Introduction to the UDP Echo Program

The UDP Echo program originally comes from the Donahoo "Sockets Programming in C".  The program (UDPEcho) is located in git in the code directory.  Note that there also is a similar program that uses TCP (TCPEcho).  The UDPEcho code is here:  https://people.cs.clemson.edu/~jmarty/courses/CPSC6240-Student/code/UDPEcho/

Conceptual:

• UDPEcho is meant to be similar to the ping program
  
• The purpose of the code is to allow the client and server to exchange a ping echo request and reply either for a specified number of iterations, or forever. over and over - at the end (upon CNT-C) the program provides statistics including the avg Round Trip Time (RTT) and the observed loss rate.
  
• Over the Internet, we might observe an average RTT of  60 ms and a loss rate of perhaps 1%.
  

UDPEcho client .------ R1 ------R2 ------- Host ---- UDPEcho server

Implementation and use of buffers. :

• The client uses a single buffer for the send and receive. It updates the seq number and add a timestamp. We'll talk about how internal representation of data messages need to be serialized in an understood format so the data can be sent as an unstructured stream of data.
  
  

last updated: 3/13/2019