| Module 1.2 - Network Math |
[Sep. 15th, 2007|09:19 am] |
| [ | Tags | | | binary, bits, booleon, bytes, cisco, decimal, hexidecimal, ip address, logic, math, subnet mask | ] |
Section 1.2.1 - Computers work with and store data but using switches. Switches are either ON (1) or OFF (0). We use decimal number system, computers use the binary number system. Sometimes binary numbers are converted to hexidecimal numbers.
Section 1.2.2 -
Bit (b)
Byte (B)
Kilobyte (KB)
Megabyte (MB)
Gigabyte (GB)
Terabyte (TB)
The value range of a byte is 0 to 255.
Section 1.2.3 - Base 10 uses 10 symbols, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9.
10^0=1
10^1=10
10^2=100
10^3=1000
10^4=10,000
10^5=100,000
10^6=1,000,000
10^7=10,000,000
10^8=100,000,000
10^9=1,000,000,000
Section 1.2.4 - The 2 system has 2 symbols, 1 and 0.
Example: 10110 in binary is equal to 16 in decimal.
...128 64 32 16 8 4 2 1 - Read from right to left.
Section 1.2.5 - Conversion in pretty simple once you get the hang of it, it can take some practicce though since we're so used to working with the decimal system.
Section 1.2.6 - More conversion.
Example: 01110000 is equal to 112 in decimal.
Section 1.2.7 - Dotted decimal notation. Currently IP addresses are assigned to every computer on the Internet. They're 32-bits. First the binary number is split into four groups of 8 binary digits and then converted into a decimal equivelent.
11001000 01110010 00000110 00110011
200.114.6.51
10000000 01011101 00001111 10101010
128.95.15.170
Section 1.2.8 - The hexidecimal number system is base 16. It's commonly used to represent binary numbers in a more readable format. Cisco router have a configuration register that is 16 bit long. For example, 00100000100000010 coould be represented as 0x2102 in hexidecimal format. Remember to include the 0x for hexidecimal. It uses the symbols 0-9 and A-F.
Section 1.2.9 - Boolean logic is based on digital circutry. It accepts one or two incoming voltages. It's either ON or OFF. They're either a 1 or a 0. Boolean logic uses AND, OR and NOT.
NOT will take the value and reverse it so that 0 will becomes 1 and 1 becomes 0.
AND will compare the 2 values and if both values are 1 it equals one, if there's a 0 for either of the values it equals 0.
The OR operation looks at the values and if there's a 1 it equals 1, if they're both 0 it equals 0.
The two networking operations that use Boolean logic are subnetwork and wildcard masking.
Section 1.2.10 - When IP addresses are assigned some of the bits on the left side represent a network. The bits that are left over identify the computer in the network. To help determine how the address get splits a second address called a subnet mask is assigned.
10.34.23.134
255.255.0.0
Network portion of IP is 10.34.0.0
My Note - I think I am actually starting to understand how this all works. I used to be quite confused about it all, but it's not to bad anymore :) |
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| Module 1.1 - Introduction to Networking |
[Sep. 11th, 2007|08:35 pm] |
Section 1.1.1 - The Internet is the largest data network ever. It can be broken down into physical & logical connections and applications. Physical connections are like NICs, logical is the protocols use and the applications display the data in a form that we can read. Examples of applications are web browsers, email clients, FTP clients, etc.
Protocols are simply rules. It tells us how things have to communicate. TCP/IP is the primary set of protocols used on the Internet.
Section 1.1.2 - This section pretty much talks about components of a computer. Nothing to interesting.
• Transistor – Device that amplifies a signal or opens and closes a circuit.
• Integrated circuit – Device made of semiconductor material that contains many transistors and performs a specific task.
• Resistor – An electrical component that limits or regulates the flow of electrical current in an electronic circuit.
• Capacitor – Electronic component that stores energy in the form of an electrostatic field that consists of two conducting metal plates separated by an insulating material.
• Connector – The part of a cable that plugs into a port or interface.
• Light emitting diode (LED) – Semiconductor device that emits light when a current passes through it.
• Printed circuit board (PCB) – A circuit board which has conducting tracks superimposed, or printed, on one or both sides. It may also contain internal signal layers and power and ground planes. Microprocessors, chips and integrated circuits and other electronic components are mounted on the PCB.
• CD-ROM drive – A device that can read information from a CD-ROM.
• Central processing unit (CPU) – The part of a computer that controls the operation of all the other parts. It gets instructions from memory and decodes them. It performs math and logic operations, and translates and executes instructions. 
• Floppy disk drive – A computer drive that reads and writes data to a 3.5-inch, circular piece of metal-coated plastic disk. A standard floppy disk can store approximately 1 MB of information. 
• Hard disk drive – A computer storage device that uses a set of rotating, magnetically coated disks called platters to store data or programs. Hard drives come in different storage capacity sizes.
• Microprocessor – A microprocessor is a processor which consists of a purpose-designed silicon chip and is physically very small. The microprocessor utilizes Very Large-Scale Integration (VLSI) circuit technology to integrate computer memory, logic, and control on a single chip. A microprocessor contains a CPU.
• Motherboard – The main printed circuit board in a computer. The motherboard contains the bus, the microprocessor, and integrated circuits used for controlling any built-in peripherals such as the keyboard, text and graphics display, serial ports and parallel ports, joystick, and mouse interfaces. 
• Bus – A collection of wires on the motherboard through which data and timing signals are transmitted from one part of a computer to another.
• Random-access memory (RAM) – Also known as read-write memory because new data can be written to it and stored data can be read from it. RAM requires electrical power to maintain data storage. If a computer is turned off or loses power all data stored in RAM is lost.
• Read-only memory (ROM) – Computer memory on which data has been prerecorded. Once data has been written onto a ROM chip, it cannot be removed and can only be read.
• System unit – The main part of a PC, which includes the chassis, microprocessor, main memory, bus, and ports. The system unit does not include the keyboard, monitor, or any external devices connected to the computer.
• Expansion slot – A socket on the motherboard where a circuit board can be inserted to add new capabilities to the computer. Figure  shows Peripheral Component Interconnect (PCI) and Accelerated Graphics Port (AGP) expansion slots. PCI is a fast connection for boards such as NICs, internal modems, and video cards. The AGP port provides a high bandwidth connection between the graphics device and the system memory. AGP provides a fast connection for 3-D graphics on computer systems.
• Power supply – The component that supplies power to a computer.
The following backplane components are also important:
• Backplane – A backplane is an electronic circuit board containing circuitry and sockets into which additional electronic devices on other circuit boards or cards can be plugged; in a computer, generally synonymous with or part of the motherboard.
• Network interface card (NIC) – An expansion board inserted into a computer so that the computer can be connected to a network.
• Video card – A board that plugs into a PC to give it display capabilities.
• Audio card – An expansion board that enables a computer to manipulate and output sounds.
• Parallel port – An interface capable of transferring more than one bit simultaneously that is used to connect external devices such as printers.
• Serial port – An interface that can be used for serial communication in which only one bit is transmitted at a time.
• Mouse port – A port used to connect a mouse to a PC.
• USB port – A Universal Serial Bus connector. A USB port connects devices such as a mouse or printer to the computer quickly and easily.
• Firewire – A serial bus interface standard offering high-speed communications and isochronous real-time data services.
• Power cord – A cord used to connect an electrical device to an electrical outlet that provides power to the device.
You need to have a working computer to connect to a network.
Section 1.1.3 - NICs or LAN adapter cards allow your computer to connect to a network. It's a physical piece of hardware. A NIC uses and IRQ and upper memory space to work with the operating system. When you're purchasing a NIC (which is rarely done much anymore since it all come built-in now adays, although for a second NIC) you should be aware of the protocols it supports, the types of media it supports (coaxial, wireless, fibre obtic, twisted pair cabling) and the type of slot it fits into (PCI, ISA, PCMCIA).
Section 1.1.4 - Modem = modulator-demodulator. Modems essentially convert analog signals into digital signals.
Section 1.1.5 - Modems were introduced in the 1960s. 300bps was the going speed rate. Super slow and companies usually rented computer time since it was to expensive to own your own. In the 1970s BBSs became popular, then 300bps became to slow. In the 1990s the speed increased to 9600bps. In 1998 they hit 56kbps (56k modems). In 2000 high-speed started to get big (cable & DSL).
Section 1.1.6 - TCP/IP is a set of protocols that lets computers communicate and share resources. Most if not all operating systems come with tools to configure these protocols.
Section 1.1.7 - Ping is a command you can use to test network connectivity. It sends out special packets called Internet Control Message Protocol (IMCP) Echo Request datagrams. If you get them returned then you know you're connected to the network. Ping is a simple command ping IP-of-another-computer.
Section 1.1.8 - This section explains what a web browser and plug-ins are. Hopefully you already know what that is. The plug-ins they list are simple media ones, like QuickTime, Real Player and Flash.
Section 1.1.9 - This section talks about troubleshooting computer and network connectivity issues.
1. Define the problem
2. Gather the facts
3. Consider the possibility
4. Create an action plan
5. Implement the plan
6. Observe the results
7. Document the results
8. Introduce problems and troubleshoot
This is a very basic section that every should already understand if you're looking into getting CCNA. |
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| Greetings! |
[Sep. 9th, 2007|02:57 pm] |
| [ | mood |
| | working | ] |
| [ | music |
| | // Mae - "Summertime" // | ] |
Hello all,
Before we begin let's have a bit of an introduction. I've already done this, I've taken notes, tests, quizzes and all that for CCNA. That was about 4 years ago. Now I am going to run through all the semester again and do it all over. Why, you ask? Well for one networking and computers interests me very much, second, I am doing this for me. I am not in a class, I have no teacher but only my online resources. I am not under pressure to get grades, only to learn as much as I can. I don't have a specific amount of time in which I must complete these semesters.
This is mainly for my learning purposes but if you all can get something out of my notes, great. I would recommend that you note just read this notes as-is. I will be setting up a better system using this journal software's "memories" system. That way I can put notes in the correct categories and it will be easy for anyone to find a specific thing (hopefully). Each semester will be orangized into modules and it'll all be orangized on one post from which you can click to visit which ever section you want.
Enjoy. |
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