1 Computing Basics Honolulu Community College Cisco Academy Training Center Semester 1 Version 2.1.1

2 Overview n Components of the computer. n Role of the computer in networking. u Internet is like a tree, and computers are like leaves on the tree. u Computers are sources and receivers of information on the Internet. n Computers are an integral part of a network, and they play a vital role in the world of work. u Many business applications like spreadsheets, word processors, browsers, etc.

3 Major Components of a PC n Small, discrete components: u Transistor u Integrated circuit (IC) u Resistor u Capacitor u LED (light emitting diode)

4 Major Components of a PC (cont.) n Personal computer subsystems: u CPU (central processing unit) u Memory: F RAM, ROM F CD-ROM drive F Floppy disk drive u Bus u System unit u Expansion slots u Power supply

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6 Major Components of a PC (cont.) n Backplane components: u Backplane u network card (NIC) or LAN adapter u Video card u Sound card u Parallel ports u Serial ports u Mouse port n For a laptop, cards and slots are referred to as PCMCIA.

7 Information Flow in a Computer n Some important information flow: u Boot instructions (ROM). u Software applications (moved into RAM). u Application information (data) -stored in RAM. u Saved information - from RAM to storage device. u Exported information - from RAM and CPU to external devices. n Almost all data flows in parallel through the bus.

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9 NIC n Provides network communications capabilities. n Also called a LAN adapter. n Communicates serially with network, in parallel with computer. n Requires an IRQ, I/O address, and upper memory addresses (for DOS or Windows). n 3 factors in selecting NIC. u Type of network (Ethernet, Token Ring, or FDDI). u Type of media. u Type of system bus.

10 Installing a NIC n You may need to install a NIC because: u there is none. u NIC is bad or damaged. u Need to upgrade from 10Mbps (standard Ethernet) to 100Mbps (Fast Ethernet). u Need to alter settings on a NIC using a jumper.

11 Configuring Network Settings on PC n Computer software - essentially to get the computer to do what you want. n Procedure: u 1.select the NIC for software configuration. u 2.input the correct TCP/IP address. u 3.adjust the display (if necessary). u 4.install and set up the browser. u 5.perform a few other tasks (if necessary).

12 Web Browser n Software application that interprets html (hypertext markup language). n Two most popular browsers: u Netscape Communicator. u Internet Explorer. n Terms: u Hyperlinks - commands that point to another location in PC or on network. u Plug-ins - special purpose software used to display special or proprietary files in browser.

13 Binary Number System n Computers use binary signals either "on" or "off", corresponding to 1 or 0. n This is a base 2 or binary number system. u Bits - individual 1 or 0. u Byte - group of 8 bits. n In decimal, multipliers for each digit is a power of 10. u 368 = 3x x x10 0 n In binary, multipliers for each bit is a power of 2. u 1101 = 1x x x x2 0 = 13(decimal).

14 Binary to Decimal Conversion n Converting binary to decimal is understanding what a abase 2 number system is. n Each bit has a multiplier (power of 2). u Powers of 2 are: 1, 2, 4, 8, 16, 32, 64, 128, etc. n (binary) = 1x x x x x x x x2 0 = = 157 in decimal.

15 Decimal to Binary Conversion n Note that any decimal number is made up of a unique sum of powers of 2. n Ex1: 25 decimal = u In binary: (i.e. 1x16 + 1x8 + 0x4 + 0x2 + 1x1) n Ex2: 107 decimal = u In binary: n Note: Curriculum gives a general method to convert any decimal to binary.

16 Other Binary Calculations n How many different values can you represent with a 5 bit number? u In general: 2 n values with n bits. u 2 5 = 32 different values (from 0 to 31 in decimal). n What is the largest value you can represent with an 8 bit number? u In general, highest value is 2 n -1, with n bits. u = 255 u Note you can represent 256 values with 8 bits (from 0 to 255 in decimal).

17 What is Networking? n Networking is the interconnection of workstations, peripherals terminals and other devices. n Networking addressed 3 problems: u How to avoid duplication of equipment and resources. u How to communicate efficiently. u How to set up and manage a network. n First networks were LANs (local area networks), in a limited geographical area.

18 Networking Protocols n Networking protocols are a formal set of rules and conventions, determining how devices communicate on the network. n Protocols are like languages. n Devices must use the same protocol in order to communicate.

19 Evolution of Networking n Early 1980s - rapid development of networking. n Manufacturers developed their own equipment, leading to problem of compatibility between equipment of different vendors. n Initial networks were LANs, generally using one manufacturer’s equipment. n As business demands on networking grew, networks grew to span large geographical areas, and became WANs (wide area networks). u WANS can connect cities or even countries.

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22 WAN Technologies n Some common WAN technologies are: u modems u ISDN (Integrated Services Digital Network) u DSL (Digital Subscriber Line) u Frame relay u ATM (Asynchronous Transfer Mode) u The T (US) and E (Europe) Carrier Series: F T1, E1, T3, E3, etc. u SONET (Synchronous Optical Network)

23 Digital Bandwidth n Bandwidth - a measure of how much information can flow from one place to another in a given amount of time. n Bandwidth represents the capacity of network connection (max possible data rate). n Bandwidth is measured in bits per second.

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26 Bandwidth is limited by the media

27 Bandwidth is limited by the service

28 Bandwidth is limited by the service

29 Throughput n The actual data rate you get. n Often far less then the maximum possible digital bandwidth of the medium.

30 Bandwidth vs Throughput n When you design a network, you consider the theoretical bandwidth. Your network will be no faster than what your media will allow. n When you actually work on networks, you measure throughput and decide if the throughput is adequate for the user.

31 File Transfer Time Calculations

32 Calculations n A 10 Mbps channel is used to transfer a 5Mbyte file. What is the fastest time required to transfer the file? u T=S/BW = 5MB(8bits/byte)/10Mbps = 4 secs. n Due to congestion, the throughput of the channel is only 40% of capacity. What is the actual time to transfer the file? u P = throughput = 40%(10Mbps) = 4Mbps. u T= S/P = 5MB(8bits/byte)/4Mbps = 10 sec.

33 Importance of Bandwidth n It is finite. n It can save money. n It’s a key measure of network design and performance. n It’s a key to understanding the Internet. n Demand for it increases constantly. The End