WHAT IS THE PURPOSE OF THE TTL FIELD WITHIN AN IP PACKET HEADER

25. What is the purpose of the TTL field within an IP packet header?

• clears an unreachable route from the routing table after the invalid timer expires

• prevents regular update messages from inappropriately reinstating a route that may have gone bad

• removes an unreachable route from the routing table after the flush timer expires

• limits the period of time or number of hops a packet can traverse through the network before it should be

discarded

• used to mark the route as unreachable in a routing update that is sent to other routers