Computer Networks - TDC 463 - Autumn 2000

Room Lewis Center 1209, Tuesdays 5:45 - 9:00 p.m.

Course Homepage: http://condor.depaul.edu/~jkristof/2000Aut463/
Online Discussion Forum: http://forums.depaul.edu/HyperNews/get/F00/TDC-463-101.html

Office
Instructor: John Kristoff (jtk@depaul.edu)
243 S. Wabash Avenue, Room 714 (enter via Networks Room 711)
(312) 362-5878 voice
(312) 362-8274 fax
Hours: Mondays, 5:00 p.m. to 6:30 p.m. and by appointment

Grading

• 30% Homework


Four homework assignments for 30% total. The lowest homework grade will be dropped. Homework must be done individually and not in groups. Homework assignments are used to solidfy concepts and your understanding of "how things work". They will generally take about one to three hours of your time. Assignments will come from the text, lectures and external sources.

TURN IN HOMEWORK BY THE START OF THE FOLLOWING CLASS TO RECEIVE CREDIT. Submission by e-mail is OK. However, be sure formatting is readable and that I receive it by the start of class or you will receive an incomplete. Homework assignments will be assigned at class time and also posted to the HyperNews groups. General questions on homework can be asked in the HyperNews group. Homework answers will be covered in class and posted the course web page.


• 30% Mid-term Exam


One Mid-term exam which makes up for 30% of your total grade will cover all topics we have discussed in class, homework assignments and reading material up to that point in the course. You will have the entire class time to finish the exam, but you will probably not need it. A sample exam will be available a week prior so you have an idea of what to expect. You will not do well on the exam if you either don't come to the lectures, fail to complete the reading assignments or blow off the homework assignments. I will try to make myself readily available the week prior to the exam for questions and discussion. Check the HyperNews group for any common questions, tips and clarifications to covered material which may be relevant to the exam.

Mid-term exam IS CLOSED BOOK AND NOTES.


• 30% Final Project


See the Final Project section of this web page for more information about the details on what is required by the last day of class. During the class, you must provide a project topic, project outline and a rough draft (see schedule below). Failure to do so will lower your Final Project grade by 10% or more. I will be looking for your progress during the quarter. Projects done entirely the "night before" will be obvious and will receive a lower grade. Projects done in groups will be graded as a group. It is up to the group members that everyone pull their weight appropriately. In addition, you should make every attempt to ensure anything that you write or present is of appropriate professional quality. Basic spelling/grammatical errors or low quality diagrams will not help your grade. Be sure to cite your references completely!


• 10% Attendance/Participation


Although I don't expect everyone to be able to sit at the front of the class and constantly ask questions and provide feedback at every lecture, everyone should always attend class (except in the case of family/work emergencies), participate when called upon to do so and be attentive in the classroom. I encourage class discussion and questions either in the classroom or online. If you fail to come to class, sleep in class or generally avoid interaction you will lose 10% off your final grade.

Textbook(s)

Required
Computer Networks by Andrew Tanenbaum
ISBN: 0-13-349945-6
Author homepage: http://www.cs.vu.nl/~ast/

Recommended
Internetworking with TCP/IP: Volume 1 Principles, Protocols and Architecture by Douglas E. Comer
ISBN: 0-13-216987-8
Author homepage: http://www.cs.purdue.edu/people/comer

Computer Networks and Internets by Douglas E. Comer
ISBN: 0-13-083617-6
Author homepage: http://www.cs.purdue.edu/people/comer

Computer Networks by Larry L. Peterson and Bruce S. Davie
ISBN: 1-55860-368-9
Authors homepages: http://www.cs.princeton.edu/~llp/ and http://www.mkp.com/books_catalog/cn/bd/home.htm

Data and Computer Communications by William Stallings
ISBN: 0-13-084370-9
Author homepage: http://WilliamStallings.com

Interconnections, Second Edition: Bridges, Routers, Switches and Internetworking Protocols by Radia Perlman
ISBN: 0-201-63448-1
Authors homepage: http://cseng.aw.com/bookdetail.qry?ISBN=0-201-63448-1&ptype=0

An Engineering Approach to Computer Networking by S. Keshav
ISBN: 0-201-63442-2
Author's homepage: http://www.cs.cornell.edu/skeshav/

Routing in the Internet by Christian Huitema
ISBN: 0130226475
Author's homepage: http://www.huitema.net/

Schedule

Class Notes/Slides

• September 12, 2000 - Course Overview [ppt]


• September 12, 2000 - Introduction to Computer Networks [ppt]


• September 12, 2000 - Physical Layer [ppt]


• September 19, 2000 - Datalink Layer [ppt]


• September 26, 2000 - LAN Bridges and Switches [ppt]


• October 3, 2000 - Network Layer [ppt]


• October 10, 2000 - Transport Layer [ppt]


• October 17, 2000 - Congestion Control [ppt]


• October 24, 2000 - Congestion Avoidance [ppt]


• October 24, 2000 - Applications [ppt]


• October 24, 2000 - Network Management [ppt]


• October 31, 2000 - Security [ppt]


• October 31, 2000 - Wide Area Networks [ppt]


• November 7, 2000 - IP Multicast [ppt]


• November 7, 2000 - Mobile IP [ppt]


• November 7, 2000 - IPv6 [ppt]


• November 14, 2000 - Other Network Protocols [ppt]


• November 21, 2000 - Internet2 and Next Generation Networks - Dave Carr, Northwestern University [ppt]

Homework

• Homework Set #1 - Assigned September 12, 2000, due September 19, 2000



1. Answer Tanenbaum book question number 15 at the end of chapter 1. (1 point)


2. What are the purposes of headers (and sometimes trailers) for data packets (or frames). Why can't you just send data from one place to another? Please answer in 2 to 3 complete sentences. (1 point)


3. What is the binary representation for the decimal number 195? Show the math or no credit. (1 point)


4. Visit http://flowstats.is-net.depaul.edu. Approximately what percentage of overall traffic to/from the Internet involves the Computer Science department for DePaul? (1 point)


5. Answer Tanenbaum book question number 18 at the end of chapter 1. (2 points)


6. What is the difference between propagation delay and attenuation? Please answer in at least 2 to 3 complete sentences. (2 points)


7. In order to increase your sensitivity to new networking developments and their possible significant impact, read/scan current articles for significant new computer network technology news. Prepare a one to two paragraph discussion of the article's impact and why it is the most significant article for the week. Sources may include various magazines and Internet sites such as CNN, Tasty Bits from the Technology Front, ACM TechNews, Slashdot, QuickLinks, Wired and so on. Attach the referenced article with your write-up or include a link in your email. Please be prepared to talk briefly about your article in class on the following week. (2 points)




• Homework set #2 - Assigned September 26, 2000, due October 3, 2000



1. Explain in 3 complete sentences or more, why bridging between dissimiliar LAN technologies is so hard. Use valid examples in your answer. (2 points)


2. Should address lookup or address aging take a higher priority in a transparent bridge? Explain your answer in at least one complete sentence. (1 point)


3. What is the difference between a LAN switch and a LAN bridge? (1 point)


4. What should a transparent bridge do with a frame whose destination address it doesn't recognize? (1 point)


5. In an Ethernet LAN, would it be worse to have a late collision or for a station to receive a frame with an FCS error (frame was corrupted somewhere along the way)? Please explain your answer in detail. (1 point)


6. What are some of the technical reasons that make cut-through switching generally of little value in most common network environments? (1 point)


7. Answer Tanenbaum question 37 at the end of Chapter 4. (1 point)


8. In order to increase your sensitivity to new networking developments and their possible significant impact, read/scan current articles for significant new computer network technology news. Prepare a one to two paragraph discussion of the article's impact and why it is the most significant article for the week. Sources may include various magazines and Internet sites such as CNN, Tasty Bits from the Technology Front, ACM TechNews, Slashdot, QuickLinks, Wired and so on. Attach the referenced article with your write-up or include a link in your email. Please be prepared to talk briefly about your article in class on the following week. (2 points)




• Homework set #3 - Assigned October 10, 2000, due October 24, 2000



1. For the given IP address 24.15.99.6/20, find the following: 1) How many addressable hosts can exist on this subnet, 2) the subnet mask in dotted decimal notation and 3) the directed broadcast address. (2 points)


2. The original class hierarchy of IP addressing proved inadequate. Discuss at least one of the solutions we covered in class to alleviate the IP address shortage problem. Please write in complete sentences and include examples as necessary. (2 points)


3. What is the TTL field in an IP datagram header used for? (1 point)


4. Visit ARIN's whois information page. Enter "140.192.0.0" into the field (without the quotes) and click submit. What is the email address for the coodinator of this address block? (1 point)


5. What is 1 advantage and 1 disadvantage of a link state routing protocol versus a distance vector routing protocol? (1 point)


6. Answer Tanenbaum question 23 at the end of Chapter 6. (1 point)


7. Why should you never see an IP packet with the source or destination address of 127.0.0.1 on any network? (1 point)


8. A TCP receiver can adjust the rate of flow for a connection by advertising varying window sizes. Assuming a TCP sender has plenty of data to send. What besides the advertised window may cause the sender to slow down? (1 point)




• Homework set #4 - Assigned October 31, 2000, due November 7, 2000



1. Various networking devices are critical to the operation of an internet. If you had to choose one, would you consider the IP router or the DNS server as the most critical device on your network? Why? Explain your answer in detail. (1 point)


2. Read/browse RFC 959. List the "FTP Commands" that are available to a client (note, there are more than 7, look past the first page of the RFC! (1 point)


3. With a Netscape or IE browser, visit http://www.cnn.com@2361393414. If you have IE, also visit http://www.cnn.com@0x8C.C0.01.06. What page(s) did you go to? Explain what you think happened. (1 point)


4. Why would you use an application level gateway instead of just packet filtering and firewalls? (1 point)


5. Assume you implement NAT between your organization and the Internet, and you only have 1 valid IP address to use for all internal hosts. Theoretically, how many internal hosts can be supported in this scenario? Assume you can use port address translation as well. (1 point)


6. If you had to choose to use one or the other, would you choose to implement a network security solution (e.g. packet filtering router) or strong host based security (e.g. encryption, secure OS installation)? Why? (1 point)
7. In a approximately two paragraphs, explain in detail the most useful thing you've learned in this class. (1 point)
8. The cell size used in ATM is 53 bytes. This is not only an odd number, but also a prime number. Besides its strange size and format (compared to other technologies we've studied), why do you think a small, fixed cell size may be advantageous in some scenarios? (1 point)
9. Given a file of 512,000 bytes, compare the header overhead between transmitting the file over an ATM network versus an Ethernet network. Assume the MTU of an Ethernet frame is 1500 bytes and the header for all Ethernet frames are 18 bytes (ignore IFG, preamble and other things in this example, just worry about the basic frame size). Also assume the ATM cell has a 48 byte MTU and a 5 byte header. How many bytes are used for overhead in the ATM network? How many bytes are used in overhead for the Ethernet network? What is the percentage to total bytes (headers plus data) that is overhead in both the ATM and Ethernet networks? (1 point)
10. In order to increase your sensitivity to new networking developments and their possible significant impact, read/scan current articles for significant new computer network technology news. Prepare a one to two paragraph discussion of the article's impact and why it is the most significant article for the week. Sources may include various magazines and Internet sites such as CNN, Tasty Bits from the Technology Front, ACM TechNews, Slashdot, QuickLinks, Wired and so on. Attach the referenced article with your write-up or include a link in your email. Please be prepared to talk briefly about your article in class the following week. (1 point)

Midterm

• Midterm Studyguide


• Midterm [doc]

Project

A Final Project on a topic of your choice will be either in a report, a presentation or a combination of the two. The topic must be on something we have covered in class or related to computer networks with instructor approval. Projects can be done in groups of three or less people. You must receive approval for your topic by the 5th class.

You will be graded primarily on your ability to coordinate material, presenting a thorough investigation of your topic. A good approach is often to compare and contrast particular technologies or services. Try to choose topics which stress networking technology we have covered in class. Expect to write about 10 pages per person or to present for about 20-30 minutes per project. Some topics may include: Mbone, Router Configurations, Networking History, VPNs, directory services, DNS, Using TCPDUMP, Network Programming, Voice over IP, Wireless Networks and so on.

You should find and read magazines, books, web sites and interview people related to your topic. Here are some resources you may find valuable.


• Network Magazine http://www.networkmagazine.com
• IEEE Spectrum http://www.institute.ieee.org/
• IEEE Communications Magazine http://www.comsoc.org/pubs/commag/
• IEEE Network Magazine http://www.comsoc.org/socstr/techcom/ntwrk/
• IETF RFCs, Internet-Drafts and mailing lists http://www.ietf.org
• Computer Communication Review http://www.acm.org/sigcomm/
• Communications of the ACM http://www.acm.org/cacm/
• Business Week http://www.businessweek.com
• Cisco IP Protocol Journal http://www.cisco.com/ipj/
• Computer Emergency Response Team http://www.cert.org
• North American Network Operators Group http://www.nanog.org
• Charles Spurgeon's Ethernet Web Site http://wwwhost.ots.utexas.edu/ethernet/
• Internet2 http://www.internet2.edu
• NLANR http://www.nlanr.net

Project List

Name/Team	Topic	Paper	Presentation
Mike Krueger	DDoS Attacks
Charlotte Gill Bill Sander J.A. Bonilla	Wireless Communications
Fernando Castro	Internet2
Christine Ndirangu	Voice over IP
Orlan Hooper	Session Initiation Protocol
Steve Pribyl	Building a Firewall/Proxy Server
Moe Moe Thwe Manwit Puchitkanont	Virtual Private Networks
Supachoke Suwiwattanapunnadee	Internet Traffic Caching & Filtering
WeiChao Huang	Virtual Private Networks
Arturo Fernandez	ATM Quality of Service
Rommel Gandeza	ATM
Kook Chung	Configuring Cisco Routers
Xuan Qiu Frank Guo	WAP
George Iliopoulos	Voice Over IP
Michelle Trayne	DNS
Shui Jiang	Wireless LANs
Shenghang Huang	CDMA
Mingxu Zhou	Virtual Private Networks
Syed Anam	Virtual Private Networks
Shakeel Ahmed Khawaja Amit Ramesh Jagtiani Bhavi Sanghvi	Cluster Computing
Mark Ventimiglia	Stream Control Transport Protocol
Mohammed Shahbaz Khan	Voice over IP
Sarah Merrion	Rijndael Encryption
Sharad Chaudhary	Wide Area Networks
Srecko Vujasin	Voice over IP
Tenzing Baro	DNS

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Last updated: November 21, 2000