On Sun, 06 Mar 2011 20:25:10 PST ron minnich <rminn...@gmail.com> wrote: > I used to work with David Mills, back long ago. He was one of the > original Internet Buzzards, a really great guy. One of the many things > he invented was NTP.
I wonder if he still owns a class B block of IP addresses :-) [A friend did his PhD with him so we heard stories.] > He would get pretty exercised about keep-alives. Felt that it was not > the business of TCP to make these kinds of decisions. I can't remember > if he actually called them an abomination, but at the same time, one > was left with the feeling that he might have. Agreed 100%. TCP is supposed to be resilient and not throw a fit every time a link goes down. > I never fully appreciated his argument until John DeGood described ham > radio internet tcp sessions (this is also long ago) that would halt > for days, then come back to life. That's pretty neat, and it can be > hard if you are depending on keepalives. Just about any value you pick > will be wrong. A TCP connection is defined as <src-ip-addr, src-port, dst-ip-addr, dst-port>. As long as these are in use, and a path exists *when* a packet is to be sent, it is no one else's business to consider it dead! > So, yeah, they're out there and I guess nowadays everyone does them. > Whether they are a good idea is somebody else's guess, I suppose. I > note that today I slept my mac several times during this workshop and > my ssh session was always there when I opened the lid again. That's > nice. I routinely leave ssh, xterm etc. alive for weeks on end and my macbookpro puts itself to sleep a few times a day! Even when I used to take my laptop to work, no connexion broke as long as avoided accidentally typing in the window (which would generate traffic).
