What does 'TTL' stand for in the context of IPv4 headers?

In the context of IPv4 headers, 'TTL' stands for Time to Live. This field in the IP packet header is used to specify the maximum lifespan or hop limit of the packet as it travels through the network. Each time the packet is forwarded by a router, the TTL value is decremented by one. If the TTL reaches zero before the packet reaches its destination, the packet is discarded. This mechanism is crucial for preventing packets from endlessly circulating in the network, which can occur due to routing loops or other issues.

The concept of Time to Live helps maintain the efficiency and reliability of IP networks by ensuring that packets that cannot be delivered within a reasonable time frame are removed from the network. This field plays an essential role in network management, contributing to overall network performance and reducing unnecessary traffic.

Other options like Transmission Time Limit or Time to Load do not represent standard terms used within IPv4 networking, and Time to Loop is not relevant to how packets are managed across routers and networks.