Brigded Interface & Traffic Graph Question

[NogBadTheBad]

I've bridged my LAN & OPT1 interfaces and named the bridge OPT99

The traffic graph for OPT99 show what I'd expect, I have an Apple Timecapsule connected to OPT1 and the traffic (backups) from my Mac-Mini is going in the LAN interface and out the OPT1 interface.

I'm seeing the traffic i'd expect on the bridge but I'm also seeing a small amount of traffic on the LAN & OPT1 interface, nothing that matches the bridge.

Any ideas ?

[NogBadTheBad]

Think I've answered my own question, I think it's multicast and broadcasts.

I did try a packet capture on the LAN & OPT1 interfaces but I see everything.