1. Lecture 1: Facts of network technologies developments
(A historical background)

2. Computer Networks
Computer networks? A group of interconnected computers
-Represent a logical Result of the evolution of two of the most important scientific and technical branches of modern civilization – Computing and Telecommunications technologies.

3. From Batch Processing Toward Time-Sharing
Queuing Theory
1957
Centralized system based on mainframe
Multi-terminal System
Time sharing

4. The Necessity: Time and Resource Sharing
“Time sharing tried to make it possible for research institutions to use the processing power of other institutions computers when they had large calculations to do that required more power, or when someone else's facility might do the job better”

5. Early communications systems
I.e. telephone
point-to-point links
directly connect together the users wishing to communicate
use dedicated communication circuit
if distance between users increases beyond the length of the cable, the connection is formed by a number of sections connected end-to-end in series.

6. Data Networks set of interconnected nodes exchange information
sharing of the transmission circuits= "switching".
many links allow more than one path between every 2 nodes.
network must select an appropriate path for each required connection.

7. Networking Issues - Telephone
Addressing - identify the end user
phone number = country code + city code + exchange + number
Routing - How to get from source to destination.
Telephone circuit switching: Based on the phone number.
Information Units - How is information sent

8. Networking Issues - Internet
Addressing - identify the end user
IP addresses , Refer to a host interface = network number + host number
Routing- How to get from source to destination
Packet switching: move packets (chunks) of data among routers from source to destination independently.
Information Units - How is information sent.
packet = data + metadata (header/Addresses).

9. Related Definitions and terminologies
The Internet is a global system of interconnected computer networks that use the standard Internet protocol suite (TCP/IP) to link several billion devices worldwide. 
Packet switching is a digital networking communications method that groups all transmitted data – regardless of content, type, or structure – into suitably sized blocks, called packets.
The Advanced Research Projects Agency Network (ARPANET) is one of the world's first packet switching networks, the first network to implement TCP/IP, and was the main progenitor of what was to become the global Internet. (later DARPA)

10. Related Definitions and Concepts
 ARBA network was initially funded by the Advanced Research Projects Agency (ARPA, later DARPA) within the U.S. Department of Defense for use by its projects at universities and research laboratories in the US.
The packet switching of the ARPANET, together with TCP/IP, would form the backbone of how the Internet works.

11. Related Definitions and Concepts
The packet switching was based on concepts and designs by:
American engineer Paul Baran,  scientist Donald Davies and Lawrence Roberts of the Lincoln Laboratory.
The TCP/IP communication protocols were developed for ARPANET by computer scientists Bob Kahn and Vint Cerf, and also incorporated some designs from Louis Pouzin.

12. History 1961-1972: Early packet-switching principles
1961: Kleinrock - queuing theory shows effectiveness of packet- switching
1964: Baran - packet-switching in military networks
1967: ARPAnet – conceived by Advanced Research Projects Agency
1969: first ARPAnet node operational
1972: ARPAnet demonstrated publicly
NCP (Network Control Protocol) first host-host protocol
first program
ARPAnet has 15 nodes

13. History 1972-1980: Internetworking, new and proprietary nets
1970: ALOHAnet satellite network in Hawaii
1973: Metcalfe’s PhD thesis proposes Ethernet
1974: Cerf and Kahn - architecture for interconnecting networks
late70’s: proprietary architectures: DECnet, SNA, XNA
late 70’s: switching fixed length packets (ATM precursor)
1979: ARPAnet has 200 nodes

14. Cerf and Kahn’s internetworking principles:
minimalism, autonomy - no internal changes required to interconnect networks
best effort service model
stateless routers
decentralized control
Defines today’s Internet architecture

15. History 1980-1990: new protocols, proliferation of networks
1983: deployment of TCP/IP
1982: SMTP protocol defined
1983: DNS defined for name-to-IP-address translation
1985: FTP protocol defined
1988: TCP congestion control
new national networks: CSnet, BITnet, NSFnet, Minitel
100,000 hosts connected to confederation of networks

16. History 1990 - : commercialization and WWW
early 1990’s: ARPAnet decomissioned
1991: NSF lifts restrictions on commercial use of NSFnet (decommissioned, 1995)
early 1990s: WWW
hypertext [Bush 1945, Nelson 1960’s]
HTML, http: Berners-Lee
1994: Mosaic, later Netscape
late 1990’s: commercialization of WWW

17. Demand and Supply Huge growth in users Faster home access
The introduction of the web
Faster home access
Better user experience.
Infrastructure
Significant portion of telecommunication.
New evolving industries
Although, sometimes temporary setbacks

18. Internet: Users

19. Users around the Globe (2002)

20. Users around the Globe (2005)

21. Technology: Modem speed

22. Today’s options Modem: 56 K ISDN: 64K – 128K Frame Relay: 56K ++
Today High Speed Connections
All are available at 5Mb (2005)
Cable, ADSL, Satellite.

23. Internet Users: By language

24. Internet Content: By language

25. Questions Which appeared earlier than the other: WANs or LANs? Why?
Reference: EP pdf
Summaries this video in Arabic and English