On Wed, 30 Jun 2004 14:03:28 -0400 "Eble, Dan" <DanE@xxxxxxxxxx> wrote: > What if someone (or something) attempts to change the MTU on the port after > it has been added to the bridge? Perhaps SIOCSIFMTU should do something > special for bridge ports, such as return -EBUSY, or maybe ask the bridge > whether or not the new MTU is acceptable? If a port's MTU changes, the > bridge may have to adjust its own MTU to maintain consistency. It could get > hairy. That can be handled by a notifier callback. > I faced this question recently when trying to implement bridging over Cisco > HDLC. I finally decided not to try to maintain consistency of MTUs between > two devices, but rather to drop *all* transmitted packets when the MTU of > the lower-layer device was insufficient to handle the largest possible > packets from the upper-layer device. I decided that would be enough to > prevent someone from wrongly thinking they had configured it properly, since > not even a cheap a 64-byte ping would work. Probably a good idea as well. Also, we could check when adding interface to a bridge that the MTU is big enough for the existing ports in the bridge.
