DC-Lec-6 (Protocols & Standards)

8/3/2019 DC-Lec-6 (Protocols & Standards)

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DATA

COMMUNICATION

Lecture-6


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Recap of Lecture 4 & 5

Physical Structure of Network

Line Configuration/ Type of Connection Topologies

Categories of Topologies


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Overview of Lecture 6

Protocols

Elements of Protocols

Standards

De-Jure De-Facto


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Protocols

A protocol is a set of rules that govern datacommunications.

A protocol defines

what is communicated, how it is communicated, and when it is communicated.

For communication to occur, the entities must agree on aprotocol.

The key elements of a protocol are Syntax Semantics timing.


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Protocols (Cont.)

Syntax: The term syntaxrefers to the structure or format of the

data, meaning the order in which they are presented. For example, a simple protocol might expect the first 8

bits of data to be the address of the sender, the second 8bits to be the address of the receiver, and the rest of thestream to be the message itself.

Semantics:

The wordsemantics

refers to the meaning of each sectionof bits. How is a particular pattern to be interpreted, andwhat action is to be taken based on that interpretation?For example, does an address identify the route to betaken or the final destination of the message?


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Protocols (Cont.)

Timing:

The term timing refers to two characteristics: when data should be sent?

and how fast they can be sent?

For example, if a sender produces data at 100 Mbps

but the receiver can process data at only 1 Mbps, thetransmission will overload the receiver and some datawill be lost.


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Standards

A standard provides a model for

development that makes it possible

for a product to work regardless of

the individual manufacturer


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Why Standards are Essential?

Standards are essential in:

1. Creating/Maintaining Open and Competitive Markets.

2. Guaranteeing National/International Interoperability of data andtelecommunications technology and processes.

Standards provide guidelines to manufacturers, vendors,government agencies, and other service providers to ensure thekind of interconnectivity necessary in today's marketplace and ininternational communications.


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Why Standards are Essential?


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Categories of Standards

Proprietary NonProprietary

De facto

(By Fact or "byconvention)

De jure

("by law" or "byregulation")

Standards


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De jure Those standards that have been legislated by

an officially recognized body.


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De facto Standards that have not been approved by an

organized body but have been adopted asstandards through widespread use.

De facto standards are often establishedoriginally by manufacturers who seek todefine the functionality of a new product or

technology.


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De facto Proprietary (Closed Standards) Standards that are originally invented by a commercial

organization as a basis for the operation of its product. They are wholly owned by the company. They are also called Closed Standards because they close off

communication systems. e.g. IGRP & EIGRP Routing Protocols.

Non Proprietary (Open Standards) They are originally developed by groups or communities that

have passed them into public domains. They are also called Open standards because they open

communication between different systems.


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Standards Organizations

Standards are developed mainly by 3 entities:

Standard Creation Committees Forums Regulatory Agencies


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Standard Creation Committees They are procedural bodies and are slow moving and cannot

co-op with the fast growing communication industry.

ISO (International Standard Organization)

ITU-T (International telecommunication Union-

telecommunication Standard Sector) ANSI

(The American National Standard Institute) IEEE

(Institute of Electrical and Electronics Engineers)


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FORUMS Special Interest Groups with representatives from interested

corporations they facilitate and fasten standardization processby working with universities, and users to test, evaluate, andstandardize new technology.

Frame Relay Forum ATM Forum Internet Society Internet Engineering Task Force (IETF)


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Regulatory Agencies All communication technology is subject to regulation and

laws by government agencies. The purpose is to protect

public interest by regulating radio, television and cablecommunication.

FCC


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Summary

Protocols

Elements of Protocols Standards

De-Jure

De-Facto


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Suggested Reading Section 1.4, Data Communications and Networking 4th Edition by

Behrouz A. Forouzan

Sections 1.3, Data and Computer Communication 6th Edition by William

Stallings

DC-Lec-6 (Protocols & Standards)

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Transcript of DC-Lec-6 (Protocols & Standards)