Giáo trình CCNA - Chương 1

CCNA – Semester1 Module 1 Introduction to Networking Objectives • Network physical connection • Basic computer components • Network math and IP address concept Connecting to the Internet Requirements for Internet Connection • Connection to the Internet can be broken down into the following: – Physical connection: used to transfer signals between PCs within the local network and to remote devices on the Internet – Logical connection: uses standards called protocols. A protocol is a formal description of a set of rules and conventions that govern how devices on a network communicate. – The application: interprets the data and displays the information in an understandable form Information flow Case Study: Boot process BIOS OS SHELL User Interface ROM RAM HDD RAM RAM IO Network Interface Cards • When you select a network card, consider the following three factors: – Type of network – Type of media – Type of system bus • A network interface card (NIC) is a printed circuit board that provides network communication capabilities to and from a personal computer Modem • A modem, or modulator- demodulator, is a device that provides the computer with connectivity to a telephone line. • The modem converts (modulates) the data from a digital signal to an analog signal that is compatible with a standard phone line. NIC and Modem Installation • Connectivity to the Internet requires an adapter card, which may be a modem or NIC. • Notebook computers may have a built-in interface or use a PCMCIA card. Desktop systems may use an internal or external NIC. High-Speed and Dialup Connectivity • By the 1990s modems were running at 9600 bps and reached the current standard of 56 kbps (56,000 bps) by 1998. • High-speed services used in the corporate environment, such as Digital Subscriber Line (DSL) and cable modem access, moved to the consumer market. • These services no longer required expensive equipment or a second phone line. These are "always on" services that provide instant access and do not require a connection to be established for each session. TCP/IP Description and Configuration • Transmission Control Protocol/Internet Protocol (TCP/IP) is a set of protocols or rules developed to allow cooperating computers to share resources across a network. • To enable TCP/IP on the workstation, it must be configured using the operating system tools. Testing Connectivity with Ping • Ping is a program that is useful for verifying a successful TCP/IP installation. • It works by sending multiple packets to a specified destination requesting for replies. Ping Command • ping 127.0.0.1 - This ping is unique and is called an internal loopback test. It verifies the operation of the TCP/IP stack and NIC transmit/receive function. • ping IP address - A ping to a host PC verifies the TCP/IP address configuration for the local host and connectivity to the host. Web Browser and Plug-Ins • Web browsers acts on behalf of a user by – Contacting a web server – Requesting information – Receiving information – Displaying the results on a screen • Plug-ins is to view special, or proprietary, file types that standard web browsers are not able to display – Flash/Shockwave, QuickTime, Real Audio Network math and IP address Binary presentation of data • Computers operate with electronic switches that are either "on" or "off", corresponding to 1 or 0. • Computers have to translate in order to use decimal numbering. Number Systems • Knowing what base someone refers to – Decimal uses 10 digits: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9. – Binary uses 2 digits: 0 and 1. • Base conventions – 101 in base 2 is spoken as one zero one. • Working with exponents –10 3 = 10 X 10 X 10 = 1000 –2 4 = 2 x 2 x 2 x 2 = 16 • Binary numbers – Use principle of place value just as decimal numbers do ASCII • The American Standard Code for Information Interchange (ASCII) is the most commonly used code for representing alpha-numeric data in a computer. 1000011 1001001 1010000 1010100 ? Bits and Bytes • Bits are binary digits. They are either 0s or 1s. In a computer, they are represented by On/Off switches or the presence or absence of electrical charges, light pulses, or radio waves. Base 10 Numbers Example [...]... 11 111 111 .11 110 000.00000000.00000000 000 010 10.0 010 0000.00000000.00000000 10 .34.23 .13 4 (IP address) 255.240.0.0 (subnetmask) 10 .32.0.0 (subnetwork address) Address Example • IP address • Subnetmask • IP address: 10 .34.23 .13 4 255.0.0.0 000 010 10.0 010 0 010 .00 010 111 .10 00 011 0 = 10 .34.23 .13 4 • Network address: 000 010 10.00000000.00000000.00000000 = 10 .0.0.0 • Broadcast address: 000 010 10 .11 111 111 11 111 111 11 111 111 =10 .255.255.255... 1s until the network address is identified and then be all 0s from there to the right most bit of the mask SubnetMask Example • Converting the IP address 10 .34.23 .13 4 to binary would result in: 000 010 10.0 010 0 010 .00 010 111 .10 00 011 0 • Performing a Boolean AND of the IP address 10 .34.23 .13 4 and the subnet mask 255.240.0.0 produces the network address of this host: 000 010 10.0 010 0 010 .00 010 111 .10 00 011 0 11 111 111 .11 110 000.00000000.00000000... Binary 27 12 8 26 64 25 32 24 16 23 8 22 4 21 2 20 1 1 1 0 0 1 1 0 1 Hexadecimal • The base 16 , or hexadecimal (hex), number system is used frequently when working with computers, because it can be used to represent binary numbers in a more readable form Converting Binary to Hexadecimal • Remember that hexadecimal is sometimes abbreviated 0x so hex 5D might be written as "0x5D" Four-Octet Dotted-decimal... Transfer Mode (ATM) T (US) and E (Europe) carrier series: T1, E1, T3, E3 Synchronous Optical Network (SONET) 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 Storage-Area Networks (SANs) • A SAN is a dedicated, high-performance network used to move data between servers... address: 10 .34.23 .13 4 255.0.0.0 000 010 10.0 010 0 010 .00 010 111 .10 00 011 0 = 10 .34.23 .13 4 • Network address: 000 010 10.00000000.00000000.00000000 = 10 .0.0.0 • Broadcast address: 000 010 10 .11 111 111 11 111 111 11 111 111 =10 .255.255.255 View computer address • ipconfig : brief IP configuration • ipconfig /all : detail IP configuration • ipconfig /renew : renew IP address with DHCP • Practise IP and subnetmask Summary... terminates sessions between two communicating hosts – – – – Sessions Dialog Conversations Data exchange 7 layers of the OSI reference model End-to-end connections • Provides reliable, transparent transfer of data over networks – – – – – Segments, data stream, datagram End-to-end flow control Error detection and recovery Segmentation & reassembly … ... within a limited geographic area • Allow many users to access high-bandwidth media • Provide full-time connectivity to local services • Connect physically adjacent devices LAN Devices and Technology • Some common LAN technologies are: – Ethernet – Token Ring – FDDI WANs • Operate over a large geographically separated areas • Provide full-time remote resources connected to local services WAN Technologies... assigned to computers on the Internet are 32-bit binary numbers • The 32-bit binary addresses used on the Internet are referred to as Internet Protocol (IP) addresses IP Addresses and Network Masks • The IP address of a computer usually consists of a network, and a host part that represents a particular computer on a particular network • Subnetwork mask a second 32-bit number to identify how many of the... Topology: Broadcast • Each host sends its data to all other hosts on the network medium • First-come, first-serve • Eg: Ethernet Logical Topology: Token Passing • Access to media is controlled by an electronic token • Possession of the token gives the host the right to pass data to its destination • Eg: Token-Ring, FDDI Network Protocols • Protocol suites are collections of protocols that enable network... technology compatibility • Accelerates evolution • Simplifies teaching and learning 7 layers of the OSI reference model Network processes to applications Data representation Interhost communication End-to-end connections Address and best path Direct link control, access to media a Binary transmission •All People Seem To Need Data Processing 7 layers of the OSI reference model Network processes to applications . CCNA – Semester1 Module 1 Introduction to Networking Objectives • Network physical connection • Basic