DATACOM

Connecting to the Internet
Internet is a valuable resource, and connecting to it is essential for business and industry and education. Building a network that will connect to the internet requires CAREFUL PLANNING. Computer as well as the device itself must be considered. The correct protocol must be configured.

Requirement for internet connection

To understand the role of computer play in the networking system consider the internet. Computer can be thought of as a tree. (Computer Functionality)
The internet is the largest data network in the world. The internet is consist of millions of interconnected networks.

Connecting to the Internet Can be broken down into the following components

Physical Connection – it is responsible for connections transfer to signals between PC’s in the local Network or the remote devices on the network.
Logical Connection – logical connection uses standard protocol connecting to the internet uses multiple protocol. The Transmission Control Protocol / Internet Protocol or TCP/IP suite is the primary protocol used on the internet
Applications – it interprets the data and displays information in an understandable format. Application.

PC BASICS

Devices in your Personal Computer What are the major components in your PC.
Backplane components of your computer Mboard,Memory,VideoCard,Parallel ports,
serial ports.

Browsers and Plug-ins

Browsers is a software that interprets HTML,SGML,XML provide more features for creating dynamic and interactive WebPages

IE

Integrated with other MS product
Takes up more disk space
Display HTML perform email.

Communicator

First popular Browser
Takes up less disk space
Display HTML perform email.

Bit - Smallest unit of data in a computer 8 bits = 1 byte

Byte - A unit of measure that describes the size of a data file, the amount of space on a disk or another storage medium, or the amount of data being transferred over a network.

Kbps - A standard measurement of the rate at which data is transferred over a network connection.

MHz - A unit of frequency; the rate of change in the state or cycle in a sound wave alternating current

Network Math
Binary – Number system that is characterized by 1’s and 0’s. In computer Bits are binary Digits that are represented by on/off or the presence or absence of electrical charges.
Hexadecimal – another number system that uses 16 symbols because only tem symbols represent digits (0 – 9)and because base16 requires more 6 symbols the extra symbols are the letters A,B,C,D,E and F.
A = 10 , B=11, C=12, D=13, E=14, F=15,
the position of each symbols (digits) in a hex number represents the base number 16 raise to a power base on its position. Moving from right to left our network adopter or NIC addresses are expressed as a string of 12 hexadecimal characters.

4 Octet Dotted-Decimal representation of a 32-bit Binary Number

Currently Address assigned to computer on networks that use TCP/IP have IP Address that are 32-bit binary number. Any device that wants to communicate using the internet must have an IP address. to make it easier to work with theses addresses, the 32-bit binary number is broken down into a series of decimal number.
When written the complete decimal number is represented as four groups of decimal digits separated by periods. Such as 10.15.129.201 this is a sample of an IP address . this is called dotted-decimal notation and provides a compact, easy-to-remember way of referring to 32-bit addresses.
10 = 00001010
15 = 00001111
129 = 10000001
201= 11001001

Hexadecimal

Converting a hexadecimal number to binary form and vice versa is a common task when dealing with the configuration register in routers configuration register that is 16bit long. The 16bit binary number can be represented as a four digit hexadecimal number. For example 00100001.00000010 in binary equals to 2102 in hex
For Ethernet this MAC addresses are 48bit or six octets. Because this address is consist of six distinct octets. They can be expressed as 12 hex numbers instead. Every 4 bits is a hex digits
Example :
10101010.11110000.11000001.11100010.01110111.01010001
Mac Address
AA.F0.C1.E2.77.51
A = 1010, A = 1010, F = 1111, 0 = 0000, C = 1100, 1 = 0001, E = 1110,
2 = 0010, 7 = 0111, 7 = 0111, 5 = 0101, 1 = 0001

IP address
The 32 bit binary addresses used on the internet are called Internet Protocol addresses.
1.) 32-bit address assigned to hosts using TCP/IP. An IP address belongs to one of five classes (A, B, C, D, or E) and is written as 4 octets separated with periods (dotted decimal format). Each address consists of a network number, an optional subnetwork number, and a host number. A subnet mask is used to extract network and subnetwork information from the IP address. Also called an Internet address.
2.) Command used to establish the logical network address of this interface.

IP address
Testing Connectivity with Ping Command
Ping is a program that is useful for verifying a successful TCP/IP installation. It is named after the sonar Operation used to locate and determine the distance to an underwater object. PING stands for Packet INTERNETWORK GROUPER
Ping command works by sending internet Control Message Protocol (ICMP) datagram's to request a reply. The output response for a ping contains the success ratio and round-trip time to the destination.
Ping command also use to test NIC transmit/ receive function, TCP/IP configuration, and Network connectivity.

IP address
Usage of PING Command
127.0.0.1 (Internal Loopback test) – because no packets are transmitted pinging the loop back interface tests basic TCP/IP network configuration.
Ping IP address of the host computer – Verifies the TCP/IUP address configuration for the local host.
Ping the default gateway IP address – verifies whether the router that connects the local network to other networks can be accessed.

Ping Remote Destination host – Ping www.yahoo.com / ping www.google.com.