Explain the purpose and
functions of TCP/IP protocol. Also define the terms IP address, URL and DNS in
this context.
Ans
The Transmission Control Protocol/Internet Protocol
(TCP/IP) suite are a set of standards that describe the functions necessary to
send data over a network. They are designed to divide the responsibility for
the various aspects of data transmission into categories
Features
Rather than write one protocol for each category,
specialized protocols cover smaller aspects of each task. This means there are
sub-groups of protocols. These groupings are called "Layers," and the
layers are represented as levels in a stack. Each layer uses services from the
layer below and provides services to the layer above. This principle is called
"abstraction."
Function
International open standards enable different companies
to write compatible software. When data travels over the Internet, both the
sender and receiver have to speak the same language. The TCP/IP protocols
provide a common set of procedures and codes everyone follows.
Considerations
The membership of the TCP/IP protocol suite changes
constantly. New protocols are added and others are adopted from other systems.
The most influential protocol in the suite is the Internet Protocol. This
defines the address formats for all devices contactable over the Internet, and
is used by all networking systems communicating over the Internet
terms IP address
An IP address is an identifier for a computer or device
on a TCP/IP network. Networks using the TCP/IP protocol route messages based on
the IP address of the destination.
The format of an IP address is a 32-bit numeric address written as four
numbers separated by periods. Each number can be zero to 255. For example,
1.160.10.240 could be an IP address.
Within an isolated network, you can assign IP addresses
at random as long as each one is unique. However, connecting a private network
to the Internet requires using registered IP addresses (called Internet
addresses) to avoid duplicates.
URL
Stands for "Uniform Resource Locator." A URL is
the address of a specific Web site or file on the Internet. It cannot have
spaces or certain other characters and uses forward slashes to denote different
directories. Some examples of URLs are http://www.cnet.com/,
http://web.mit.edu/, and ftp://info.apple.com/. As you can see, not all URLs
begin with "http". The first part of a URL indicates what kind of
resource it is addressing. Here is a list of the different resource prefixes:
http - a hypertext directory or document (such as a Web
page)
ftp - a directory of files or an actual file available to
download
gopher - a gopher document or menu
telnet - a Unix-based computer system that you can log
into
news - a newsgroup
WAIS - a database or document on a Wide Area Information
Search database
file - a file located on your hard drive or some other
local drive
DNS
Stands for "Domain Name System." The primary
purpose of DNS is to keep Web surfers sane. Without DNS, we would have to
remember the IP address of every site we wanted to visit, instead of just the
domain name. Can you imagine having to remember "17.254.3.183"
instead of just "apple.com"? While I have some Computer Science
friends who might prefer this, most people have an easier time remembering
simple names.
The reason the Domain Name System is used is because Web
sites are acutally located by their IP addresses. For example, when you type in
"http://www.adobe.com," the computer doesn't immediately know that it
should look for Adobe's Web site. Instead, it sends a request to the nearest
DNS server, which finds the correct IP address for "adobe.com." Your
computer then attempts to connect to the server with that IP number. DNS is
just another one of the many features of the Internet that we take for granted.
