Compression Performance of the Xremote Protocol

The Xremote protocol is a compressed transformation of the XWindow System protocol, designed to e ciently implement X connections across relatively slow serial lines. Using an Xremote simulator and 11 traces of X sessions, we found that Xremote's overall compression ratio is 2.4:1. This gure varies widely depending on the trace. A study of compression ratio as a function of message type shows text based messages commonly achieving 3:1 compression, while geometric messages usually achieve only 1.6:1 compression. By examining bandwidth requirements and compression performance as a function of time, we see that Xremote performs adequately for some applications which are text based or which use small geometric datasets, except at application startup where more bandwidth is required. Further work is required to adequately support the initialization stage of X applications and medium to large geometric databases.