Internet Network, Protocols

and Standards

Pradini Puspitaningayu

References : William Stallings, Behrouz Forouzan

Have you find the books?

William Stallings, Data and Computer CommunicationBehrouz Forouzan, Data Communication and Networking

Wide Area Networks (WAN)

• Large geographical area

• Crossing public right-of-ways

• Rely at least in part on circuit provided by a common carrier

• Consisit of a number of interconnected switching nodes

• Alternate technologies :

– Circuit Switching

– Packet Switching

– Frame Relay

– ATM

Circuit Switching

• A dedicated communications path is established between two stations through the nodes of the network

• Data generated by the source station are transmitted along the dedicated path as rapidly as possible

• At each node, incoming data are routed or switched to the appropriate outgoing channel without delay

• Example : telephone network

Packet Switching

• Data are sent out in a sequence of small chunks,called packets

• Each packet is passed through the network from node to node along some path leading from source to destination

• At each node, the entire packet is received, stored briefly, and then transmitted to the next node

• Example : terminal-to-computer and computer-to-computer communications

Frame Relay

• Packet switching systems have large overheads to compensate for errors

• Modern systems are more reliable

• Errors can be caught in end system

• Most overhead for error control is stripped out

• Packet Switching vs Frame Relay

– Packet switching’s data rate about 64 kbps

– Frame relay’s data rate up to 2 Mbps

Asynchronous Transfer Mode

• ATM

• Developments in circuit switching and packet switching

• Evolution of frame relay

• Little overhead for error control

• Fixed packet (called cell) length

• Anything from 10Mbps to Gbps

• Constant data rate using packet switching technique

Integrated Service Digital Network (ISDN)

• Designed to replace public telecom system

• Wide variety of services

• Entirely digital domain

Local Area Network (LAN)

• 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

Protocols

• Used for communications between entities in a system

• Must speak the same language

• Entities– User applications

– e-mail facilities

– terminals

• Systems– Computer

– Terminal

– Remote sensor

Key Elements of Protocols

• Syntax

– Data formats

– Signal levels

• Semantics

– Control information

– Error handling

• Timing

– Speed matching

– Sequencing

Protocols Architecture

• Task of communication broken up into modules

• For example file transfer could use three modules

– File transfer application

– Communication service module

– Network access module

Simplified File Transfer Architecture

Protocol Architecture & Network

Protocol Data Unit (PDU)

• At each layer, protocols are used to communicate

• Control information is added to user data at each layer

• Transport layer may fragment user data

• Each fragment has a transport header added– Destination SAP

– Sequence number

– Error detection code

• This gives a transport protocol data unit

Operation of a Protocol Architecture

Standards

• What is standards?

– A standards provides a model for development that makes it possible for a product to work regardless of the individual manufacturer

• Why we need standardization?

– Creating competitive market

– International interoperability and interconectivity

– Simplification

Non-standard VS Standard

K sources and L receivers leads to K*L protocols and 2*K*L implementations. If common protocol used, K + L implementations needed

Standard Organization

• International Standards Organization (ISO)

• International Telecommunication Union –Telecommunication Standards Sector (ITU-T)

• American National Standards Institute (ANSI)

• Institute of Electrical and Electronics Engineering (IEEE)

• Electronics Industries Association (EIA)

• Telecordia

Task

• Find out what standards have been made by ISO, ITU-T, ANSI, IEEE, EIA, Telecordia

• Translate William Stalling’s Data and Computer Communication– Page 25-53

– Format MS Word, Include the graphics

– Deadline : Thursday 25/09/2014 11:00 AM

Quiz 29/09/2014