Introduction to TCP/IP
TCP/IP is the communication protocol for the
Computer Communication Protocol
A computer communication protocol
is a description of the rules computers must follow
to communicate with each other.
What is TCP/IP?
TCP/IP is the communication
protocol for communication between computers
connected to the Internet.
TCP/IP stands for Transmission
Control Protocol / Internet
The standard defines how
electronic devices (like computers) should be
connected to the Internet, and how data should be
transmitted between them.
Hiding inside the TCP/IP standard
there are a number of protocols for handling data
TCP (Transmission Control
Protocol) communication between applications
UDP (User Datagram Protocol)
simple communication between applications
IP (Internet Protocol)
communication between computers
ICMP (Internet Control
Message Protocol) for errors and statistics
DHCP (Dynamic Host
Configuration Protocol) for dynamic addressing
You will learn more about these
standards later in this tutorial.
TCP Uses a Fixed Connection
TCP is for communication between
When an application wants to
communicate with another application via TCP, it
sends a communication request. This request must be
sent to an exact address. After a "handshake"
between the two applications, TCP will setup a
"full-duplex" communication between the two
The "full-duplex" communication
will occupy the communication line between the two
computers until it is closed by one of the two
UDP is very similar to TCP, but is
more simple and less reliable.
IP is Connection-Less
IP is for communication between
IP is a "connection-less"
communication protocol. It does not occupy the
communication line between two communicating
computers. This way IP reduces the need for network
lines. Each line can be used for communication
between many different computers at the same time.
With IP, messages (or other data)
are broken up into small independent "packets" and
sent between computers via the Internet.
IP is responsible for "routing"
each packet to its destination.
When an IP packet is sent from a
computer, it arrives at an IP router.
The IP router is responsible for
"routing" the packet to its destination, directly or
via another router.
The path the packet will follow
might be different from other packets of the same
communication. The router is responsible for the
right addressing depending on traffic volume, errors
in the network, or other parameters.
Communicating via IP is like
sending a long letter as a large number of small
postcards, each finding its own (often different)
way to the receiver.
TCP/IP is TCP and IP working
TCP takes care of the
communication between your application software
(i.e. your browser) and your network software.
IP takes care of the communication
with other computers.
TCP is responsible for breaking
data down into IP packets before they are sent, and
for assembling the packets when they arrive.
IP is responsible for sending the
packets to the receiver.