WHAT IS COMPUTER NETWOR
A computer network is a system in which multiple computers are connected to each
other to share information and resources.
Characteristics of a computer network
•Share Resources from one computer to another
•Create files and store them in one computer, access those files from the other computer(s)
connected over the network
•Connect a printer, scanner, or a fax machine to one computer within the network and let
other computers of the network use the machines available over network.
Data communications
•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. Data communications
•The physical connection between networked computing devices is established using either
cable media or wireless media. The best- known computer network is the Internet.
Classification of Computer Networks
•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
other to share information and resources.
Characteristics of a computer network
•Share Resources from one computer to another
•Create files and store them in one computer, access those files from the other computer(s)
connected over the network
•Connect a printer, scanner, or a fax machine to one computer within the network and let
other computers of the network use the machines available over network.
Data communications
•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. Data communications
•The physical connection between networked computing devices is established using either
cable media or wireless media. The best- known computer network is the Internet.
Classification of Computer Networks
•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 buslike
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 adiistrator’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
•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 buslike
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 adiistrator’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
Geographical Span
•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
•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.
•For example, Piconet is Bluetooth-enabled Personal Area Network which may contain up to 8 devices connected together in a master-slave fashion. Personal Area Network
•For example, Piconet is Bluetooth-enabled Personal Area Network which may contain up to 8 devices connected together in a master-slave fashion. Personal Area Network
Local Area Network
•A computer network spanned inside a building and operated under single administrative system
is generally termed as Local Area Network (LAN). Usually , LAN covers an orgaizatio’ offices,
schools, colleges or universities.
•LAN provides a useful way of sharing the resources between end users . The resources
schools, colleges or universities.
•LAN provides a useful way of sharing the resources between end users . The resources
such as printers, file servers, scanners, and internet are easily sharable among computers.
•LANs are composed of inexpensive networking and routing equipment. It may contains local
servers serving file storage and other locally shared applications. It mostly operates on
private IP addresses and does not involve heavy routing. LAN works under its own locl
domain and controlled centrally.
•LAN uses either Ethernet or Token-ring technology. Ethernet is most widely employed
LAN technology and uses Star topology, while Token-ring is rarely seen.
•LAN can be wired , wireless, or in both forms
at once.
Metropolitan Area Network
•The Metropolitan Area Network (MAN) generally expands throughout a city such as
cable TV network. It can be in the form of Ethernet , Token-ring, ATM, or Fiber
Distributed Data Interface (FDDI).
•Metro Ethernet is a service which is provided by ISPs. This service enables its users to expand their
Local Area Networks. For example, MAN can help an organization to connect all of its offices in a
city.
•Backbone of MAN is high-capacity and high- speed fiber optics. MAN works in between Local
Area Network and Wide Area Network. MAN provides uplink for LANs to WANs or internet.
Wide Area Network
•As the name suggests, the Wide Area Network (WAN) covers a wide area which may span
across provinces and even a whole country. Generally, telecommunication networks are
Wide Area Network. These networks provide connectivity to MANs and LANs. Since they are
•LANs are composed of inexpensive networking and routing equipment. It may contains local
servers serving file storage and other locally shared applications. It mostly operates on
private IP addresses and does not involve heavy routing. LAN works under its own locl
domain and controlled centrally.
•LAN uses either Ethernet or Token-ring technology. Ethernet is most widely employed
LAN technology and uses Star topology, while Token-ring is rarely seen.
•LAN can be wired , wireless, or in both forms
at once.
Metropolitan Area Network
•The Metropolitan Area Network (MAN) generally expands throughout a city such as
cable TV network. It can be in the form of Ethernet , Token-ring, ATM, or Fiber
Distributed Data Interface (FDDI).
•Metro Ethernet is a service which is provided by ISPs. This service enables its users to expand their
Local Area Networks. For example, MAN can help an organization to connect all of its offices in a
city.
•Backbone of MAN is high-capacity and high- speed fiber optics. MAN works in between Local
Area Network and Wide Area Network. MAN provides uplink for LANs to WANs or internet.
Wide Area Network
•As the name suggests, the Wide Area Network (WAN) covers a wide area which may span
across provinces and even a whole country. Generally, telecommunication networks are
Wide Area Network. These networks provide connectivity to MANs and LANs. Since they are
equipped with very high speed backbone, WANs use very expensive network equipment.
•WAN may use advanced technologies such as Asynchronous Transfer Mode (ATM), Frame
Relay, and Synchronous Optical Network (SONET). WAN may be managed by multiple
administration.
•WAN may use advanced technologies such as Asynchronous Transfer Mode (ATM), Frame
Relay, and Synchronous Optical Network (SONET). WAN may be managed by multiple
administration.
Internetwork
•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.
•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.
•Internet is widely deployed on World Wide Web services using HTML linked pages and is
accessible by client software known as Web Browsers. When a user requests a page using
some web browser located on some Web Server anywhere in the world, the Web Server
responds with the proper HTML page. The communication delay is very low.
•Internet is serving many proposes and is involved in many aspects of life. Some of them are:
•Web sites
•E-mail
•Instant Messaging
•Blogging
•Social Media
•Marketing
•Networking
•Resource Sharing
•Audio and Video Streaming
us as submarine communication cable.
•Internet is widely deployed on World Wide Web services using HTML linked pages and is
accessible by client software known as Web Browsers. When a user requests a page using
some web browser located on some Web Server anywhere in the world, the Web Server
responds with the proper HTML page. The communication delay is very low.
•Internet is serving many proposes and is involved in many aspects of life. Some of them are:
•Web sites
•Instant Messaging
•Blogging
•Social Media
•Marketing
•Networking
•Resource Sharing
•Audio and Video Streaming
