Chapter 7 Networking Concepts PDF

Chapter 7: Networking Concepts Chapter7: Networking Concepts 7.0: Introduction 7.0.1: Welcome 7.0.1.1: Networking Concepts This chapter provides an overview of network principles, standards, and purposes. To meet the expectations and needs of your customers and network users, you must be familiar...

Chapter 7: Networking Concepts Chapter7: Networking Concepts 7.0: Introduction 7.0.1: Welcome 7.0.1.1: Networking Concepts This chapter provides an overview of network principles, standards, and purposes. To meet the expectations and needs of your customers and network users, you must be familiar with networking concepts. You will learn the basics of network design and how some components affect the flow of data on a network. This knowledge will help you successfully design, implement, and troubleshoot networks. 7.1.1.1: Network Definition Networks are systems that are formed by links. For example, roads that connect groups of people together create a physical network. Connections with your friends create your personal network. Websites that allow individuals to link to each other’s pages are called social networking sites. People use the following networks every day:  Mail delivery system  Telephone system  Public transportation system  Corporate computer network  The Internet The public transportation system shown in the figure is similar to a computer network. The cars, trucks, and other vehicles are like the messages that travel within the network. Each driver defines a starting point (source computer) and P a g e | 48 Chapter7: Networking Concepts an ending point (destination computer). Within this system there are rules, similar to stop signs and traffic lights, which control the flow from the source to the destination. 7.1.1.2: Host Devices Computer networks consist of a variety of devices. Some devices can serve either as hosts or peripherals. A host is any device that sends and receives information on the network. A printer connected to your laptop is a peripheral. If the printer is connected directly to a network, it is acting as a host. Many different types of host devices can connect to a network. Some of the more common ones are shown in Figure 1. Note: An Internet Protocol phone, which is known as an IP phone, connects to a computer network instead of the traditional telephone network. Computer networks are used in businesses, homes, schools, and government agencies. Many networks are connected to each other through the Internet. A network can share many different types of resources, as shown in Figure 2. P a g e | 49 Chapter7: Networking Concepts 7.1.1.3: Intermediary Devices Computer networks contain many devices that exist in between the host devices. These intermediary devices ensure that data flows from one host device to another host device. The most common intermediary devices are shown in the figure. A switch is used to connect multiple devices to the network. A router is used to forward traffic between networks. A wireless router connects multiple wireless devices to the network. In addition, a wireless router often includes a switch so that multiple wired devices can connect to the network. An access point (AP) provides wireless connectivity, but has fewer features than a wireless router. A modem is used to connect a home or small office to the Internet. 7.1.1.4: Network Media Communication across a network is carried on a medium. The medium provides the channel over which the message travels from source to destination. The plural for medium is media. Network devices are linked together using a variety of media, these media are:  Copper cabling - Uses electrical signals to transmit data between devices  Fiber-optic cabling - Uses glass or plastic fiber to carry information as light pulses P a g e | 50 Chapter7: Networking Concepts  Wireless connection - Uses radio signals, infrared technology, or satellite transmissions The icons shown in Figure 2 are used throughout this course to represent the different types of network media. Local area network (LANs), wide area networks (WANs), and wireless networks are discussed in the next topic. The Cloud will be used throughout this course to represent connections to the Internet. The Internet is often the medium for communications between one network and another network. 7.1.1.5: Activity - Identify Network Devices & Media Representations P a g e | 51 Chapter7: Networking Concepts 7.1.2: Types of Networks 7.1.2.1: LANs A computer network is identified by the following specific characteristics:  Size of the area covered  Number of users connected  Number and types of services available  Area of responsibility Traditionally, a LAN is defined as a network that encompasses a small geographical area. However, the distinguishing characteristic for LANs today is that they are typically owned by an individual, such as in a home or small business, or wholly managed by an IT department, such as in a school or corporation. This individual or group enforces the security and access control policies of the network. P a g e | 52 Chapter7: Networking Concepts 7.1.2.2: WLANs A Wireless LAN (WLAN) is a LAN that uses radio waves to transmit data between wireless devices. In a traditional LAN, devices are connected together using copper cabling. In some environments, installing copper cabling might not be practical, desirable, or even possible. In these situations, wireless devices are used to transmit and receive data using radio waves. As with LANs, on a WLAN, you can share resources, such as files, printers, and Internet access. WLANs can operate in two modes. In infrastructure mode, wireless clients connect to a wireless router or access point (AP). The AP in Figure 1 is connected to a switch, which provides access to the rest of the network and to the Internet. Access points are typically connected to the network using copper cabling. Instead of providing copper cabling to every network host, only the wireless access point is connected to the network with copper cabling. The range (radius of coverage) for typical WLAN systems varies from under 98.4 ft. (30 m) indoors to much greater distances outdoors, depending on the technology used. Ad hoc means the WLAN is created when it is needed. Ad hoc is usually temporary. Figure 2 shows an example ad hoc mode. The laptop is wirelessly connected to the smartphone, which has access to the Internet through cellular service provider. P a g e | 53 Chapter7: Networking Concepts 7.1.2.3: PANs A personal area network (PAN) is a network that connects devices, such as mice, keyboards, printers, smartphone, and tablets within the range of an individual person. All of these devices are dedicated to a single host and are most often connected with Bluetooth technology. Bluetooth is a wireless technology that enables devices to communicate over short distances. A Bluetooth device can connect up to seven other Bluetooth devices. Described in the IEEE standard 802.15.1, Bluetooth devices are capable of handling voice and data. Bluetooth devices operate in the 2.4 to 2.485 GHz radio frequency range, which is in the Industrial, Scientific, and Medical (ISM) band. The Bluetooth standard incorporates Adaptive Frequency Hopping (AFH). AFH allows signals to "hop" around using different frequencies within the Bluetooth range, thereby reducing the chance of interference when multiple Bluetooth devices are present P a g e | 54 Chapter7: Networking Concepts 7.1.2.4: MANs A metropolitan area network (MAN) is a network that spans across a large campus or a city. The network consists of various buildings interconnected through wireless or fiber optic backbones. The communication links and equipment are typically owned by a consortium of users, or by a network service provider who sells the service to the users. A MAN can act as a high-speed network to enable sharing of regional resources 7.1.2.5: WANs A WAN connects multiple networks that are in geographically separated locations. The distinguishing characteristic of a WAN is that it is owned by a service provider. Individuals and organizations contract for WAN services. The most common example of a WAN is the Internet. The Internet is a large WAN that is composed of millions of interconnected networks. In the figure, the Tokyo and Moscow networks are connected through the Internet. P a g e | 55 Chapter7: Networking Concepts 7.1.2.8: Activity – Matching Network Types 7.4: Basic Networking Concepts and Technologies 7.4.1: Networked Equipment Addressing 7.4.1.1: Network Addressing The fingerprint and addressed letters in Figure 1 are two ways of identifying a person. A person's fingerprints usually do not change. They provide a way to physically identify people. The mailing address of a person can change, as it relates to where the person lives or picks up mail. A fingerprint is like a MAC addr5ess A mailing address is like an IP address P a g e | 56 Chapter7: Networking Concepts Devices that are attached to a network have two addresses that are similar to a person’s fingerprints and a person’s mailing address. These two types of addresses are the Media Access Control (MAC) address and the IP address. The MAC address is hard coded onto the network interface card (NIC) by the manufacturer. The address stays with the device regardless of what network the device is connected. A MAC address is 48 bits and can be represented in one of the three hexadecimal formats shown in Figure below. 7.4.1.2: IP Addresses Today, it is common for a computer to have two versions of IP addresses. In the early 1990s there was a concern about running out of IPv4 network addresses. The Internet Engineering Task Force (IETF) began to look for a replacement. This led to the development of what is now known as IP version 6 (IPv6). Currently IPv6 is operating alongside and is beginning to replace IPv4. An IPv4 address is 32 bits long and is represented in dotted decimal. An IPv6 address is 128 bits long and is represented in hexadecimal. Figure 1 shows examples of IPv4 and IPv6 addresses. IP addressing is assigned by network administrators based on the location within the network. When a device moves from one network to another, its IP address will most likely change. Figure 2 shows a topology with two LANs. This topology demonstrates that MAC addresses do not change when a device is moved. But IP addresses do change. Laptop was moved to LAN 2. Notice that Laptop’s MAC address did not change, but its IP addresses did change. P a g e | 57 Chapter7: Networking Concepts 7.5: Summary Many different devices can connect to today's networks including computers, laptops, tablets, smartphones, TVs, watches, and home appliances. These devices use a variety of media to connect to the network including copper, fiber, and wireless. Intermediary devices, such as switches and routers, ensure that data flows between source and destination. The type of networks these devices connect to include LANs, WLANs, PANs, MANs, and WANs. Devices must agree on a set of rules before they can effectively communicate with each other. These rules are called standards and protocols. The OSI reference model and the TCP/IP protocol suite help network administrators and technicians understand the interaction of these various standards and protocols. Ethernet standards come in wired and wireless varieties. The wired standard is IEEE 802.3 and the wireless standard is IEEE 802.11. Data requires several different types of addresses and numbering to make sure it is received by the correct destination. MAC addresses are used by switches to forward traffic within a LAN. IP addresses are used by routers to determine the best path to a destination network. Port numbers are used by computers to determine which application should receive the data. P a g e | 58