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Computer Networks
(Lecture 1)
Bijendra Jain([email protected])
Dept. of Computer Sc. And Engg.
Indian Institute of Technology Delhi
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Course ScheduleStructure:
LTP 4-0-2
Lectures 42
Associated Home Assignments (12%)
Programming and Laboratory Assignments (24%)
2 Minor and Major Exams (64%)
Pre-requisites:
Computer Architecture and Data Structures
Recommended: Operating systems
Topics in Communication Systems & Probability Theory
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Text
A. S. Tanenbaum: Computer Networks,
Prentice Hall India, 4th edition
(reference only) W. Stallings: Data andComputer Communications, Prentice Hall
India, 7th edition
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Definition of Computer Networks
A "computer network" is an interconnected set ofautonomous computers, and other resources, thatpermit distributed access to information
Interconnection both at physical and application level
Autonomy in using or providing resources
Access to different resources by remote users
Rules out multi-processor systems based master-slave relationships
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Course outline
Basics of data communication (channel capacity, encoding, etc.)
Data-link protocols for reliable communication (CRC, multi-
access protocols)
Network layer protocols (topology, routing, congestion control,
and internetworking)
Transport layer protocols and error recovery
Application layer services and protocols (email, ftp, http, dns,
etc.)
Secure communication (confidentiality, authentication andintegrity)
Network management
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Why Networks?
Resource sharing (CPU, peripherals,
information and software)
Communications (person-to-person, text +graphics + audio + video)
(more recently) environment monitoring and
control
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Network applications
Super computing
Collaborative research and development
Integrated system for design, manufacturing, inventory control,
marketing, etc. Banking (fund transfers, ATM)
Transportation (courier, cargo, rail, air)
WEB
E-commerce
Electronic publishing and digital libraries Multi-media communication (tele-training, collaborative
computing, etc.)
Voice-over-IP, Video-on-demand
Health-care delivery (remote diagnosis)
Sensor networks
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Design Issues
Variety of Resources:
*computer systems
*operating systems
*transmission media
Variety of applications
Errors and Breakdown:*transmission line errors and communication equipment failure
*computer equipment breakdown
*incompatible or incorrect implementations
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Design Issues (2)
Capacity Limitations:
*CPU, storage
*transmission bandwidth
Security:
*confidentiality
*authentication
*integrity
Cost and Performance
User-friendly access
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Fundamental problems in networking Information transfer:
*store-n-forward packet switching
*addressing and routing
*flow control
*data integrity*efficiency
Performance assessment and quality of service
Information representation
Network and computing resource management
Security Management
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Store-n-forward packet switching
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Store-n-forward packet switching (2)
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Network architecture: OSI model
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Network architecture: TCP/IP model
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Network architecture
The concept of layering results in:
*modular construction
*top-down design
*independence from underlying implementation
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Network architecture (2)
Concept of service, and of protocol
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Information representation
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Classification of Networks On geographical basis:
*LAN
*MANs
*WANs
*interconnected LANs, MANs and WANs*home networks
On basis of protocol stack (TCP/IP, OSI, SNA, Novell, )
On basis of underlying technology (Ethernet, wireless, optical-fibre,)
On basis of ownership
On basis of applications
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LANs
Privately owned media and services
Local, fast
Shared access to a broadcast medium
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Local wireless networks
Two modes:
Infrastucture-based
Peer-to-peer
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Infrastucture-based wireless network
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Infrastucture-less wireless network
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(TV cable-based) MANs
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(Telephone-network based) MANs
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Interconnected LANs, WAN
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Wire-less sensor networks
sensor
sensor
sensor
sensor
sensor
sensor sensor
sensor
sensor
sensor
sensorcollators
collators collators
collators
Self-
configuring
network
Central
manager
