Steve Deering had a nice set of slides in London about the horrible things that we were doing to "the wasp waist" (IP), but that doesn't mean that "wasp waists" don't have real advantages. We like to say in TSV that having applications handle congestion control is wrong because if 19 applications out of 20 do it correctly, the guy who hoses it up, hoses it for everyone. Although the potential for disaster on interface selection is limited, what we're trying to do isn't trivial, and the chances a stack can do a better job than a random application seem pretty large to me. I'd vote for Stephen's "latter". Spencer --- Stephen Sprunk <stephen@sprunk.org> wrote: > > Which is harder, having the stack give the app a list of > source and > destination addresses and then expect the app to figure out > which to use, or > have the stack attempt various combinations of source and > destination > addresses and just notify the application which one(s) worked? > > Something tells me the latter is both easier and more likely > to be > implemented correctly.