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The OSI model helps you gain this understanding by showing how network protocols are modular in nature.Network adapters are hardware used to connect your computer to the network.. The Pr

Chapter 11

Managing Network Connections

MICROSOFT EXAM OBJECTIVES COVERED IN THIS CHAPTER

Install, configure, and troubleshoot network adapters

Configure and troubleshoot the TCP/IP protocol.

For successful network connection management, you need to understand how network protocols work The OSI model helps you gain this understanding by showing how network protocols are modular in nature.Network adapters are hardware used to connect your computer to the network You also need a driver for the network adapter installed on your computer.

Managing network connections also involves configuring your network protocols The three protocols supported by Windows 2000 Professional are TCP/IP, NWLink IPX/SPX/NetBIOS, and NetBEUI

This chapter begins with an overview of network protocols, including a discussion of network data flow and the OSI model Then you will learn how

to install and configure network adapters and network protocols

Reviewing Networking Protocols

Communications over a network are accomplished through the use of networking protocols To understand the purpose of networking protocols, you should have a basic knowledge of the OSI (Open Systems Interconnec- tion) model The OSI model is not an actual product It is a theoretical model that describes how networks work

There are several advantages to using the OSI model as a framework for understanding network protocols:

 Breaking down a large concept, such as a network, makes it easier to understand

Reviewing Networking Protocols 497

 Modularizing network functions allows you to apply specific ogies or protocols at specific layers in a mix-and-match manner

technol- Understanding how one network system works and applying it to the OSI model allows you to easily apply that knowledge to other operat-ing systems

We’ll start by looking at an example of how data flows through a work Then we’ll examine how the seven layers of the OSI model work to move data through a network

net-Network Data Flow

Figure 11.1 illustrates an example of how data flows from Computer A on one network segment to Computer B on a separate network segment

F I G U R E 1 1 1 Data flows from Computer A on one network segment to Computer B on

another network segment.

In this example, the following steps are involved in moving the data from Computer A to Computer B:

1. Starting at Computer A, you create a message (file) using some type of program that offers file services In this example, the message says

“Hello.”

2. The computer doesn’t understand the characters in “Hello,” but does understand ones and zeros The message must be translated into ones and zeros through a protocol such as ASCII

3. At the higher levels of communication, a connection (or session) is established The connection determines when requests are made so

Computer A Send “Hello”

Computer B Receive “Hello”

498 Chapter 11  Managing Network Connections

4. You next need to determine if you want the connection to be reliable, called a connection-oriented service, or if you want the connection to use less overhead and assume that the connection is reliable, called a connectionless service An analogy for the reliability of the two ser-vices is that you can communicate by making a telephone call, which

is like using a connection-oriented service, or you can communicate by mailing a letter, which is like using a connectionless service

5. Because Computer A and Computer B are on separate network ments, you must figure out how to route the message across an inter-network based on the best possible path available

seg-6. Once the message gets to the correct network segment, it must be delivered to the correct computer on the segment

7. The message needs to travel over the physical connection that actually exists between Computer A and Computer B, which is at the lowest level of communication The data moves through the cabling and net-work cards that connect the network At this level, you are sending ones and zeros over the physical network

The steps in this data-flow example correlate to the seven layers of the OSI model, which are covered in the next section

The OSI Model Layers

Each of the OSI model layers has a specific function in providing networking capabilities The seven layers of the OSI model are Application, Presentation, Session, Transport, Network, Data Link, and Physical Table 11.1 lists a couple of mnemonics to help you remember the order of the layers

T A B L E 1 1 1 Mnemonics for the OSI Model Layers

Layer

Memory Trick Top to Bottom

Memory Trick Bottom to Top

Application All Albert

Presentation People Prince

Reviewing Networking Protocols 499

The Application Layer

The Application layer is used to support the following services:

In addition, the Application layer advertises any services that are being offered and determines whether requests that are made by the client should

be processed locally or remotely (through another network resource)

The Presentation Layer

The Presentation layer is used for four main processes:

Physical Processing People

File services Used to store, move, control access to, and retrieve

filesPrint services Used to send data to local or network printersMessage services Used to transfer text, graphics, audio, and video

over a networkApplication

services

Used to process applications locally or through distributed processing

Database services

Used to allow a local computer to access network services for database storage and retrieval

Character-code translation

The process of converting symbolic characters like the letter h into ones and zeros like 01101000,

T A B L E 1 1 1 Mnemonics for the OSI Model Layers (continued)

Layer

Memory Trick Top to Bottom

Memory Trick Bottom to Top

500 Chapter 11  Managing Network Connections

The Session Layer

The Session layer is responsible for managing communication between a sender and a receiver The following are some of the communication tasks that are performed at this layer:

Data transfer and dialogue control are used to determine which computer

is making requests and which computer is making responses This also mines if acknowledgments are required for data transmission

deter-The Transport Layer

The Transport layer is associated with reliable data delivery With reliable delivery, the sender and receiver establish a connection, and the receiver acknowledges the receipt of data by sending acknowledgment packets to the sender

Depending on the protocol used, you can send data through the Transport layer using a connection-oriented service or a connectionless service A connection-oriented service is like a telephone conversation, where the con-nection is established and acknowledgments are sent This type of commu-nication has a high overhead A connectionless service does not establish a connection and is similar to communicating through the mail You assume that your letter will arrive, but this form of communication is not as reliable

as a telephone conversation (a connection-oriented service)

Data compression The process of making data take less space at the

sending end for transportData expansion The process of restoring compressed data to its

original format at the receiver’s end

Reviewing Networking Protocols 501

The Network Layer

The primary responsibility of the Network layer is to move data over an network An internetwork is made up of multiple network segments that are connected with some device, such as a router Each network segment is assigned a network address Network layer protocols build routing tables that are used to route packets through the network in the most efficient manner

inter-The Data Link Layer

The Data Link layer is responsible for establishing and maintaining the munication channel, identifying computers on network segments by their physical address, and organizing data into a logical group called a frame There are two main sublayers at the Data Link layer: the Logical Link Con- trol (LLC) sublayer, which defines flow control, and the Media Access Control (MAC) sublayer, which is used for physical addressing

com-The communication channel that is established at the Data Link layer is

a low-level channel that manages whether or not a communication channel exists All higher-level communication is handled at the Session layer Com-puters are identified by their physical address, which is called the MAC address Ethernet and Token Ring cards have their MAC address assigned through a chip on the network card Frames are logical groupings of the bits from the Physical layer Frames contain information about the destination physical address and the source physical address, as well as all of the data that has been used at the upper layers of the OSI model

The Physical Layer

When you get down to the details of sending ones and zeros across a cable, you are dealing with the Physical layer The Physical layer is responsible for determining the following information:

 The physical network structure you are using

 The mechanical and electrical specifications of the transmission media that will be used

 How the data will be encoded and transmitted

502 Chapter 11  Managing Network Connections

Installing and Configuring Network Adapters

Network adapters are hardware used to connect computers (or other devices) to the network They function at the Physical and Data Link layers

of the OSI model, as shown in Figure 11.2

F I G U R E 1 1 2 Network adapters function at the Physical and Data Link layers of the OSI

model.

Network adapters are responsible for providing the physical connection

to the network and the physical address of the computer Network adapters (and all other hardware devices) need a driver in order to communicate with the Windows 2000 operating system

In the following sections, you will learn how to install and configure work adapters, as well as how to troubleshoot network adapters that are not working

net-Installing a Network Adapter

Before you physically install you network adapter, you should read the instructions that came with your hardware If your network adapter is new,

it should be self-configuring, with Plug-and-Play capabilities After you install a network adapter that supports Plug-and-Play, it should work the next time you start up the computer

Installing and Configuring Network Adapters 503

New devices will auto-detect settings and be self-configuring Older devices rely on hardware setup programs to configure hardware Really old devices require you to manually configure the adapter through switches or jumpers.

If the network adapter is not Plug-and-Play, after you install it, the ating system should detect that you have a new piece of hardware and start

oper-a Wizoper-ard thoper-at leoper-ads you through the process of looper-ading the oper-adoper-apter’s driver

You take the following steps to install a driver for a network adapter that is not Plug-and-Play:

1. If the Add/Remove Hardware Wizard doesn’t start automatically, select Start  Settings  Control Panel  Add/Remove Hardware

2. The Welcome to the Add/Remove Hardware Wizard dialog box appears, as shown in Figure 11.3 Click the Next button to continue

F I G U R E 1 1 3 The Welcome to Add/Remove Hardware Wizard dialog box

3. The Choose a Hardware Task dialog box appears, as shown in ure 11.4 Select the Add/Troubleshoot a Device radio button and

Fig-504 Chapter 11  Managing Network Connections

F I G U R E 1 1 4 The Choose a Hardware Task dialog box

4. Windows 2000 runs the process to detect new hardware and then displays the Choose a Hardware Device dialog box, as shown in Figure 11.5 Choose the Add a New Device option, which is at the top of the Devices list box Then click the Next button

F I G U R E 1 1 5 The Choose a Hardware Device dialog box

5. The Find New Hardware dialog box appears, as shown in Figure 11.6 Select the Yes, Search for New Hardware option to let Windows 2000 attempt to detect your hardware If the operating system detects the new network adapter, click Next and then skip to step 9 If Windows 2000 cannot detect your hardware, select the No, I Want to Select the Hard-ware from a List radio button, click the Next button and continue with step 6.

F I G U R E 1 1 6 The Find New Hardware dialog box

6. The Hardware Type dialog box appears, as shown in Figure 11.7 In the Hardware Type list box, select Network Adapters Then click the Next button

7. The Select Network Adapter dialog box appears, as shown in ure 11.8 If your manufacturer and network adapter model are listed in this dialog box, select them If your manufacturer and model do not appear, click the Have Disk button and specify the location of the driver’s distribution files

Fig-F I G U R E 1 1 7 The Hardware Type dialog box

F I G U R E 1 1 8 The Select Network Adapter dialog box

8. In the case that Windows 2000 cannot detect the settings of the device, you will see a warning message At this point, you will need to refer to the manufacturer’s documentation on how to set up the network card After you configure your device, click the OK button

9. The Start Hardware Installation dialog box appears, as shown in ure 11.9 If the driver shown in this dialog box is correct, click the Next button.

Fig-F I G U R E 1 1 9 The Start Hardware Installation dialog box

10. The Completing the Add/Remove Hardware Wizard dialog box appears, as shown in Figure 11.10 Click the Finish button

F I G U R E 1 1 1 0 The Completing the Add/Remove Hardware Wizard dialog box

Configuring a Network Adapter

Once the network adapter has been installed, you can configure your network adapter through its Properties dialog box To access this dialog box, select Start  Settings  Control Panel  Network and Dial-up Connections  Local Area Connection  Properties and click the Configure button Alterna-tively, right-click My Network Places and choose Properties, then right-click Local Area Connection, choose Properties, and click the Configure button

In the network adapter Properties dialog box, the properties are grouped

on four tabs: General, Advanced, Driver, and Resources The properties on these tabs are covered in the following sections

General Network Adapter Properties

The General tab of the network adapter Properties dialog box, shown in ure 11.11, shows the name of the adapter, the device type, the manufacturer, and the location The Device Status box reports whether or not the device is working properly If the device is not working properly, you can click the Troubleshooter button to have Windows 2000 display some general trouble-shooting tips You can also enable or disable the device through the Device Usage drop-down list options

Fig-F I G U R E 1 1 1 1 The General tab of the network adapter Properties dialog box

Advanced Network Adapter Properties

The contents of the Advanced tab of the network adapter Properties dialog box vary depending on the network adapter and driver that you are using Figure 11.12 shows an example of the Advanced tab for a Fast Ethernet adapter To configure options in this dialog box, choose the property you want to modify in the Property list box on the left and specify the value for the property in the Value box on the right

F I G U R E 1 1 1 2 The Advanced tab of the network adapter Properties dialog box

You should not need to change the settings on the Advanced tab of the work adapter Properties dialog box unless you have been instructed to do so

net-by the manufacturer.

 The date that the driver was released

 The driver version, which is useful in determining if you have the latest driver installed

 The digital signer, which is the company that provides the digital nature for driver signing (driver signing is covered in Chapter 4, “Con-figuring the Windows 2000 Environment”)

sig-F I G U R E 1 1 1 3 The Driver tab of the network adapter Properties dialog box

Clicking the Driver Details button at the bottom of the Driver tab brings

up the Driver File Details dialog box, as shown in Figure 11.14 This dialog box lists the following details about the driver:

 The location of the driver file, which is useful for troubleshooting

 The original provider of the driver, which is usually the manufacturer

 The file version, which is useful for troubleshooting

 Copyright information about the driver

F I G U R E 1 1 1 4 The Driver File Details dialog box

The Uninstall button at the bottom of the Driver tab removes the driver from your computer You would uninstall the driver if you were going to replace the driver with a completely new driver Normally, you update the driver rather than uninstalling it

To update a driver, click the Update Driver button at the bottom of the Driver tab This starts the Upgrade Device Driver Wizard, which steps you through upgrading the driver for an existing device

If you cannot find the driver for your network card or the configuration tions, check the vendor’s Web site Usually, you will be able to find the latest drivers You also should be able to locate a list of Frequently Asked Questions (FAQs) about your hardware.

instruc-Resource Properties

Each device installed on a computer uses computer resources Resources include interrupt request (IRQ), memory, and I/O (input/output) settings The Resources tab of the network adapter Properties dialog box lists the resource settings for your network adapter, as shown in Figure 11.15 This information is important for troubleshooting, because if other devices are trying to use the same resource settings, your devices will not work properly The Conflicting Device List box at the bottom of the Resources tab shows if any conflicts exist

F I G U R E 1 1 1 5 The Resources tab of the network adapter Properties dialog box

In Exercise 11.1, you will view the properties of your network adapter This exercise assumes that you have a network adapter installed in your computer.

Troubleshooting Network Adapters

If your network adapter is not working, the problem may be with the ware, the driver software, or the network protocols The following are some common causes for network adapter problems:

hard-E X hard-E R C I S hard-E 1 1 1

Viewing Network Adapter Properties

1. Select Start  Settings  Control Panel  Network and Dial-up nections  Local Area Connection  Properties and click the Config- ure button.

Con-2. In the General tab of the connection Properties dialog box, click the Configure button under Connect Using.

3. In the General tab of the network adapter Properties dialog box, verify that the Device Status box shows “This device is working properly.”

4. Click the Advanced tab Note the properties that are available for your driver.

5. Click the Driver tab Note the driver date and version tion Click the Driver Details button to see the location of your net- work adapter’s driver file Click OK to close the Driver File Details dia- log box.

informa-6. Click the Resources tab Note the resources that are being used by your network adapter Verify that the Conflicting Device List box shows “No conflicts.”

Network adapter not on the HCL

If the device is not on the HCL, you should contact the adapter vendor for advice

Check Event Viewer to see if there are any messages that give you a hint about what is causing a network adapter error See Chapter 15 “Performing System Recovery Functions,” for details on using Event Viewer.

Installing and Configuring Network Protocols

Network protocols function at the Network and Transport layers of the OSI model They are responsible for transporting data across an inter-network You can mix and match the network protocols you use with Win-dows 2000 Professional, which supports three protocols: TCP/IP, NWLink IPX/SPX/NetBIOS, and NetBEUI The following sections describe how to install and configure these protocols

Network adapter not recognized by Windows 2000

Check Device Manager to see if Windows 2000 recognizes your device If you do not see your adapter, you will need to manually install it (see the “Installing

a Network Adapter” section earlier in the chapter) You should also verify that the adapter’s resource settings do not conflict with the resource settings of other devices (check the Resources tab of the network adapter Properties dialog box)

Hardware that

is not working properly

Verify that your hardware is working properly Run any diagnostics that came with the adapter If everything seems to work properly, make sure that the cable is good and that all of the applicable network hardware is installed properly and is working This is where it pays off to have spare hardware (such as cables and extra network adapters) that you know works properly

Improperly configured network protocols

Make sure that your network protocols have been configured properly Network protocols are covered

in detail in the next section of this chapter

Using TCP/IP

TCP/IP (Transmission Control Protocol/Internet Protocol) is one of the

most commonly used network protocols TCP/IP was originally developed in the 1970s for the Department of Defense (DoD) as a way of connecting dis-similar networks Since then, TCP/IP has become an industry standard

On a clean installation of Windows 2000 Professional, TCP/IP is installed

by default TCP/IP has the following benefits:

 It is the most commonly used protocol and is supported by almost all network operating systems It is the required protocol for Internet access

 TCP/IP is scalable for use in small and large networks In large works, TCP/IP provides routing services

net- TCP/IP is designed to be fault tolerant and is able to dynamically reroute packets if network links become unavailable (assuming alter-nate paths exist)

 Protocol companions like DHCP (Dynamic Host Configuration tocol) and DNS (Domain Name System) offer advanced functionality

Pro-In the next sections, you will learn the basics of using TCP/IP, and then how to configure and test TCP/IP

Reviewing TCP/IP Basics

TCP/IP requires an IP address and a subnet mask You can also configure many other optional parameters, including the default gateway, DNS server settings, and WINS server settings

IP Address

The IP address uniquely identifies your computer on the network The

IP address is a four-field, 32-bit address, separated by periods Part of the address is used to identify your network address, and part of the address is used to identify the host (or local) computer’s address

If you use the Internet, then you should register your IP addresses with one of the Internet registration sites There are three main classes of IP addresses Depending on the class you use, different parts of the address show the network portion of the address and the host address, as illustrated in Figure 11.16

F I G U R E 1 1 1 6 IP class network and host addresses

You can find more information about Internet registration at InterNIC’s Web site, www.internic.net.

Table 11.2 shows the three classes of network addresses and the number

of networks and hosts that are available for each network class

Subnet Mask

The subnet mask is used to specify which part of the IP address is the

net-work address and which part of the address is the host address By default, the following subnet masks are applied:

By using 255, you are selecting the octet or octets (or in some cases, a piece

of an octet) used to identify the network address For example, in the class B network address 191.200.2.1, if the subnet mask is 255.255.0.0, then 191.200 is the network address and 2.1 is the host address

Default Gateway

You configure a default gateway if the network contains routers A router is

a device that connects two or more network segments together Routers function at the Network layer of the OSI model

You can configure a Windows 2000 server to act as a router by installing two

or more network cards in the server, attaching each network card to a different network segment, and then configuring each network card for the segment that

it will attach to You can also use third-party routers, which typically offer more

T A B L E 1 1 2 IP Class Assignments

Network Class

Address Range

of First Field

Number of works Available

Net-Number of Host Nodes Supported

B 128-191 16,384 65,534

C 192-223 2,097,152 254

Class A 255.0.0.0Class B 255.255.0.0Class C 255.255.255.0

router should be configured with an IP address from the segment that the network card is addressed to.

You configure the computers on each segment to point to the IP address

of the network card on the router that is attached to their network segment For example, in Figure 11.17, the computer W2K1 is attached to Network A The default gateway that would be configured for this computer is

131.1.0.10 The computer W2K2 is attached to Network B The default gateway that would be configured for this computer is 131.2.0.10

F I G U R E 1 1 1 7 Configuring default gateways

DNS Servers

DNS servers are used to resolve host names to IP addresses This makes it

easier for people to access domain hosts

Do you know what the IP address is for the White House? It’s 198.137.240.91 Do you know the domain host name of the White House? It’s www.whitehouse.gov You can understand why many people might not know the IP address but would know the domain host name

When you access the Internet and type in www.whitehouse.gov, there are DNS servers that resolve the host name to the proper IP address If you did not have access to a properly configured DNS server, you could configure a HOSTS file for your computer that contains the mappings of IP addresses to the domain hosts that you need to access

WINS Servers

WINS servers are used to resolve NetBIOS names to IP addresses

Win-dows 2000 uses NetBIOS names in addition to host names to identify work computers This is mainly for backward compatibility with

net-Network A: 131.1.0.0

IP: 131.1.0.101 Subnet: 255.255.0.0 Default gateway: 131.1.0.10

IP: 131.2.0.101 Subnet: 255.255.0.0 Default gateway: 131.2.0.10

Network B: 131.2.0.0

W2K2

Windows NT 4, which used this addressing scheme extensively When you attempt to access a computer using the NetBIOS name, the NetBIOS name must be able to be resolved to an IP address This address resolution can be accomplished by using one of the following methods:

 Through a broadcast (if the computer you are trying to reach is on the same network segment)

 Through a WINS server

 Through an LMHOSTS file, which is a static mapping of IP addresses to NetBIOS computer names

Configuring TCP/IP

Depending on your network setup, TCP/IP configuration is done either ually or dynamically You can also use advanced TCP/IP options to config-ure DNS and WINS settings

man-Manual IP Configuration

You can manually configure IP if you know your IP address and subnet mask If you are using optional components such as a default gateway or a DNS server, you need to know the IP addresses of the computers that host these services as well

To manually configure IP, take the following steps:

1. From the Desktop, right-click My Network Places and choose

Properties

2. Right-click Local Area Connection and choose Properties

3. In the Local Area Connection Properties dialog box, highlight Internet Protocol (TCP/IP) and click the Properties button

4. The Internet Protocol (TCP/IP) Properties dialog box appears, as shown in Figure 11.18 Choose the Use the Following IP Address radio button

5. In the appropriate text boxes, specify the IP address, subnet mask, and default gateway (optional) that you want to use