What is TTL?

The Time To Live field (TTL) in the IP header limit the period of time  the packet can experience before it
should be discarded. TTL is 8 bit field in IP header as you can experience in the simulation the TTL field is set by the
sender's computer and will be reduces by 1 each time a router route the packet to its destination.
If TTL reaches 0 before it arrived to  its destination  the packet will discarded by the router and the
router will generate ICMP error message back to the source (icmp type = 11, Time Exceeded)  indicating the
packet has reach its hop limit.
 

How to set TTL?

Different operating system allow different ways to set the ttl. in Microsoft windows
open the commands promot and type ping -i TTL <ip address>
Real Life Vs Simulation

Time field   - In this Simulation we try to show how the application is using time to measure the delay between
your computer and the host, also called RTT. in real life you most likely to get different numbers

RTT field - Different Operating systems are using different default RTT. in this simulation the default RTT is 64 for all
nodes in the network

Simulation

Use the ping simulation with TTL  to learn how TTL is used in the network. ping any host you wish in the
network and set the TTL to different values. First use the simulation to set  the TTL to a low number,
observe how the router generate ICMP errors back to the client then change the TTL to a greater number and see how the packet reach to its desination