NW line coding

Course Overview

Department: Information Technology

Course Code: 22IT402

Course Title: Networking and Communication

Faculty Name: Mr. K. Suresh Kumar, Assistant Professor/IT

Academic Year: 2023 - 2024 (Even Semester)

Institution: Sri Krishna College of Technology, Kovaipudur, Coimbatore-641042

  • CO1: Understand the fundamentals of data communications, including definitions, key principles, and the significance of layered architecture in networking, emphasizing the roles of the application, transport, network, data link, and physical layers (Understanding Level - U).

  • CO2: Illustrate various error detection and correction methods such as checksums, CRC, and acknowledge the critical role of different network technologies including LAN, WAN, and MAN (Understanding Level - U).

  • CO3: Analyze the requirements for a given organizational structure by assessing aspects like scalability, security needs, and performance, to select the most appropriate networking architecture and routing technologies suitable for specific use cases (Analyzing Level - AN).

  • CO4: Construct Routers and Switches to facilitate efficient Data Transfer, understanding the significance of routing algorithms and configurations in enhancing network performance and reliability (Applying Level - AP).

  • CO5: Understand the application layer protocols, such as HTTP, FTP, and SMTP, along with the essential measures for network security including firewalls, intrusion detection systems, and encryption techniques (Understanding Level - U).

  • CO6: Analyze the connection establishment and termination process in the transport layer, focusing on protocols like TCP and UDP, which manage how data is sent over networks (Applying Level - AP).

Module 1: Data Communications and Physical Layer

Overview

This module delves into critical concepts in data communications and the physical layer of networking, which serves as the foundation for understanding more complex networking protocols and technologies. It spans topics such as network topologies, essential networking models (ISO/OSI and TCP/IP), various performance metrics, and an in-depth exploration of different transmission media employed in networking.

Topics and Hours

S. No

Topic Description

Hours

Cumulative Hours

Learning Outcomes

RBT

Textbooks

1

Introduction, Networks Topologies

2

2

CO1

U

T1

2

ISO/OSI Model

2

4

CO1

U

T1

3

TCP/IP Model and Protocols

2

6

CO1

U

T1

4

Performance Metrics

2

8

CO2

U

T1

5

Different Types of Transmission Media, Errors in Transmission: Attenuation, Noise, Repeaters

2

10

CO2

U

T1

6

Encoding (NRZ, NRZI, Manchester, 4B/5B)

1

11

CO2

U

T1

7

Networking Devices: Hubs, Bridges, Switches, Routers, and Gateways

2

13

CO3

AN

T1

8

Switching - Circuit Switched Networks, Packet Switched Networks

2

15

CO4

AP

T1

Key Concepts in Data Communications

Signal Transmission

Information in computer networks is transmitted as either digital or analog signals. The techniques for conversion between these signals are critical for ensuring data integrity.

Techniques of Conversion:

  • Digital-to-Digital Conversion: Directly converts one digital signal to another without any modulation.

  • Digital-to-Analog Conversion: Converts digital signals into analog signals to facilitate transmission over various media.

Important Encoding Techniques

  • Line Coding: A fundamental process needed in signal transmission, converting digital data into digital signals.

  • Block Coding & Scrambling: Sometimes required based on network protocols and applications to maintain signal integrity and minimize errors.

Key Encoding Techniques:

  • Non-Return to Zero (NRZ): Constant signal during the bit interval for efficient representation but may suffer from long sequences of identical digits.

  • Non-Return to Zero Inverted (NRZI): Utilizes signal inversion for the representation of '1' bits, providing resilience against DC bias.

  • Manchester Encoding: Guarantees a transition in the middle of each bit interval which helps in clock recovery at the receiving end.

  • 4B/5B Encoding: Efficiently maps 4 bits of data into 5 bits providing a balance between data transmission and signal quality.

Error Detection and Transmission Integrity

Understanding errors in transmission such as attenuation, noise, and jitter is crucial. Techniques and tools like repeaters are employed to enhance signal quality and recover lost or distorted information during transmissions.

Data Rate and Signal Rate Definitions

  • Data Rate (bps): Represents the number of bits transmitted in one second and is crucial for assessing network capacity.

  • Signal Rate (baud): The number of distinct signal events or changes in signal level per second, directly influencing the transmission quality and efficiency.

  • Understanding the relationship between data rate and signal rate is essential for optimizing network performance and capabilities in various applications.

Applications of Line Coding Schemes

  • Understanding practical applications of encoding such as NRZ Protocols for traditional data networks, NRZI for Fiber Distributed Data Interfaces, Manchester for Ethernet systems, and 4B/5B for Fast Ethernet protocols is critical for networking professionals to design and troubleshoot networks effectively.

Practice Questions

  1. For the input stream to a 4B/5B block encoder, analyze the output stream and determine the longest sequence of zeros.

  2. Calculate the average signal rate and bandwidth for a system using NRZ-I to transfer data at 100-Mbps, detailing the implications for network performance and reliability.