  The classes of depth-bounded and name-bounded processes are fragments of the
pi-calculus for which some of the decision problems that are undecidable for
the full calculus become decidable. P is depth-bounded at level k if every
reduction sequence for P contains successor processes with at most k active
nested restrictions. P is name-bounded at level k if every reduction sequence
for P contains successor processes with at most k active bound names.
Membership of these classes of processes is undecidable. In this paper we use
binary session types to decise two type systems that give a sound
characterization of the properties: If a process is well-typed in our first
system, it is depth-bounded. If a process is well-typed in our second, more
restrictive type system, it will also be name-bounded.
