Data communication and engineering gtu notes, Cheat Sheet of Engineering

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Unit- 1 Dr. Mani Shekhar Gupta, Department of Information & Communication Technology Adani University Gujarat, India March 10, 2023 Data Communication & Computer Networks (Course Code: 3143201), Sem.- IV

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Unit 1. Learning Objectives

⚫ Be aware of the history of communications, information systems and the Internet ⚫ Be aware of the applications of data communications networks ⚫ Be familiar with the major components of and types of networks ⚫ Understand the role of network layers ⚫ Be familiar with the role of network standards ⚫ Be aware of key trends in communications and networking

Components of a data communication system

PROTOCOLS A protocol is synonymous with rule. It consists of a set of rules that govern data communications. It determines what is communicated, how it is communicated and when it is communicated. The key elements of a protocol are syntax, semantics and timing ▪ Syntax ▪ Semantics ▪ Timing Elements :

Standards

Standard ⚫ Standard: which are agreed upon rules. ⚫ It provides guidelines to manufactures, venders, govt agencies to ensure the kinds of interconnectivity at the level of international. ⚫ Standard organization: ⚫ (1) ISO( International organization for standardization. ⚫ (2) ITU-T( international telecommunication union- Telecommunication standard sector): it is formed by US a committee called CCITT( consultative committee for international telegraphy and telephony). It 1993, its name is changed to ITU-T ⚫ ANSI(American National Standard Institute): US private but not profit organization. ⚫ IEEE( Institute of Electrical and Electronics Engineers): it is largest engg professional society of the world. Its aims is to advance theory, creativity and product quality in the field of electrical, electronics and radio as well as in all related branch of engg ⚫ Electronics Industries Association(EIA): non profit organization in the field of electronics manufacturing concern

Data Transmission - transmission techniques ⚫ Type of Connection ⚫ Point to Point - single transmitter and receiver ⚫ Multipoint - multiple recipients of single transmission ⚫ Physical Topology ⚫ Connection of devices ⚫ Type of transmission - unicast, mulitcast, broadcast

Types of connections: point-to-point and multipoint

Network Criteria ⚫ Performance ⚫ Depends on Network Elements ⚫ Measured in terms of Delay and Throughput ⚫ Reliability ⚫ Failure rate of network components ⚫ Measured in terms of availability/robustness ⚫ Security ⚫ Data protection against corruption/loss of data due to: ▪ Errors ▪ Malicious users

Topologies

A star topology connecting four stations Dedicated point link to central controller called hub.  Advantages: (1) Less expensive than mesh topology (2) Easy to install and reconfigure (3) Less cabling need (4) It is more robust. (5) Easy fault identification Disadvantages: (1) If hub fails then topology will not work.

A bus topology connecting three stations It is multipoint. One long cable acts as a backbone to all devices in a network.  Advantages: (1) Easy to install and reconfigure (2) Less cabling need Disadvantages: (1) Difficult to reconnection and fault isolation. (2) Signal reflection at tap cause degradation in quality. (3) Fault and break in bus stops all transmission.

A hybrid topology: a star backbone with three bus networks

Categories of Networks ⚫ Local Area Networks (LANs) ⚫ Short distances ⚫ Designed to provide local interconnectivity ⚫ Wide Area Networks (WANs) ⚫ Long distances ⚫ Provide connectivity over large areas ⚫ Metropolitan Area Networks (MANs) ⚫ Provide connectivity over areas such as a city, a campus