Copyright 2003 www.ciscopress.com CCNA 1 Chapter 1 Introduction to Networking By Your Name. - презентация

1 Copyright CCNA 1 Chapter 1 Introduction to Networking By Your Name

2 Copyright Objectives The connection to the Internet Networking math

3 Copyright 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

4 Copyright PC Basics Electronic components –Connector, IC, LED, resistor, transistor Personal computer subsystems –Bus, CD-ROM drive, CPU, disk drives, microprocessor, motherboard, RAM, ROM Backplane components –Mouse port, network card, parallel port

5 Copyright All Computers Have a CPU, Memory, Storage, and Interfaces

6 Copyright Network Interface Cards When you select a network card, consider the following three factors: –Type of network –Type of media –Type of system bus Installing a NIC in a PC

7 Copyright 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.

8 Copyright High-Speed and Dialup Connectivity

9 Copyright 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.

10 Copyright Testing Connectivity with Ping Ping is a program that is useful for verifying a successful TCP/IP installation. It works by sending multiple IP packets to a specified destination. Each packet sent is a request for a reply. Each reply contains the success ratio and round- trip time to the destination.

11 Copyright Web Browser and Plug-Ins Web browsers –A web browser acts on behalf of a user by Contacting a web server Requesting information Receiving information Displaying the results on a screen Plug-ins –Flash/Shockwave, QuickTime, Real Audio

12 Copyright 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

13 Copyright Binary Number System

14 Copyright 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.

15 Copyright Base 10 Numbers

16 Copyright Base 10 Calculations The upper table shows the actual math. The lower table is a simplified version that requires the following: –Start the value row and position row with 1 in the rightmost box. –Each subsequent value is current value times the base (10 in this case). –Value to be calculated is entered in the digit row. –Multiply digit amount times value entry above.

17 Copyright Base 2 Table

18 Copyright Base 2 (Binary) Numbers

19 Copyright Base 2 Calculations 8-Bit Values Binary Value: Binary Value: Start the value row and position row with 1 in the rightmost box. Each subsequent value is the current value times the base (2 in this case).

20 Copyright Converting Decimal to Binary Example: 35 = =

21 Copyright Converting Decimal to Binary Start by dividing the decimal by the largest number in the Value row that will go.

22 Copyright Looking At the Table Relationships The table will work with larger numbers, such as this 12-bit example. Sometimes its easier to subtract the 0 values from 255 (largest 8-bit value). - For any number in the value row, the sum of all numbers to the right is the current value minus 1 ( = 63).

23 Copyright Powers of 2 Powers of 2 are used extensively in networking. One solution: 1. Start with 2 (which is 2 1 ). 2. Double the number to get the next value. 3. If you need 2 6, continue until you have 6 values. Look over the example to the right. The second column is included only for reference.

24 Copyright Converting 8-Bit Binary to Decimal Binary numbers are converted to decimal numbers by multiplying the binary digits by the base number of the system, which is base 2, and raised to the exponent of its position.

25 Copyright Four-Octet Dotted-decimal Representation of 32-Bit Binary Numbers Split the binary number into four groups of eight binary digits. Then convert each group of eight bits, also known as an octet into its decimal equivalent.

26 Copyright 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.

27 Copyright Boolean or Binary Logic Boolean logic is based on digital circuitry that accepts one or two incoming voltages. Boolean logic is a binary logic that allows two numbers to be compared and generate a choice based on the two numbers.

28 Copyright IP Addresses and Network Masks When IP addresses are assigned to computers, use a portion of the bits on the left side of the 32-bit IP number to represent a network. The bits left over in the 32- bit IP address identify a particular computer on the network. The IP address of a computer usually consists of a network, and a host part that represents a particular computer on a particular network.