1. Introduction
Computer Networks

2. Motivation and Scope
Computer networks and internets: an overview of concepts, terminology and technologies that form the basis for digital communication in private corporate networks the the global Internet.

3. Motivation for Networks
Information Access
Sharing of Resources
Facilitate Communications

4. What a Network Includes
Transmission hardware
Special-purpose hardware devices
interconnect transmission media
control transmission
run protocol software
Protocol software
encodes and formats data
detects and corrects problems

5. What a Network Does Provides communication that is Reliable Fair
Efficient
From one application to another

6. What a Network Does [continued]
Automatically detects and corrects
Data corruption
Data loss
Duplication
Out-of-order delivery
Automatically finds optimal path from source to destination

7. Data Communication versus Networking
With only two nodes, mostly EE issues.
With more than two nodes, lot more issues!

8. Direction of Transmission
Point to Point
Broadcast

9. Network Topologies

10. Transmission Media Wireline Wireless String Garden Hose Copper
Twisted Pair
Coax
Optical Fiber
Wireless
Sound
Light and mirrors
Infrared RF
Microwave

11. Network Scope Local Area Network (LAN) Metropolitan Area Network (MAN)
Wide Area Network (WAN)

12. Data Transmission
Serial
Parallel

13. Multiplexing

14. Communication Modes
Simplex
Half-duplex
Full-duplex

15. Connection-oriented versus Connectionless
Connection Setup
Data Transfer
Connection Termination
Data Transfer

16. Circuit Switching versus Packet Switching
Dedicated
fixed bandwidth
route fixed at setup
idle capacity wasted
network state
Best Effort
end-to-end control
multiplexing technique
re-route capability
congestion problems

17. Examples Public Switched Telephone Network Internet Postal Service
Train
Car and highway system

18. Standards Hardware Software Protocols Advantages and Disadvantages
Proprietary, De Facto, De Jure
Standards Bodies
IETF, IEEE, OSI, ANSI, ATM Forum, etc.

19. Protocols Rules, standards and etiquette Metric System English
Dinner party
Morse Code
TCP/IP
HTML

20. Layering

21. Headers, Data and Trailers

22. Encapsulation

23. ISO OSI Reference Model
7: Application Layer
6: Presentation Layer
5: Session Layer
4: Transport Layer
3: Network Layer
2: Data link Layer
1: Physical Layer

24. Interfaces and Services
PDUs
SDUs
SAPs
Peer communications
Service Primitives
etc... read Tanenbaum and 1.3.5

25. TCP/IP Model 5: Application Layer 4: Transport Layer 3: Network Layer
2: Data link Layer
1: Physical Layer

26. TCP/IP versus OSI "Rough consensus and running code” Simplicity
Time to market
Availability

27. Network Classification
Physical medium: copper, fiber, wireless
Scope: LAN, MAN, WAN
Topology: bus, star, ring, mesh
Switching style: circuit, packet
Application: voice, data, video
Protocol: IP, OSI, Ethernet, ATM
Transmission rate: 10Mb/s, Gigabit

28. Terms I (we) Often Use Frames: think data link layer
Packets: think network layer
Datagrams: think IP
Segments: think TCP
Cells: think ATM
Layer <x>: refer to reference models

29. The End-to-End Argument
"End-to-End Arguments in System Design”
J.H. Saltzer, D.P. Reed, and D.D. Clark