Disable Bridge Loop Detection?

[Tim Wilde]

I'm looking for a way to disable the loop detection in the bridging code
in FreeBSD 4.x - I'd prefer a sysctl, but I haven't been able to find one.
Any suggestions for how to do so would be appreciated.

In case anyone's wondering why I'm looking for such a thing, my problem is
with the following topology:

 +----------+       +----------+
 | router 1 |       | router 2 |
 +----------+       +----------+
      |                  |
 63.208.196.1/25    63.208.196.2/25
      |                  |
 +---------------+  +---------------+
 | FBSD bridge 1 |  | FBSD bridge 2 |
 +---------------+  +---------------+
      |                  |
 +----------+       +----------+
 | switch 1 |-------| switch 2 |
 +----------+       +----------+
      |                  |
  various servers, 63.208.196.0/25

The two routers run VRRP for redundancy, with a shared MAC address.
Occasionally, router2 is failing to receive packets from router1 (for
reasons we're looking into), and decides it should become the master,
taking over the 63.208.196.1 IP with the shared MAC.  Now my two bridges
both see that same MAC address on both of their interfaces, and the loop
detection kicks in.  This cuts out the various links (and they fight back
and forth cutting off - it's not pretty) with the end result of router2
NEVER being able to get the next VRRP packet from router1 (by necessity
they have to communicate for failover across the bridges + switches;
otherwise they wouldn't be able to detect failures internal to that
network).  We have to manually down the interface on router2, let things
calm down on the FreeBSD boxen, and then bring it back up (it starts in
backup mode, and waits at least 30 seconds, plenty of time to hear from
router1, before it will take control again).

Thanks,
Tim

-- 
Tim Wilde
twilde at dyndns.org
Systems Administrator
Dynamic DNS Network Services
http://www.dyndns.org/