Bridging troubles (with vtund)

Hello all;

I'm trying to set up a bridge between two networks that are connected
not
via a physical connect, but by a vtund connection (type ether). I've
got
the link up and running but its only partially working. More
specifically, brodcast traffic seems to be moving back and forth
freely,
but not unicast traffic.

My attempt at a diagram to explain how things are set up can be
viewed
here:

http://www.bludgeon.org/~rayvd/images/bridge.png

Host A and Host B can ping each other via their 10.49 IP's and the
traffic appears to go over the vtun tunnel as expected, but other
hosts
on the 10.49, when they attempt to ping 10.49.103.163 exhibit the
following:

- An initial broadcast ARP packet is sent out asking who owns
10.49.103.163.
- A reply with the correct MAC is received.
- ICMP packets are generated to 10.49.103.163 with the correct MAC
as
the destination
- I see no corresponding packets hitting Host A on tap0
- I see no corresponding packets entering br0 on Host B

I'm not sure if this means the 10.49 network switch has no idea where
to
send the traffic?

I had to set net.ipv4.conf.all.arp_ignore = 1 on Host A because it
was
sending out ARP replies for 10.49.103.163 on its eth0 interface which
I
thought might be confusing the router. Maybe there's some caching
going
on on the router or switch level...

Does anyone see anything obviously wrong here? I should probably try
to
simplify this setup and remove vtund from the equation...

Thanks,
Ray