T. S. Eugene Ng eugeneng at cs.rice.edu Rice University 1

COMP/ELEC 429/556Introduction to Computer Networks

Overview

Some slides used with permissions from Edward W. Knightly, Ion Stoica, Hui Zhang

T. S. Eugene Ng eugeneng at cs.rice.edu Rice University 2

A bit about me...

• Grew up in Hong Kong• B.S. University of Washington• Ph.D. Carnegie Mellon University

• Research interests in networked systems• Teach courses related to computer networks at both

undergraduate and graduate levels

• CS Graduate Committee Co-Chair

T. S. Eugene Ng eugeneng at cs.rice.edu Rice University 3

The BOLD Project in the News

T. S. Eugene Ng eugeneng at cs.rice.edu Rice University 4

A bit more about me...

• Love cycling, but don’t have much time for it anymore...

• Besides teaching, research, administrative work, and other professional obligations...

I’m Curious: What Motivated You to Take 429?

• Introduce yourself to your neighbor• Interview neighbor on what motivated him/her to take

429?

T. S. Eugene Ng eugeneng at cs.rice.edu Rice University 5

Obviously Internet Makes These Possible...

T. S. Eugene Ng eugeneng at cs.rice.edu Rice University 6

Network Crucial to Solving Hard Computational and Data Intensive

Problems

T. S. Eugene Ng eugeneng at cs.rice.edu Rice University 7

Software Defined Networking

T. S. Eugene Ng eugeneng at cs.rice.edu Rice University 8

Optical Networking

T. S. Eugene Ng eugeneng at cs.rice.edu Rice University 9

T. S. Eugene Ng eugeneng at cs.rice.edu Rice University 10

Internet Remains Unreliable

Internet Remains Unreliable

T. S. Eugene Ng eugeneng at cs.rice.edu Rice University 11

So whatever happened internally at Verizon caused aggregation for these prefixes to fail which resulted in the introduction of thousands of new /24 routes into the global routing table

Internet Remains Insecure

T. S. Eugene Ng eugeneng at cs.rice.edu Rice University 12

Course Goals

• Understand how today’s computer network works

• Understand how to utilize it

• Understand its weaknesses

• Understand alternatives

• Become equipped to innovate, solve problems, do great things

T. S. Eugene Ng eugeneng at cs.rice.edu Rice University 13

T. S. Eugene Ng eugeneng at cs.rice.edu Rice University 14

Long before there were computers...

• 1876: Alexander Bell invented telephone• 1878: Public switches installed at New Haven and San

Francisco, public switched telephone network is born

– People can talk without being on the same wire!

Without Switch With Switch

T. S. Eugene Ng eugeneng at cs.rice.edu Rice University 15

The Advent of Computer Technology 1940s

• Different networking requirements• Computers to computers communication

– vs. communication between human beings

• Digital information, discrete messages – vs. continuous analog voice

• Circuit switching technique in telephone network hugely inefficient for computer communications

T. S. Eugene Ng eugeneng at cs.rice.edu Rice University 16

Major Internet Milestones

• 1960-1964 Basic concept of “packet switching” was independently developed by Paul Baran (RAND), Leonard Kleinrock (MIT)– AT&T insisted that packet switching would never work!

MIT TX-2SDC Q32

dial-up

• 1965 First time two computers talked to each other using packets (Roberts, MIT; Marill, System Development Corp (SDC))

T. S. Eugene Ng eugeneng at cs.rice.edu Rice University 17

Major Internet Milestones• 1968 BBN group proposed to use Honeywell 516 mini-

computers for the Interface Message Processors (i.e. packet switches)

• 1969 The first ARPANET message transmitted between UCLA (Kleinrock) and SRI (Engelbart)– We sent an “L”, did you get the “L”? Yep!– We sent an “O”, did you get the “O”? Yep!– We sent a “G”, did you get the “G”?

Crash!

T. S. Eugene Ng eugeneng at cs.rice.edu Rice University 18

Major Internet Milestones

• 1970 First packet radio network ALOHANET (Abramson, U Hawaii)

• 1973 Ethernet invented (Metcalfe, Xerox PARC)• 1974 “A protocol for Packet Network Interconnection”

published by Cerf and Kahn– First internetworking protocol TCP

T. S. Eugene Ng eugeneng at cs.rice.edu Rice University 19

The 2004 A. M. Turing Award Goes to...

• "For pioneering work on internetworking, including the design and implementation of the Internet's basic communications protocols, TCP/IP, and for inspired leadership in networking.”

Bob Kahn Vint Cerf

T. S. Eugene Ng eugeneng at cs.rice.edu Rice University 20

Major Internet Milestones

• 1977 First TCP operation over ARPANET, Packet Radio Net, and SATNET

• 1985 NSF commissions NSFNET backbone• 1991 NSF opens Internet to commercial use

T. S. Eugene Ng eugeneng at cs.rice.edu Rice University 21

Network Component Examples

Links Interfaces Switches/routers

Ethernet

WiFi

T. S. Eugene Ng eugeneng at cs.rice.edu Rice University 22

T. S. Eugene Ng eugeneng at cs.rice.edu Rice University 23

Design Philosophy of the DARPA Internet Protocolsby David D. Clark (1988)

1. Internet communication must continue despite loss of networks or gateways

2. The Internet must support multiple types of communications service

3. The Internet architecture must accommodate a variety of networks

4. The Internet architecture must permit distributed management of its resources

5. The Internet architecture must be cost effective

6. The Internet architecture must permit host attachment with a low level of effort

7. The resources used in the Internet architecture must be accountable