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IEC-802 : DATA COMMUNICATION NETWORK
Unit-1Basic concepts And ISO-OSI-Model
QAZI SAEED AHMADASSISTANT PROFESSORDEPARTMENT OF ELECTRONICS & COMMUNICATIN ENGINEERINGINTEGRAL UNIVERSITY LUCKNOW
A Communication Network
• Source– generates data to be transmitted
• Transmitter– Converts data into transmittable signals
• Transmission System– Carries data
• Receiver– Converts received signal into data
• Destination– Takes incoming data
Communications Tasks
Transmission system utilization Addressing
Interfacing Routing
Signal generation Recovery
Synchronization Message formatting
Exchange management Security
Error detection and correction Network management
Flow control
Simplified Communications Model - Diagram
Simplified Data Communications Model
Networking
• Point to point communication not usually practical– Devices are too far apart– Large set of devices would need impractical
number of connections• Solution is a communications network
– Wide Area Network (WAN)– Local Area Network (LAN)
Wide Area Networks
• Large geographical area• Crossing public rights of way• Rely in part on common carrier circuits• Alternative technologies
– Circuit switching– Packet switching– Frame relay– Asynchronous Transfer Mode (ATM)
Local Area Networks
• Smaller scope– Building or small campus
• Usually owned by same organization as attached devices
• Data rates much higher• Usually broadcast systems• Now some switched systems and ATM are
being introduced
LAN Configurations
• Switched– Switched Ethernet
• May be single or multiple switches– ATM LAN– Fibre Channel
• Wireless– Mobility– Ease of installation
Metropolitan Area Networks
• MAN• Middle ground between LAN and WAN• Private or public network• High speed• Large area
NetworkingConfiguration
Line Configuration
Point-to-Point Line Configuration
Multipoint Line Configuration
Network Topology
Mesh Topology
Mesh Topology
Star Topology
Tree Topology
Ring Topology
Hybrid Topology
Transmission modes
Simplex
Half-Duplex
Full-Duplex
ISO-OSI Model
OOO OSI MODEL
OSI LAYERS
An Exchange using OSI Model
Physical Layer
Duties
• 1. Physical Characteristics of Interfaces and Medium
• 2. Representation of Bits• 3. Data Rate• 4. Synchronization of Bits• 5. Line Configuration• 6. Physical Topology• 7. Transmission Mode
Data Link Layer
Duties
• 1. Framing• 2. Physical Addressing• 3. Flow Control• 4. Error Control• 5. Access Control
Data Link Layer example
Network Layer
Duties
• 1. Logical Addressing• 2. Routing
Transport Layer
Duties
Network Layer Example
Transport Layer
WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998
Session Layer
Presentation Layer
Application Layer
Summary of Layer Functions
Thank You