Transcript Computer Networks - International Institute of Information

Computer Networks
Instructor: Bruhadeshwar
Monsoon 2007
Design Motivation
“While highly survivable and reliable
communications systems are of primary interest to
those in the military concerned, (for automated
decision making),…,
the basic notions are also of interest to
communications systems planners and designers
having need to transmit digital data” –Paul
Baran, August 1964
The Necessity: Time 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”
-Ian Peter (www.nethistory.info)
Networking History






Origins of Internet are hazy, visit www.nethistory.info for interesting
reading
1961: Kleinrock - queuing theory shows effectiveness of packet-switching
1964: Baran - packet-switching in military applications for survivable
networks
1967: ARPAnet conceived by Advanced Research Projects Agency
1969: First ARPAnet node operational
 Prof.Kleinrock sends a message across from UCLA to Stanford
1972:




ARPAnet demonstrated publicly
NCP (Network Control Protocol) first host-host protocol
First e-mail program
ARPAnet has 15 nodes
Networking History...



1970: ALOHAnet satellite network in Hawaii
(CSMA developed), later connects to ARPANet
1973: Bob Metcalfe’s PhD thesis proposes
Ethernet (CSMA/CD developed)
1974: Cerf and Kahn - architecture for
interconnecting networks: the word “Internet”
makes its appearance from Cerf’s writings
Networking History...



Time sharing became difficult since different machines
had different operating systems, versions and programs
–however, these led to development of Internet
Vinton Cerf. Bob Kahn, Bob Braden and Jon Pestel
developed TCP/IP
Cerf and Kahn’s internetworking principles:
 minimalism, autonomy - no internal changes required
to interconnect networks
 best effort service model
 stateless routers
 decentralized control define today’s Internet architecture
Networking History...

1978: TCP/IP v4 was released








Aimed to interconnect different kinds of networks
1979: ARPAnet has 200 nodes
1983: deployment of TCP/IP in ARPAnet
1983: SMTP e-mail protocol defined
1983: DNS defined for name-to-IP-address translation
1985: FTP protocol defined
1988: TCP congestion control
100,000 hosts connected to confederation of networks
Networking History...
Early 1990’s: ARPAnet decommissioned

Early 1990s: WWW
 Hypertext (1945 Bush: “As We May Think” article, Ted Nelson, Engelbert,
Andries in 1968 )
 HTTP: Tim Berners-Lee develops WWW an Internet based hypermedia
initiative at CERN, specifies URLs, HTTP and HTML which became basis for
today’s WWW
 1994: Mosaic (Univ. of Illinois), later Netscape the major browsers until late
1990’s
 late 1990’s: commercialization of the WWW, with introduction of HTTPS ecommerce is realized
Late 1990’s:

est. 50 million computers on Internet

est. 100 million+ users

backbone links running at 1 Gbps

The ARPANET


Growth of the ARPANET (a) December 1969. (b) July 1970.
(c) March 1971. (d) April 1972. (e) September 1972.
Hosts on the Web
Over the past year, the UK added a net increase of 6.1 subscribers per 100 inhabitants. The US added 4.7
subscribers, while Japan added 2.6. The UK's superior growth rate propelled it past the US and Japan to
become second only to Canada among G7 countries surveyed in broadband penetration.
Source: http://www.websiteoptimization.com/bw/0611/
Total Broadband Subscribers

Over the past year, the US has maintained its lead with 31% of total
broadband subscribers worldwide.
Source: http://www.websiteoptimization.com/bw/0611/
Course Overview

Aimed to impart





Fundamentals of Networking principles
Application of these principles in Internet
Understanding of Issues in Theory and Practical Design
of networking hard ware and software
Understand some network programming principles
Practice of using standard networking tools
Some Pre-requisites




Brush up on your probability and statistics
concepts, especially, probability distributions
Revise a bit of operating systems (memory
addressing in CAMs, TCAMs etc)
Bit of processor architecture
Try to learn C++ in the first two weeks before the
labs/programming assignments begin
Grading Overview








Homework Assignments: 20%
Programming Assignments: 20%
Mid-terms: 40%
Final Exam: 15%
Class Participation: 5%
 Anyone sent out of class even once for causing disruption will receive
not receive this credit
Important: Minimum pass mark for the course is 50% of overall marks
achievable (in absolute sense)
Any copied * will get 0 marks for * and anyone caught more than once
fails the course
One lab and/or tutorial per week, schedule will be announced soon
Course Textbook and References
Text Book
 Jim Kurose and Ross “Internetworking: A topdown Approach”
 Bertsekas and Gallagher “Data Networks”
References
 S.Keshav “An Engineering Approach to
Computer Networking”
 Radia Perlman “Interconnections: Bridges and
Routers”