From Mycomputer Notes

The Introduction chapter of the CCNA 1 & 2 presents the computer basics and connection to the Internet. It also introduces the Binary and Hexadecimal numbering system but I will go through them very fast.

Contents 1 Connecting to the Internet 1.1 PC Basics 1.2 Network Interface Card 2 Network Math 2.1 Binary Presentation of Data

[edit] Connecting to the Internet

The Internet is the largest data network in the world. The internet consist of millions of interconnected netwokrs, both large and small. Connection to the Internet can be broken down into the physical connection, the logical connection, and applications:

• Physical Connection (Adapter card, modem or NIC from PC to a Network)
• Logical Connection (Standard called Protocols)
• Applications that interpret the data and display the information (Software Programs)

Physical Connections

Is used to transfer signals between PCs within the local-area network (LAN) and to remote devices on the Internet.

Logical Connections

Connections to the Internet may use multiple protocols. The Transmission Control Protocol/Internet Protocol (TCP/IP) suite is the primary set of protocols used on the Internet.

Applications

Applications are programs that interpret and display data in an understandable form. Applications work with protocols to send and receive data across the Internet. A Web browser displays HTML as a Web page.

[edit] PC Basics

Because Networks are built around computers it is important to know the major components in a computer. Many networking devices, such as routers and switches, are special-pupose computers and have many of the same parts as normal PCs.

Small Components

• Transistor
• Integrated circuit
• Resistor
• Capacitor
• Connector
• LED

Backplane Components

• Parallel & Serial Port
• Video Cards
• Power Cord
• Mouse & Keyboard Cord.
• Netowrk Interface Card

[edit] Network Interface Card

A NIC, or LAN adapter, provides network communication capabilities for each host. Different types of NICs are used for various device configurations

• PCMCIA card
• Wireless network cards
• (USB) Ethernet adapter

These considerations are important in the selection of a NIC:

1. Protocols – Ethernet, Token Ring, or FDDI
2. Types of media – Twisted-pair, coaxial, wireless, or fiber-optic
3. Type of system bus – PCI or ISA

Situations that require NIC installation include the following:

• Installation of a NIC on a PC that does not already have one
• Replacement of a malfunctioning or damaged NIC
• Upgrade from a 10-Mbps NIC to a 10/100/1000-Mbps NIC
• Change to a different type of NIC, such as wireless
• Installation of a secondary, or backup, NIC for network security reasons

To perform the installation of a NIC or modem the following resources may be required:

• Knowledge of how the adapter, jumpers, and plug-and-play software are configured
• Availability of diagnostic tools
• Ability to resolve hardware resource conflicts

[edit] Network Math

This section introduces the way in which data is represented inside a computer and the form in which hit is transmitted accross a network.

[edit] Binary Presentation of Data

Computers are electromechanical devices made up of electronic swithces. Since they are electronical drives they only react to electronic impulses, These impulses are understood as either ON or OFF states (1s or 0s)

Bits and Bytes

Bits are binary digits, tehy are either 0s or 1s and represented by ON/OFF switches (presence or absence)of electrical charges.

• Binary 0 = 0 Volts
• Binary 1 = +- 5 Volts

Computers are designed to used a groupig of 8 bits. 8 bits is called a byte.