I have two multi-port bridges connected together with a lot of cables.
Current setup is as follows:
--------eth0-------
| |
[Bridge A] <-eth1-> [Bridge B]
| |
--------eth5-------
Bridge A is root-bridge, and eth0 is set to lowest path-cost.
Consequently on Bridge B interfaces eth1 and eth5 are in blocking state.
However, when looking at the mac-address table on bridge B I see that it has
learned the mac-address of bridge A on the eth1-port (which is in
blocking state) and tries to use that port to communicate with
bridge A, and since the port is blocking this fails.
It seems that the STP-bpdu's are responsible for the bridge learning
the mac-address on the wrong port.
This is tested with kernel 2.6.11.12 and 2.6.13.2, and both exhibit
this problem.
The following fix solved it for me on 2.6.11.12:
In net/bridge/br_stp_bpdu.c, in function br_stp_handle_bpdu i changed
br_fdb_insert(p->br, p, eth_hdr(skb)->h_source,0);
to
if (!br->stp_enabled || p->state == BR_STATE_LEARNING
|| p->state == BR_STATE_FORWARDING)
br_fdb_insert(p->br, p, eth_hdr(skb)->h_source, 0);
/B
