP may also specify where network devices are to be placed. Many of these specifications relate to safety—for example, where cables are to be run and where to place network

devices so that they are immune to sources of extreme heat or cold. Also, critical network components (such as servers and routers) should be placed in a room away from “busy fingers.”

You should also consider the needs of users when you are deciding where to place network devices. For example, although placing a printer in the middle of the office might seem logical,

it probably makes more sense to place it near the employees who use it the most.

Real World Scenario 
Network Documentation

I don’t know how many times I’ve gone into a place and asked where their documentation was only to be met with a blank stare. I was recently at a small business that was experiencing network problems. The first question I had was, “Do you have any kind of network documentation?” I got the blank stare. So, we proceeded to search through lots of receipts and other paperwork to try to work out the network layout and figure out exactly what was on the network. As it turns out, they had recently bought a wireless access point and it was having trouble connecting, which was causing the aforementioned problems. However, to solve the problem,
I had to take two hours to answer a fairly simple question that would have taken five minutes had the network documentation been readily available.
Documentation doesn’t have to be anything fancy; it can start with a three-ring binder filled with a simple network map, any receipts for network equipment, and a stack of loose-leaf paper to record services, changes, network addressing assignments, and so on. Just this little bit of documentation can save the owner lots of steps, especially in the critical first few months of a new network install.

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Before Installing New Hardware or Software

Before Installing New Hardware or Software

Before you add a new hardware component to a network, upgrade the operating system, install a new application, or make any other such change, you need a clear picture of the current condition
of the network. Additionally, you need to have an understanding of how a network behaves when it is functioning normally so that you will be able to tell when the network is malfunctioning.
This includes an understanding of standard operating procedures and how they are being implemented and an awareness of any environmental issues that affect the way the network is set up. You also need to take a close look at error messages and log files, which will give you a lot of information about the health of the network, and be sure you are familiar with the current configuration and baselines. In addition, don’t forget to review the manufacturers’ documentation that you should have at hand. A 15-minute perusal of the documentation beforehand could save you hours of work later.

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Wired and Wireless Networks "Network + Chapter 6"

Wired and Wireless Networks

THE FOLLOWING NETWORK+ EXAM OBJECTIVES
ARE COVERED IN THIS CHAPTER:

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), 802.11x (direct sequence spread spectrum)

• Infrared
• Bluetooth

1.8 Identify factors which affect the range and speed of

wireless service (for example, interference, antenna type,

and environmental factors).

3.3 Identify the appropriate tool for a given wiring task (for

example, wire crimper, media tester/certifier, punchdown

tool, or tone generator).

This chapter brings you to the most important test of all: your

ability to install new network hardware and software. The Network+ exam tests your knowledge of the basic network hardware components that you might install as well as how to successfully upgrade outdated hardware or software. In this chapter, we’re going to examine what you should consider before you upgrade, some common network components you might install, whether they should be wired or wireless, and how you connect them.

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Wired and Wireless Networks "Network + Chapter 6"

Wired and Wireless Networks 
    Before Installing New Hardware or Software 
         Standard Operating Procedures 
         Environmental Issues 
         Error Messages and Log Files 
         Current Configuration and Baselines 
         Other Documentation 
    Wireless Networking 
         Wireless Network Components 
         Wireless Network Installation 
         Installation Type 
    Workstation Configuration 
         Configuring a Windows 9x Network 
         Configuring a Windows 2000 Network Client 
         Configuring Windows Clients for NetWare Network                         Access Network Installation Tools 
         Wire Crimper 
         Media Testing Tools 
         Punchdown Tool 
     Summary 
Exam Essentials  
Review Questions  

Answers to Review Questions

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Answers to Review Questions " Network + Chapter 5 "

Answers to Review Questions

1. B. The only two options listed that are directory services are NTDS and NDS. Of those two, the only one that is an X.500-compliant directory service is NDS.

2. A, B, D. All of the NOSes listed, except NetWare 4, have a graphical interface. UNIX has X Window, NetWare 5 has the Graphical Java Console, and Windows Server uses a Windowsbased interface.

3. B. Novell Client for Windows is Novell’s NetWare client for the Windows platform, including Windows 98. It enables a Windows 98 machine to access the full range of NetWare (and NDS)
services.

4. B, C. Novell Client for Windows (as previously mentioned) and Microsoft Client for Microsoft Networks will allow the station to access Windows servers.

5. B. Windows Server uses Active Directory to store the names of users and groups, but it uses Kerberos during the authentication process to verify the authenticity of those users.

6. C. Although all of the listed utilities are administration utilities of some type, the name of the administration program for modifying NDS objects in NetWare 4 and above is NetWare
Administrator.

7. B. Typefull distinguished names always have leading periods and call out the object types with their appropriate prefixes (CN=, OU=, etc.).

8. B. Active Directory (AD) is the directory service used by default by Windows Server 2003.

9. A. Novell Directory Services (NDS) is the default directory service used by NetWare 4 and later.

10. A, B, C, D. All the operating systems listed are available in one form or another for the Intel platform.

11. A. Typeless distinguished names still include the leading period, but without the object type identifiers (CN=, OU=, etc.).

12. B, C. There are two main methods users can use to interact with UNIX: through a text-based command line and through a graphical interface.

13. B. An object’s context is the complete name of all the containers in which it resides, so Admin.ACME is the only correct response.

14. B, C, D. The only platforms that NDS runs on natively are NetWare 4.x, 5.x, and 6.x. NDS will not run natively on NetWare 3.x.

15. B. There is no such thing as Windows XP Server. Windows XP is a desktop operating system.

16. D. Samba is the technology that allows Mac OS X Server to respond to Windows SMB network calls and will make a Mac appear as another Windows server.


17. D. Apple’s own directory, similar to NDS and Active Directory, is known as Open Directory.

18. B. The schema defines what types of objects can exist in a directory.

19. B. Although all of the listed distributions have ports to the Intel platform, the Slackware distribution was developed specifically for the Intel platform.


20. B. The main command-line interface in UNIX is known as a shell.

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