TTl :Time to Live concept in networking

disclaimer : i am already half asleep . will try to put in as much as i can now

, see its not circular routing , its more of bringing down the network with same packet being sent downin the network a million times and nothing to stop it. when TTL value has been provided, for each hop the packet does, the TTL is decremented, thus even if network goes down , we wont ave repeated packets.
Consider this network L1 <-->R1<-->R2<-->R3<-->L2, when link between L1 and R1 goes down, R1 says out -" guys! dont update your routin table, i dont see L1 ", R2 says -" dont worry, i have a route". Now, it has to be noted that R2 gets the route to L1 only thorugh R1, but since there is no feild to validate, R1 takes it up, hence though theoritically its only 1 hop away, R1 sees it as 2 hops ( R1 -->R2 -->R1), when TTL is introduced, though this continues it dies off when offset is 0, thus packet is discard and the network is self healing, as we another possibilty what i can see is, when there are duplicate routing entries, TTL helps to see if this packet has already been sent

hahaaa , hey thanks for the answer so i got advanatage of using ttl , nice explanation , ur master of networking !!