Office Automation & Intranets

Clarke, R. J (2001) L909-02: 1

Office Automation & Intranets

BUSS 909

Lecture 2Data Communication

Technologies

Clarke, R. J (2001) L909-02: 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 ReservePickup a copy of Learning Development

Student Services Brochure and Timetable

Clarke, R. J (2001) L909-02: 3

Agenda L909-02

Data Communications Principles and Technologiesin this lecture we consider only the Data

Communications technologies relevant to Office Automation

we will revisit this topic in subsequent lectures

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Agenda T909-01

Writing for Commerce: Essays and Case Studies (differs from the published schedule)

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Office Automation Overview

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Office Automation

the greatest proportion of work involves information in textual form:proceduresreportsmemoes

applies to:service industries, bureaucracies, public

sector organisations, and small-large private sector organisations

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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 meetingsbrainstorming sessionsformal reviewsshareholders meetings

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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)

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Office Automation

these technologies at that time were very expensive (special hardware and software)

the leader was Wang Computersby the mid 80s experimental systems

were being researched to support group-based activities- this research is still ongoing (Nunamaker et al 1991 40-61)

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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

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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

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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)

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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

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Network Processing & Topologies

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Network Termstopology = 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

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Network Processing (1)

Timesharing Networks oldest approach introduced in 3rd generation consists of a single computer performance limited to the computer

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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)

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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

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Network Topologies (1)

describes how multiple computers are connected together (eg/ distributed processing, client/server computing) on a network

several different topologies are available

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Star Network central computer called the central node guarentees centralised control failure on central node causes failure

over entire network

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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

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Network Management, Planning & Control

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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 ?

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in large companies network manager network analysts software analysts datacom technicians

in small companies LAN manager

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Network Manager:responsible for

planning implementing operating controlling

responsible to CIO

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Network Analyst perform same function as systems

analysts restricted to communication-oriented

systems

Software Analysts program & maintain datacom

software

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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

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Network Planning

all activities that aim to anticipate firms networking needsCapacity planning analyses & plans for traffic volumes

Staff planning people to manage network & skills

Performance monitoring analyse response times and potential

changes

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Network Control

day-to-day monitoring of the networkinvolves fault detection, fault

isolation, network restorationfirm needs standard procedures to

implement network control

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Network Architectures

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Network Architectures (1)

variety of hardware & softwareproducts available from:

computer manufacturers common carriers data coms specialist companies

many suppliers & standards is a ‘mixed blessing’

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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

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Industry standards include:SNA (IBM)BNA (Burroughs)DSE (Honeywell)

One of the most common data coms standards is called OSI

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SNA Systems Network Architecture developed by IBM because it

marketed 200 different data coms products

one of the first standards developed a proprietary standard

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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

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separates physical activities that transmit data

and logical activities that control transmission

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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

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OSI Model

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OSI Model (1)

OSI = Open Systems Interconnectionalmost 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

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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

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Frame Check

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

Address Control MessageEnding

FlagBeginning

Flag

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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

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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

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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

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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)

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OSI Model (8)7: Application Layer

consists of application programs that use the network

6: Presentation Layerstandardises data presentation to applications

5: Session Layermanages sessions between applications

4: Transport Layerprovides end-to-end error detection and correction

3: Network Layermanages connections across the network for the upper layers

2: Data Link Layerprovides reliable data delivery across the physical link

1: Physical Layerdefines the physical characteristics of the network media

Low

High

USER HOST

Low

High

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Layer 7

Layer 6

Layer 5

Layer 4

Layer 3

Layer 2

Layer 1

Protocols

Layer 7

Layer 6

Layer 5

Layer 4

Layer 3

Layer 2

Layer 1

2

1

2

1

33

Front-end processor Cluster Control Unit

P

P

P

P

P

P

P

P

P

AP

SP

SP

SP/P

User Node Host UserIntermediate Nodes

TerminalSoftwareor ROMRoutines

UserActions

Host

ChannelDevices

Front-endProcessor

Front-endor switching Node

OSI Model (9)

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

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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)

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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!

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InternetTransmission Control Protocol

networks are unreliable and IP does not guarantee that all pieces arrive (no notion of a connection)

TCP defines conventions that make sure the pieces arrive in the correct order- by specifying another envelope around the data packets

IP layer moves packets, TCP manages the connection

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InternetOther Services & Protocols

the layering or encapsulation which is a characteristic of OSI also works in much the same way with other services supported by the Internet (TCP/IP)

File Transfer Protocol defines the conventions which describe how computers can cooperate in order to copy files from one computer to another on the Internet- it uses TCP/IP to do this

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InternetOther Services & Protocols

TCP

IP

FTP

TCP

FTP

IP

Physical Network

Internet Protocol; Transmission Control Protocol; File Transfer Protocol

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InternetWeb Services & Protocols

the web is just another internet service!Hypertext Transfer Protocol (HTTP) is the

set of rules for making and fulfilling web requests

however, the web is also designed to encapsulate other protocols including FTP, Gopher, WAIS, telnet and NNTP- we will talk about these services latter

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InternetWeb Services

works as a client-server- in terms of services not necessarily hardware

differs from other network models (terminal to mainframe; and peer-to-peer) because client and server are independent, fully functional computer systems in their own right

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InternetWeb Services

Mainframe & Terminal

Client-server

Peer-to-Peer

Typing

Printing

Request

Reply

Send Message

Send Messageemail

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Intranets & OASuccess of WWW- Open Standards

machines on the Internet are effectively decentralised

an important aspect of the web is that it is a set of open (not proprietary) protocols:Uniform Resource Locators URLs Hypertext Transfer Protocol (HTTP) Hypertext Markup Language (HTML)

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Intranets & OASuccess of WWW- Specific Issues

web protocols are general enough to be implemented on any computerweb application are the ‘topmost’ layer in

the Internet protocol hierarchycomplex processes of transfer of data are

‘hidden’ from the web application developer and user

as a consequence there is a great variety of web applications available

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Web Servers & ClientsSource: Yeager & McGrath (1996, 11-16)

Web

TCP

Web

IP

FTP

TCP

FTP

IP

Physical Network

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Summary

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Intranets & OAFailure of OA- Proprietary Technologies

OA did not become very important because they were based on proprietary technologiesimplies ‘closed’ technologies and

markets- ultimately counter-productive!slow development time, large market lags,

small client bases, under utilised technology, increased expense in setup, use, maintenance, upgrade

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Intranets & OAFailure of OA- Specific Issues

data sometimes had to be re-entered- proprietary technologies mean that other vendors don’t have the technical information needed to write transfer routines

had to rely on the vendor to keep the technology current- there development team is the only one available to service your needs

incompatibilities- can’t supplement the OA vendors equipment with other vendors products

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From OSI to TCP/IP

OSI

7: Application Layer

6: Presentation Layer

5: Session Layer

4: Transport Layer

3: Network Layer

2: Data Link Layer

1: Physical Layer

TCP/IP4: Application Layer

consists of applications and processes that use the network

3: Host-to-Host Transport Layer

provides end-to-end data delivery services

2: Internet Layer

defines the datagram and handles the

routing of data

1: Network Access Layer

consists of routines for accessing physical networks

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Next Week

Lecture (L909-03):Office Automation Systems Computer

supported Cooperative Work/Groupware

Tutorial (T909-02):Search Engines & Techniques (differs

from Tutorial Schedule)

Documents

Office Automation & Intranets