On 20/05/14 14:25, Valdis.Kletnieks@xxxxxx wrote:
So yes, we*do* need to do something sensible there - either frag the packet on the way out, or something.
I think the problem is that a bridge cannot be used across incompatible media. That's the job of a router.
A bridge should act like a bridge, not a router. Fragmenting the packet is wrong; that's IP's job. Dropping the packet is also arguably wrong; that's the real device-driver's job. What seems right to me is to act like a bridge and forward packets by looking inside of them *no more than is necessary*. Looking beyond MAC address is perhaps too much.
We can finish the job of processing IP options, or at least in this scenario, but that seems wrong-headed and invites more work as more problems are discovered; or we could remove the half-hearted attempt it currently does and leave the bridge as a simple bridge.
This problem wouldn't occur if all devices in a bridge were required to be compatible media; particularly identical MTU.
