Time to Live

Time to live (sometimes abbreviated TTL) is a limit on the period of time or number of iterations or transmissions in computer and computer network technology that a unit of data (e.g. a packet) can experience before it should be discarded.
See more at Wikipedia.org...

(TTL) A field in the Internet Protocol header which indicates how many more hops this packet should be allowed to make before being discarded or returned.
(1994-12-12)