3.1.2.6 Timer Events
When the ping set timer expires, the object resolver SHOULD assume that the client is either dead or is unreachable and MUST perform the following:
For each OID in the ping set entry:
It MUST look up the OID entry.
It MUST decrement the reference count of the OID entry held by the SETID entry.
If the reference count drops to zero:
It MUST remove the OID entry.
It MUST instruct the object exporter of the OID to reclaim the object.
It MUST remove the ping set entry from the SETID table.