On Fri, May 10, 2013 at 04:53:18PM +0200, Mike Belopuhov wrote: > > if (tr->tr_ac.ac_if.if_mtu != ifp->if_mtu) seems wrong. what about people > > who want to use trunk between two totally different interfaces for failover? > > > > i think the trunk mtu should simply be the lowest common of the group. > > > > i agree with chris. doesn't mtu get propogated into the routing table? > what if you failover and your other trunk port can't handle packets that > big but ip_output thinks it should be fine? >
I disagree and I think sthen's diff is doing it right. The order that you add the ports always mattered, that's how I implemented it in the first place. The implementation will make sure that you cannot add ports with a different configured MTU and the configured MTU if_mtu cannot be higher than the hardware MTU if_hardmtu. So a failover cannot cause problems with packets that are too big. You can still trunk two totally different interfaces with different hardware MTUs, like the popular WLAN + LAN failover trunk, but you have to configure the same MTU before adding them to the trunk. This totally makes sense! 1. if0: if_hardmtu 65535, if_mtu 9000 2. if1: if_hardmtu 9200, if_mtu 9000 3. trunk0: if_hardmtu 9000, if_mtu 9000 4. \o/ reyk
