One of the header fields in an IP datagram is the Time to Live (TTL) field. Which
of the following statements best explains the need for this field?
(A) It can be used to prioritize packets
(B) It can be used to reduce delays
(C) It can be used to optimize throughput
(D) It can be used to prevent packet looping
Ans is D. You can see the same kind of question asked in GATE 2006.