Fig. 1: Use of Window Scaling
The following plots track the deployment status of TCP's window scale, timestamp and selective acknowledgment options. The plots are based on packet traces of our lab's WWW server since November 1998. The plots are based on 682,837 TCP connections from 50,194 clients (distinct IP addresses). The following plots report the number of connections, bytes and clients that use a particular option. The number of bytes and connections may be biased by the fact that we only observed a single server. For instance, we note that the use of window scaling and timestamps jumps towards the end of the observation period. This is (mostly) caused by a few WWW crawlers upgrading from a stack that did not support the options to a stack that does support the options. The number of bytes transfered from our server reflects the content being provided. Hence a different server may report a different percentage of bytes using the given option. However, we believe the percentage of clients shown supporting a given option provides a representative view of the deployment of the option.
The following paper contains more about these plots, as well as several other findings based on the above described WWW traffic data:
