1. Technologies and Applications of Computer Networks
林永松
台灣大學資訊管理學系
(02)

2. Syllabus Textbook: Course objectives
“Computer Networks”, 5rd Ed., by Andrew S. Tanenbaum, carried by 新月
Course objectives
to introduce the importance of computer networks
to discuss hardware, software and architecture issues for computer networks
to discuss essential layers that constitute a protocol stack
to discuss a number of applications over networks
to introduce methodology for network planning & management
to train executive professionals who need to know computer networks

3. Syllabus (cont’d) Course outline (tentative) introduction
uses of computer networks
network hardware
network software
reference models
network standardization

4. Syllabus (cont’d) Course outline (cont’d) physical layer
the theoretical basis for data communication
transmission media
wireless transmission
the telephone system
data link layer
data link layer design issues
error detection and correction
elementary data link protocols
sliding window protocols

5. Syllabus (cont’d) Course outline (cont’d) medium access sublayer
the channel allocation problem
multiple access protocols
IEEE standard 802 for LANs and MANs

6. Syllabus (cont’d) Course outline (cont’d) network layer
network layer design issues
routing algorithms
congestion control algorithms
internetworking
the network layer in the Internet
transport layer
the transport service
elements of transport protocols
the Internet transport protocols (TCP and UDP)

7. Syllabus (cont’d) Course outline (cont’d) application layer
network security
Content-based information retrieval/filtering
multimedia
network planning and capacity management
network planning
network capacity management
lectures from distinguished speakers
other materials

8. Introduction Uses of computer networks resource sharing
information retrieval
information distribution
communication
reliability/survivability/availability
gradual growth
performance to cost ratio

9. Introduction (cont’d)
Network hardware
network classification
broadcasting, multicasting and unicasting (point-to-point)
scale of interconnected processors
Fig. 1-2 (p. 8)

10. Introduction (cont’d)
Network hardware (cont’d)
local area networks (LANs)
size
transmission technology
medium access protocols
topology
Fig. 1-3 (p. 9)

11. Introduction (cont’d)
Network hardware (cont’d)
metropolitan area networks (MANs)
characteristics
DQDB (distributed queue dual bus)
Fig 1-4 (p. 11)

12. Introduction (cont’d)
Network hardware (cont’d)
wide area networks (WANs)
size
host and subnet
Fig. 1-5 (p.12)

13. Introduction (cont’d)
Network hardware (cont’d)
wide area networks (cont’d)
circuit switching versus packet switching
topology
Fig. 1-6 (p. 13)

14. Introduction (cont’d)
Network hardware (cont’d)
wireless networks
need for mobile and/or wireless communication
Fig. 1-7 (p.14)

15. Introduction (cont’d)
Network hardware (cont’d)
wireless networks (cont’d)
e.g. PDAs (personal data assistants) and CDPD (cellular digital packet data)
different combinations of wired and wireless networking
Fig. 1-8 (p. 15)

16. Introduction (cont’d)
Network hardware (cont’d)
internetworks
internet: a collection of interconnected networks, e.g. a collection of LANs connected by a WAN
Internet
subnet: a collection of routers and communication lines owned by the network operator
network: the combination of a subnet and its hosts

17. Introduction (cont’d)
Network software
protocol hierarchies
Fig. 1-9 (p. 17)

18. Introduction (cont’d)
Network software (cont’d)
example information flow
Fig (p.20)

19. Introduction (cont’d)
Network software (cont’d)
design issues for the layers
identification of senders and receivers
simplex, half-duplex and full-duplex
error control
sequencing
flow control
message length (SAR and multiplexing)
multiplexing and demultiplexing
routing

20. Introduction (cont’d)
Network software (cont’d)
interfaces and services
Fig (p.23)

21. Introduction (cont’d)
Network software (cont’d)
connection-oriented and connectionless services
Fig (p.25)

22. Introduction (cont’d)
Network software (cont’d)
service primitives
Fig (p. 25)

23. Introduction (cont’d)
Network software (cont’d)
a simple connection-oriented service example
CONNECT.request
CONNECT.indication
CONNECT.response
CONNECT.confirm
DATA.request
DATA.indication
DISCONNECT.request
DISCONNECT.indication

24. Introduction (cont’d)
Reference models
OSI (Open Systems Interconnection) reference model
principles of layering
different level of abstraction
well defined functions
defining internationally standardized protocols
minimal information flow across the interfaces
appropriate number of layers

25. Introduction (cont’d)
Reference models (cont’d)
OSI reference model (cont’d)
Fig (p.29)

26. Introduction (cont’d)
Reference models (cont’d)
OSI reference model (cont’d)
Fig (p.34)

27. Introduction (cont’d)
Reference models (cont’d)
TCP/IP reference model
Fig (p.36)

28. Introduction (cont’d)
Reference models (cont’d)
TCP/IP reference model (cont’d)
Fig (p.37)

29. Introduction (cont’d)
The Internet
a collection of interconnected TCP/IP networks
to be on the Internet, a machine must
run the TCP/IP protocol stack
have an IP address
be able to send IP packets to all the other machines on the Internet
applications: , news, telnet, ftp, SNMP, WWW
millions of hosts and tens of millions of users

30. Introduction (cont’d)
The Internet (cont’d)
standard organizations
IAB (Internet Activities Board) by DoD in 1983, later changed to Internet Architecture Board, using RFCs (Request For Comments) for communication
IRTF (Internet Research Task Force) and IETF (Internet Engineering Task Force) under IAB in 1989
Internet Society in 1992
from a proposed standard to a draft standard and finally to an Internet standard