Tài liệu học CCNA kỳ 1 mod2 netfundamentals

1 Module 2 – Networking Fundamentals NIIT-ICT Hanoi info@niithanoi.vn 2 Overview Students completing this module should be able to: • Explain the importance of bandwidth in networking. • Use an analogy from their experience to explain bandwidth. • Identify bps, kbps, Mbps, and Gbps as units of bandwidth. • Explain the difference between bandwidth and throughput. • Calculate data transfer rates. • Explain why layered models are used to describe data communication. • Explain the development of the Open System Interconnection model (OSI). • List the advantages of a layered approach. • Identify each of the seven layers of the OSI model. • Identify the four layers of the TCP/IP model. • Describe the similarities and differences between the two models. • Briefly outline the history of networking. • Identify devices used in networking. • Understand the role of protocols in networking. • Define LAN, WAN, MAN, and SAN. • Explain VPNs and their advantages. • Describe the differences between intranets and extranets 2 NIIT-ICT Hanoi info@niithanoi.vn 3 Data networks • Evolution of networking – Duplication of Equipment Resources – Low communication efficiency – Difficult to setup and manage network • One early solution was the creation of local-area network (LAN) standards. Because LAN standards provided an open set of guidelines for creating network hardware and software, the equipment from different companies could then become compatible. NIIT-ICT Hanoi info@niithanoi.vn 4 Data networks • As the use of computers in businesses grew, it soon became obvious that even LANs were not sufficient. • What was needed was a way for information to move efficiently and quickly, not only within a company, but also from one business to another. • The solution was the creation of metropolitan-area networks (MANs) and wide-area networks (WANs). 3 NIIT-ICT Hanoi info@niithanoi.vn 5 Network History • 1970’s: Small computer came into existence • 1983: TCP/IP become the universal language • 1984: Cisco founded; up to 1000 Internet host • 1996: Number of Internet host exceeds 10 mill • 1998: Network Academy launched. • 1999: Video, Voice and Data convergence • 2001: Number of Internet host exceeds 110 mill NIIT-ICT Hanoi info@niithanoi.vn 6 Networking devices 4 NIIT-ICT Hanoi info@niithanoi.vn 7 NIIT-ICT Hanoi info@niithanoi.vn 8 Networking devices 5 NIIT-ICT Hanoi info@niithanoi.vn 9 Network topology • Network topology defines the structure of the network. • Physical topology, which is the actual layout of the wire or media. • Logical topology, which defines how the media is accessed by the hosts for sending data. • The logical topology of a network is how the hosts communicate across the medium. • The two most common types of logical topologies are broadcast and token passing. NIIT-ICT Hanoi info@niithanoi.vn 10 Bus Topology “A bus topology uses a single backbone segment (length of cable) that all the hosts connect to directly.” 6 NIIT-ICT Hanoi info@niithanoi.vn 11 Ring Topology “A ring topology connects one host to the next and the last host to the first. This creates a physical ring of cable.” NIIT-ICT Hanoi info@niithanoi.vn 12 Token Ring • Token Ring NIC and Hub (or MAU) Multistation Access Unit 7 NIIT-ICT Hanoi info@niithanoi.vn 13 Star Topology “A star topology connects all cables to a central point of concentration. This point is usually a hub or switch, which will be described later in the chapter.” NIIT-ICT Hanoi info@niithanoi.vn 14 Extended Star Topology “An extended star topology uses the star topology to be created. It links individual stars together by linking the hubs/switches. This, as you will learn later in the chapter, will extend the length and size of the network.” 8 NIIT-ICT Hanoi info@niithanoi.vn 15 Mesh Topology “A mesh topology is used when there can be absolutely no break in communications, for example the control systems of a nuclear power plant. So as you can see in the graphic, each host has its own connections to all other hosts. This also reflects the design of the Internet, which has multiple paths to any one location.” There are also full mesh and partial mesh topologies, both physical and logical, which will be discussed later in CCNA semester 4. NIIT-ICT Hanoi info@niithanoi.vn 16 Network protocols • Protocol suites are collections of protocols that enable network communication from one host through the network to another host. • A protocol is a formal description of a set of rules and conventions that govern a particular aspect of how devices on a network communicate. Protocols determine the format, timing, sequencing, and error control in data communication. • Without protocols, the computer cannot make or rebuild the stream of incoming bits from another computer into the original format. 9 NIIT-ICT Hanoi info@niithanoi.vn 17 Network protocols Protocols control all aspects of data communication, which include the following: • How the physical network is built • How computers connect to the network • How the data is formatted for transmission • How that data is sent • How to deal with errors Examples • Institute of Electrical and Electronic Engineers (IEEE), • American National Standards Institute (ANSI), • Telecommunications Industry Association (TIA), • Electronic Industries Alliance (EIA) • International Telecommunications Union (ITU), formerly known as the Comité Consultatif International Téléphonique et Télégraphique (CCITT). NIIT-ICT Hanoi info@niithanoi.vn 18 Local-area networks (LANs) Some common LAN technologies are: • Ethernet • Token Ring • FDDI 10 NIIT-ICT Hanoi info@niithanoi.vn 19 Wide-area networks (WANs) Some common WAN technologies are: • Modems • Integrated Services Digital Network (ISDN) • Digital Subscriber Line (DSL) • Frame Relay • US (T) and Europe (E) Carrier Series – T1, E1, T3, E3 • Synchronous Optical Network (SONET) NIIT-ICT Hanoi info@niithanoi.vn 20 Metropolitan-area networks (MANs) • A MAN is a network that spans a metropolitan area such as a city or suburban area. • A MAN usually consists of two or more LANs in a common geographic area. • For example, a bank with multiple branches may utilize a MAN. [...]... Layer 010 010 10 010 010 010 011 1 010 010 0 011 010 00… NIIT-ICT Hanoi info@niithanoi.vn Layer 1: Physical Layer 46 23 Summary NIIT-ICT Hanoi info@niithanoi.vn 47 Web References • • • • • • • • • • • • • • • http://www.webwisdom.com/edu_content/cps640fall00/lectures/module3/WAN/sld004.h tm http://searchnetworking.techtarget.com/sDefinition/0,,sid7_gci 214 083,00.html http://www.gcn.com/ 21_ 16/guide /19 055 -1. html http://www.pcunix.com/Basics/vpn.html... http://english.peopledaily.com.cn/20 010 5 /18 /eng20 010 518 _70356.html http://www.commweb.com/article/COM20020 517 S0004 http://www.teamits.com/internet/support/?/internet/support/datatransferfaq.html http://www.olemiss.edu/courses/EE/ELE_335/Spring2000/Htmlnotes/DigitalvsAnalog/ http://nes.aueb.gr/presentations/p2p.pdf http://www.pku.edu.cn/academic/research/computer-center/tc/html/TC 010 2.html http://www.firewall.cx/osi-encap-decap.php... regardless of the kind of information it is NIIT-ICT Hanoi info@niithanoi.vn 31 Digital and Analog Bandwidth Bandwidth = The width or carrying capacity of a communications circuit Digital bandwidth = the number of bits per second (bps) the circuit can carry • used in digital communications such as T -1 or DDS • measure in bps • T -1 -> 1. 544 Mbps Analog bandwidth = the range of frequencies the circuit can carry... disaster tolerance built in, because data can be mirrored using a SAN up to 10 kilometers (km) or 6.2 miles away • Scalability – Like a LAN/WAN, it can use a variety of technologies This allows easy relocation of backup data, operations, file migration, and data replication between systems NIIT-ICT Hanoi info@niithanoi.vn 21 Virtual private network (VPN) • VPN is a private network that is constructed... frequencies the circuit can carry • used in analog communications such as voice (telephones) • measured in Hertz (Hz), cycles per second • voice-grade telephone lines have a 3 ,10 0 Hz bandwidth NIIT-ICT Hanoi info@niithanoi.vn 32 16 Networking Models • • • • The concept of layers is used to describe communication from one computer to another The OSI and TCP/IP models have layers that explain how data... Interconnection (OSI) reference model released in 19 84 was the descriptive network model that the ISO created It provided vendors with a set of standards that ensured greater compatibility and interoperability among various network technologies produced by companies around the world NIIT-ICT Hanoi info@niithanoi.vn 35 OSI layers NIIT-ICT Hanoi info@niithanoi.vn 36 18 OSI layers • • • • • It breaks network... info@niithanoi.vn 41 TCP/IP model Networking professionals differ in their opinions on which model to use Due to the nature of the industry it is necessary to become familiar with both Both the OSI and TCP/IP models will be referred to throughout the curriculum The focus will be on the following: • TCP as an OSI Layer 4 protocol • IP as an OSI Layer 3 protocol • Ethernet as a Layer 2 and Layer 1 technology... PC and a VPN router in the headquarters A VPN is a service that offers secure, reliable connectivity over a shared public network infrastructure such as the Internet NIIT-ICT Hanoi info@niithanoi.vn 22 11 Benefits of VPNs The following are the three main types of VPNs: • Access VPNs – Access VPNs provide remote access to a mobile worker and small office/home office (SOHO) to the headquarters of the Intranet... passwords, user IDs, and other applicationlevel security NIIT-ICT Hanoi info@niithanoi.vn 24 12 Importance of bandwidth Bandwidth is defined as the amount of information that can flow through a network connection in a given period of time NIIT-ICT Hanoi info@niithanoi.vn 25 Analogies NIIT-ICT Hanoi info@niithanoi.vn 26 13 Measurement • • In digital systems, the basic unit of bandwidth is bits per second (bps)... one layer from affecting other layers It divides network communication into smaller parts to make learning it easier to understand NIIT-ICT Hanoi info@niithanoi.vn 37 NIIT-ICT Hanoi info@niithanoi.vn 38 19 Peer-to-peer communications • In order for data to travel from the source to the destination, each layer of the OSI model at the source must communicate with its peer layer at the destination • This