Comment by sadjad
The primary purpose of TTL is to prevent packets from looping endlessly during routing. If a packet gets stuck in a loop, its TTL will eventually reach zero, and then it will be dropped.
The primary purpose of TTL is to prevent packets from looping endlessly during routing. If a packet gets stuck in a loop, its TTL will eventually reach zero, and then it will be dropped.
Then random internet routers could break internet traffic by setting it really low and the user could not do a thing about it. They technically still can by discarding all traffic whose value is less than some value, but they don’t. The idea that they should set their own policy could fundamentally break network traffic flows if it ever became practiced.
It does make traceroute, where each packet is fired with one more available step than the last, feasible, whereas 'up' wouldn't. Of course, then we'd just start with max-hops and walk the number down I suppose. I still expect it would be inconvenient during debugging for various devices to have various ceilings.
That doesn't answer my question. If it counted up then it would be up to each hop to set its own policy. Things wouldn't loop endlessly in that scenario either.