CMSC 417 Computer Networks Spring 2009
Programming Assignment 0
Assigned: 01/30/2009 Due: 02/04/2009, 11:59:59 PM.
You should use the CSIC Linux cluster systems and obtain your account information from the TA.
1 Introduction
For this assignment, you will write a client program which will communicate using sockets with
aserver program provided by us. We will give you a a sketch of the client program — all you have
to do is fill in socket-specific bits.
For each client request, our server generates and returns two cookies, and then the server and
clientembarkonalonggoodbye. Obviously,theprotocolis trivial/useless, however,this exercise
will get youstarted onthecluster andfamiliarize youwithsockets, networkprogrammingand
distributed debugging.
2 The Protocol
The server runs on the machine SERVER HOSTNAME andlistensforrequestsonaTCPsocket bound
to port SERVER PORT. Both constants are defined in the header file provided for you. This exercise
hasfourtypes ofmessages: HELLO,STATUS,BYEandCONFIRMBYE.Eachmessageis an
ASCII string, and consists of multiple fields separated by spaces (0x20). The maximum length of
eachmessageis MAX STR SIZE, which is also defined in the header file given to you.
Client Server
HELLO
STATUS
BYE
CONFIRM_BYE
Figure 1: protocol outline
The protocol outline is given in Fig 1. The client initiates the protocol by sending a HELLO
messagetotheserver.Theserver replies withaSTATUSmessage. Theclientthen sendsaBYE
message, and the server terminates the connection by sending a CONFIRM BYE message. A
1
