Which IPv4 field determines how long a packet can travel before it gets dropped?1 分Type of ServiceHeader ChecksumTime to LiveOptions

The "Time to Live" field in the IPv4 header determines how long a packet can travel before it gets dropped. This field is used to avoid a situation where packets are looping around the network indefinitely due to routing errors. Here's how it works:

1. When a packet is sent, the "Time to Live" field is set to a certain value, typically 64.

2. Each time the packet passes through a router, the "Time to Live" value is decreased by one.

3. If the "Time to Live" value reaches zero, the packet is dropped and a message is sent back to the sender informing them of this.

4. If the packet reaches its destination before the "Time to Live" value reaches zero, it is processed normally.

So, in summary, the "Time to Live" field in the IPv4 header is used to ensure that packets do not circulate in the network indefinitely.