NIELIT 2018-44

Question

Time to Live(TTL) field in the IP datagram is used ______

• A. to optimize throughput
• B. to prevent packet looping
• C. to reduce delays
• D. to prioritize packets

Answer 1

If a routing loop occurs between two or more routers, the packet will keep moving back and forth until it passes sixty four or defined number of maximum hops allowed. When it reaches maximum allowed hop count or when the TTL field becomes zero, the packet is dropped from the network.(TTL HEADER IS 8 BIT)

THEREFORE TTL IS USED TO PREVENT PACKET LOOPING.

SO  OPTION B IS CORRECT.

Answer 2

See The reason of choosing  TTL for looping is straight forward, if any packet or datagram having no TTL field then there might be chance that a packet can falling in infinite loop and due to this there is a huge congestion on routers.So TTL shows after a finite no of hopes this packet is going to be discarded. THIS is the reason why  we choose the TTL field.

Hope it hleps!

Answer 3

→ Time to Live (TTL) is a limit on the period of time or transmissions in computer and computer network technology that a unit of data (e.g. a packet) can experience before it should be discarded.
→ If the limit is not defined then the packets can go into an indefinite loop.
→ The packet is discarded when the time to live field reaches 0 to prevent looping.