Transcript intro - UTRGV Faculty Web

Introduction to Computer Networks
Dr. John P. Abraham
INTRODUCTION TO COMPUTER
NETWORKS
What is covered in the course





Network Applications & Network
programming
Data communications (low level details)
Packet switching and network technologies
Internetworking with TCP/IP
Other concepts such as interoperability
standards, protocol suites and layering
models
Socket programming


All underlying network applications such as email,
ftp, web, etc. use underlying technologies and
programs
The goal of this course is not to teach you
programming. Students should write three socket
programs in a language of their choice
Data Communication

Technologies used to send data across
communication lines





Modulation
Digital to analog
Light
Multiplexing
Encryption
Packet Switching and networking
technologies

Evolved from telegraph and telephone
technologies


Mechanical connections are replaced with
electronic switches
Packet switching – eliminated the need for a
dedicated circuit


Devices through out the network should have
information about how to reach the target destination
Takes into account speed, cost, distance and size of
packets
Internetworking with TCP/IP


Tolerance of heterogeneity of underlying
technologies.
The internet is formed by interconncecting
multiple packet-switching networks, as well
as public and private networks.
Introduction to Computer Networks
Applications of Networks
Resource Sharing
Hardware (computing resources, disks, printers)
Software (application software)
Information Sharing
Easy accessibility from anywhere (files, databases)
Search Capability (WWW)
Communication
Email
Message broadcast
See next slide
Application of network 2
Remote computing
Virtualization (see future slided)
Supercomputing - used
for highly calculation-intensive
tasks in quantum physics, genetics, weather
modeling, etc.
Distributed processing – A program running on top of a
network distributes the job.
GRID Computing – very similar to distributed. A middleware
is used to manage all the computers in the system (see next
slide).
Cloud computing (see future slide)
Grid computing



Multiple independent computing clusters
which act like a “grid” because they are
composed of resource nodes not located
within a single administrative domain.
Offering online computation or storage
(like electricity sale).
The creation of a “virtual supercomputer”
by using spare computing resources
within an organization
Virtualization
the act of decoupling one computing resource
from others without impacting the usability
across these resources.
User state virtualization
Application virtualization.
Client-Hosted Desktop virtualization
Server-based Desktop virtualization
Application Virtualization
User state virtualization.

separates the user data and settings from
any PC and enables IT to store them
centrally (i.e., in the datacenter) while also
making them accessible on any PC. It also
simplifies the central backup of user data
since data is already stored centrally on
servers.
Application virtualization


Isolates applications from each other and
solves application to application compatibility
issues by allowing applications to run
together even though they may require the
same resources from the OS
Application virtualization allows IT to store the
application centrally and stream the
application to a desktop based on user
access.
Client-Hosted Desktop Virtualization.

technology (such as Microsoft® Virtual PC or
Sun xVM Virtual Box ) that separates
the operating system from the physical
hardware and allows a single PC to run
virtual machines side by side with the host
OS.
Server-Based Desktop Virtualization:

Allows the execution of an environment at one place
and presentation of that environment or user
interface at a different location. These technologies
usually use remote desktop protocols, such as RDP,
to decouple the user interface location from the
execution environment location. Remote execution
enables organizations to use older PCs as “thin
clients,” giving users the benefit of newer
applications and versions of Windows while helping
save the environment by avoiding the dumping of
electronics into landfills.
Cloud Computing




is location independent computing
shared servers provide resources, software, and
data to computers.
computing is moved away from personal computers
or an individual application server to a “cloud” of
computers.
Users of the cloud only need to be concerned with
the computing service being asked for, as the
underlying details of how it is achieved are hidden.
This method of distributed computing is done
through pooling all computer resources together and
being managed by software rather than a human.
Introduction to Computer Networks
Network Components
Physical Media
Interconnecting Devices
Computers
Networking Software
Applications
Introduction to Computer Networks
Networking Media
Networking media can be
defined simply as the
means by which signals
(data) are sent from one
computer
to
another
(either
by
cable
or
wireless means).
Introduction to Computer Networks
Networking Devices
HUB,
Switches,
Wireless
Access
Modems etc.
Routers,
Points,
Introduction to Computer Networks
Computers: Clients and Servers
In a client/server network
arrangement,
network
services are located in a
dedicated
computer
whose only function is to
respond to the requests
of clients.
The server contains the
file, print, application,
security,
and
other
services in a central
computer
that
is
continuously available to
respond
to
client
requests.
Introduction to Computer Networks
Networking Protocol: TCP/IP
Introduction to Computer Networks
Applications
E-mail
Searchable Data (Web Sites)
E-Commerce
News Groups
Internet Telephony (VoIP)
Video Conferencing
Chat Groups
Instant Messengers
Internet Radio