-\anchor pf_host_churn
-### Expressing churn ###
-
-To express the fact that a host can change state over time (as in P2P
-systems, for instance), it is possible to use a file describing the time
-at which the host is turned on or off. An example of the content
-of such a file is presented below.
-
-#### Adding a state file ####
-
-\verbatim
-<platform version="4">
- <host id="bob" power="500Gf" state_file="bob.fail" />
-</platform>
-\endverbatim
-
-#### Example of "bob.fail" file ####
-
-~~~{.py}
- PERIODICITY 10.0
- 1.0 0
- 2.0 1
-~~~
-
-A zero value means <b>down</b> (i.e., OFF) while a positive one means <b>up and
- running</b> (i.e., ON). From time 0.0 to time 1.0, the host is on as usual. At time 1.0, it is
-turned off and at time 2.0, it is turned on again until time 12 (2 plus the
-periodicity 10). It will be turned off again at time 13.0 until time 23.0, and
-so on.
-
-