[ih] TTL [was Exterior Gateway Protocol]

[Joseph Touch]

> On Sep 5, 2020, at 3:06 PM, vinton cerf via Internet-history <internet-history at elists.isoc.org> wrote:
> 
> no disagreement about discard - just that TTL wasn't interpreted as time
> but hop count in the implementations with which I am familiar;

That’s the spec requirement since RFC 1009 (1987), i.e., decrement by as many seconds as the packet is held, but never less than 1. For most routers, that effectively means TTL equates to hop count (few queues build up by seconds, except in more recent bufferbloat examples - because, AFAICT, before bufferbloat the cost of memory made such long queues rare relative to link speeds).

IPv6 made that change complete, calling the field “hopcount” anyway.

Joe