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CSc 450/550Computer Networks

Introduction

Jianping Pan

Summer 2007

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About the course

• Computer Communications and Networks– lectures: MR 11:30am - 1pm, MAC D116– http://www.csc.uvic.ca/~csc450

• lectures, labs, discussion board, etc

– prerequisites (from UVic calendar)• Computer organization (CSc 355)• Operating systems (CSc 360)

– CSc 360 prereq: CSc 225, 230, SENG 265

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What's new this summer?

• The course– in the process of redesign and redevelopment

• The lectures– focus on TCP/IP networking

• a foundation for the advanced networks courses

– new! guest lecture: May 10 by Mr Ron Kozsan

• The labs– new! Ethereal (Wireshack) tutorials– focus on TCP/IP networking

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About the course instructor

• Dr Jianping Pan– pan@uvic.ca, x5796– office hours: MR 10:30-11:30am, ECS566

• or by appointments

– work experience• UVic, industry research labs, UWaterloo, …

– research area• computer networks and distributed systems• http://web.uvic.ca/~pan

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About the lab instructors

• Deer (Dale) Li– deerli@uvic.ca

• Ming Lu– luming@uvic.ca

• Two sections!– check WebTT for your lab time/place

• Three lab projects– lab starts this week!

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Why study computer networks?

• How to use networks– not as a network user– but as a network programmer/engineer!

• configure, diagnose, troubleshoot, improve networks

• How to design network protocols– or design any large-scale, distributed systems

• How to implement network protocols– or write any effective and efficient code

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Internet history: ARPAnet (70’s)

Dec. 1969 March 1971July 1970

Apr. 1972 Sep. 1972 56Kbps

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Internet history: NSFnet (80’s)

1988 1.5Mbps

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“The Internet”

• Dialup• DSL• Cable• wireless

• Ethernet• FDDI• leased• wireless

• T1/T3• OC12/48/192• satellite

data center

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AT&T US backbone

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Internet Service Providers

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Internet in Canada

• CA*net: 1990-1997; CANARIE: 1993– 56Kbps, T1 (1.5Mbps), T3 (45Mbps)

• CA*net II: 1995-2000– national test network: ATM (155Mbps)

• CA*net 3: 1998-2002– the world’s first national optical R&E network

• CA*net 4: 2002-now– high-speed optical network (40Gbps)

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Internet @ UVic

• UVicNet: Gigabit Ethernet backbone– switched 10/100Mbps Ethernet access– also, UVic research network

• ResNet: switched 10Mbps Ethernet• UVic AirNet: 11Mbps wireless LAN• Upstream providers

– BCnet ORAN: CA*net4– VicTX: commercial Internet

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UVic => Google

• # traceroute google.com

traceroute: Warning: google.com has multiple addresses; using 72.14.207.99

traceroute to google.com (72.14.207.99), 30 hops max, 38 byte packets

1 gw.net.engr.UVic.CA (142.104.127.254) 8.686 ms 1.471 ms 5.732 ms

...

5 csc1cled050.bb.uvic.ca (142.104.252.21) 1.375 ms 1.244 ms 1.156 ms...

8 UVicB-Policy1.VICTX.BC.net (207.23.241.221) 2.041 ms 1.821 ms 2.795

9 ra1cv-ge3-2-11.gv.bigpipeinc.com (64.251.72.41) 1.832 ms 1.937 ms...

12 rc1wt-pos2-1.wa.shawcable.net (66.163.77.21) 7.415 ms 196.976 ms ...

13 six.sea01.google.com (198.32.180.17) 4.779 ms 4.769 ms 4.657 ms

14 72.14.233.55 (72.14.233.55) 23.586 ms 24.045 ms 23.684 ms...

18 72.14.207.99 (72.14.207.99) 63.148 ms 63.026 ms 63.126 ms

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How to study computer networks?

• The design and implementation of protocols– algorithms: error checking, sliding window, etc– mechanisms: flow, error, congestion control, etc– policies: e.g., reliable vs unreliable data transfer

• Protocols: the machine-to-machine language– syntax: “how do you do?”– semantics: what do you mean by “how do you...”– synchronization: the sequence of conversation

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Google!

• # wget -d www.google.comConnecting to www.google.com:80... Caching www.google.com <-> 66.102.7.104

Created fd 3.

connected!

---request begin---

GET / HTTP/1.0

User-Agent: Wget/1.7

Host: www.google.com

Accept: */*

Connection: Keep-Alive

---request end---

HTTP request sent, awaiting response...

HTTP/1.0 302 Found

Location: http://www.google.ca/

Cache-Control: private

Content-Type: text/html

Server: GWS/2.1

Content-Length: 218

client server

request

response

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Things involved

• You say “www.google.com”, I say “66.102.7.104”– Domain Name System (DNS)– User Datagram Protocol (UDP)

• “connected”– Transmission Control Protocol (TCP)– Internet Protocol (IP)

• “request begin”– Hyper Text Transfer Protocol (HTTP)

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More things involved

• TCP– connection management– flow, error, and congestion control

• IP– Internet addressing and routing

• Link layer– Ethernet: IEEE 802.3– wireless Ethernet: IEEE 802.11

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Course objectives

• “Understand the principles and practice of designing, building, and operating computer networks, particularly the Internet.”

• Selected topics– application layer: client-server, HTTP, DNS– transport layer: TCP, UDP– network layer: IP, Internet routing– link layer: IEEE 802.3, IEEE 802.11

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Course materials

• Required textbook– Tanenbaum, Computer networks, 4th edition– Kurose & Ross Computer networking, a top-

down approach featuring the Internet, 3rd edition (4th edition is out!)

• Explore further– web links @ course web site– IETF, ACM, IEEE, ..., Google!

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Your participation

• Lectures• Lab projects (CSc 450: 45%; 550: 30%)

– bonus features!

• Course projects (CSc 550: 15%)• Exams (CSc 450/550: 20%, 20%, 15%)

– three in-class midterms• May 31, June 28, August 2

– 60-minute exam, 20-minute after-exam review

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Suggested approaches

• Before lectures– read textbook; find questions

• Attend lectures– take notes; ask questions!

• After lectures– explore further; get help and help others

• Attend lab tutorials– start projects early!

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Common mistakes

• “The slides are already out there”– slides: intended to be brief and as a guide map– a lot of details, discussion, questions and

answers only appear in class– attending lectures is essential

• “I'll do the lab project on the due date”– simple fact: you cannot finish (and even start) it!– design and implementation take a lot of time– starting early is essential

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More systems courses @ UVic

• Embedded systems (CSc 460)• Multimedia systems (CSc 461)• Distributed systems (CSc 462)• Fault-tolerant (CSc 454) and Parallel (464)• Topics in systems (CSc 485A-H)

– advanced operating systems– advanced computer networks (offering now!)– wireless mobile networks, etc

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Your feedback

• Teaching/learning is interactive– two-way communications

• Let me know– what do you think about lectures, tutorials, labs,

projects, exams, topics, …– what do you want to know more, probe further

• You can always reach me– in class, during office hours, by email/phone

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Course policies

• See official course outline– late assignments, mark appeals, etc– academic integrity– accommodation, etc

• No group projects– collaboration/participation is encouraged– responsibility: your submitted work is yours– obligation: give credits to references

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Assignment 0

• Due on Friday, May 11th, 2007• From you@uvic.ca to pan@uvic.ca

– Subject: [csc450] A0, or [csc550] A0• name, student number, academic program• things you want to know most in networks• your research topics and projects (csc550 required)• issues with course logistics• a URL to a mug shot

– let me know you!

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This lecture

• An introduction to the course– who, when, where, what, and how– course objectives, materials, topics– you and the course!

• Explore further– your traceroute to www.google.com

• at home, or to your other favourite web sites– on Windows, it's tracert

• anything interesting, unusual, confusing?

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One more message...

• NSERC Undergraduate Research Awards– awards allocated to UVic CS

• Fall 2007 application deadline: June 15

– get a taste of doing research• a good experience before graduation, going to

graduate school, or committing to research career

– impress employers in your resume• can be used as Co-op, work term as well

– some projects• http://www.cs.uvic.ca/~pan/usra

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Next lecture

• Guest lecture– UVicNet, BCNET, CA*Net4 and more– by Mr Ron Kozsan

• UVic Network Services Managers

– May 10, 11:30am-1pm, MAC D116