> On Tue, 4 Sep 2007, Stephen Stuart wrote: > >>> Operators are probably more interested in the "fairness" part of > >>> "congestion" than the "efficiency" part of "congestion." > >> > >> TCP's idea of fairness is a bit weird. Shouldn't it be per-user, not > >> per-flow? > > > > How would you define "user" in that context? > > Operators always define the "user" as the person paying the bill. One > bill, one user.
It's easy to imagine a context where authentication at the application layer determines "user" in a bill-paying context. Passing that information into the OS, and having the OS try to schedule fairness based on competing applications' "guidance," seems like a level of complexity that adds little value over implementing fairness on a per-flow basis. In theory, any such notion of "user" is lost once the packet gets out on the wire - especially when user is determined by application-layer authentication, so I don't consider 802.1X or the like to be helpful in this instance. > Its fun to watch network engineers' heads explode. What if the person paying the bill isn't party to either side of the TCP session? Stephen
