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LECTURE
KEY DATA COMMUNICATION TERMINOLOGY
Link : connects adjacent nodes Wires, Cables, Any thing that physically connects two nodes
Path: end-to-end route within a network
Circuit: the conduit over which data travels
Packetizing : dividing messages into fixed-length packets prior to transmission over a network’s communication media
Routing: determining a message’s path from sending to receiving nodes
The transmission medium may itself be a network, so route needs to be specified
Network
“A NETWORK is a set of devices (Nodes) connected by Communication Links”
Node : Can be a Computer, Printer or any other device capable of sending or receiving
The links connecting Nodes are called COMMUNICATION CHANNELS Networks- Why we need them?
Networks- Why we need them?
It is often impractical for devices to be directly connected for two major reasons:
o The devices are very far apart. They are expensive to connect just two devices with one in Lahore and other in Islamabad o Large set of devices would need impractical number of connections e .g. Telephone Lines in the world and all the computers owned by a single organization
Solution to the Problem=Networks
o Solution is to connect all devices to a central system known as a NETWORK in which all terminals or computers share the links.
o Two Main Classifications of the Networks
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LANS
WANS
DISTRIBUTED PROCESSING
o Instead of a single large machine being responsible for all aspects of a process , each separate computer handles a subset of the task Example – Project Given as a part of the Course Example – Office Work
Advantages of Distributed Processing
Security
A system designer can limit the kind of interaction that a given user can have with the entire system.
For example : Bank’s ATM
Distributed Data bases
No one system need to provide storage capacity for the entire database
For example WWW gives user access to pages stored anywhere on Internet
Faster Problem Solving
Multiple computers working on a problem can solve a problem faster than a computer working alone
Security through Redundancy
Multiple computers running the same program provide security through redundancy If one computer hardware breaks down then others cover up.
Collaborative Processing
Both multiple computers and multiple users can interact for a task
Network Criteria docsity.com
Software processes data at sender , receiver and
steps need software:
e sender and receiver
an speed up the process
intermediate nodes All communication Moving message from node to node Transforming, Processing at th Error Free Delivery Well designed software c
Reliability
o Depends on a no. of Factors:
Frequency of Failure etwork after Failure
ake or Theft
Security
Recovery Time of a N Catastrophe Fire , Earthqu
o Unauthorized Access
Sensitive data ultiple levels: ser ID codes
Viruses
Protection at m Lower level: Passwords and u Upper Level: Encryption
o
Network Applications
Marketing and Sales
o Marketing
Collect, exchange and analyze data relating to the customers needs
o Sal
Tele shopping, on systems
Financial Services
Product development cycles es
On line reservati
o Online Banking e Transfers
o Foreign Exchang o Rates
Manufacturing
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o Computer Aided Design facturing
o Computer Assisted Manu o Network Applications
Electronic Messaging
Teleconferencing
o Conferences to occur w/o participants at the same place
Conferencing
o Chat o Voice o Video Conferencing
Cable Television
ummary
Key Data Communication Terminology
ions
eading Sections
Section 1.3, “Data Communications and Networking” 4th Edition by Behrouz A.
.3, “Data and Computer Communication” 6th Edition by William
S
Networks and why we need them? Distributed Processing Network Criteria Network Applicat
R
Forouzan Sections 1 Stallings
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