On Mon, Jul 25, 2005 at 08:57:06PM -0700, Jonathan Walther wrote: > >You could run ospfd (or quagga) on each host. (You'll need to use gif > >or gre tunnels to give a multicast capable link over the vpns). Make > >the dsl tunnel the lower cost route and ospf will change the routing > >tables to use the other link if it goes down. When it comes back up, > >ospfd will switch the routing table back to the lower cost route. I use > >precisely this method to provide a backup to a 100Mb WAN link using > >ipsec/adsl. > > Thank you Stephen! This is exactly what I was looking for. One > question; does this solution drop any connections during the change of > the routing table? For my application, that isn't a problem, but it is
Nothing is explicitly dropped, but the behaviour depends on how long you set the router dead time to and how the application behaves. The default dead time is 40sec, but I use 10secs in my setup. TCP/IP is able to handle some packet loss and routing table changes without dropping connections. -- stephen
