Office Automation & Intranets

1. Office Automation & Intranets BUSS 909 Lecture 2 Data Communication Technologies

2. Notices • Assignment 1: • Pickup Assignment 1 Handout now • Assistance with Assignment 1: • Buy a copy of Woodward-Kron’s book from UniCentre Bookshop (if available) • Also refer to Academic Essay Writing Notes in Closed Reserve • Pickup a copy of Learning Development Student Services Brochure and Timetable

3. Agenda L909-02 • Data Communications Principles and Technologies • in this lecture we consider only the Data Communications technologies relevant to Office Automation • we will revisit this topic in subsequent lectures

4. Agenda T909-01 • Writing for Commerce: Essays and Case Studies (differs from the published schedule)

5. Office Automation Overview

6. Office Automation • the greatest proportion of work involves information in textual form: • procedures • reports • memoes • applies to: • service industries, bureaucracies, public sector organisations, and small-large private sector organisations

7. Office Automation • additionally, decision making (work about work) in any organisation is conducted in groups • these groups almost always are involved in language activities (reading, writing etc) • board room meetings • brainstorming sessions • formal reviews • shareholders meetings

8. Office Automation • technologies called OA systems have been developed since the mid-1970s to cope with these kinds of work • generally these systems are based on networks of various kinds (we review the various types and some standard terminology used to describe them this lecture)

9. Office Automation • these technologies at that time were very expensive (special hardware and software) • the leader was Wang Computers • by the mid 80s experimental systems were being researched to support group-based activities- this research is still ongoing (Nunamaker et al 1991 40-61)

10. Office Automation • OA systems were augmented with systems that had similar functionality • other names that can be found include: OIS- Office Information Systems; EMS- Electronic Meeting Systems; Collaborative Management Systems

11. Office Automation • much of this has been superceded by developments in the marketplace- including proprietary integrated software eg. Lotus Notes; Microsoft Office97 • also the WWW and graphical browsers provide a way for organisations to transform desktop computing to webtop computing

12. Office Automation • but the research that led to these systems is still relevant as we try to implement the same functionality in the form of intranets and extranets (private networks based on Internet technology)

13. Office Automation • an additional trend is to create the virtual organisation, which again is based on theory and principles established and developed during the mid-1970s • telework, remote work, mobile data systems etc

14. Network Processing & Topologies

15. Network Terms • topology = pattern of a network • circuit • transmission facility provides =>1 channels of communication eg/ phone line, microwave signal, optical cable • node • point in a network where circuits are interconnected by one or more units • may be other computers

16. Network Processing (1) Timesharing Networks • oldest approach • introduced in 3rd generation • consists of a single computer • performance limited to the computer

17. Network Processing(2) Distributed Processing • when minicomputers became popular • companies started distributing minis and micros throughout the organisation • when interconnected the technique is called distributed computing or distributed data processing (DDP)

18. Network Processing(3) Client/Server Computing • some functions are best handled locally and some are best handled centrally • blend of timesharing approach (central use) and distributed processing (local) • usually LANs but can be WANs • client: user has access to network by means of desktop computer • server: computer of any size which provides control of network function

19. Network Topologies (1) • describes how multiple computers are connected together (eg/ distributed processing, client/server computing) on a network • several different topologies are available

20. Network Topologies (2) • Star Network • central computer called the central node • guarentees centralised control • failure on central node causes failure over entire network

21. Network Topologies (3) • Ring Network • does not include a central node • control is distributed throughout network • failure in any link causes problem for network • Hybrid Network • star & rings can be used together • when this occurs the topology is referred to as a Hybrid Topology

22. Network Management, Planning & Control

23. Network Management (1) • often critical to firms • network failures can be catastropic • require planning and control • need to be managed What would happen if a your banks ATM data comms network fails ?

24. Network Management (2) • in large companies • network manager • network analysts • software analysts • datacom technicians • in small companies • LAN manager

25. Network Management (3) Network Manager: • responsible for • planning • implementing • operating • controlling • responsible to CIO

26. Network Management (4) Network Analyst • perform same function as systems analysts • restricted to communication-oriented systems Software Analysts • program & maintain datacom software

27. Network Management (5) Datacom technicians • concerned with hardware and operations LAN Manager • found in smaller organisations • members of information services • generally a member of using organisation • may perform all of the duties of network manager

28. Network Planning all activities that aim to anticipate firms networking needs Capacity planning • analyses & plans for traffic volumes Staff planning • people to manage network & skills Performance monitoring • analyse response times and potential changes

29. Network Control • day-to-day monitoring of the network • involves fault detection, fault isolation,network restoration • firm needs standard procedures to implement network control

30. Network Architectures

31. Network Architectures (1) • variety of hardware & software • products available from: • computer manufacturers • common carriers • data coms specialist companies • many suppliers & standards is a ‘mixed blessing’

32. Network Architectures (2) • network architectures specify protocols • rule for interfacing (interconnecting) various units • all data coms devices will follow specific protocols • variety of units led to a small number of ‘industry’ standards

33. Network Architectures (3) Industry standards include: • SNA (IBM) • BNA (Burroughs) • DSE (Honeywell) One of the most common data coms standards is called OSI

34. Network Architectures (4) • SNA • Systems Network Architecture • developed by IBM because it marketed 200 different data coms products • one of the first standards developed • a proprietarystandard

35. Network Architectures (5) • SNA: • defines all activities involved in transmitting data through a network • transmitted from a user node • transmitted to a host node • transmitted through one or more intermediate nodes

36. Network Architectures (6) • separates physical activities that transmit data • and logical activities that control transmission

37. Network Architectures (7) • SNA • classifies logical activities into layers • layers insulate users from changes in the datacom hardware and software • layers have become a common strategy in other datacoms standards

38. OSI Model

39. OSI Model (1) • OSI = Open Systems Interconnection • almost all Network rely upon this Model to organise communications between Clients and Servers • uses layers like SNA to define physical and logical layers • 7 layers are used; all nodes have them

40. OSI Model (2) • A layer at one node (user) ‘talks’ to its corresponding layer at the other (host) end • Layers 1-3 needed at every node; Layers 4-7 at host & user nodes only

41. OSI Model (3) • 1: Physical Layer • Transmits the data from one node to another • eg./ RS232c • 2: Data Link Layer • Formats the data into a record called a frame • Performs error detection Beginning Flag Address Control Message Frame Check Ending Flag

42. OSI Model (4) • 3: Network Layer • causes the physical layer to transfer the frames from node to node • 4: Transport Layer • enables user and host nodes to communicate with each other • synchronizes fast- and slow- speed equipment as well as overburdened and idle units

43. OSI Model (5) • 5: Session Layer • initiates, maintains and terminates each session • sessions consist of all frames that comprise an activity, and all signals that identify beginning and end • eg./ log-on and user id routines to initiate sessions

44. OSI Model (6) • 6: Presentation Layer • formats data for presenting to user or host • eg./ information to be displayed on users screen is formatted into proper number of screen lines and characters per line • 7: Application Layer • controls user input from the terminaland executes the user’s application program

45. OSI Model (7) • Eg./ User needs host software • L7 (application) takes request • L6 (presentation) changes input data to correct format for transmission • L5 (session) starts the session on the host machines • L4 (transport) selects route from user to host • L3 & 2 (network & data link) cause data to be transmitted through L1 (physical)

46. OSI Model (8) USER HOST High 7: Application Layer consists of application programs that use the network 6: Presentation Layer standardises data presentation to applications 5: Session Layer manages sessions between applications 4: Transport Layer provides end-to-end error detection and correction 3: Network Layer manages connections across the network for the upper layers 2: Data Link Layer provides reliable data delivery across the physical link 1: Physical Layer defines the physical characteristics of the network media High Low Low

47. Host User Intermediate Nodes User Node User Actions Layer 7 Layer 6 Layer 5 Layer 4 Layer 3 Layer 2 Layer 1 Layer 7 Layer 6 Layer 5 Layer 4 Layer 3 Layer 2 Layer 1 AP Terminal Software or ROM Routines SP Host SP SP/P Front-end or switching Node 3 P P P 3 Protocols Front-end Processor P P P 2 2 Channel Devices P 1 P P 1 Front-end processor Cluster Control Unit OSI Model (9)

48. Web Clients & ServersSource: Yeager & McGrath (1996, 11-16)

49. Internet • Internet (=Internetworking) collection of computer networks and to allow interoperability between them • networks can consist of many types of network technologies, protocols, and computers • Several protocols are required for transmitting data across the Internet (TCP/IP)

50. InternetInternet Protocol • IP manages the transfer of data across physically distinct networks • transfers data into packets within an ‘envelope’ that describing its source and destination • a message is in effect shattered into pieces, packaged as packets in envelopes, and burst transmitted to the destination • IP looks after delivering these packages- one packet at a time!