Which field in the IPv4 header is used to prevent a packet from traversing a network endlessly?
- Time-to-Live
- Sequence Number
- Acknowledgment Number
- Differentiated Services
| Answers Explanation & Hints:
The value of the Time-to-Live (TTL) field in the IPv4 header is used to limit the lifetime of a packet. The sending host sets the initial TTL value; which is decreased by one each time the packet is processed by a router. If the TTL field decrements to zero, the router discards the packet and sends an Internet Control Message Protocol (ICMP) Time Exceeded message to the source IP address. The Differentiated Services (DS) field is used to determine the priority of each packet. Sequence Number and Acknowledgment Number are two fields in the TCP header. |