1. COMP2322 Networks in Organisations
Richard Henson
February 2016

2. Week 1: Computers and Computer Networks
Objectives
list advantages & disadvantages of networking computers
explain why the world is now said to be “hyperconnected”
outline requirements for a network to be “trustworthy”

3. Learning Outcomes (LOs)
Systematically compare client-server and peer-peer networks
Relate the various topologies, cabling, and networking technologies (including wireless technologies) to function and real world situations
Use a layered model to explain how protocols work together to deliver reliable networking functionality
Explain the roles of a network operating system in controlling communication across a network
Configure a network operating system to coordinate and control users and peripherals

4. Coverage of Outcomes
Historical look at evolution of networks to explain why todays networks are as they are…
Practical investigation of contemporary network architectures (i.e. cabling & wireless hardware)
Theory behind network functions & protocols
how to exploit network weakness
and ensure that software is secure (i.e. not easily hacked…)

5. History of Electricity-based Communication Networks
Used for centuries before computers… (!)
Chronologically:
Telegraph (1840s)
Telephone (1910s)
Telex (1930s)
Internet & digital networks (1970s on)

6. Standards
The basis of technological advancement (and human enterprise to support new technology…)
Some say standards stifle creativity (?!)
in fact, essential for developing stuff that fits together with other stuff…
especially important for communications….

7. Each network type developed its own standards for…
Creation of data
Format of transmitted data
Voltage
Error-checking
Receiving, storing, presentation of transmitted data

8. Standards for National and International Networks
Telegraph:
data transmitted within a particular country
National standards…
became International
International standards
initially along wires
then as radio waves

9. Telephone Initially National, like Telegraph network
International calling possible… required a standard
French-based standards became the Internationally recognised ones (CCITT)
Comité Consultatif International Téléphonique et Télégraphique

10. A Tale of Standards… (1) Roman Empire, 2000 years ago
streets in cities open sewers

11. A Tale of Standards… (2) Problem: how wide?
Romans needed crossing places
stone paths across the street
Chariots also used street
needed spaces in stones for chariot wheels
Problem: how wide?

12. What width would you choose?
Suggestions…
How did the Romans Decide?

13. Ways to agree a Standard
“De Facto”
A product or service that is a standard by virtue of its widespread use by interested users
“De Jure”
The standard devised by a committee of the organisation

14. Roman “Wheelbase” Standard “wheelbase” width agreed (4’ 8½’’)
used for chariots throughout Roman Empire
And much later for “horse and stagecoach”

15. New Technology, new standard?
Continued in UK as “standard gauge” when railway tracks started (1830s)
Was it still a good standard?

16. Breaking a standard?
The Great Western Railway tried to change the standard to 6’ 0’’
“Broad Gauge”… all their tracks
wider carriages, more passenger comfort…
Other railways kept 4’ 8½’’ !!!

17. What happened?
GWR eventually gave up and converted all their tracks back to the standard gauge…

18. What happen then?
If the Great western Railway couldn’t change a standard
…. no-one could!
Most railways around the world still use 4’ 8½
Modern space rockets transported on 4’ 8½’’ track

19. Lessons from this story
Large, powerful organisations try to make their own standards universal
Existing standards difficult to change
Once established, standards may well be adopted world-wide
therefore need to be right!

20. Standards Today…
Would a modern-day Great Western Railway have their own way?
Maybe… if an International committee agreed with them (de jure)
IETF… best ever standards body?

21. Lessons from this story
Large, powerful organisations try to make their own standards universal
Existing standards difficult to change
Once established, standards may well be adopted world-wide
therefore need to be right!

22. Standards Today… Often market-driven?
Would a modern-day GWR have their own way?

23. CCITT, Communication Standards, and Computers
In the early days, CCITT laid down the standard… (like the Romans…)
More recently, CCITT became ITU:
International Telecommunication Union
Through ITU, many CCITT standards applied to computer networks evolving in the 1980s:
Group 3: protocol for sending fax documents across (analogue) telephone lines
Group 4: protocol for sending fax documents over ISDN (early digital) networks
“V” modem standards

24. Comparison of Computer & Telecoms Networks
All prior CCITT etc. standards were
analogue…
centrally controlled
Information sent along computer networks is…. digital (!)
Internet created a new paradigm….
control doesn’t have to be centralised
potential range of uses of networked devices much more flexible

25. Standards in Computing
Characterised by rapid change
Early emerging standard may be eclipsed by new technology
Standards usually follow many years after the products themselves have been on the market (but market-driven…)
therefore often based on specific products (usually the market leader at the time!)

26. What is a Standard? Definition: Communication protocols…
“A standard is an established or accepted model”
Communication protocols…
“Elements of a communication system that are defined by an agreed set of rules, conditions, parameters or methods”

27. Type of Standards De Facto De Jure
A product or service that is a standard by virtue of its widespread use by interested users
De Jure
The standard devised by a committee of the organisation or, a working group of a subcommittee of a committee of the organisation

28. Standards and IT Professionals
ensure that products can communicate
identify incompatibilities between products
provide a check that customers are buying the correct product
ensure that customers are not buying a manufacturer dependent product

29. ISO (International Standards Organisation)
Been providing International standards for many areas
Even for management systems:
ISO9001
ISO14001
ISO27001

30. ISO Standards Development Process
Panel of experts convened:
decide the contents of the definition of draft standard
proposal passed to the parent committee for ratification before publication as, first, a draft for discussion (DD)

31. ISO Development Process
Once ratified, proposal becomes a draft international standard
draft made available for a certain amount of time…
allows full scrutiny…
Once any issues have been resolved…
becomes a full ISO Standard

32. Proprietary Systems
Big computer manufacturers in the 1960s and 1970s worked independently to produce their own software
Teams of researchers to develop their own systems for communicating between devices
Different research teams, different company aims, so products incompatible

33. Proprietary Systems 
Considered to be a good thing by companies such as IBM and ICL, because it “locked” customers into their products
Not popular with customers, who wanted to be able to buy more freely
Also using incompatible systems was a barrier to communication:
between companies
sometimes between different parts of the same company

34. Open Systems
ISO:
aware that the basic infrastructure for global digital communications was rapidly emerging in the form of the Internet
decided that the existing proprietary isolationist stance was not condusive to the growth of effective digital data communications on a world-wide basis
agreed that what was needed was open systems

35. Open Systems Definition: Open systems…
“a computer system that is ‘open’ for the purpose of information exchange”
Open systems…
therefore not restricted to one particular manufacturers own system of communicating
should provide the ability to:
interchange applications and data
between systems with different underlying hardware and software

36. Open Systems Interconnect (OSI)
Historic meetings in Geneva coordinated by ISO (back in 1977, 1978)
Involved proprietary systems manufacturers, telecomms companies, govt representatives, researchers
Agreed to produce a software model for open systems (known as OSI)
accepted that this would take DECADES to achieve
the industry could, however, at least aspire to this in new developments…

37. Battle Lines Drawn (old v new?)
CCITT v ISO
Proprietary v Open

38. Break….

39. Practical Download CISCO Packet Tracer…

40. Joining PCs together…
An alternative to the telephone for organisational communications!
No longer so dependent on (expensive) Telecoms companies… or (expensive) centralised computer manufacturers

41. Why link PCs together anyway? (not just to annoy telecoms companies!)
Small groups
Each group - 3 reasons for… and against
Ten minutes

42. LANs, WANs, Standards The PC network changed everything…
didn’t happen overnight…
new sets of protocols and technologies had to be developed
New classification emerged (LAN)
standards provided by engineers (IEEE)
LAN: PC/Unix networks within institutions
Existing networks known as WANs
existing standards CCITT; emerging standards ISO

43. OSI Model & WAN standards
People liked open systems
OSI caught on quicker than expected
challenge to CCITT
teamed up with IEEE (802.x standards)
In 1984, OSI became an International Standard (!)
open systems now had credibility!!!
proprietary systems had competition…

44. How did technology succeed in changing a world standard in the 1980s & 1990s?
Money, money, money…
Cheaper to use PCs than mainframes
Cheaper to use the Internet than expensive telecom companies

45. Change also requires Vision!
OSI model: the world could communicate without proprietary lock in or centralised control
Came into sharp focus with “Live Aid” concert in 1985