Download Chapter 4. - Amoud University

Faculty of Computing and ICT
Under Department
Bachelor of Science in
Information Technology
Seniorr
Date: April. 13, 2014.
Monday Evening.
Chapter 4. Three basic building blocks of
the Internet.
Introduction
The Internet is basically a hierarchy that allows any
Internet connected device in one geographic location,
talking to another Internet connected device in another
geographic location. The way that the information is
transmitted varies greatly, and in some countries, wireless
ham radios are even used to transmit email. Keep in mind
that the word "connected" is used very loosely here.
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 The Open Systems Interconnection (OSI) Model
The seven open systems interconnection
layers (OSI) are a staple of most networking
textbooks. The idea is that a network will work on
many different levels, or "layers" each of which will
perform a supporting function for the next layer.
Open Systems Interconnection Models
( OSI Model)
Application Layer
Presentation Layer
Session Layer
Transport Layer
Network Layer
Link Layer
Physical Layer
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 Application layer:
The application layer is provided by the program
that uses TCP/IP for communication. An application is
a user process cooperating with another process
usually on a different host (there is also a benefit to
application communication within a single host).
Examples of applications include Telnet and the File
Transfer Protocol (FTP). The interface between the
application and transport layers is defined by port
numbers and sockets,
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 Transport layer:
The transport layer provides the end-toend data transfer by delivering data from an
application to its remote peer. Multiple applications
can be supported simultaneously. The most-used
transport layer protocol is the Transmission Control
Protocol (TCP), which provides connection-oriented
reliable data delivery, duplicate data suppression,
congestion control, and flow control.
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 Network layer
The internetwork layer, also called the
internet layer or the network layer, provides the
“virtual network” image of an internet (this layer
shields the higher levels from the physical network
architecture below it). Internet Protocol (IP) is the
most important protocol in this layer. It is a
connectionless protocol that does not assume
reliability from lower layers. IP does not provide
reliability, flow control, or error recovery. These
functions must be provided at a higher level.
IP provides a routing function that
attempts to deliver transmitted messages to their
destination.
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The Network layers are the first three,
being the physical link layer, the link layer, and the
Network layer. Since the Internet is based on the
Internet protocol which is in the Network Layer, and
since the Internet can run on any number of different
types of layers below that, we normally are not too
concerned with the physical layers unless we are
building an Ethernet cable, or transmitting an
Internet signal through wireless means, and not to
interested in the link layer unless we are registering a
network card or router MAC address with our service
provider.
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The top three layers (session, presentation,
and
application
layers)
are
for
program
communication, and are completely independent of
the network so that the two communicating programs
could even be on the same machine.
We also sometimes include the transport
layer when discussing the Internet, and often link the
transport with the network layer as in the TCP/IP
protocols. Transmission Control Protocol (TCP) is in the
transport layer, and Internet Protocol (IP) is in the
Network layer. Most Internet based functions such as
the world wide web, and email, use TCP/IP, so this is a
basic building block for the Internet.
.
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The transport layer also makes sure that
the top three layers are network independent
The Simple Network Management
Protocol (SNMP) is an application-layer protocol that
facilitates the exchange of management information
between a network management system (NMS),
agents, and managed devices. SNMP uses the
Transmission Control Protocol/Internet Protocol
(TCP/IP) protocol suite.
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 The Basic Components of SNMP?
• Agent
A
network-management
software
module, such as the Cisco IOS software, that
resides in a managed device. An agent has local
knowledge of management information and
makes that information available by using SNMP.
• Network Management Systems (NMS)
Run applications that monitor and
control managed devices. NMS provide resources
required for network management.
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Portals and its Types
What is a portals?
A portal is a mechanism that is used in e-marketplaces,
e-stores, and other types of Electronic Commerce
e.g E-learning.
In other words a portal is an information gate way, it
attempts to address information overload by enabling
people to search and access relevant information.
 Information Portal: A single point of access through a
web browser to business information inside and/or
outside and organization.
Types of Portal
There are six major types of portal which are as following:
1: Commercial (Public) portal: these portals offer content for
diverse communities and are the most popular portals on the
internet.
2: Corporate Portals: provide organized access to rich content
within relative narrow corporate and partners communities.
3: Publishing Portals.
4: Personal Portals.
5: Mobile Portals: A portal accessible via a mobile device.
6: Voice Portals: a portal accessed by telephone or cell phone.
Electronic Catalogs
What is an Electronic Catalogs?
Is the presentation of product information in an
electronic form; the backbone of most e-selling sites.
 Catalogs have been printed on paper for generations.
 Recently electronic catalogs on CD ROM and the
internet have gained the popularity.
 Electronic catalogs consist of product database,
directory and search capabilities and a presentation
function.
Classification of Electronic Catalogs
1: The dynamics of the information presentation:
Information is presented in motion pictures or
animation.
2: The degree of the customization; catalogues may
be standard or customized. In standard catalogues
merchants offer the same catalog to any customer.
In customized catalogs content, pricing, and display
are tailored to characteristics of specific customers.
3: Integration with business processes.
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