On Wed, May 11, 2016 at 03:48:19PM +0200, Juliusz Chroboczek wrote:
BTW, why Babel accepts unfeasible updates of non-selected routes? It will not cause problems as such route cannot be selected later (due to its unfeasibility) but it seems strange.
Yeah, very good question. It's counterintuitive for me too, but it turns out to work better that way:
1. Having an unfeasible route available makes it possible to use it for fallback after a single seqno increase. If the route were not in your routing table at all, you'd need to acquire it after your selected route disappears, which may take some time, and will require even more time for things like link quality and hysteresis to converge. ...
Thanks, that makes sense. But now i wonder why not to accept unfeasible updates of selected routes? (At least in a case where router ids differ and the the update is handled as retraction.) Obviously, that would case the route to be de-selected. -- Elen sila lumenn' omentielvo Ondrej 'Santiago' Zajicek (email: santiago@crfreenet.org) OpenPGP encrypted e-mails preferred (KeyID 0x11DEADC3, wwwkeys.pgp.net) "To err is human -- to blame it on a computer is even more so."