Per default, the whole dispatcher cache is invalidated whenever a page is activated/deactivated. This behavior is not efficient for sites having independent content branches (eg. /site/en, /site/de, ...)
To only invalidate a content branch of the dispatcher cache upon page replication, you can use the /statfileslevel parameter.
For example, if your site is multilingual, with independent branches :
You simply set in the dispatcher.any :
/cache ... /statfileslevel "1" ...
The dispatcher will create a .stat file below /site/<country>, which is used to invalidate the cache at the <country> level.
When a page from /site/en is replicated, the cache of the corresponding branch will be invalidated by the dispatcher. A request for a page below /site/en will be delivered through Communiqué. But a request for a page below /site/de will be delivered directly from the dispatcher cache.
See also the official dispatcher documentation : http://docs.day.com/content/en/home/docutools/thedispatcher/configuring_the_dispatcher/Configuration_Parameters.html