IP Header

Question 1
For which one of the following reasons does Internet Protocol (IP) use the time-to- live (TTL) field in the IP datagram header?
Ensure packets reach destination within that time
Discard packets that reach later than that time
Prevent packets from looping indefinitely
Limit the time for which a packet gets queued in intermediate routers
       Computer Networks        IP Header       Gate-2006
Question 1 Explanation: 
It prevent infinite looping over network .Bcz each router decrease its value by one and when this(TTL) value become zero ,then it is discarded by router silently.
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