CS 640 Introduction to Computer Networks

Programming Assignment 2: Routing Protocol

Please check this page for FAQs and frequent updates on instructions.
Note: we will also have demo. Two groups will work together to demostrate that their server can work with each other. You also need to tell TA about what tests you have done on your server to ensure the robustness.

Frequently Asked Questions:

(1) You should be able to run the commands (update, step, packets,  display,  disable, crash) while the servers are running.
      Use the select( ) call and add the fd of the standard input/output as show below:

FD_ZERO(&socket_set);//clears it out
        FD_SET(sockfd,&socket_set);//places our socket into the set
        FD_SET(0,&socket_set);//add fd of standard input/output
        results = select(FD_SETSIZE, &socket_set, (fd_set *) 0, (fd_set *) 0,NULL);


(2) For sending periodic updates you will have to use setitimer( ) and  sigaction( ). Look at the man pages for usage.

• When using signact(), it may cause some problem in using select() function. If you use printf("%m\n", errno); to print out the error message, it will show "Interrupted system call".
  Please use the following code to check whether the error is caused by system interruption. If so, please just neglect it.
  result = select(...);
  if(result < 0){
  if(errno != EINTR){
  printf("Erros is not caused by system interrupt\n");
  }
  }
  

(3) Here are the topology files for the example topology. You can use them to test your code. Right click and save the files. top1.txt is for
       server 1, top2.txt for server 2 and so on. You will have to modify the IP addresses and the port numbers in the files.
top1.txt
top2.txt
top3.txt
top4.txt
top5.txt

• The topology file is complete and thus it contain the IP address and port of the server which read this topology file. You may get your IP address and port by using server ID and the server list in the toopoly file

(4) Do appropriate error checks. 


Submission Instructions:

What to submit:

You will need to submit the source code along with the Makefile in a single tar.gz file (name it p2.tar.gz). The extracted directory p2 should contain the server code and the Makefile.
Do not submit object files, or compiled executables. The Makefile should have two rules: clean and all.

clean will delete previous .o files, executables, etc.

all should produce a single executable called server.

How to submit:

First add the following line to your .cshrc.local file if you have not done that before(located in your home directory):
    set path = ($path /s/handin/bin)

Then run the following command at the shell prompt:

    source ~/.cshrc.local

Finally, to handin your files, enter the following command:

    handin -c cs640-1 -a PA2 -d <directory>

where <directory> is the path to the directory where  p2.tar.gz is located

handin will go through the specified directory and hand in the tar ball.

Make sure both the group members submit the same code.

The example topology files described in FAQ4 will be used for testing your code.