Chapter 3

Telecommunication Architectures and Standard

Agenda

• Network architectures & standards

• Standard-making organizations

• Pros and cons of standards

• Open System Interconnection Model (OSI)

• TCP/IP

• Manufacturer architecture

• Pros and cons of architecture

Network Architectures

• Design principles for– Functions– Data format– Procedures

• Describe “what”

Communication Standards

• Rules for compatibility

• Specify “how”

Needs for Architectures and Standards

• Complex communication systems

• Maintenance and future growth

• Connectivity between network devices

• Distributed processing systems

• Diagnostic and performance management

Standards-Making Organizations

• International Telecommunications Union-Telecommunication Standardization Section (ITU-T)

• International Organization for Standardization (ISO)

• American National Standard Institute (ANSI)• Electrical Industries Association (EIA)• National Institute of Standards and Technology

(NIST)• Institute of Electrical and Electronic Engineers

(IEEE)

Standards• V.

– Connection of digital equipment to telephone analog line

• X.– Connection of digital equipment to telephone

digital line– X.400

• Allow communication between incompatible electronic mail systems

– X.500• Create and maintain a directory of e-mail users and

their network addresses

Pros and Cons of Standards

• Pros– Compatibility between vendors

– Fewer products

• Cons– Slow processing

– Obsolescence

– Freezing technology

– Discouraging innovation

Open System Interconnection Model• International Organization for Standardization• Interconnection of Dissimilar Network• Seven Layers

– Application

– Presentation

– Session Control

– Transport Control

– Network Control

– Data Link Control

– Physical Link Control

Application Layer

• Determine data to be send at originating end

• Process data at receiving end

Presentation Layer

• Change data format

• Compression/expansion

• Encryption/decryption

Session Control Layer

• Communication rules

• Rate of transmission

• Accounting functions

Transport Control Layer

• Identify receiving address

• Calculate and check checksum of entire message

Network Control Layer

• Route message

• Dissemble and assemble data (transmission unit)

• Accounting functions

Data Link Control Unit

• Determine line usage

• Establish link between two ends

• Detect and correct transmission error

• Add header and trailer

• Divide data unit for transmission

Physical Link Control Layer

• Hardware specification

• Electrical characteristics

TCP/IP Protocol

• Transmission Control Protocol/Internet Protocol

• Advanced Research Project Agency

• ARPANET

TCP/IP Structure

• Application layer– User application

• Transport layer (TCP protocol)– Communication, error-checking procedure

• Internet layer (IP protocol)– Routing

• Network access layer– Connection

• Physical– Physical & electrical interface

Manufacturers’ Architecture

• Objectives– Base for future products– Control customers

• Types– IBM: Systems Network Architecture (SNA)– Digital Equipment Corporation: Digital

Network Architecture (DNA)

Pros and Cons of Layered Architectures

• Pros– Modularize structure for simplify maintenance– Specify interfaces for easy change & future

growth

• Cons– Complex Rules– Cost of sophisticated intelligence– Complex software

Points to Remember

• Network architectures & standards

• Standard-making organizations

• Pros and cons of standards

• Open System Interconnection Model (OSI)

• TCP/IP

• Manufacturer architecture

• Pros and cons of architecture

Discussion

• What are your thoughts on selecting network equipment for an organization?