This article will tell you what is TTL.
Given to that fact, TTL is also calledhop limit.
In the IPv6 header, it is the 8thoctet of 44.

What is TTL meaning?
The above description has already told you that.
Whats the working principle of TTL?
To get the answer and find more information about TTL, just keep reading this post ofMiniTool.
The frequently used online grid commands like ping and traceroute utilize TTL.
Some networks run in a traditional way rather than measuring the hop time between routers.
What does TTL mean?
Read here, you may obtain the answers.