Intel ER8100STUS - Express 8100 Router Reference Manual page 119

Controlled bridging with
bridge learning
The above diagram represents the data forwarded (unshaded area) of the total
number of packets received for bridging.
This way of controlling bridged data traffic can be used for security purposes and
to restrict the bridged data traffic over expensive WAN links.
It is still possible to have controlled bridging with bridge learning enabled. In this
case, the bridge still forwards packets to learned and defined (static) destinations
if permitted by the Source and Type Forwarding Tables. That is, only packets
with unknown destinations or discarded by static Destination Forwarding Table
entries are discarded by the Destination Forwarding Tables.
WAN Bridging Services
How Bridging Works
107