Video chatting with a friend working overseas or
sending emails to relatives in faraway cities is now easy and possible. But
have you ever wondered how these messages are being transferred or how they get
to the right receiver in no time? Do you pause for a while and think how these
days, sending and receiving information is so easy with a snap of your finger
and connecting with anyone anywhere around the globe is like a miracle, thanks
to the intricately interconnected worldwide computers or simply called the
The rise of the internet opened a lot of opportunities
and possibilities to make life and work easier. Nowadays, the internet is so
ubiquitous and can be considered an important part of everyday life of many
people but most do not know how it works or take for granted how its continuous
operation impacts our daily lives.
In order to know how the internet really works, one
must know the definition of the word “internet” and what comprises the
internet. Many think that internet is simply going online. Dictionary.com
defines the internet as a vast computer network that links smaller networks
around the world. The internet, according to this definition, encompasses
commercial, educational, governmental and other networks which use an identical
set of communication protocols. It is basically the infrastructure of
interconnected computers globally. Simply put, internet is similar to a network
of highways connecting people or places from one another and the running
vehicles are like data packets being transported from place to place.
Imagine several computers located in different places
around the world. These computers interact or “talk to each other” so they can
generate and distribute information. In order to communicate with each other,
each of these computers must have a unique address. This unique address is
called an “IP address” where IP stands for Internet Protocol. IP addresses are
in the form of a series of numbers separated by three dots or periods. Each
number can range from 0 to 255. An example of an IP address is 188.8.131.52. There
are two types of IP addresses: a temporary and a permanent IP address.
Temporary IP addresses are usually assigned by an Internet Service Provider or
ISP for the duration of a session when one connects to the internet. Permanent
IP addresses, on the other hand, are provided when one connects to the internet
through a local area connection or LAN although a temporary IP address may also
be obtained from a dynamic host configuration protocol, or DHCP, server.
Once a computer has a unique IP address and connected
through an ISP or LAN, the
computer can communicate with other computers on the internet. This is
accomplished by sending and receiving, for example, alphabetic text. However,
an alphabetic text cannot travel from the computer to the ISP/LAN then to another computer and back on its own.
The alphabetic text message must be translated first into electronic signals in
order to be transmitted through the internet and then translated back to text
so the message can be read by the recipient. This is accomplished through the
use of a protocol stack. A protocol stack is a group of protocol layers
embedded into the computer’s operating system, such as Windows, needed by the
computer in order to communication on the internet. The protocol stack that is
primarily utilized for communicating on the internet is called TCP/IP protocol stack. It is named so due to the
use of two main protocols in this stack: TCP and IP. TCP stands for Transmission
Control Protocol while IP is for Internet Protocol. TCP points packets to a
particular application on a computer via a port number. IP, on the other hand,
uses an IP address to direct packets to a particular computer. In addition to
these two, there are two other layers included in this protocol stack; these
are: application protocols layer and hardware layer. Application protocols
layer contain protocols related to software like WWW, e-mail and FTP. Hardware
layer translates binary packet data into network signals and back. The latter
is the function of ethernet network cards and modems for phone lines.
Knowing the components needed for the computer to talk
to each other, one can trace the route of the message from one user to the next
and back. First, a message is typed or input into a program or application in a
computer with a unique IP address. Data then goes to the TCP, then to IP and
eventually to the hardware where binary data is converted to network signals.
These signals pass through the internet and reach the other computer with a
different IP address. The network signals are converted back binary data which
then go to IP, TCP and finally to the program or application where it is read
by the other user.
Earlier, the internet was described as the bridge or
the link between two different computers. But what really is the internet? What
makes up the internet? The following illustrates the physical connections and
components that comprise the internet. Currently there are many types of
internet connections available to consumers such as wireless, mobile, hotspots,
dial-up, broadband, DSL (Digital
Subscriber Line), cable, satellite and ISDN (Integrated Services Digital
Network). For the sake of simplicity, we will use as example two of the most
basic and familiar types: dial-up and LAN.
Dial-up usage has been steadily declining because of
the slow speed and antiquity of this system but this still provides access to a
minority of internet users. In this type of connection, the computer is
connected to a modem which is, in turn, connected to the public telephone
network. On the other end of the public telephone network is the modem pool
which is connected to the ISP Port Server. It is called a port server because
its purpose is to ‘serve’ access to the network. A router links the ISP Port
Server to the ISP backbone. It is referred to as a router because it ‘routes’
data packets into the ISP backbone. After reaching the ISP backbone, the data
packets may move along other routers and ISP backbones until the packets find
When it comes to LAN, the modem is replaced by the LAN
itself which is connected to a router. The router is linked to CSU/DSU (Channel
Service Unit/Data Service Unit) which is a digital-interface device. CSU
connects to the telecommunications network while the DSU manages the interface
with the router. Just like in the dial-up, the router then routes data packets
to the ISP backbone.
So how does data find its way in the complex jungle of
the internet? Routers are the key for this process. The information needed to
get packets to their destinations or the instructions on a letter to find their
addressee are embedded in routing tables maintained by each router linked to
the internet. Routers serve as packet switches since routers are attached
between networks to direct packets between these networks. A router can
determine its sub-networks and the IP addresses they have.
The internet backbone is composed of various large
networks, called Network Service Providers (NSPs), interconnected with each
other. Each NSP needs to connect to three Network Access Points (NAPs) which
enable NSPs to peer with each other and have their packet traffic jump from
backbone to backbone of NSPs. After navigating the large networks, data
packets, through the help of routers, make their way through Regional ISP
backbones which are sub-networks. More sub-networks may be encountered under
the sub-networks until the data packets arrive at the LAN where several
computers could be connected.
Data packets eventually find their destination after
travelling so far because of the presence of a collection of computer names and
IP addresses in the distributed database called the Domain Name Service or DNS.
Computers linked to the internet maintain part of the DNS database and the
software that allows others to use it. Domain names are arranged in a hierarchy
and resolved from the lowest level to the top when the correct DNS server is
located. In short, when a user enters a web address onto a web browser, the
browser initially connects to the main DNS server where the IP address and
domain name are ascertained. The browser then links with the specified computer
which then retrieves the requested web page.
One other tool displaying the marvel of the internet is
the electronic mail or e-mail. How does an e-mail reach its destination?
E-mails use a protocol called Simple Mail Transfer Protocol or SMTP which is a
text-based protocol and connection oriented. When a user opens a mail client to
read e-mail, the mail client initially opens a connection to the default
server. IP addresses or domain name are pre-determined during a mail client
setup. The mail server will then send the first message to its identification.
The mail client recognizes this and sends a confirmation. Through this
request/response transaction method, a user can read, write and send e-mails.
In summary, this is how the internet and its most basic
and notable tools operate. Under the hood, the workings of this digital
revolution belie the simplicity and user-friendliness of the internet as we
know it. Moreover, myriad modifications and advances happen every minute that
the internet is online which only adds to the already formidable power and
potential of this technology.