Network traffic measurement of the X window system

The X Window System is a popular windowing system that runs on a wide range of computing and graphics machines. X servers and clients communicate over a network so that applications running on remote hosts can be displayed locally through graphical interfaces. This paper presents measurements of network traffic and message transfer for the X Window System. A network traffic monitoring tool, tcpdump, is used to collect packet traces in order to study the traffic between a server and a client for various X applications. X protocol messages for the applications are also recorded by a monitor called xmon. The measurements are taken on a 10 Mb/s Ethernet LAN. Experimental results show that packets are produced equitably between clients and servers. The bulk of the bytes are, however, directed from dients to servers. The bandwidth requirements are particularly high for applications that display documents, images, or video. Examination of X protocol messages manifests the dominance of request messages in frequency as well as size.