I am in the office most days and you are welcome anytime you see the door open. Call ahead if you want to be sure I am there. Otherwise, just stop in.
Graduate Assistant:
Name:  Sandeep Gandra
Office:  G50
e-mail:  sandeep_gandra@hotmail.com or sgandra@monet.csc.villanova.edu
Office hours:  Monday and Friday afternoons -- times to be determined

Text book:
 Cassel, Lillian N. And Richard H. Austing.  Computer Networks An Application Development Perspective
Due from the publisher "soon."

You will need regular access to the class web page and bulletin board. You will need access to a computer system where you can prepare web materials and make them accessible to the rest of the class. You will also need to be able to write programs that use network resources and allow others in the class to have access to your programs. You will have an account on the department computers for this purpose. You may use other computers as long as the access requirements are met.

Course content and grading:

This course requires the active involvement of all participants. Reading and other assignments will be discussed in class. Questions that arise will be addressed by everyone. Each student will make at least one presentation to the class on a topic central to the course. Writing assignments and class presentations will be evaluated for content and for effective presentation. Each class member will critique the materials produced by other class members. Conscientious attention to constructive feedback on these materials is as important as producing your own materials.

The usual rule of thumb for course work is that 2 - 3 hours of work outside of class time is needed for each one hour in class. Since this is a 3 credit course, that translates to 6 to 9 hours of work outside of class time each week. Of course, some weeks will be a bit lighter and some a bit heavier. Some people will manage with somewhat less time; others will require more. If you find you are spending much more than 10 hours a week on this course on a regular basis, come see me about it.

Requirements:

Basic expectations of the Web page assignment:

• For this purpose, the page must include at least the following characteristics:
• A Title, suitably displayed.
• An address section at the bottom identifying you as the author and providing access to you if the reader wants to send feedback.
• A good background image.  Be careful that the text is still legible when displayed on the background you choose.
• At least one image.
• Links of the following kinds: to another place in the page, to another file in the same filespace as the web page, to another file that is not on the same computer system as the web page itself.
• A table or frames to organize the space of the page.
There is lots of room for creativity and imagination in this assignment.  These guides are given to describe a base expectation.  Go on from there in any way that seems appropriate for you.

• For this purpose, the page must have the following characteristics:
• The page must be located in a directory called netclass, from your root html directory.  The page must be named index.html in that directory.  (You will have a directory called html in your root directory.  In that html directory, you will have a directory called netclass.  In the netclass directory, all files related to this course will be found.  The file index.html in netclass will be the path through which your other files are seen.  If your login is kthomas, the address of your page is www.csc.villanova.edu/~kthomas/netclass)
• There will be a link on this page called Reports.  That will link to another file or to another location on this same page where the names of the reports you do during the semester will be placed.  Each report will reside in this directory and will be pointed to by this list.
• There will be another link for Projects.
• We will add others as needed.

Guidelines and Suggested topics for Class Presentation

Suggested topics:

1. MIME.   This is an example of Presentation layer activity provided in the Internet context.  You should work from the RFC and other materials readily available.
2. HTTP.  What information is really exchanged in the interactions between a browser and a server?
3. The new IP v6 and its 128 bit address scheme.  Clearly the distribution of the new IP throughout the Internet will be a monumental task.  There are several potential presentation topics.  One might focus on the 128 bit addresses and how the bits will be used.  Another might address the problems associated with the transition to the new scheme.
4. Multicast.  Multicast means distributing communications to a selected subset of all possible recipients.  It supports conference "calls" and group work, for example.  Multicast is one of the issues addressed in the new IP.
5. Security in electronic commerce applications
6. Connecting the Internet to your home: cable modems, ISDN, DSL, etc.  What are the requirements, what is available, how do you choose?
7. High speed LANs.  How do 10Mbps and 100Mbps Ethernets compare?  What is the projection for higher speed Ethernets?  Similar topics for Token Ring, FDDI, etc.
8. ARP (Address Resolution Protocol) -- how a machine discovers its own identity.  The relationship between an IP address and a local network address
9. DNS (Domain Name Service) -- how machine names are converted to IP addresses.
10. Registering names in the Web.  Procedures, costs, who is in charge.
11. Others......

Calendar scheduler project

The requirements above consititute the base requirements for this project.  Successful completion of this work with a good display will receive a grade of B.  To improve your grade, enhance your project with some or all of the following features.  You may add other features as well.  The best calendar will be used in the class to schedule the end-of-semester presentations.

Enhancement 1:  Make an initial form that asks the user what time period they want to schedule.  Display the month requested.  Even better, display the month or the week or the day (requires times as below), as required by the user.  Best, allow the user to specify any time period, even if it begins in the middle of one week and ends in the middle of another week, which may be in another month and/or year.
Enhancement 2:  Include times on the days.  Make the time slots of fixed size (one hour, perhaps) or, better, allow the user to choose the time slot size.
 
 
 

Semester Project

Base requirements:

• Your project must involve an application that runs on two or more computers and includes interaction between them.
• Your project must be original work by your team.  You may refer to others' work, but must be very clear about what you get from others.  You will get credit for creating something.  Building on what others have done is ok in this project, but you will be judged by what you accomplish.  Any project that includes work done by others, which is not clearly identified as such, will result in a report of academic cheating and the serious consequences outlined in the University's policy on academic integrity.
• Each of these projects requires you to do some investigating to learn about available resources.  Spend some time at the beginning to find what is available to help you.  Don't reinvent standard network resources!
• There are a lot of tools available to you in Java that will make these projects easier than they have been for people who had to open sockets directly and create the communication link between the systems.  You will probably want to investigate Java's RMI (Remote Method Invocation).  Plan your time so that you can learn to use these resources if you do not already know how to use them.
• You may choose a different project from anything suggested here.  However, the project must be something connected closely to the way the lower layers of the network work.  If you are not sure about the appropriateness of a project, ask early.

• Write a program to display the approximate round trip time for messages exchanged between the client computer and a given remote host.  Use this information to choose which of several available servers is most accessible at the present time.  Your user should provide the names of the servers.  You should display the round trip time for each server and highlight the shortest time.  (There are several resources available that will help with this.  Look for a time service that runs on many machines and learn how to convert from a host name to its IP address).
• Implement a very basic authentication service and a resource manager that uses the service.  A user wishing to use a resource first contacts the authentication service.  The user provides an id (user name) and password and the name of the desired resource.  The authentication server checks to see if the id/password pair is valid.  The authentication server computes a randomizing function (a ticket) on the id/password and the IP address of the user's system.  This ticket is then passed back to the user and is also sent to the resource manager.  The user then has a fixed time, perhaps a minute, in which to contact the resource manager and request the desired resource.  If the ticket presented matches one the manager expects, the resource is made available.  For your purposes, the resource can be a simple as being allowed to see the contents of a file and report back what is stored there.  The user should receive the file contents displayed on the screen.  The point here is the interaction between the user, the authentication server, and the resource manager.  What is your opinion of this system as a security measure?
• When you begin this project, we will not yet have discussed the transport layer except in general principles.  Here is a simple function of the transport layer that you can implement in anticipation of further details.  The role of the transport layer is to provide the appearance of error-free communication between two end systems.  To do that, the transport layer sends a messages to its peer and looks for acknowledgements that those messages arrived safely.  If a message did not arrive safely, the transport layer must resend it.  On the receiver side, the transport layer must recognize that it has received a message, must acknowledge receipt and pass the messages up to the user of the transport layer.  A very simple protocol for these acknowledgements is called stop-and-wait. In this protocol, the sender transmits a message and then waits for an acknowledgement.  When the acknowlegement arrives, the sender transmits another message.  Even this simple protocol has some complications, however.  If an acknowledgement does not arrive, the sender must give up and retransmit.  How long should it wait?  Suppose the acknowledgement is sent but does not arrive safely?  Then the sender will resend and the receiver will have two copies of the same message.  To address this problem, each message has a sequence number: either a 0 or a 1.  If the receiver sees two messages numbered 0, it knows it has a duplicate and it discards one.  The question of the waiting period is handled with a timer.  When the sender transmits, a timer starts.  If the timer expires, the sender resends the message.  Implement and test a stop-and-wait protocol.  Be sure to test cases where messages get through, messages get lost and acknowledgements get lost.
• The data link layer appends an error check sequence to the end of a message before it is transmitted.  The error check is created on the fly as the bit stream is sent and the corresponding error check is generated while the incoming message is arriving at the destination.  An interesting project is to do that error check (CRC).  In other words, you would receive a string of bits, say 40 bits, and calculate the CRC.  You send the bits with the CRC appended to another program which calculates the CRC as the bits arrive and checks the last bits to see if they match the value it calculated.  You would write two programs, one to send and one to receive.  You should make the sender send some errors now and then to test the receiver.   To do this assignment, you will probably want to look into the CRC a bit before we would get there.  There are lots of resources available in addition to the book.  Use the 32-bit CRC code.  We will probably talk about the code in time for you to complete the project, but getting a head start might be wise.

cassel@vill.edu
4 January 2000