Lifetime leases are used as an alternative mechanism to reference
counting with which the framework can reclame memory resources through
garbage collecting remotely activated objects.

Every object that is activated out of the application domain (remote
object) is granded a time lease. The lease manager of the remote
application domain has the responsibility to check periodically if the
lease of a particual instance has expired. If a lease manager finds
that an object's lease has expired it iterates through the sponsors
list associated with this object to query if there is a lease renewal
and if there lease is not renewed the lease manager deletes the object.

Sponsors are ISponsor implementations that are registered to a
particular lease and are responsible for managing the lease time of
remote objects. A sponsor can be registered in a lease. When the
procedure above executes (the lease manager iterates through the
sponsors) the sponsor is asked whether he wants to renew the time lease
of the object.

A high-level description would be : An object is given a specific
lifetime and after that it will be destroyed. The user can add sponsors
to the object that controls the destruction of these objects, where
this sponsors can ask for more time for the object.

The above have effect only for remotely activated objects.

I hope I helped a little.

Tasos