Fri Oct 15 18:51:15 1999
Yes, it does stand for Time To Live. The main idea is to prevent
packets from bouncing around forever if the routing tables get into
In the old days, it was the number of additional seconds that a packet
should be allowed to live. But each router counts as at least 1
second. I'm not sure any router ever bumped the TTL down by more
than 1 but it would make sense on a slow link with long queues.
Now, it's really a hop count. The name is historic.
The sending host initializes that field. Usually it's hard coded
into the protocol stack. Older systems used 16. That stopped working
several years ago when the internet got too big. I think most modern
systems just set it to 255 - the max that will fit.
[I might be off on some of the details above, but the general idea