2. SYLLABUS
Data Link Layer – MAC Sublayer, CSMA, CSMA/CD, Ethernet, IEEE
Standards, LLC, ATM ,Network layer – Routing algorithms, Congestion
control algorithms, IPV4 and IPV6, Subnetting ,Transport Layer –
Services, Service primitives, Addressing , Application Layer – DNS,
E-mail architecture, SMTP, POP3, MIME, Network Management Devices
– Repeater, Hub, Switch, Router, Gateway, Wireless access point
Protocols -UDP, HTTP, FTP, TELNET, VOIP
3. Reference Books:
● Computer Networks : Andrew S Tanenbaum
● Data Communications and Networking - Behrouz A Forouzan
4. What is computer network?
○ A computer network is a series of interconnected nodes that can transmit,
receive and exchange data. Also referred to as Data Network.
○ A node can be a computer,printer or any other devices capable of sending
or/and receiving data generated by other nodes.
○ Distributed Processing :The task is divided among multiple nodes ,instead of a
single large machine being responsible for the entire processing.Distributed
systems appear to the user as a single coherent system.World wide web is a
distributed model where everything looks like a document .
5.
6. Computer Networks Vs. Distributed Systems
• Computer Networks:
– A computer network is an interconnected collection of autonomous computers
able to exchange information.
– A computer network usually require users to explicitly login onto one machine,
explicitly submit jobs remotely, explicitly move files/data around the network.
• Distributed Systems:
– The existence of multiple autonomous computers in a computer network is
transparent to the user.
– The operating system automatically allocates jobs to processors, moves files
among various computers without explicit user intervention.
– It is a software system built on the top of the network
7. Internet VS World Wide Web
● The internet is a globally connected network system facilitating worldwide
communication and access to data resources through a huge collection of personal,
public, business, academic and government networks.World Wide Web (WWW), by
name Web, is leading information retrieval service of web.
● Think of the internet as the roads that connect towns and cities together. The world
wide web contains the things you see on the roads like houses and shops.And the
vehicles are the data moving around.
8. Network properties :
● Network Criteria: Performance,Reliability and security
● Physical Structure :
○ Type of Connection :Point-to-point ,Multipoint
○ Physical Topology: Mesh,Star,Bus,Ring
● Network Models :ISO/OSI ,TCP/IP
● Network Categories: LAN,MAN,WAN
● Protocols and Standards :Protocol are the rules and the agreed-upon rules are
called standards
9. Protocols :
● For communication to occur ,the entities must agree on a protocol.A protocol is
a set of rules that govern data communication.
● A protocol defines
○ what is communicated
○ how it is communicated
○ when it is communicated
● The key elements of protocol are
○ Syntax:Structure ,format and order of data transmitting
○ Semantics: What is the meaning of the data sections
○ Timing :When to send the data and how fast they can send
10. Standards :
● It is essential in creating and maintaining an open and competitive market for
equipment manufacturers and in guaranteeing national and international
interoperability of data and telecommunications technology and processes.
● Two Categories
○ De facto standard : Standard not been approved by an organization
○ De jure standard :Standards that have been legislated by an officially
organized body Eg: ISO,ITU,ANSI,IEEE
11. Network Models/Reference Models
● Computer networks are created by different entities. Standards are needed so
that these heterogeneous networks can communicate with one another.
● The two best-known standards are the
○ OSI model
○ TCP/IP Model (Internet model)
12. ISO/OSI Model
● Open System
Interconnection Model
● ISO is the organization
● OSI is the model that
follows the standards
and agreements of ISO
13.
14. The purpose of a computer network is ___.
A) Sharing information
B) Sharing of resources
C) Monitoring and controlling of devices in the network from a
central location
D) All the above
15. The purpose of a computer network is ___.
A) Sharing information
B) Sharing of resources
C) Monitoring and controlling of devices in the network from a
central location
D) All the above
