UNIT I
INTRODUCTION:
Data communications refers to the transmission of this digital data between two or
more computers and a computer network or data network is a telecommunications
network that allows computers to exchange data. The physical connection between
networked computing devices is established using either cable media or wireless media.
The best-known computer network is the Internet.
This tutorial should teach you basics of Data Communication and Computer Network
(DCN) and will also take you through various advance concepts related to Data
Communication and Computer Network.
Why to Learn Data Communication & Computer Network?
Network Basic Understanding
A system of interconnected computers and computerized peripherals such as printers
is called computer network. This interconnection among computers facilitates
information sharing among them. Computers may connect to each other by either wired
or wireless media.
Network Engineering
Networking engineering is a complicated task, which involves software, firmware, chip
level engineering, hardware, and electric pulses. To ease network engineering, the whole
networking concept is divided into multiple layers. Each layer is involved in some
particular task and is independent of all other layers. But as a whole, almost all
networking tasks depend on all of these layers. Layers share data between them and
they depend on each other only to take input and send output.
Internet
A network of networks is called an internetwork, or simply the internet. It is the largest
network in existence on this planet.The internet hugely connects all WANs and it can
have connection to LANs and Home networks. Internet uses TCP/IP protocol suite and
uses IP as its addressing protocol. Present day, Internet is widely implemented using
IPv4. Because of shortage of address spaces, it is gradually migrating from IPv4 to IPv6.
Internet enables its users to share and access enormous amount of information
worldwide. It uses WWW, FTP, email services, audio and video streaming etc. At huge
level, internet works on Client-Server model.
Internet uses very high speed backbone of fiber optics. To inter-connect various
continents, fibers are laid under sea known to us as submarine communication cable.
Applications of Communication & Computer Network
,Computer systems and peripherals are connected to form a network.They provide
numerous advantages:
Resource sharing such as printers and storage devices
Exchange of information by means of e-Mails and FTP
Information sharing by using Web or Internet
Interaction with other users using dynamic web pages
IP phones
Video conferences
Parallel computing
Instant messaging
A system of interconnected computers and computerized peripherals such as printers
is called computer network. This interconnection among computers facilitates
information sharing among them. Computers may connect to each other by either wired
or wireless media.
Classification of Computer Networks
Computer networks are classified based on various factors.They includes:
Geographical span
Inter-connectivity
Administration
Architecture
Geographical Span
Geographically a network can be seen in one of the following categories:
It may be spanned across your table, among Bluetooth enabled devices,. Ranging
not more than few meters.
, It may be spanned across a whole building, including intermediate devices to
connect all floors.
It may be spanned across a whole city.
It may be spanned across multiple cities or provinces.
It may be one network covering whole world.
Inter-Connectivity
Components of a network can be connected to each other differently in some fashion.
By connectedness we mean either logically , physically , or both ways.
Every single device can be connected to every other device on network, making
the network mesh.
All devices can be connected to a single medium but geographically
disconnected, created bus like structure.
Each device is connected to its left and right peers only, creating linear structure.
All devices connected together with a single device, creating star like structure.
All devices connected arbitrarily using all previous ways to connect each other,
resulting in a hybrid structure.
Administration
From an administrator’s point of view, a network can be private network which belongs
a single autonomous system and cannot be accessed outside its physical or logical
domain.A network can be public which is accessed by all.
Network Architecture
Computer networks can be discriminated into various types such as Client-
Server,peer-to-peer or hybrid, depending upon its architecture.
There can be one or more systems acting as Server. Other being Client, requests
the Server to serve requests.Server takes and processes request on behalf of
Clients.
Two systems can be connected Point-to-Point, or in back-to-back fashion. They
, both reside at the same level and called peers.
There can be hybrid network which involves network architecture of both the
above types.
Network Applications
Computer systems and peripherals are connected to form a network.They provide
numerous advantages:
Resource sharing such as printers and storage devices
Exchange of information by means of e-Mails and FTP
Information sharing by using Web or Internet
Interaction with other users using dynamic web pages
IP phones
Video conferences
Parallel computing
Instant messaging
Computer network types
Generally, networks are distinguished based on their geographical span. A network can
be as small as distance between your mobile phone and its Bluetooth headphone and
as large as the internet itself, covering the whole geographical world,
Personal Area Network
A Personal Area Network (PAN) is smallest network which is very personal to a user.
This may include Bluetooth enabled devices or infra-red enabled devices. PAN has
connectivity range up to 10 meters. PAN may include wireless computer keyboard and
mouse, Bluetooth enabled headphones, wireless printers and TV remotes.
INTRODUCTION:
Data communications refers to the transmission of this digital data between two or
more computers and a computer network or data network is a telecommunications
network that allows computers to exchange data. The physical connection between
networked computing devices is established using either cable media or wireless media.
The best-known computer network is the Internet.
This tutorial should teach you basics of Data Communication and Computer Network
(DCN) and will also take you through various advance concepts related to Data
Communication and Computer Network.
Why to Learn Data Communication & Computer Network?
Network Basic Understanding
A system of interconnected computers and computerized peripherals such as printers
is called computer network. This interconnection among computers facilitates
information sharing among them. Computers may connect to each other by either wired
or wireless media.
Network Engineering
Networking engineering is a complicated task, which involves software, firmware, chip
level engineering, hardware, and electric pulses. To ease network engineering, the whole
networking concept is divided into multiple layers. Each layer is involved in some
particular task and is independent of all other layers. But as a whole, almost all
networking tasks depend on all of these layers. Layers share data between them and
they depend on each other only to take input and send output.
Internet
A network of networks is called an internetwork, or simply the internet. It is the largest
network in existence on this planet.The internet hugely connects all WANs and it can
have connection to LANs and Home networks. Internet uses TCP/IP protocol suite and
uses IP as its addressing protocol. Present day, Internet is widely implemented using
IPv4. Because of shortage of address spaces, it is gradually migrating from IPv4 to IPv6.
Internet enables its users to share and access enormous amount of information
worldwide. It uses WWW, FTP, email services, audio and video streaming etc. At huge
level, internet works on Client-Server model.
Internet uses very high speed backbone of fiber optics. To inter-connect various
continents, fibers are laid under sea known to us as submarine communication cable.
Applications of Communication & Computer Network
,Computer systems and peripherals are connected to form a network.They provide
numerous advantages:
Resource sharing such as printers and storage devices
Exchange of information by means of e-Mails and FTP
Information sharing by using Web or Internet
Interaction with other users using dynamic web pages
IP phones
Video conferences
Parallel computing
Instant messaging
A system of interconnected computers and computerized peripherals such as printers
is called computer network. This interconnection among computers facilitates
information sharing among them. Computers may connect to each other by either wired
or wireless media.
Classification of Computer Networks
Computer networks are classified based on various factors.They includes:
Geographical span
Inter-connectivity
Administration
Architecture
Geographical Span
Geographically a network can be seen in one of the following categories:
It may be spanned across your table, among Bluetooth enabled devices,. Ranging
not more than few meters.
, It may be spanned across a whole building, including intermediate devices to
connect all floors.
It may be spanned across a whole city.
It may be spanned across multiple cities or provinces.
It may be one network covering whole world.
Inter-Connectivity
Components of a network can be connected to each other differently in some fashion.
By connectedness we mean either logically , physically , or both ways.
Every single device can be connected to every other device on network, making
the network mesh.
All devices can be connected to a single medium but geographically
disconnected, created bus like structure.
Each device is connected to its left and right peers only, creating linear structure.
All devices connected together with a single device, creating star like structure.
All devices connected arbitrarily using all previous ways to connect each other,
resulting in a hybrid structure.
Administration
From an administrator’s point of view, a network can be private network which belongs
a single autonomous system and cannot be accessed outside its physical or logical
domain.A network can be public which is accessed by all.
Network Architecture
Computer networks can be discriminated into various types such as Client-
Server,peer-to-peer or hybrid, depending upon its architecture.
There can be one or more systems acting as Server. Other being Client, requests
the Server to serve requests.Server takes and processes request on behalf of
Clients.
Two systems can be connected Point-to-Point, or in back-to-back fashion. They
, both reside at the same level and called peers.
There can be hybrid network which involves network architecture of both the
above types.
Network Applications
Computer systems and peripherals are connected to form a network.They provide
numerous advantages:
Resource sharing such as printers and storage devices
Exchange of information by means of e-Mails and FTP
Information sharing by using Web or Internet
Interaction with other users using dynamic web pages
IP phones
Video conferences
Parallel computing
Instant messaging
Computer network types
Generally, networks are distinguished based on their geographical span. A network can
be as small as distance between your mobile phone and its Bluetooth headphone and
as large as the internet itself, covering the whole geographical world,
Personal Area Network
A Personal Area Network (PAN) is smallest network which is very personal to a user.
This may include Bluetooth enabled devices or infra-red enabled devices. PAN has
connectivity range up to 10 meters. PAN may include wireless computer keyboard and
mouse, Bluetooth enabled headphones, wireless printers and TV remotes.
