Tài liệu Managing Network Connections pptx

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. Copyright © 2000 SYBEX Inc., Alameda, CA. www.sybex.com F or 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 C ommunications 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. Copyright © 2000 SYBEX Inc., Alameda, CA. www.sybex.com Reviewing Networking Protocols 497  Modularizing network functions allows you to apply specific technol- ogies or protocols at specific layers in a mix-and-match manner.  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 net- work. Then we’ll examine how the seven layers of the OSI model work to move data through a network. 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. FIGURE 11.1 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 that appropriate responses can be made. Just like human conversa- tions, computer communications are usually a series of requests and responses that must be answered sequentially. Computer A Send “Hello” Computer B Receive “Hello” Router Router Copyright © 2000 SYBEX Inc., Alameda, CA. www.sybex.com 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 seg- ments, you must figure out how to route the message across an inter- network based on the best possible path available. 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. TABLE 11.1 Mnemonics for the OSI Model Layers Layer Memory Trick Top to Bottom Memory Trick Bottom to Top Application All Albert Presentation People Prince Session Seem See Copyright © 2000 SYBEX Inc., Alameda, CA. www.sybex.com 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: Transport To To Network Need Need Data Link Data Don’t Physical Processing People File services Used to store, move, control access to, and retrieve files Print services Used to send data to local or network printers Message services Used to transfer text, graphics, audio, and video over a network Application 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, which is the ASCII code equivalent Data encryption The process of coding data so that it is protected from unauthorized access TABLE 11.1 Mnemonics for the OSI Model Layers (continued) Layer Memory Trick Top to Bottom Memory Trick Bottom to Top Copyright © 2000 SYBEX Inc., Alameda, CA. www.sybex.com 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:  Establishing connections  Maintaining connections  Synchronizing communications  Controlling dialogues  Terminating connections When you create a connection, you authenticate the user account at the sending and receiving computers. Connection creation also involves deter- mining the type of communication that will take place and the protocols that will be used by the lower layers. Data transfer and dialogue control are used to determine which computer is making requests and which computer is making responses. This also deter- mines if acknowledgments are required for data transmission. 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 transport Data expansion The process of restoring compressed data to its original format at the receiver’s end Copyright © 2000 SYBEX Inc., Alameda, CA. www.sybex.com Reviewing Networking Protocols 501 The Network Layer The primary responsibility of the Network layer is to move data over an inter- 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. The Data Link Layer The Data Link layer is responsible for establishing and maintaining the com- 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. 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 Copyright © 2000 SYBEX Inc., Alameda, CA. www.sybex.com 502 Chapter 11  Managing Network Connections Installing and Configuring Network Adapters N etwork 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. FIGURE 11.2 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 net- work adapters, as well as how to troubleshoot network adapters that are not working. 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.  Microsoft Exam Objective Install, configure, and troubleshoot network adapters. Data Link Physical MAC Sublayer LLC Sublayer Network Adapters Copyright © 2000 SYBEX Inc., Alameda, CA. www.sybex.com 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 oper- ating system should detect that you have a new piece of hardware and start a Wizard that leads you through the process of loading the adapter’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. FIGURE 11.3 The Welcome to Add/Remove Hardware Wizard dialog box 3. The Choose a Hardware Task dialog box appears, as shown in Fig- ure 11.4. Select the Add/Troubleshoot a Device radio button and click the Next button. Copyright © 2000 SYBEX Inc., Alameda, CA. www.sybex.com 504 Chapter 11  Managing Network Connections FIGURE 11.4 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. FIGURE 11.5 The Choose a Hardware Device dialog box Copyright © 2000 SYBEX Inc., Alameda, CA. www.sybex.com [...]... www.sybex.com 508 Chapter 11 Managing Network Connections 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 Alternatively, right-click My Network Places and... address 131.1.0.0 Network B uses the IP network address 131.2.0.0 In this case, each network card in the Copyright © 2000 SYBEX Inc., Alameda, CA www.sybex.com 518 Chapter 11 Managing Network Connections 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... 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 features than Windows 2000 servers configured as routers As an example, suppose that your network is configured as shown in Figure 11.17 Network A uses the IP network. .. network adapter Properties dialog box Copyright © 2000 SYBEX Inc., Alameda, CA www.sybex.com Installing and Configuring Network Adapters 513 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 EXERCISE 11.1 Viewing Network Adapter Properties 1 Select Start Settings Control Panel Network and Dial-up Connections. .. address show the network portion of the address and the host address, as illustrated in Figure 11.16 FIGURE 11.16 IP class network and host addresses Class A Network Host Class B Network Host Class C Network Host You can find more information about Internet registration at InterNIC’s Web site, www.internic.net Copyright © 2000 SYBEX Inc., Alameda, CA www.sybex.com Installing and Configuring Network Protocols... classes of network addresses and the number of networks and hosts that are available for each network class TABLE 11.2 IP Class Assignments Network Class Address Range of First Field Number of Networks Available Number of Host Nodes Supported A 1-126 126 16,777,214 B 128-191 16,384 65,534 C 192-223 2,097,152 254 Subnet Mask The subnet mask is used to specify which part of the IP address is the network. .. 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... 11.12 The Advanced tab of the network adapter Properties dialog box You should not need to change the settings on the Advanced tab of the network adapter Properties dialog box unless you have been instructed to do so by the manufacturer Copyright © 2000 SYBEX Inc., Alameda, CA www.sybex.com 510 Chapter 11 Managing Network Connections Driver Properties The Driver tab of the network adapter Properties dialog... Note the resources that are being used by your network adapter Verify that the Conflicting Device List box shows “No conflicts.” Troubleshooting Network Adapters If your network adapter is not working, the problem may be with the hardware, the driver software, or the network protocols The following are some common causes for network adapter problems: Network adapter not on the HCL If the device is... Usage drop-down list options FIGURE 11.11 The General tab of the network adapter Properties dialog box Copyright © 2000 SYBEX Inc., Alameda, CA www.sybex.com Installing and Configuring Network Adapters 509 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 . Chapter 11  Managing Network Connections Configuring a Network Adapter Once the network adapter has been installed, you can configure your network adapter. network adapter installed on your computer. Managing network connections also involves configuring your network protocols. The three protocols supported