That was part of the original ip specification, it was modeled after army telecom patterns. where there are priority levels baked in. when the net starts to ove

That was part of the original ip specification, it was modeled after army telecom patterns. where there are priority levels baked in. when the net starts to overload the lower priority traffic gets discarded first. https://www.rfc-editor.org/rfc/rfc791 https://www.rfc-editor.org/rfc/rfc791 calls it precedence Precedence 111 - Network Control 110 - Internetwork Control 101 - CRITIC/ECP 100 - Flash Override 011 - Flash 010 - Immediate 001 - Priority 000 - Routine https://en.wikipedia.org/wiki/Type_of_service https://en.wikipedia.org/wiki/Type_of_service The bits ended up being reassigned for service codes. mainly because nobody used them. I also suspect there would be problems with a priority system in a peer network like the internet. It works in a more managed network(like the army) where strict priority control can be enforced. but it would probably be an arms race when one peer starts setting their priority a notch higher so their messages start getting through better on a congested link.