Confused on the listener.trc content :

....
global context check-out (from slot 3) complete
Deallocating cxd 0x7fca3c.
Command specified to exit tnslsnr.
connect string inst->lcxd[0]: (ADDRESS=(PROTOCOL=tcp)(DEV=92)(HOST=192.168.1.199 )(PORT=1521))
Shutdown at 27-AUG-02 17:52:39
no timer allocated
closing transport
global context check-out (from slot 2) complete
no timer allocated
closing transport
global context check-out (from slot 1) complete
Deallocating cxd 0x7fcbac.
.....

It possible to have a brieft explanation on the general rule ?