1. Chapter 3 Telecommunication Architectures and Standard

2. 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

3. Network Architectures Design principles for –Functions –Data format –Procedures Describe “what”

4. Communication Standards Rules for compatibility Specify “how”

5. Needs for Architectures and Standards Complex communication systems Maintenance and future growth Connectivity between network devices Distributed processing systems Diagnostic and performance management

6. 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)

7. 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

8. Pros and Cons of Standards Pros –Compatibility between vendors –Fewer products Cons –Slow processing –Obsolescence –Freezing technology –Discouraging innovation

9. 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

10. Application Layer Determine data to be send at originating end Process data at receiving end

11. Presentation Layer Change data format Compression/expansion Encryption/decryption

12. Session Control Layer Communication rules Rate of transmission Accounting functions

13. Transport Control Layer Identify receiving address Calculate and check checksum of entire message

14. Network Control Layer Route message Dissemble and assemble data (transmission unit) Accounting functions

15. 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

16. Physical Link Control Layer Hardware specification Electrical characteristics

17. TCP/IP Protocol Transmission Control Protocol/Internet Protocol Advanced Research Project Agency ARPANET

18. 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

19. Manufacturers’ Architecture Objectives –Base for future products –Control customers Types –IBM: Systems Network Architecture (SNA) –Digital Equipment Corporation: Digital Network Architecture (DNA)

20. 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

21. 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

22. Discussion What are your thoughts on selecting network equipment for an organization?