* the arguments are packed into a data structure suitable

for transfer across the network,

* an RPC identifier is generated for this call,

* a timer is set.

* the arguments are unpacked from the network buffer data structure

in a form suitable for making a local procedure call,

* the RPC identifier is noted.

* the return arguments are packed into a network buffer,

* another timer is set.

* the return arguments are unpacked,

* the timer set at point A is disabled,

* an acknowledgement is sent for this RPC id

(the timer at D can then be deleted).