Communication protocol presentation

Communication Protocol

Authored by Gopi.A24/06/2013Email: [email protected]

What is communication?● The transmission of data from one computer to another, or from one

device to another.

● A communications device, therefore, is any machine that assists data transmission.

For example, modems, cables, and ports are all communications devices.

● Communications software refers to programs that make it possible to transmit data.

(i.e) Software that makes it possible to send and receive data over telephone lines through modems.


What is Protocol ?● It is a set of rules governing the format and meaning of frames, packets, or messages that are exchanged by peer entities within a layer.

● Protocols are normally defined in a layered manner and provide all or part of the services specified by a layer of the OSI reference model.

● Protocol are used for communications between entities in a systems.

● Entities use protocols in order to implement their service definitions.

The key elements of a protocol are:Syntax : Include Time data formats and signal levelsSemantics: Includes control information and error handling

Communications Protocol● communications protocol is a system of digital rules for

message exchange within and/or between computers.

● The way they organize and transmit the data in bit and bytes of electronic signals.(encode the data).

● A protocol can therefore be implemented as hardware, software, or both. Communications protocols have to be agreed upon by the parties involved.

● To reach agreement a protocol may be developed into a technical standard.

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A communications protocol must define the following:

● Rate of transmission (in baud or bps)whether transmission is to be synchronous or asynchronous

I n t e r v a l s (Asynchronous)

( synchronous )

● Whether data is to be transmitted in half-duplex or full-duplex mode

Sender Stop Data Stop Data Start Receiver

Sender ReceiverData

Start

Synchronous is real time, and asynchronous is time delayed.

Synchronous communication takes place when people are connected at the same time (real time communication) whereas asynchronous communication does not require people to be online at the same time.

ExampleSynchronous: phone calls, skype, text chat, face-to-face talk.Asynchronous: snail post, e-mails, springdoo messages, blogs, forums, podcasts, video blogs or vlogs

SynchronousAdvantages: you can get an immediate response; instant feedback fosters communication; there seems to be a more emotional bonding effect between people when there is a possibility to communicate in real time (synchronously), spontaneity.Weaknesses: there is less time to think about what you want to say or your response to another; time may be a limiting factor, e.g time zones; synchronous communication over the computer may be difficult because of the speed of data transaction with slower connections; you need extra equipment (speakers, microphone, web camera)

AsynchronousAdvantages: you have time to think about what you want to say; time is not a constraint. You can receive the message whenever you have time and you can analyze the content of the message more carefully so the answer you give can be even more meaningful because it has gone through a process of elaboration.Weaknesses: no immediate response, especially where time is significant; you may not know if the other person has received your message; the message loses human contact.




Communication protocol development methods

There are two ways of design and development ofCommunication protocols

1. Informal

2. Formal Methods


Informal

● Informal communication networks do not follow any set of rules, definite liners or ways.

● In informal communication, everybody can freely interact as there are no restriction or rules. Any secret matter is likely to be flashed without any problem or hesitation. This may cause a huge damage to any organization

● The informal way specification of the protocols include Textual description (natural language like English) and message exchange sequence.

● Often leads to unclear and ambiguous specification and not suitable for large complex protocols.

● The complexity of protocols make them very hard to analyze in an informal way.


Formal methods

Components of a protocols are to be specified by using the Formal methods.

- Communication Service. - Peer entity of a protocol. - Communication interface. - Interaction.

● Use of formal specification languages.

● These protocols must be of high quality with higher performance with low cost.

● After informal specification has been written,a formal specification is created,that can be validate and simulate with a FDT tool.This formal specification is used as model for the implementation.

Formal Specification: in development methods The common way of application of formal techniques for formal specification is,After the informal specification has been written,a formal specification is created,that can be validated and simulated with FDT(Formal description technique) tool.The formal specification is later used as a model for the implementation.


Informal specification of needs

Formal Specification

Simulation Validation Compilation

Repeat

until

Validation

OK

Implementation

Programmer

Thank you


Service Specification Verification /

Validation

Synthesis

Protocol Specification

Performance Analysis

Monitoring Diagnosis

ProtocolImplementation

Conformance Testing

Communication protocol presentation

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