1. Understanding Networked Applications: A First Course Chapter 7 by David G. Messerschmitt

2. Understanding Networked Applications: A First Course Industry by David G. Messerschmitt

3. Understanding Networked Applications A First Course 3 Component: A subsystem purchased “as is” from an outside vendor A component implementation is encapsulated (although often configurable) Components

4. Understanding Networked Applications A First Course 4 Examples of components Computer Disk drive Network Network router Operating system Integrated circuit Database management system Why is a component implementation encapsulated?

5. Understanding Networked Applications A First Course 5 Interoperability Components are interoperable when they interact properly to achieve some desired functionality Increasingly component interoperability cannot be dependent on integration, or is dependent on end- user integration –PC and peripherals –Enterprise, inter-enterprise, consumer applications –Role for standardization

6. Understanding Networked Applications A First Course 6 Outsourcing: A subsystem design is contract to an outside vendor Responsibility is delegated Outsourcing

7. Understanding Networked Applications A First Course 7 System integration Architecture  subsystem implementation  system integration Bring together subsystems and make them cooperate properly to achieve desired system functionality –Always requires testing –May require modifications to architecture and/or subsystem implementation

8. Understanding Networked Applications A First Course 8 Why system decomposition? Divide and conquer approach to containing complexity Reuse Consonant with industry structure (unless system is to be supplied by one company) Others?

9. Understanding Networked Applications A First Course 9 Component: A subsystem purchased “as is” from an outside vendor A component implementation is encapsulated (although often configurable) Components

10. Understanding Networked Applications A First Course 10 Examples of components Computer Disk drive Network Network router Operating system Integrated circuit Database management system Why is a component implementation encapsulated?

11. Understanding Networked Applications A First Course 11 Interoperability Components are interoperable when they interact properly to achieve some desired functionality Increasingly component interoperability cannot be dependent on integration, or is dependent on end- user integration –PC and peripherals –Enterprise, inter-enterprise, consumer applications –Role for standardization

12. Understanding Networked Applications A First Course 12 System requirements Decomposition from system requirements Requirements Assembly from available components Available components Two ways to design a system

13. Understanding Networked Applications A First Course 13 Outsourcing: A subsystem design is contract to an outside vendor Responsibility is delegated Outsourcing

14. Understanding Networked Applications A First Course 14 Three types of software Application Infrastructure: Basic services (communication, storage, concurrency, presentation, etc.) Components and frameworks: What is in common among applications

15. Understanding Networked Applications: A First Course Standardization by David G. Messerschmitt

16. Understanding Networked Applications A First Course 16 Outline Motivation for standards Elements of a standard Types of standards Process to develop a standard

17. Understanding Networked Applications A First Course 17 Network effects The value of a product to the adopter depends on the number of other adopters –Direct e.g. fax machine –Indirect, through common content or software e.g. Windows, CD music

18. Understanding Networked Applications A First Course 18 Lock-in Consumer: –Switching costs make consumer reluctant to adopt a new product Supplier: –Switching costs or cannibalization of existing products make supplier reluctant to pursue new product opportunity

19. Understanding Networked Applications A First Course 19 Consumer lock-in Prevalence increases as the industry fragments, and consumer has to purchase complementary products to get a “complete solution” –Switching costs discourage moving to complete new solution –Supplier with a “better mousetrap” can’t penetrate market unless product is compatible with existing complementary product

20. Understanding Networked Applications A First Course 20 Purpose of a standard Infrastructure: –Allow products or services from different suppliers or providers to be interoperable Application: –Enable applications to run across uncoordinated administrative domains

21. Understanding Networked Applications A First Course 21 Scope of a standard Included: –architecture (reference model) –interfaces (physical, electrical, information) –formats and protocols (FAP) –compliance tests (or process) Excluded: –implementation –(possibly) extensions

22. Understanding Networked Applications A First Course 22 Reference model Decide decomposition of system –where interfaces fall Defines the boundaries of competition and ultimately industrial organization –competition on the same side of an interface –complementary suppliers on different sides –hierarchical decomposition at the option of suppliers –(possibly) optional extensions at option of suppliers

23. Understanding Networked Applications A First Course 23 Some issues Once a standard is set –becomes possible source of industry lock-in; overcoming that standard requires a major (~10x?) advance –may lock out some innovation In recognition, some standards evolve –IETF, CCITT (modems), MPEG –backward compatibility

24. Understanding Networked Applications A First Course 24 Types of standards de jure –Sanctioned and actively promoted by some organization with jurisdiction, or by government de facto –Dominant solution arising out of the market Voluntary industry standards body Industry consortium Common or best practice

25. Understanding Networked Applications A First Course 25 Examples de jure –Ada, VHDL de facto –Hayes command set, Windows API, Pentium instruction set, Ethernet Voluntary industry standards body –OMG/CORBA, IAB/IETF, IEEE Industry consortium –W3C/XML, SET Best practice –Windowed GUI

26. Understanding Networked Applications A First Course 26 The changing process As technology and industry move more quickly, the global concensus standards activity has proven too unwieldy –e.g. ISO (protocols, SGML) “New age” standards activities are more informal, less consensus driven, a little less political, more strategic, smaller groups –e.g. OMG, IETF, ATM Forum, WAP Programmable/extensible approaches for flexibility –e.g. XML, Java

27. Understanding Networked Applications A First Course 27 Old giving way to the new

28. Understanding Networked Applications A First Course 28 Reasons for change From government sanction/ownership to market forces –Increasing fragmentation –Importance of time to market Greater complexity –Less physical/performance constraint for either hardware or software

29. Understanding Networked Applications A First Course 29 Lock-in (Particularly open) standards reduce consumer lock-in –Consumers can mix and match complementary products –e.g. IBM (in their day) and Microsoft are perceived to be lock-in problems, other agendas in addition to pleasing customers Increase supplier lock-in –Innovation limited by backward compatibility –e.g. IP/TCP, x86, Hayes command set

30. Understanding Networked Applications A First Course 30 Question What are some examples of open standards that reduce consumer lock-in? –Intranet applications WWW, newsgroups, calendar, etc –Linux –PC peripherals ISA, serial/parallel port, etc –Others?

31. Understanding Networked Applications A First Course 31 Network effects Standards can harness network effects to the industry advantage –Revenue = (market size) x (market share) Increases value to customer Increases competition –Only within confines of the standard –But forces customer integration or services of a system integrator

32. Understanding Networked Applications A First Course 32 Question What are examples of standards that serve to tame network effects? –Internet protocols –XML –CORBA –DVD –others?

33. Understanding Networked Applications A First Course 33 Why standards? de jure are customer driven to reduce confusion and cost de facto standards are sometimes the result of positive feedback in network effects Customers and suppliers like them because they –increase value –reduce lockin Governments like them because they –promote competition in some circumstances –May believe they can be used to national advantage

34. Understanding Networked Applications A First Course 34 Sanctioning organization(s) Ongoing committees Participating companies Voluntary standards process

35. Understanding Networked Applications A First Course 35 Approaches Consensus –ISO Collaborative design –MPEG Competitive “bake off” –ITEF Coordination of vendors –OMG

36. Understanding Networked Applications A First Course 36 Why companies participate Pool expertise in collaborative design –e.g. MPEG Have influence on the standard Get technology into the standard –Proprietary, with expectation of royalties –Non-proprietary Reduced time to market