To understand TCP/IP, we have to first understand what is a protocol. In simple terms, a protocol is a set of rules for communication between computers. TCP/IP is a protocol for internet communication. Actually, as you might have guessed, TCP/IP is an acronym, which stands for Transmission Control Protocol/Internet Protocol.
TCP/IP does not consist only of TCP and IP. It is in fact, a protocol suite, which consists of the following protocols for data communication :-
TCP : Transmission Control Protocol
IP : Internet Protocol
UDP : User Datagram Protocol
ICMP : Internet Control Message Protocol
DHCP : Dynamic Host Configuration Protocol
Whenever on application wants to communicate with another application, it takes the help of TCP. TCP sets up a full duplex path between the two communicating applications, which ends only when one of the application decides to break the connection. UDP is a much more simpler version of TCP, but its simplicity comes at the cost of reliability.
For transmission, data is usually broken up into a number of manageable fragments called "packets". IP is responsible for routing these packets so that they arrive at the correct destination. There are a number of factors by which IP routers decide which path to take. Some of them are errors, broken transmission media, traffic congestion etc.
Addressing in TCP/IP is done using 32 bits, or in a more understandable way, 4 sets of numbers between 0 and 255. Every computer must have a valid IP address to connect to the internet. The packets have a destination address, which is in the form of an IP number. That is why it is necessary to have a unique IP address for each machine. A common example of an IP address is 172.123.100.10.
The IP addresses are difficult to remember since humans are not as good with numbers as computers. So naturally we require a more easy "alphabet" name, say something like "cauniversity.org". To map the IP address to such a domain name, Domain Name Servers (DNS) are required. Whenever a new domain name is registered, DNS servers all over the world are updated to reflect the changes.
This article was originally published by CyberArmy.net in the CyberArmy Library.
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