— Web usage mining exploits data mining techniques to discover valuable information from navigation behavior of World Wide Web (WWW) users. The required information is captured by web servers and stored in web usage data logs. The first phase of web usage mining is the data processing phase. In the data processing phase, first, relevant information is filtered from the logs. After that, sessions are reconstructed by using heuristics that select and group requests belonging to the same user session. If we are processing requests after they are handled by the web server, this technique is called "reactive" while in "proactive" techniques the same (pre)processing occurs during the interactive browsing of the web site by the user. Reactive session reconstruction uses "time" and "navigation" oriented heuristics. We propose to combine these heuristics with "site topology" information in order to increase the accuracy of the reconstructed se...