TCP/IP NETWORKING

TCP/IP

1.      TCP/IP is an acronym for Transmission Control Protocol/Internet Protocol, and refers to a family of protocols used for computer communications.

2.      TCP and IP are just two of the separate protocols contained in the group of protocols developed by the Department of Defense, sometimes called the DoD Suite, but more commonly known as TCP/IP.

3.      In addition to Transmission Control Protocol and Internet Protocol, this family also includes Address Resolution Protocol (ARP), Domain Name System (DNS), Internet Control Message Protocol (ICMP), User Datagram Protocol (UDP), Routing Information Protocol (RIP), Simple Mail Transfer Protocol (SMTP), Telnet and many others.

4.      To be able to send and receive information on the network, each device connected to it must have an address.

5.      The address of any device on the network must be unique and have a standard, defined format by which it is known to any other device on the network.

6.      This device address consists of two parts

a.      Network addresses are IP addresses that have assigned to the device.

b.      The two unique address are typically called Network layer addresses and Media Access Control (MAC) addresses

7.      Devices that are physically connected to each other (not separated by routers) would have the same network number but different node, or host numbers.

8.      This would be typical of an internal network at a company or university, these types of networks are now often referred to as intranets.

Data Transfer in TCP/IP

1)     The data transfer is accomplished by breaking the information into small pieces of data called packets or datagram.

2)     It’s necessary to break data into small pieces because of two reasons which are sharing resources and error correction.

a)      Sharing resources

(1)   If two computers are communicating with each other, the line is busy. If these computers were sharing a large amount of data, other devices on the network would be unable to transfer their data.

(2)   When long streams of data are broken into small packets, each packet is sent individually, and the other devices can send their packets between the packets of the long stream.

b)     Error correction

(1)   Because the data is transmitted across media that is subject to interference, the data can become corrupt.

(2)   One way to deal with the corruption is to send a checksum along with the data,  A checksum is a running count of the bytes sent in the message.

3)     These packets are made up of two parts, the header, which contains the address and reassembly instructions and the body which contains the data.

4)     Keeping all this information in order is the protocol, The protocol is a set of rules that specifies the format of the package and how it is used.