Transcript Lecture 4 unit 1 - Dr. Rajiv Srivastava

Lecture 4
unit 1
categories of network
• A network can be categorized as a
1. Local area network.
2. Wide area network.
3. Metropolitan area network.
4. Personal area network
Local area network
• A LAN is a data communication system within a
building, plant, or campus, or between nearby
buildings.
• Its depend on the need of an organization and
the type of technology used, a LAN can be simple
as two PCs and a printer in someone’s office.
• It can be extend throughout a company and
include audio and video peripherals.
• LAN size is limited to a few kilometers.
• LAN are designed to allow resources to be shared
between personal computer or workstation.
• The resource to be shared can include hardware,
software or data.
An isolated LAN connecting 12 computers to a
hub in a closet
Wide area network
• A WAN provide long distance transmission of
data, image, audio and video information over
large geographic areas that may comprise a
state, a country, a continent, or even the whole
world.
• A WAN is a data communication system
spanning states, countries, or the whole world.
• A WAN can be complex as the backbones that
connect the internet or as simple as a dial-up
line that connect a home computer to the
internet.
• A WAN can contain multiple smaller networks,
such as LANs or MANs. The Internet is the bestknown example of a public WAN.
WANs: a switched WAN and a point-to-point WAN
Metropolitan area network.
• A MAN is a network with a size between a LAN and a
WAN.
• A MAN is a data communication system covering an
area the size of a town or city.
• A MAN is larger than a LAN, which is typically limited
to a single building, campus or site.
• A MAN is often used to connect several LANs
together to form a bigger network. When this type of
network is specifically designed for a college campus,
it is sometimes referred to as a campus area network,
or CAN.
• It is designed for costumer who need a high speed
connectivity, normally to the internet, and have end
points spread over a city or a part of city.
A heterogeneous network made of WANs & LANs
Personal area network
• A personal area network, or PAN, is a computer network
organized around an individual person within a single
building. This could be inside a small office or residence.
A typical PAN would include one or more computers,
telephones, peripheral devices, video game consoles and
other personal entertainment devices.
• If multiple individuals use the same network within a
residence, the network is sometimes referred to as a
home area network, or HAN. In a very typical setup, a
residence will have a single wired Internet connection
connected to a modem. This modem then provides both
wired and wireless connections for multiple devices. The
network is typically managed from a single computer but
can be accessed from any device.
• This type of network provides great flexibility.
For example, it allows you to:
– Send a document to the printer in the office
upstairs while you are sitting on the couch with
your laptop.
– Upload the photo from your cell phone to your
desktop computer.
– Watch movies from an online streaming service to
your TV.
What is the difference between a
LAN, a MAN, and a WAN?
• A LAN (local area network) is a group of
computers and network devices connected
together, usually within the same building. By
definition, the connections must be high speed
and relatively inexpensive (e.g., token
ring or Ethernet).
• A LAN connection is a high-speed connection to a
LAN. Most connections are either Ethernet (10
Mbps) or Fast Ethernet (100 Mbps), and a few
locations can have Gigabit Ethernet (1000 Mbps)
connections also.
• A MAN (metropolitan area network) is a
larger network that usually spans several
buildings in the same city or town.
• A WAN (wide area network), in comparison
to a MAN, is not restricted to a geographical
location, although it might be confined
within the bounds of a state or country.
• A WAN connects several LANs, and may be
limited to an enterprise (a corporation or an
organization) or accessible to the public. The
technology is high speed and relatively
expensive. The Internet is an example of a
worldwide public WAN.
Connection Oriented & Connectionless Services
• Connection Oriented services
– Connection Oriented services, the source first makes a
connection with the destination before sending a
packet.
– When the connection is established, a sequence of
packets from the same source to the same destination
can be sent one after another.
– There is a relationship between packets.
– They are sent on a same path in sequential order.
– When all packets of a message have been delivered,
the connection is terminated.
– Requires a session connection to be established
before any data can be sent. This method is often
called a "reliable" network service.
– the connection oriented services are used in TCP.
Connectionless Services
– Connectionless Services, the network layer protocol
treats each packet independently, with each packet
having no relationship to any other packet.
– The packet in the message may or may not travel the
same path to their destination.
– Does not require a session connection between sender
and receiver. The sender simply starts sending packets
(called datagram) to the destination.
– Connectionless communication is just packet switching
where no call establishment and release occur. A
message is broken into packets, and each packet is
transferred separately.
– Connectionless service is typically provided by the UDP
(User Datagram Protocol). The packets transferred using
UDP are also called datagram.
Difference between connection oriented
and connectionless services
1. In connectionless communication there is no need to
establish connection between source (sender) and
destination (receiver) but in connection-oriented
communication connection must be established before
data transfer.
2. Connection-oriented communication is more reliable
then connectionless communication.
3. In connection-oriented communication information can
be resend if there is an error in receiver side (missing
data, corrupt data etc. ) but in connectionless
communication it is not possible because the destination
does not inform the source about data is received or not.